[PATCH v2 net-next 00/14] Scheduled packet Transmission: ETF

[PATCH v2 net-next 00/14] Scheduled packet Transmission: ETF

[Jesus Sanchez-Palencia]

Changes since v1:
  - moved struct sock_txtime from socket.h to uapi net_tstamp.h;
  - sk_clockid was changed from u16 to u8;
  - sk_txtime_flags was changed from u16 to a u8 bit field in struct sock;
  - the socket option flags are now validated in sock_setsockopt();
  - added SO_EE_ORIGIN_TXTIME;
  - sockc.transmit_time is now initialized from all IPv4 Tx paths;
  - added support for the IPv6 Tx path;


Overview
========

This work consists of a set of kernel interfaces that can be used by
applications that require (time-based) Scheduled Tx of packets.
It is comprised by 3 new components to the kernel:

  - SO_TXTIME: socket option + cmsg programming interfaces.

  - etf: the "earliest txtime first" qdisc, that provides per-queue
	 TxTime-based scheduling. This has been renamed from 'tbs' to
	 'etf' to better describe its functionality.

  - taprio: the "time-aware priority scheduler" qdisc, that provides
	    per-port Time-Aware scheduling;

This patchset is providing the first 2 components, which have been
developed for longer. The taprio qdisc will be shared as an RFC separately
(shortly).

Note that this series is a follow up of the "Time based packet
transmission" RFCv3 [1].



etf (formerly known as 'tbs')
=============================

For applications/systems that the concept of time slices isn't precise
enough, the etf qdisc allows applications to control the instant when
a packet should leave the network controller. When used in conjunction
with taprio, it can also be used in case the application needs to
control with greater guarantee the offset into each time slice a packet
will be sent. Another use case of etf, is when only a small number of
applications on a system are time sensitive, so it can then be used
with a more traditional root qdisc (like mqprio).

The etf qdisc is designed so it buffers packets until a configurable
time before their deadline (Tx time). The qdisc uses a rbtree internally
so the buffered packets are always 'ordered' by their txtime (deadline)
and will be dequeued following the earliest txtime first.

It relies on the SO_TXTIME API set for receiving the per-packet timestamp
(txtime) as well as the config flags for each socket: the clockid to be
used as a reference, if the expected mode of txtime for that socket is
deadline or strict mode, and if packet drops should be reported on the
socket's error queue or not.

The qdisc will drop any packets with a Tx time in the past, or if a
packet expires while waiting for being dequeued. Drops can be reported
as errors back to userspace through the socket's error queue.

Example configuration:

$ tc qdisc add dev enp2s0 parent 100:1 etf offload delta 200000 \
            clockid CLOCK_TAI

Here, the Qdisc will use HW offload for the txtime control.
Packets will be dequeued by the qdisc "delta" (200000) nanoseconds before
their transmission time. Because this will be using HW offload and
since dynamic clocks are not supported by hrtimers, the system clock
and the PHC clock must be synchronized for this mode to behave as expected.

A more complete example can be found here, with instructions of how to
test it:

https://gist.github.com/jeez/bd3afeff081ba64a695008dd8215866f [2]


Note that we haven't modified the qdisc so it uses a timerqueue because
the modification needed was increasing the number of cachelines of a sk_buff.



This series is also hosted on github and can be found at [3].
The companion iproute2 patches can be found at [4].


[1] https://patchwork.ozlabs.org/cover/882342/

[2] github doesn't make it clear, but the gist can be cloned like this:
$ git clone https://gist.github.com/jeez/bd3afeff081ba64a695008dd8215866f scheduled-tx-tests

[3] https://github.com/jeez/linux/tree/etf-v2

[4] https://github.com/jeez/iproute2/tree/etf-v2



Jesus Sanchez-Palencia (10):
  net: Clear skb->tstamp only on the forwarding path
  net: ipv4: Hook into time based transmission
  net: ipv6: Hook into time based transmission
  net/sched: Add HW offloading capability to ETF
  igb: Refactor igb_configure_cbs()
  igb: Only change Tx arbitration when CBS is on
  igb: Refactor igb_offload_cbs()
  igb: Only call skb_tx_timestamp after descriptors are ready
  igb: Add support for ETF offload
  net/sched: Make etf report drops on error_queue

Richard Cochran (2):
  net: Add a new socket option for a future transmit time.
  net: packet: Hook into time based transmission.

Vinicius Costa Gomes (2):
  net/sched: Allow creating a Qdisc watchdog with other clocks
  net/sched: Introduce the ETF Qdisc

 arch/alpha/include/uapi/asm/socket.h          |   3 +
 arch/ia64/include/uapi/asm/socket.h           |   3 +
 arch/mips/include/uapi/asm/socket.h           |   3 +
 arch/parisc/include/uapi/asm/socket.h         |   3 +
 arch/s390/include/uapi/asm/socket.h           |   3 +
 arch/sparc/include/uapi/asm/socket.h          |   3 +
 arch/xtensa/include/uapi/asm/socket.h         |   3 +
 .../net/ethernet/intel/igb/e1000_defines.h    |  16 +
 drivers/net/ethernet/intel/igb/igb.h          |   1 +
 drivers/net/ethernet/intel/igb/igb_main.c     | 256 ++++++---
 include/linux/netdevice.h                     |   1 +
 include/net/inet_sock.h                       |   1 +
 include/net/pkt_sched.h                       |   7 +
 include/net/sock.h                            |  11 +
 include/uapi/asm-generic/socket.h             |   3 +
 include/uapi/linux/errqueue.h                 |   4 +
 include/uapi/linux/net_tstamp.h               |  18 +
 include/uapi/linux/pkt_sched.h                |  18 +
 net/core/skbuff.c                             |   2 +-
 net/core/sock.c                               |  39 ++
 net/ipv4/icmp.c                               |   2 +
 net/ipv4/ip_output.c                          |   3 +
 net/ipv4/ping.c                               |   1 +
 net/ipv4/raw.c                                |   2 +
 net/ipv4/udp.c                                |   1 +
 net/ipv6/ip6_output.c                         |  11 +-
 net/ipv6/raw.c                                |   7 +-
 net/ipv6/udp.c                                |   1 +
 net/packet/af_packet.c                        |   6 +
 net/sched/Kconfig                             |  11 +
 net/sched/Makefile                            |   1 +
 net/sched/sch_api.c                           |  11 +-
 net/sched/sch_etf.c                           | 484 ++++++++++++++++++
 33 files changed, 864 insertions(+), 75 deletions(-)
 create mode 100644 net/sched/sch_etf.c

-- 
2.18.0

[PATCH v2 net-next 01/14] net: Clear skb->tstamp only on the forwarding path

[Jesus Sanchez-Palencia]

This is done in preparation for the upcoming time based transmission
patchset. Now that skb->tstamp will be used to hold packet's txtime,
we must ensure that it is being cleared when traversing namespaces.
Also, doing that from skb_scrub_packet() before the early return would
break our feature when tunnels are used.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 net/core/skbuff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 1357f36c8a5e..c4e24ac27464 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4898,7 +4898,6 @@ EXPORT_SYMBOL(skb_try_coalesce);
  */
 void skb_scrub_packet(struct sk_buff *skb, bool xnet)
 {
-	skb->tstamp = 0;
 	skb->pkt_type = PACKET_HOST;
 	skb->skb_iif = 0;
 	skb->ignore_df = 0;
@@ -4912,6 +4911,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet)
 
 	ipvs_reset(skb);
 	skb->mark = 0;
+	skb->tstamp = 0;
 }
 EXPORT_SYMBOL_GPL(skb_scrub_packet);
 
-- 
2.18.0

[PATCH v2 net-next 02/14] net: Add a new socket option for a future transmit time.

[Jesus Sanchez-Palencia]

From: Richard Cochran <rcochran@linutronix.de>

This patch introduces SO_TXTIME. User space enables this option in
order to pass a desired future transmit time in a CMSG when calling
sendmsg(2). The argument to this socket option is a 8-bytes long struct
provided by the uapi header net_tstamp.h defined as:

struct sock_txtime {
	clockid_t 	clockid;
	u32		flags;
};

Note that new fields were added to struct sock by filling a 2-bytes
hole found in the struct. For that reason, neither the struct size or
number of cachelines were altered.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 arch/alpha/include/uapi/asm/socket.h  |  3 +++
 arch/ia64/include/uapi/asm/socket.h   |  3 +++
 arch/mips/include/uapi/asm/socket.h   |  3 +++
 arch/parisc/include/uapi/asm/socket.h |  3 +++
 arch/s390/include/uapi/asm/socket.h   |  3 +++
 arch/sparc/include/uapi/asm/socket.h  |  3 +++
 arch/xtensa/include/uapi/asm/socket.h |  3 +++
 include/net/sock.h                    | 10 ++++++++
 include/uapi/asm-generic/socket.h     |  3 +++
 include/uapi/linux/net_tstamp.h       | 15 ++++++++++++
 net/core/sock.c                       | 35 +++++++++++++++++++++++++++
 11 files changed, 84 insertions(+)

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index be14f16149d5..065fb372e355 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -112,4 +112,7 @@
 
 #define SO_ZEROCOPY		60
 
+#define SO_TXTIME		61
+#define SCM_TXTIME		SO_TXTIME
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index 3efba40adc54..c872c4e6bafb 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -114,4 +114,7 @@
 
 #define SO_ZEROCOPY		60
 
+#define SO_TXTIME		61
+#define SCM_TXTIME		SO_TXTIME
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 49c3d4795963..71370fb3ceef 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -123,4 +123,7 @@
 
 #define SO_ZEROCOPY		60
 
+#define SO_TXTIME		61
+#define SCM_TXTIME		SO_TXTIME
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index 1d0fdc3b5d22..061b9cf2a779 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -104,4 +104,7 @@
 
 #define SO_ZEROCOPY		0x4035
 
+#define SO_TXTIME		0x4036
+#define SCM_TXTIME		SO_TXTIME
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index 3510c0fd06f4..39d901476ee5 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -111,4 +111,7 @@
 
 #define SO_ZEROCOPY		60
 
+#define SO_TXTIME		61
+#define SCM_TXTIME		SO_TXTIME
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index d58520c2e6ff..7ea35e5601b6 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -101,6 +101,9 @@
 
 #define SO_ZEROCOPY		0x003e
 
+#define SO_TXTIME		0x003f
+#define SCM_TXTIME		SO_TXTIME
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION		0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT	0x5002
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index 75a07b8119a9..1de07a7f7680 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -116,4 +116,7 @@
 
 #define SO_ZEROCOPY		60
 
+#define SO_TXTIME		61
+#define SCM_TXTIME		SO_TXTIME
+
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/net/sock.h b/include/net/sock.h
index 2ed99bfa4595..68347b9821c6 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -319,6 +319,9 @@ struct sock_common {
   *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
   *	@sk_reuseport_cb: reuseport group container
   *	@sk_rcu: used during RCU grace period
+  *	@sk_clockid: clockid used by time-based scheduling (SO_TXTIME)
+  *	@sk_txtime_deadline_mode: set deadline mode for SO_TXTIME
+  *	@sk_txtime_unused: unused txtime flags
   */
 struct sock {
 	/*
@@ -475,6 +478,11 @@ struct sock {
 	u8			sk_shutdown;
 	u32			sk_tskey;
 	atomic_t		sk_zckey;
+
+	u8			sk_clockid;
+	u8			sk_txtime_deadline_mode : 1,
+				sk_txtime_unused : 7;
+
 	struct socket		*sk_socket;
 	void			*sk_user_data;
 #ifdef CONFIG_SECURITY
@@ -790,6 +798,7 @@ enum sock_flags {
 	SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
 	SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
 	SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
+	SOCK_TXTIME,
 };
 
 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
@@ -1585,6 +1594,7 @@ void sock_kzfree_s(struct sock *sk, void *mem, int size);
 void sk_send_sigurg(struct sock *sk);
 
 struct sockcm_cookie {
+	u64 transmit_time;
 	u32 mark;
 	u16 tsflags;
 };
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 0ae758c90e54..a12692e5f7a8 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -107,4 +107,7 @@
 
 #define SO_ZEROCOPY		60
 
+#define SO_TXTIME		61
+#define SCM_TXTIME		SO_TXTIME
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
index 4fe104b2411f..c9a77c353b98 100644
--- a/include/uapi/linux/net_tstamp.h
+++ b/include/uapi/linux/net_tstamp.h
@@ -141,4 +141,19 @@ struct scm_ts_pktinfo {
 	__u32 reserved[2];
 };
 
+/*
+ * SO_TXTIME gets a struct sock_txtime with flags being an integer bit
+ * field comprised of these values.
+ */
+enum txtime_flags {
+	SOF_TXTIME_DEADLINE_MODE = (1 << 0),
+
+	SOF_TXTIME_FLAGS_MASK = (SOF_TXTIME_DEADLINE_MODE)
+};
+
+struct sock_txtime {
+	clockid_t       clockid;        /* reference clockid */
+	u32             flags;          /* flags defined by enum txtime_flags */
+};
+
 #endif /* _NET_TIMESTAMPING_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index 6429982eb976..fe64b839f1b2 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -91,6 +91,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <asm/unaligned.h>
 #include <linux/capability.h>
 #include <linux/errno.h>
 #include <linux/errqueue.h>
@@ -697,6 +698,7 @@ EXPORT_SYMBOL(sk_mc_loop);
 int sock_setsockopt(struct socket *sock, int level, int optname,
 		    char __user *optval, unsigned int optlen)
 {
+	struct sock_txtime sk_txtime;
 	struct sock *sk = sock->sk;
 	int val;
 	int valbool;
@@ -1070,6 +1072,24 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 		}
 		break;
 
+	case SO_TXTIME:
+		if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
+			ret = -EPERM;
+		} else if (optlen != sizeof(struct sock_txtime)) {
+			ret = -EINVAL;
+		} else if (copy_from_user(&sk_txtime, optval,
+			   sizeof(struct sock_txtime))) {
+			ret = -EFAULT;
+		} else if (sk_txtime.flags & ~SOF_TXTIME_FLAGS_MASK) {
+			ret = -EINVAL;
+		} else {
+			sock_valbool_flag(sk, SOCK_TXTIME, true);
+			sk->sk_clockid = sk_txtime.clockid;
+			sk->sk_txtime_deadline_mode =
+				!!(sk_txtime.flags & SOF_TXTIME_DEADLINE_MODE);
+		}
+		break;
+
 	default:
 		ret = -ENOPROTOOPT;
 		break;
@@ -1115,6 +1135,7 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		u64 val64;
 		struct linger ling;
 		struct timeval tm;
+		struct sock_txtime txtime;
 	} v;
 
 	int lv = sizeof(int);
@@ -1403,6 +1424,13 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sock_flag(sk, SOCK_ZEROCOPY);
 		break;
 
+	case SO_TXTIME:
+		lv = sizeof(v.txtime);
+		v.txtime.clockid = sk->sk_clockid;
+		v.txtime.flags |= sk->sk_txtime_deadline_mode ?
+				  SOF_TXTIME_DEADLINE_MODE : 0;
+		break;
+
 	default:
 		/* We implement the SO_SNDLOWAT etc to not be settable
 		 * (1003.1g 7).
@@ -2137,6 +2165,13 @@ int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
 		sockc->tsflags &= ~SOF_TIMESTAMPING_TX_RECORD_MASK;
 		sockc->tsflags |= tsflags;
 		break;
+	case SCM_TXTIME:
+		if (!sock_flag(sk, SOCK_TXTIME))
+			return -EINVAL;
+		if (cmsg->cmsg_len != CMSG_LEN(sizeof(u64)))
+			return -EINVAL;
+		sockc->transmit_time = get_unaligned((u64 *)CMSG_DATA(cmsg));
+		break;
 	/* SCM_RIGHTS and SCM_CREDENTIALS are semantically in SOL_UNIX. */
 	case SCM_RIGHTS:
 	case SCM_CREDENTIALS:
-- 
2.18.0

[PATCH v2 net-next 03/14] net: ipv4: Hook into time based transmission

[Jesus Sanchez-Palencia]

Add a transmit_time field to struct inet_cork, then copy the
timestamp from the CMSG cookie at ip_setup_cork() so we can
safely copy it into the skb later during __ip_make_skb().

For the raw fast path, just perform the copy at raw_send_hdrinc().

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 include/net/inet_sock.h | 1 +
 net/ipv4/icmp.c         | 2 ++
 net/ipv4/ip_output.c    | 3 +++
 net/ipv4/ping.c         | 1 +
 net/ipv4/raw.c          | 2 ++
 net/ipv4/udp.c          | 1 +
 6 files changed, 10 insertions(+)

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 83d5b3c2ac42..314be484c696 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -148,6 +148,7 @@ struct inet_cork {
 	__s16			tos;
 	char			priority;
 	__u16			gso_size;
+	u64			transmit_time;
 };
 
 struct inet_cork_full {
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 1617604c9284..937239afd68d 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -437,6 +437,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	if (icmp_param->replyopts.opt.opt.optlen) {
 		ipc.opt = &icmp_param->replyopts.opt;
@@ -715,6 +716,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark,
 			       type, code, &icmp_param);
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index b3308e9d9762..135fb5036d18 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1153,6 +1153,7 @@ static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
 	cork->tos = ipc->tos;
 	cork->priority = ipc->priority;
 	cork->tx_flags = ipc->tx_flags;
+	cork->transmit_time = ipc->sockc.transmit_time;
 
 	return 0;
 }
@@ -1413,6 +1414,7 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
 
 	skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority;
 	skb->mark = sk->sk_mark;
+	skb->tstamp = cork->transmit_time;
 	/*
 	 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
 	 * on dst refcount
@@ -1550,6 +1552,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	if (replyopts.opt.opt.optlen) {
 		ipc.opt = &replyopts.opt;
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 2ed64bca54e3..b47492205507 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -746,6 +746,7 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	if (msg->msg_controllen) {
 		err = ip_cmsg_send(sk, msg, &ipc, false);
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index abb3c9490c55..446af7be2b55 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -381,6 +381,7 @@ static int raw_send_hdrinc(struct sock *sk, struct flowi4 *fl4,
 
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
+	skb->tstamp = sockc->transmit_time;
 	skb_dst_set(skb, &rt->dst);
 	*rtp = NULL;
 
@@ -562,6 +563,7 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	}
 
 	ipc.sockc.tsflags = sk->sk_tsflags;
+	ipc.sockc.transmit_time = 0;
 	ipc.addr = inet->inet_saddr;
 	ipc.opt = NULL;
 	ipc.tx_flags = 0;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 24e116ddae79..5c76ba0666ec 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -930,6 +930,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
 
-- 
2.18.0

[PATCH v2 net-next 04/14] net: ipv6: Hook into time based transmission

[Jesus Sanchez-Palencia]

Add a struct sockcm_cookie parameter to ip6_setup_cork() so
we can easily re-use the transmit_time field from struct inet_cork
for most paths, by copying the timestamp from the CMSG cookie.
This is later copied into the skb during __ip6_make_skb().

For the raw fast path, also pass the sockcm_cookie as a parameter
so we can just perform the copy at rawv6_send_hdrinc() directly.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 net/ipv6/ip6_output.c | 11 ++++++++---
 net/ipv6/raw.c        |  7 +++++--
 net/ipv6/udp.c        |  1 +
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index a14fb4fcdf18..f48af7e62f12 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1158,7 +1158,8 @@ static void ip6_append_data_mtu(unsigned int *mtu,
 
 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
 			  struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
-			  struct rt6_info *rt, struct flowi6 *fl6)
+			  struct rt6_info *rt, struct flowi6 *fl6,
+			  const struct sockcm_cookie *sockc)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	unsigned int mtu;
@@ -1226,6 +1227,8 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
 		cork->base.flags |= IPCORK_ALLFRAG;
 	cork->base.length = 0;
 
+	cork->base.transmit_time = sockc->transmit_time;
+
 	return 0;
 }
 
@@ -1575,7 +1578,7 @@ int ip6_append_data(struct sock *sk,
 		 * setup for corking
 		 */
 		err = ip6_setup_cork(sk, &inet->cork, &np->cork,
-				     ipc6, rt, fl6);
+				     ipc6, rt, fl6, sockc);
 		if (err)
 			return err;
 
@@ -1673,6 +1676,8 @@ struct sk_buff *__ip6_make_skb(struct sock *sk,
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
 
+	skb->tstamp = cork->base.transmit_time;
+
 	skb_dst_set(skb, dst_clone(&rt->dst));
 	IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
 	if (proto == IPPROTO_ICMPV6) {
@@ -1765,7 +1770,7 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 	cork->base.opt = NULL;
 	cork->base.dst = NULL;
 	v6_cork.opt = NULL;
-	err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt, fl6);
+	err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt, fl6, sockc);
 	if (err) {
 		ip6_cork_release(cork, &v6_cork);
 		return ERR_PTR(err);
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index afc307c89d1a..5737c50f16eb 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -620,7 +620,7 @@ static int rawv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
 
 static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length,
 			struct flowi6 *fl6, struct dst_entry **dstp,
-			unsigned int flags)
+			unsigned int flags, const struct sockcm_cookie *sockc)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct net *net = sock_net(sk);
@@ -650,6 +650,7 @@ static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length,
 	skb->protocol = htons(ETH_P_IPV6);
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
+	skb->tstamp = sockc->transmit_time;
 	skb_dst_set(skb, &rt->dst);
 	*dstp = NULL;
 
@@ -848,6 +849,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		fl6.flowi6_oif = sk->sk_bound_dev_if;
 
 	sockc.tsflags = sk->sk_tsflags;
+	sockc.transmit_time = 0;
 	if (msg->msg_controllen) {
 		opt = &opt_space;
 		memset(opt, 0, sizeof(struct ipv6_txoptions));
@@ -921,7 +923,8 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 back_from_confirm:
 	if (inet->hdrincl)
-		err = rawv6_send_hdrinc(sk, msg, len, &fl6, &dst, msg->msg_flags);
+		err = rawv6_send_hdrinc(sk, msg, len, &fl6, &dst,
+					msg->msg_flags, &sockc);
 	else {
 		ipc6.opt = opt;
 		lock_sock(sk);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e6645cae403e..ac6fc6728903 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1148,6 +1148,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc6.dontfrag = -1;
 	ipc6.gso_size = up->gso_size;
 	sockc.tsflags = sk->sk_tsflags;
+	sockc.transmit_time = 0;
 
 	/* destination address check */
 	if (sin6) {
-- 
2.18.0

[PATCH v2 net-next 05/14] net: packet: Hook into time based transmission.

[Jesus Sanchez-Palencia]

From: Richard Cochran <rcochran@linutronix.de>

For raw layer-2 packets, copy the desired future transmit time from
the CMSG cookie into the skb.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 net/packet/af_packet.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 57634bc3da74..3428f7739ae9 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1951,6 +1951,7 @@ static int packet_sendmsg_spkt(struct socket *sock, struct msghdr *msg,
 		goto out_unlock;
 	}
 
+	sockc.transmit_time = 0;
 	sockc.tsflags = sk->sk_tsflags;
 	if (msg->msg_controllen) {
 		err = sock_cmsg_send(sk, msg, &sockc);
@@ -1962,6 +1963,7 @@ static int packet_sendmsg_spkt(struct socket *sock, struct msghdr *msg,
 	skb->dev = dev;
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
+	skb->tstamp = sockc.transmit_time;
 
 	sock_tx_timestamp(sk, sockc.tsflags, &skb_shinfo(skb)->tx_flags);
 
@@ -2457,6 +2459,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
 	skb->dev = dev;
 	skb->priority = po->sk.sk_priority;
 	skb->mark = po->sk.sk_mark;
+	skb->tstamp = sockc->transmit_time;
 	sock_tx_timestamp(&po->sk, sockc->tsflags, &skb_shinfo(skb)->tx_flags);
 	skb_shinfo(skb)->destructor_arg = ph.raw;
 
@@ -2633,6 +2636,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
 	if (unlikely(!(dev->flags & IFF_UP)))
 		goto out_put;
 
+	sockc.transmit_time = 0;
 	sockc.tsflags = po->sk.sk_tsflags;
 	if (msg->msg_controllen) {
 		err = sock_cmsg_send(&po->sk, msg, &sockc);
@@ -2829,6 +2833,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
 	if (unlikely(!(dev->flags & IFF_UP)))
 		goto out_unlock;
 
+	sockc.transmit_time = 0;
 	sockc.tsflags = sk->sk_tsflags;
 	sockc.mark = sk->sk_mark;
 	if (msg->msg_controllen) {
@@ -2903,6 +2908,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
 	skb->dev = dev;
 	skb->priority = sk->sk_priority;
 	skb->mark = sockc.mark;
+	skb->tstamp = sockc.transmit_time;
 
 	if (has_vnet_hdr) {
 		err = virtio_net_hdr_to_skb(skb, &vnet_hdr, vio_le());
-- 
2.18.0

[PATCH v2 net-next 06/14] net/sched: Allow creating a Qdisc watchdog with other clocks

[Jesus Sanchez-Palencia]

From: Vinicius Costa Gomes <vinicius.gomes@intel.com>

This adds 'qdisc_watchdog_init_clockid()' that allows a clockid to be
passed, this allows other time references to be used when scheduling
the Qdisc to run.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 include/net/pkt_sched.h |  2 ++
 net/sched/sch_api.c     | 11 +++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index 815b92a23936..2466ea143d01 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -72,6 +72,8 @@ struct qdisc_watchdog {
 	struct Qdisc	*qdisc;
 };
 
+void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
+				 clockid_t clockid);
 void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);
 void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires);
 
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 54eca685420f..98541c6399db 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -596,12 +596,19 @@ static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
+void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
+				 clockid_t clockid)
 {
-	hrtimer_init(&wd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+	hrtimer_init(&wd->timer, clockid, HRTIMER_MODE_ABS_PINNED);
 	wd->timer.function = qdisc_watchdog;
 	wd->qdisc = qdisc;
 }
+EXPORT_SYMBOL(qdisc_watchdog_init_clockid);
+
+void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
+{
+	qdisc_watchdog_init_clockid(wd, qdisc, CLOCK_MONOTONIC);
+}
 EXPORT_SYMBOL(qdisc_watchdog_init);
 
 void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
-- 
2.18.0

[PATCH v2 net-next 07/14] net/sched: Introduce the ETF Qdisc

[Jesus Sanchez-Palencia]

From: Vinicius Costa Gomes <vinicius.gomes@intel.com>

The ETF (Earliest TxTime First) qdisc uses the information added
earlier in this series (the socket option SO_TXTIME and the new
role of sk_buff->tstamp) to schedule packets transmission based
on absolute time.

For some workloads, just bandwidth enforcement is not enough, and
precise control of the transmission of packets is necessary.

Example:

$ tc qdisc replace dev enp2s0 parent root handle 100 mqprio num_tc 3 \
           map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0

$ tc qdisc add dev enp2s0 parent 100:1 etf delta 100000 \
           clockid CLOCK_TAI

In this example, the Qdisc will provide SW best-effort for the control
of the transmission time to the network adapter, the time stamp in the
socket will be in reference to the clockid CLOCK_TAI and packets
will leave the qdisc "delta" (100000) nanoseconds before its transmission
time.

The ETF qdisc will buffer packets sorted by their txtime. It will drop
packets on enqueue() if their skbuff clockid does not match the clock
reference of the Qdisc. Moreover, on dequeue(), a packet will be dropped
if it expires while being enqueued.

The qdisc also supports the SO_TXTIME deadline mode. For this mode, it
will dequeue a packet as soon as possible and change the skb timestamp
to 'now' during etf_dequeue().

Note that both the qdisc's and the SO_TXTIME ABIs allow for a clockid
to be configured, but it's been decided that usage of CLOCK_TAI should
be enforced until we decide to allow for other clockids to be used.
The rationale here is that PTP times are usually in the TAI scale, thus
no other clocks should be necessary. For now, the qdisc will return
EINVAL if any clocks other than CLOCK_TAI are used.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 include/linux/netdevice.h      |   1 +
 include/uapi/linux/pkt_sched.h |  17 ++
 net/sched/Kconfig              |  11 +
 net/sched/Makefile             |   1 +
 net/sched/sch_etf.c            | 384 +++++++++++++++++++++++++++++++++
 5 files changed, 414 insertions(+)
 create mode 100644 net/sched/sch_etf.c

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 64480a0f2c16..610df79b9845 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -798,6 +798,7 @@ enum tc_setup_type {
 	TC_SETUP_QDISC_RED,
 	TC_SETUP_QDISC_PRIO,
 	TC_SETUP_QDISC_MQ,
+	TC_SETUP_QDISC_ETF,
 };
 
 /* These structures hold the attributes of bpf state that are being passed
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h
index bad3c03bcf43..d5e933ce1447 100644
--- a/include/uapi/linux/pkt_sched.h
+++ b/include/uapi/linux/pkt_sched.h
@@ -937,4 +937,21 @@ enum {
 
 #define TCA_CBS_MAX (__TCA_CBS_MAX - 1)
 
+
+/* ETF */
+struct tc_etf_qopt {
+	__s32 delta;
+	__s32 clockid;
+	__u32 flags;
+#define TC_ETF_DEADLINE_MODE_ON	BIT(0)
+};
+
+enum {
+	TCA_ETF_UNSPEC,
+	TCA_ETF_PARMS,
+	__TCA_ETF_MAX,
+};
+
+#define TCA_ETF_MAX (__TCA_ETF_MAX - 1)
+
 #endif
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index a01169fb5325..fcc89706745b 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -183,6 +183,17 @@ config NET_SCH_CBS
 	  To compile this code as a module, choose M here: the
 	  module will be called sch_cbs.
 
+config NET_SCH_ETF
+	tristate "Earliest TxTime First (ETF)"
+	help
+	  Say Y here if you want to use the Earliest TxTime First (ETF) packet
+	  scheduling algorithm.
+
+	  See the top of <file:net/sched/sch_etf.c> for more details.
+
+	  To compile this code as a module, choose M here: the
+	  module will be called sch_etf.
+
 config NET_SCH_GRED
 	tristate "Generic Random Early Detection (GRED)"
 	---help---
diff --git a/net/sched/Makefile b/net/sched/Makefile
index 8811d3804878..9a5a7077d217 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_NET_SCH_FQ)	+= sch_fq.o
 obj-$(CONFIG_NET_SCH_HHF)	+= sch_hhf.o
 obj-$(CONFIG_NET_SCH_PIE)	+= sch_pie.o
 obj-$(CONFIG_NET_SCH_CBS)	+= sch_cbs.o
+obj-$(CONFIG_NET_SCH_ETF)	+= sch_etf.o
 
 obj-$(CONFIG_NET_CLS_U32)	+= cls_u32.o
 obj-$(CONFIG_NET_CLS_ROUTE4)	+= cls_route.o
diff --git a/net/sched/sch_etf.c b/net/sched/sch_etf.c
new file mode 100644
index 000000000000..4b7f4903ac17
--- /dev/null
+++ b/net/sched/sch_etf.c
@@ -0,0 +1,384 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* net/sched/sch_etf.c  Earliest TxTime First queueing discipline.
+ *
+ * Authors:	Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
+ *		Vinicius Costa Gomes <vinicius.gomes@intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/rbtree.h>
+#include <linux/skbuff.h>
+#include <linux/posix-timers.h>
+#include <net/netlink.h>
+#include <net/sch_generic.h>
+#include <net/pkt_sched.h>
+#include <net/sock.h>
+
+#define DEADLINE_MODE_IS_ON(x) ((x)->flags & TC_ETF_DEADLINE_MODE_ON)
+
+struct etf_sched_data {
+	bool deadline_mode;
+	int clockid;
+	int queue;
+	s32 delta; /* in ns */
+	ktime_t last; /* The txtime of the last skb sent to the netdevice. */
+	struct rb_root head;
+	struct qdisc_watchdog watchdog;
+	ktime_t (*get_time)(void);
+};
+
+static const struct nla_policy etf_policy[TCA_ETF_MAX + 1] = {
+	[TCA_ETF_PARMS]	= { .len = sizeof(struct tc_etf_qopt) },
+};
+
+static inline int validate_input_params(struct tc_etf_qopt *qopt,
+					struct netlink_ext_ack *extack)
+{
+	/* Check if params comply to the following rules:
+	 *	* Clockid and delta must be valid.
+	 *
+	 *	* Dynamic clockids are not supported.
+	 *
+	 *	* Delta must be a positive integer.
+	 */
+	if (qopt->clockid < 0) {
+		NL_SET_ERR_MSG(extack, "Dynamic clockids are not supported");
+		return -ENOTSUPP;
+	}
+
+	if (qopt->clockid != CLOCK_TAI) {
+		NL_SET_ERR_MSG(extack, "Invalid clockid. CLOCK_TAI must be used");
+		return -EINVAL;
+	}
+
+	if (qopt->delta < 0) {
+		NL_SET_ERR_MSG(extack, "Delta must be positive");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static bool is_packet_valid(struct Qdisc *sch, struct sk_buff *nskb)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	ktime_t txtime = nskb->tstamp;
+	struct sock *sk = nskb->sk;
+	ktime_t now;
+
+	if (!sk)
+		return false;
+
+	if (!sock_flag(sk, SOCK_TXTIME))
+		return false;
+
+	/* We don't perform crosstimestamping.
+	 * Drop if packet's clockid differs from qdisc's.
+	 */
+	if (sk->sk_clockid != q->clockid)
+		return false;
+
+	if (sk->sk_txtime_deadline_mode != q->deadline_mode)
+		return false;
+
+	now = q->get_time();
+	if (ktime_before(txtime, now) || ktime_before(txtime, q->last))
+		return false;
+
+	return true;
+}
+
+static struct sk_buff *etf_peek_timesortedlist(struct Qdisc *sch)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	struct rb_node *p;
+
+	p = rb_first(&q->head);
+	if (!p)
+		return NULL;
+
+	return rb_to_skb(p);
+}
+
+static void reset_watchdog(struct Qdisc *sch)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb = etf_peek_timesortedlist(sch);
+	ktime_t next;
+
+	if (!skb)
+		return;
+
+	next = ktime_sub_ns(skb->tstamp, q->delta);
+	qdisc_watchdog_schedule_ns(&q->watchdog, ktime_to_ns(next));
+}
+
+static int etf_enqueue_timesortedlist(struct sk_buff *nskb, struct Qdisc *sch,
+				      struct sk_buff **to_free)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	struct rb_node **p = &q->head.rb_node, *parent = NULL;
+	ktime_t txtime = nskb->tstamp;
+
+	if (!is_packet_valid(sch, nskb))
+		return qdisc_drop(nskb, sch, to_free);
+
+	while (*p) {
+		struct sk_buff *skb;
+
+		parent = *p;
+		skb = rb_to_skb(parent);
+		if (ktime_after(txtime, skb->tstamp))
+			p = &parent->rb_right;
+		else
+			p = &parent->rb_left;
+	}
+	rb_link_node(&nskb->rbnode, parent, p);
+	rb_insert_color(&nskb->rbnode, &q->head);
+
+	qdisc_qstats_backlog_inc(sch, nskb);
+	sch->q.qlen++;
+
+	/* Now we may need to re-arm the qdisc watchdog for the next packet. */
+	reset_watchdog(sch);
+
+	return NET_XMIT_SUCCESS;
+}
+
+static void timesortedlist_erase(struct Qdisc *sch, struct sk_buff *skb,
+				 bool drop)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+
+	rb_erase(&skb->rbnode, &q->head);
+
+	/* The rbnode field in the skb re-uses these fields, now that
+	 * we are done with the rbnode, reset them.
+	 */
+	skb->next = NULL;
+	skb->prev = NULL;
+	skb->dev = qdisc_dev(sch);
+
+	qdisc_qstats_backlog_dec(sch, skb);
+
+	if (drop) {
+		struct sk_buff *to_free = NULL;
+
+		qdisc_drop(skb, sch, &to_free);
+		kfree_skb_list(to_free);
+		qdisc_qstats_overlimit(sch);
+	} else {
+		qdisc_bstats_update(sch, skb);
+
+		q->last = skb->tstamp;
+	}
+
+	sch->q.qlen--;
+}
+
+static struct sk_buff *etf_dequeue_timesortedlist(struct Qdisc *sch)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb;
+	ktime_t now, next;
+
+	skb = etf_peek_timesortedlist(sch);
+	if (!skb)
+		return NULL;
+
+	now = q->get_time();
+
+	/* Drop if packet has expired while in queue. */
+	/* FIXME: Must return error on the socket's error queue */
+	if (ktime_before(skb->tstamp, now)) {
+		timesortedlist_erase(sch, skb, true);
+		skb = NULL;
+		goto out;
+	}
+
+	/* When in deadline mode, dequeue as soon as possible and change the
+	 * txtime from deadline to (now + delta).
+	 */
+	if (q->deadline_mode) {
+		timesortedlist_erase(sch, skb, false);
+		skb->tstamp = now;
+		goto out;
+	}
+
+	next = ktime_sub_ns(skb->tstamp, q->delta);
+
+	/* Dequeue only if now is within the [txtime - delta, txtime] range. */
+	if (ktime_after(now, next))
+		timesortedlist_erase(sch, skb, false);
+	else
+		skb = NULL;
+
+out:
+	/* Now we may need to re-arm the qdisc watchdog for the next packet. */
+	reset_watchdog(sch);
+
+	return skb;
+}
+
+static int etf_init(struct Qdisc *sch, struct nlattr *opt,
+		    struct netlink_ext_ack *extack)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	struct nlattr *tb[TCA_ETF_MAX + 1];
+	struct tc_etf_qopt *qopt;
+	int err;
+
+	if (!opt) {
+		NL_SET_ERR_MSG(extack,
+			       "Missing ETF qdisc options which are mandatory");
+		return -EINVAL;
+	}
+
+	err = nla_parse_nested(tb, TCA_ETF_MAX, opt, etf_policy, extack);
+	if (err < 0)
+		return err;
+
+	if (!tb[TCA_ETF_PARMS]) {
+		NL_SET_ERR_MSG(extack, "Missing mandatory ETF parameters");
+		return -EINVAL;
+	}
+
+	qopt = nla_data(tb[TCA_ETF_PARMS]);
+
+	pr_debug("delta %d clockid %d deadline %s\n",
+		 qopt->delta, qopt->clockid,
+		 DEADLINE_MODE_IS_ON(qopt) ? "on" : "off");
+
+	err = validate_input_params(qopt, extack);
+	if (err < 0)
+		return err;
+
+	q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
+
+	/* Everything went OK, save the parameters used. */
+	q->delta = qopt->delta;
+	q->clockid = qopt->clockid;
+	q->deadline_mode = DEADLINE_MODE_IS_ON(qopt);
+
+	switch (q->clockid) {
+	case CLOCK_REALTIME:
+		q->get_time = ktime_get_real;
+		break;
+	case CLOCK_MONOTONIC:
+		q->get_time = ktime_get;
+		break;
+	case CLOCK_BOOTTIME:
+		q->get_time = ktime_get_boottime;
+		break;
+	case CLOCK_TAI:
+		q->get_time = ktime_get_clocktai;
+		break;
+	default:
+		NL_SET_ERR_MSG(extack, "Clockid is not supported");
+		return -ENOTSUPP;
+	}
+
+	qdisc_watchdog_init_clockid(&q->watchdog, sch, q->clockid);
+
+	return 0;
+}
+
+static void timesortedlist_clear(struct Qdisc *sch)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	struct rb_node *p = rb_first(&q->head);
+
+	while (p) {
+		struct sk_buff *skb = rb_to_skb(p);
+
+		p = rb_next(p);
+
+		rb_erase(&skb->rbnode, &q->head);
+		rtnl_kfree_skbs(skb, skb);
+		sch->q.qlen--;
+	}
+}
+
+static void etf_reset(struct Qdisc *sch)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+
+	/* Only cancel watchdog if it's been initialized. */
+	if (q->watchdog.qdisc == sch)
+		qdisc_watchdog_cancel(&q->watchdog);
+
+	/* No matter which mode we are on, it's safe to clear both lists. */
+	timesortedlist_clear(sch);
+	__qdisc_reset_queue(&sch->q);
+
+	sch->qstats.backlog = 0;
+	sch->q.qlen = 0;
+
+	q->last = 0;
+}
+
+static void etf_destroy(struct Qdisc *sch)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+
+	/* Only cancel watchdog if it's been initialized. */
+	if (q->watchdog.qdisc == sch)
+		qdisc_watchdog_cancel(&q->watchdog);
+}
+
+static int etf_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct etf_sched_data *q = qdisc_priv(sch);
+	struct tc_etf_qopt opt = { };
+	struct nlattr *nest;
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (!nest)
+		goto nla_put_failure;
+
+	opt.delta = q->delta;
+	opt.clockid = q->clockid;
+	if (q->deadline_mode)
+		opt.flags |= TC_ETF_DEADLINE_MODE_ON;
+
+	if (nla_put(skb, TCA_ETF_PARMS, sizeof(opt), &opt))
+		goto nla_put_failure;
+
+	return nla_nest_end(skb, nest);
+
+nla_put_failure:
+	nla_nest_cancel(skb, nest);
+	return -1;
+}
+
+static struct Qdisc_ops etf_qdisc_ops __read_mostly = {
+	.id		=	"etf",
+	.priv_size	=	sizeof(struct etf_sched_data),
+	.enqueue	=	etf_enqueue_timesortedlist,
+	.dequeue	=	etf_dequeue_timesortedlist,
+	.peek		=	etf_peek_timesortedlist,
+	.init		=	etf_init,
+	.reset		=	etf_reset,
+	.destroy	=	etf_destroy,
+	.dump		=	etf_dump,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init etf_module_init(void)
+{
+	return register_qdisc(&etf_qdisc_ops);
+}
+
+static void __exit etf_module_exit(void)
+{
+	unregister_qdisc(&etf_qdisc_ops);
+}
+module_init(etf_module_init)
+module_exit(etf_module_exit)
+MODULE_LICENSE("GPL");
-- 
2.18.0

[PATCH v2 net-next 08/14] net/sched: Add HW offloading capability to ETF

[Jesus Sanchez-Palencia]

Add infra so etf qdisc supports HW offload of time-based transmission.

For hw offload, the time sorted list is still used, so packets are
dequeued always in order of txtime.

Example:

$ tc qdisc replace dev enp2s0 parent root handle 100 mqprio num_tc 3 \
           map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0

$ tc qdisc add dev enp2s0 parent 100:1 etf offload delta 100000 \
	   clockid CLOCK_REALTIME

In this example, the Qdisc will use HW offload for the control of the
transmission time through the network adapter. The hrtimer used for
packets scheduling inside the qdisc will use the clockid CLOCK_REALTIME
as reference and packets leave the Qdisc "delta" (100000) nanoseconds
before their transmission time. Because this will be using HW offload and
since dynamic clocks are not supported by the hrtimer, the system clock
and the PHC clock must be synchronized for this mode to behave as
expected.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 include/net/pkt_sched.h        |  5 +++
 include/uapi/linux/pkt_sched.h |  1 +
 net/sched/sch_etf.c            | 71 +++++++++++++++++++++++++++++++++-
 3 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index 2466ea143d01..7dc769e5452b 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -155,4 +155,9 @@ struct tc_cbs_qopt_offload {
 	s32 sendslope;
 };
 
+struct tc_etf_qopt_offload {
+	u8 enable;
+	s32 queue;
+};
+
 #endif
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h
index d5e933ce1447..949118461009 100644
--- a/include/uapi/linux/pkt_sched.h
+++ b/include/uapi/linux/pkt_sched.h
@@ -944,6 +944,7 @@ struct tc_etf_qopt {
 	__s32 clockid;
 	__u32 flags;
 #define TC_ETF_DEADLINE_MODE_ON	BIT(0)
+#define TC_ETF_OFFLOAD_ON	BIT(1)
 };
 
 enum {
diff --git a/net/sched/sch_etf.c b/net/sched/sch_etf.c
index 4b7f4903ac17..932a136db568 100644
--- a/net/sched/sch_etf.c
+++ b/net/sched/sch_etf.c
@@ -20,8 +20,10 @@
 #include <net/sock.h>
 
 #define DEADLINE_MODE_IS_ON(x) ((x)->flags & TC_ETF_DEADLINE_MODE_ON)
+#define OFFLOAD_IS_ON(x) ((x)->flags & TC_ETF_OFFLOAD_ON)
 
 struct etf_sched_data {
+	bool offload;
 	bool deadline_mode;
 	int clockid;
 	int queue;
@@ -45,6 +47,9 @@ static inline int validate_input_params(struct tc_etf_qopt *qopt,
 	 *	* Dynamic clockids are not supported.
 	 *
 	 *	* Delta must be a positive integer.
+	 *
+	 * Also note that for the HW offload case, we must
+	 * expect that system clocks have been synchronized to PHC.
 	 */
 	if (qopt->clockid < 0) {
 		NL_SET_ERR_MSG(extack, "Dynamic clockids are not supported");
@@ -225,6 +230,56 @@ static struct sk_buff *etf_dequeue_timesortedlist(struct Qdisc *sch)
 	return skb;
 }
 
+static void etf_disable_offload(struct net_device *dev,
+				struct etf_sched_data *q)
+{
+	struct tc_etf_qopt_offload etf = { };
+	const struct net_device_ops *ops;
+	int err;
+
+	if (!q->offload)
+		return;
+
+	ops = dev->netdev_ops;
+	if (!ops->ndo_setup_tc)
+		return;
+
+	etf.queue = q->queue;
+	etf.enable = 0;
+
+	err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_ETF, &etf);
+	if (err < 0)
+		pr_warn("Couldn't disable ETF offload for queue %d\n",
+			etf.queue);
+}
+
+static int etf_enable_offload(struct net_device *dev, struct etf_sched_data *q,
+			      struct netlink_ext_ack *extack)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct tc_etf_qopt_offload etf = { };
+	int err;
+
+	if (q->offload)
+		return 0;
+
+	if (!ops->ndo_setup_tc) {
+		NL_SET_ERR_MSG(extack, "Specified device does not support ETF offload");
+		return -EOPNOTSUPP;
+	}
+
+	etf.queue = q->queue;
+	etf.enable = 1;
+
+	err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_ETF, &etf);
+	if (err < 0) {
+		NL_SET_ERR_MSG(extack, "Specified device failed to setup ETF hardware offload");
+		return err;
+	}
+
+	return 0;
+}
+
 static int etf_init(struct Qdisc *sch, struct nlattr *opt,
 		    struct netlink_ext_ack *extack)
 {
@@ -251,8 +306,9 @@ static int etf_init(struct Qdisc *sch, struct nlattr *opt,
 
 	qopt = nla_data(tb[TCA_ETF_PARMS]);
 
-	pr_debug("delta %d clockid %d deadline %s\n",
+	pr_debug("delta %d clockid %d offload %s deadline %s\n",
 		 qopt->delta, qopt->clockid,
+		 OFFLOAD_IS_ON(qopt) ? "on" : "off",
 		 DEADLINE_MODE_IS_ON(qopt) ? "on" : "off");
 
 	err = validate_input_params(qopt, extack);
@@ -261,9 +317,16 @@ static int etf_init(struct Qdisc *sch, struct nlattr *opt,
 
 	q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
 
+	if (OFFLOAD_IS_ON(qopt)) {
+		err = etf_enable_offload(dev, q, extack);
+		if (err < 0)
+			return err;
+	}
+
 	/* Everything went OK, save the parameters used. */
 	q->delta = qopt->delta;
 	q->clockid = qopt->clockid;
+	q->offload = OFFLOAD_IS_ON(qopt);
 	q->deadline_mode = DEADLINE_MODE_IS_ON(qopt);
 
 	switch (q->clockid) {
@@ -326,10 +389,13 @@ static void etf_reset(struct Qdisc *sch)
 static void etf_destroy(struct Qdisc *sch)
 {
 	struct etf_sched_data *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
 
 	/* Only cancel watchdog if it's been initialized. */
 	if (q->watchdog.qdisc == sch)
 		qdisc_watchdog_cancel(&q->watchdog);
+
+	etf_disable_offload(dev, q);
 }
 
 static int etf_dump(struct Qdisc *sch, struct sk_buff *skb)
@@ -344,6 +410,9 @@ static int etf_dump(struct Qdisc *sch, struct sk_buff *skb)
 
 	opt.delta = q->delta;
 	opt.clockid = q->clockid;
+	if (q->offload)
+		opt.flags |= TC_ETF_OFFLOAD_ON;
+
 	if (q->deadline_mode)
 		opt.flags |= TC_ETF_DEADLINE_MODE_ON;
 
-- 
2.18.0

[PATCH v2 net-next 09/14] igb: Refactor igb_configure_cbs()

[Jesus Sanchez-Palencia]

Make this function retrieve what it needs from the Tx ring being
addressed since it already relies on what had been saved on it before.
Also, since this function will be used by the upcoming Launchtime
patches rename it to better reflect its intention. Note that
Launchtime is not part of what 802.1Qav specifies, but the i210
datasheet refers to this set of functionality as "Qav Transmission
Mode".

Here we also perform a tiny refactor at is_any_cbs_enabled(), and add
further documentation to igb_setup_tx_mode().

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 60 +++++++++++------------
 1 file changed, 28 insertions(+), 32 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index f1e3397bd405..15f6b9c57ccf 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -1655,23 +1655,17 @@ static void set_queue_mode(struct e1000_hw *hw, int queue, enum queue_mode mode)
 }
 
 /**
- *  igb_configure_cbs - Configure Credit-Based Shaper (CBS)
+ *  igb_config_tx_modes - Configure "Qav Tx mode" features on igb
  *  @adapter: pointer to adapter struct
  *  @queue: queue number
- *  @enable: true = enable CBS, false = disable CBS
- *  @idleslope: idleSlope in kbps
- *  @sendslope: sendSlope in kbps
- *  @hicredit: hiCredit in bytes
- *  @locredit: loCredit in bytes
  *
- *  Configure CBS for a given hardware queue. When disabling, idleslope,
- *  sendslope, hicredit, locredit arguments are ignored. Returns 0 if
- *  success. Negative otherwise.
+ *  Configure CBS for a given hardware queue. Parameters are retrieved
+ *  from the correct Tx ring, so igb_save_cbs_params() should be used
+ *  for setting those correctly prior to this function being called.
  **/
-static void igb_configure_cbs(struct igb_adapter *adapter, int queue,
-			      bool enable, int idleslope, int sendslope,
-			      int hicredit, int locredit)
+static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 {
+	struct igb_ring *ring = adapter->tx_ring[queue];
 	struct net_device *netdev = adapter->netdev;
 	struct e1000_hw *hw = &adapter->hw;
 	u32 tqavcc;
@@ -1680,7 +1674,7 @@ static void igb_configure_cbs(struct igb_adapter *adapter, int queue,
 	WARN_ON(hw->mac.type != e1000_i210);
 	WARN_ON(queue < 0 || queue > 1);
 
-	if (enable || queue == 0) {
+	if (ring->cbs_enable || queue == 0) {
 		/* i210 does not allow the queue 0 to be in the Strict
 		 * Priority mode while the Qav mode is enabled, so,
 		 * instead of disabling strict priority mode, we give
@@ -1690,10 +1684,10 @@ static void igb_configure_cbs(struct igb_adapter *adapter, int queue,
 		 * Queue0 QueueMode must be set to 1b when
 		 * TransmitMode is set to Qav."
 		 */
-		if (queue == 0 && !enable) {
+		if (queue == 0 && !ring->cbs_enable) {
 			/* max "linkspeed" idleslope in kbps */
-			idleslope = 1000000;
-			hicredit = ETH_FRAME_LEN;
+			ring->idleslope = 1000000;
+			ring->hicredit = ETH_FRAME_LEN;
 		}
 
 		set_tx_desc_fetch_prio(hw, queue, TX_QUEUE_PRIO_HIGH);
@@ -1756,14 +1750,15 @@ static void igb_configure_cbs(struct igb_adapter *adapter, int queue,
 		 *       calculated value, so the resulting bandwidth might
 		 *       be slightly higher for some configurations.
 		 */
-		value = DIV_ROUND_UP_ULL(idleslope * 61034ULL, 1000000);
+		value = DIV_ROUND_UP_ULL(ring->idleslope * 61034ULL, 1000000);
 
 		tqavcc = rd32(E1000_I210_TQAVCC(queue));
 		tqavcc &= ~E1000_TQAVCC_IDLESLOPE_MASK;
 		tqavcc |= value;
 		wr32(E1000_I210_TQAVCC(queue), tqavcc);
 
-		wr32(E1000_I210_TQAVHC(queue), 0x80000000 + hicredit * 0x7735);
+		wr32(E1000_I210_TQAVHC(queue),
+		     0x80000000 + ring->hicredit * 0x7735);
 	} else {
 		set_tx_desc_fetch_prio(hw, queue, TX_QUEUE_PRIO_LOW);
 		set_queue_mode(hw, queue, QUEUE_MODE_STRICT_PRIORITY);
@@ -1783,8 +1778,9 @@ static void igb_configure_cbs(struct igb_adapter *adapter, int queue,
 	 */
 
 	netdev_dbg(netdev, "CBS %s: queue %d idleslope %d sendslope %d hiCredit %d locredit %d\n",
-		   (enable) ? "enabled" : "disabled", queue,
-		   idleslope, sendslope, hicredit, locredit);
+		   (ring->cbs_enable) ? "enabled" : "disabled", queue,
+		   ring->idleslope, ring->sendslope, ring->hicredit,
+		   ring->locredit);
 }
 
 static int igb_save_cbs_params(struct igb_adapter *adapter, int queue,
@@ -1809,19 +1805,25 @@ static int igb_save_cbs_params(struct igb_adapter *adapter, int queue,
 
 static bool is_any_cbs_enabled(struct igb_adapter *adapter)
 {
-	struct igb_ring *ring;
 	int i;
 
 	for (i = 0; i < adapter->num_tx_queues; i++) {
-		ring = adapter->tx_ring[i];
-
-		if (ring->cbs_enable)
+		if (adapter->tx_ring[i]->cbs_enable)
 			return true;
 	}
 
 	return false;
 }
 
+/**
+ *  igb_setup_tx_mode - Switch to/from Qav Tx mode when applicable
+ *  @adapter: pointer to adapter struct
+ *
+ *  Configure TQAVCTRL register switching the controller's Tx mode
+ *  if FQTSS mode is enabled or disabled. Additionally, will issue
+ *  a call to igb_config_tx_modes() per queue so any previously saved
+ *  Tx parameters are applied.
+ **/
 static void igb_setup_tx_mode(struct igb_adapter *adapter)
 {
 	struct net_device *netdev = adapter->netdev;
@@ -1881,11 +1883,7 @@ static void igb_setup_tx_mode(struct igb_adapter *adapter)
 			    adapter->num_tx_queues : I210_SR_QUEUES_NUM;
 
 		for (i = 0; i < max_queue; i++) {
-			struct igb_ring *ring = adapter->tx_ring[i];
-
-			igb_configure_cbs(adapter, i, ring->cbs_enable,
-					  ring->idleslope, ring->sendslope,
-					  ring->hicredit, ring->locredit);
+			igb_config_tx_modes(adapter, i);
 		}
 	} else {
 		wr32(E1000_RXPBS, I210_RXPBSIZE_DEFAULT);
@@ -2480,9 +2478,7 @@ static int igb_offload_cbs(struct igb_adapter *adapter,
 		return err;
 
 	if (is_fqtss_enabled(adapter)) {
-		igb_configure_cbs(adapter, qopt->queue, qopt->enable,
-				  qopt->idleslope, qopt->sendslope,
-				  qopt->hicredit, qopt->locredit);
+		igb_config_tx_modes(adapter, qopt->queue);
 
 		if (!is_any_cbs_enabled(adapter))
 			enable_fqtss(adapter, false);
-- 
2.18.0

[PATCH v2 net-next 10/14] igb: Only change Tx arbitration when CBS is on

[Jesus Sanchez-Palencia]

Currently the data transmission arbitration algorithm - DataTranARB
field on TQAVCTRL reg - is always set to CBS when the Tx mode is
changed from legacy to 'Qav' mode.

Make that configuration a bit more granular in preparation for the
upcoming Launchtime enabling patches, since CBS and Launchtime can be
enabled separately. That is achieved by moving the DataTranARB setup
to igb_config_tx_modes() instead.

Similarly, when disabling CBS we must check if it has been disabled
for all queues, and clear the DataTranARB accordingly.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 49 +++++++++++++++--------
 1 file changed, 33 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 15f6b9c57ccf..8c90f1e51add 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -1654,6 +1654,18 @@ static void set_queue_mode(struct e1000_hw *hw, int queue, enum queue_mode mode)
 	wr32(E1000_I210_TQAVCC(queue), val);
 }
 
+static bool is_any_cbs_enabled(struct igb_adapter *adapter)
+{
+	int i;
+
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		if (adapter->tx_ring[i]->cbs_enable)
+			return true;
+	}
+
+	return false;
+}
+
 /**
  *  igb_config_tx_modes - Configure "Qav Tx mode" features on igb
  *  @adapter: pointer to adapter struct
@@ -1668,7 +1680,7 @@ static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 	struct igb_ring *ring = adapter->tx_ring[queue];
 	struct net_device *netdev = adapter->netdev;
 	struct e1000_hw *hw = &adapter->hw;
-	u32 tqavcc;
+	u32 tqavcc, tqavctrl;
 	u16 value;
 
 	WARN_ON(hw->mac.type != e1000_i210);
@@ -1693,6 +1705,14 @@ static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 		set_tx_desc_fetch_prio(hw, queue, TX_QUEUE_PRIO_HIGH);
 		set_queue_mode(hw, queue, QUEUE_MODE_STREAM_RESERVATION);
 
+		/* Always set data transfer arbitration to credit-based
+		 * shaper algorithm on TQAVCTRL if CBS is enabled for any of
+		 * the queues.
+		 */
+		tqavctrl = rd32(E1000_I210_TQAVCTRL);
+		tqavctrl |= E1000_TQAVCTRL_DATATRANARB;
+		wr32(E1000_I210_TQAVCTRL, tqavctrl);
+
 		/* According to i210 datasheet section 7.2.7.7, we should set
 		 * the 'idleSlope' field from TQAVCC register following the
 		 * equation:
@@ -1770,6 +1790,16 @@ static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 
 		/* Set hiCredit to zero. */
 		wr32(E1000_I210_TQAVHC(queue), 0);
+
+		/* If CBS is not enabled for any queues anymore, then return to
+		 * the default state of Data Transmission Arbitration on
+		 * TQAVCTRL.
+		 */
+		if (!is_any_cbs_enabled(adapter)) {
+			tqavctrl = rd32(E1000_I210_TQAVCTRL);
+			tqavctrl &= ~E1000_TQAVCTRL_DATATRANARB;
+			wr32(E1000_I210_TQAVCTRL, tqavctrl);
+		}
 	}
 
 	/* XXX: In i210 controller the sendSlope and loCredit parameters from
@@ -1803,18 +1833,6 @@ static int igb_save_cbs_params(struct igb_adapter *adapter, int queue,
 	return 0;
 }
 
-static bool is_any_cbs_enabled(struct igb_adapter *adapter)
-{
-	int i;
-
-	for (i = 0; i < adapter->num_tx_queues; i++) {
-		if (adapter->tx_ring[i]->cbs_enable)
-			return true;
-	}
-
-	return false;
-}
-
 /**
  *  igb_setup_tx_mode - Switch to/from Qav Tx mode when applicable
  *  @adapter: pointer to adapter struct
@@ -1838,11 +1856,10 @@ static void igb_setup_tx_mode(struct igb_adapter *adapter)
 		int i, max_queue;
 
 		/* Configure TQAVCTRL register: set transmit mode to 'Qav',
-		 * set data fetch arbitration to 'round robin' and set data
-		 * transfer arbitration to 'credit shaper algorithm.
+		 * set data fetch arbitration to 'round robin'.
 		 */
 		val = rd32(E1000_I210_TQAVCTRL);
-		val |= E1000_TQAVCTRL_XMIT_MODE | E1000_TQAVCTRL_DATATRANARB;
+		val |= E1000_TQAVCTRL_XMIT_MODE;
 		val &= ~E1000_TQAVCTRL_DATAFETCHARB;
 		wr32(E1000_I210_TQAVCTRL, val);
 
-- 
2.18.0

[PATCH v2 net-next 11/14] igb: Refactor igb_offload_cbs()

[Jesus Sanchez-Palencia]

Split code into a separate function (igb_offload_apply()) that will be
used by ETF offload implementation.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 8c90f1e51add..c30ab7b260cc 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2474,6 +2474,19 @@ igb_features_check(struct sk_buff *skb, struct net_device *dev,
 	return features;
 }
 
+static void igb_offload_apply(struct igb_adapter *adapter, s32 queue)
+{
+	if (!is_fqtss_enabled(adapter)) {
+		enable_fqtss(adapter, true);
+		return;
+	}
+
+	igb_config_tx_modes(adapter, queue);
+
+	if (!is_any_cbs_enabled(adapter))
+		enable_fqtss(adapter, false);
+}
+
 static int igb_offload_cbs(struct igb_adapter *adapter,
 			   struct tc_cbs_qopt_offload *qopt)
 {
@@ -2494,15 +2507,7 @@ static int igb_offload_cbs(struct igb_adapter *adapter,
 	if (err)
 		return err;
 
-	if (is_fqtss_enabled(adapter)) {
-		igb_config_tx_modes(adapter, qopt->queue);
-
-		if (!is_any_cbs_enabled(adapter))
-			enable_fqtss(adapter, false);
-
-	} else {
-		enable_fqtss(adapter, true);
-	}
+	igb_offload_apply(adapter, qopt->queue);
 
 	return 0;
 }
-- 
2.18.0

[PATCH v2 net-next 12/14] igb: Only call skb_tx_timestamp after descriptors are ready

[Jesus Sanchez-Palencia]

Currently, skb_tx_timestamp() is being called before the Tx
descriptors are prepared in igb_xmit_frame_ring(), which happens
during either the igb_tso() or igb_tx_csum() calls.

Given that now the skb->tstamp might be used to carry the timestamp
for SO_TXTIME, we must only call skb_tx_timestamp() after the
information has been copied into the Tx descriptors.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index c30ab7b260cc..445da8285d9b 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6033,8 +6033,6 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 		}
 	}
 
-	skb_tx_timestamp(skb);
-
 	if (skb_vlan_tag_present(skb)) {
 		tx_flags |= IGB_TX_FLAGS_VLAN;
 		tx_flags |= (skb_vlan_tag_get(skb) << IGB_TX_FLAGS_VLAN_SHIFT);
@@ -6050,6 +6048,8 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 	else if (!tso)
 		igb_tx_csum(tx_ring, first);
 
+	skb_tx_timestamp(skb);
+
 	if (igb_tx_map(tx_ring, first, hdr_len))
 		goto cleanup_tx_tstamp;
 
-- 
2.18.0

[PATCH v2 net-next 13/14] igb: Add support for ETF offload

[Jesus Sanchez-Palencia]

Implement HW offload support for SO_TXTIME through igb's Launchtime
feature. This is done by extending igb_setup_tc() so it supports
TC_SETUP_QDISC_ETF and configuring i210 so time based transmit
arbitration is enabled.

The FQTSS transmission mode added before is extended so strict
priority (SP) queues wait for stream reservation (SR) ones.
igb_config_tx_modes() is extended so it can support enabling/disabling
Launchtime following the previous approach used for the credit-based
shaper (CBS).

As the previous flow, FQTSS transmission mode is enabled automatically
by the driver once Launchtime (or CBS, as before) is enabled.
Similarly, it's automatically disabled when the feature is disabled
for the last queue that had it setup on.

The driver just consumes the transmit times from the skbuffs directly,
so no special handling is done in case an 'invalid' time is provided.
We assume this has been handled by the ETF qdisc already.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 .../net/ethernet/intel/igb/e1000_defines.h    |  16 ++
 drivers/net/ethernet/intel/igb/igb.h          |   1 +
 drivers/net/ethernet/intel/igb/igb_main.c     | 138 +++++++++++++++---
 3 files changed, 138 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/e1000_defines.h b/drivers/net/ethernet/intel/igb/e1000_defines.h
index 252440a418dc..8a28f3388f69 100644
--- a/drivers/net/ethernet/intel/igb/e1000_defines.h
+++ b/drivers/net/ethernet/intel/igb/e1000_defines.h
@@ -1048,6 +1048,22 @@
 #define E1000_TQAVCTRL_XMIT_MODE	BIT(0)
 #define E1000_TQAVCTRL_DATAFETCHARB	BIT(4)
 #define E1000_TQAVCTRL_DATATRANARB	BIT(8)
+#define E1000_TQAVCTRL_DATATRANTIM	BIT(9)
+#define E1000_TQAVCTRL_SP_WAIT_SR	BIT(10)
+/* Fetch Time Delta - bits 31:16
+ *
+ * This field holds the value to be reduced from the launch time for
+ * fetch time decision. The FetchTimeDelta value is defined in 32 ns
+ * granularity.
+ *
+ * This field is 16 bits wide, and so the maximum value is:
+ *
+ * 65535 * 32 = 2097120 ~= 2.1 msec
+ *
+ * XXX: We are configuring the max value here since we couldn't come up
+ * with a reason for not doing so.
+ */
+#define E1000_TQAVCTRL_FETCHTIME_DELTA	(0xFFFF << 16)
 
 /* TX Qav Credit Control fields */
 #define E1000_TQAVCC_IDLESLOPE_MASK	0xFFFF
diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 9643b5b3d444..ca54e268d157 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -262,6 +262,7 @@ struct igb_ring {
 	u16 count;			/* number of desc. in the ring */
 	u8 queue_index;			/* logical index of the ring*/
 	u8 reg_idx;			/* physical index of the ring */
+	bool launchtime_enable;		/* true if LaunchTime is enabled */
 	bool cbs_enable;		/* indicates if CBS is enabled */
 	s32 idleslope;			/* idleSlope in kbps */
 	s32 sendslope;			/* sendSlope in kbps */
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 445da8285d9b..e3a0c02721c9 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -1666,13 +1666,26 @@ static bool is_any_cbs_enabled(struct igb_adapter *adapter)
 	return false;
 }
 
+static bool is_any_txtime_enabled(struct igb_adapter *adapter)
+{
+	int i;
+
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		if (adapter->tx_ring[i]->launchtime_enable)
+			return true;
+	}
+
+	return false;
+}
+
 /**
  *  igb_config_tx_modes - Configure "Qav Tx mode" features on igb
  *  @adapter: pointer to adapter struct
  *  @queue: queue number
  *
- *  Configure CBS for a given hardware queue. Parameters are retrieved
- *  from the correct Tx ring, so igb_save_cbs_params() should be used
+ *  Configure CBS and Launchtime for a given hardware queue.
+ *  Parameters are retrieved from the correct Tx ring, so
+ *  igb_save_cbs_params() and igb_save_txtime_params() should be used
  *  for setting those correctly prior to this function being called.
  **/
 static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
@@ -1686,6 +1699,19 @@ static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 	WARN_ON(hw->mac.type != e1000_i210);
 	WARN_ON(queue < 0 || queue > 1);
 
+	/* If any of the Qav features is enabled, configure queues as SR and
+	 * with HIGH PRIO. If none is, then configure them with LOW PRIO and
+	 * as SP.
+	 */
+	if (ring->cbs_enable || ring->launchtime_enable) {
+		set_tx_desc_fetch_prio(hw, queue, TX_QUEUE_PRIO_HIGH);
+		set_queue_mode(hw, queue, QUEUE_MODE_STREAM_RESERVATION);
+	} else {
+		set_tx_desc_fetch_prio(hw, queue, TX_QUEUE_PRIO_LOW);
+		set_queue_mode(hw, queue, QUEUE_MODE_STRICT_PRIORITY);
+	}
+
+	/* If CBS is enabled, set DataTranARB and config its parameters. */
 	if (ring->cbs_enable || queue == 0) {
 		/* i210 does not allow the queue 0 to be in the Strict
 		 * Priority mode while the Qav mode is enabled, so,
@@ -1702,9 +1728,6 @@ static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 			ring->hicredit = ETH_FRAME_LEN;
 		}
 
-		set_tx_desc_fetch_prio(hw, queue, TX_QUEUE_PRIO_HIGH);
-		set_queue_mode(hw, queue, QUEUE_MODE_STREAM_RESERVATION);
-
 		/* Always set data transfer arbitration to credit-based
 		 * shaper algorithm on TQAVCTRL if CBS is enabled for any of
 		 * the queues.
@@ -1780,8 +1803,6 @@ static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 		wr32(E1000_I210_TQAVHC(queue),
 		     0x80000000 + ring->hicredit * 0x7735);
 	} else {
-		set_tx_desc_fetch_prio(hw, queue, TX_QUEUE_PRIO_LOW);
-		set_queue_mode(hw, queue, QUEUE_MODE_STRICT_PRIORITY);
 
 		/* Set idleSlope to zero. */
 		tqavcc = rd32(E1000_I210_TQAVCC(queue));
@@ -1802,17 +1823,61 @@ static void igb_config_tx_modes(struct igb_adapter *adapter, int queue)
 		}
 	}
 
+	/* If LaunchTime is enabled, set DataTranTIM. */
+	if (ring->launchtime_enable) {
+		/* Always set DataTranTIM on TQAVCTRL if LaunchTime is enabled
+		 * for any of the SR queues, and configure fetchtime delta.
+		 * XXX NOTE:
+		 *     - LaunchTime will be enabled for all SR queues.
+		 *     - A fixed offset can be added relative to the launch
+		 *       time of all packets if configured at reg LAUNCH_OS0.
+		 *       We are keeping it as 0 for now (default value).
+		 */
+		tqavctrl = rd32(E1000_I210_TQAVCTRL);
+		tqavctrl |= E1000_TQAVCTRL_DATATRANTIM |
+		       E1000_TQAVCTRL_FETCHTIME_DELTA;
+		wr32(E1000_I210_TQAVCTRL, tqavctrl);
+	} else {
+		/* If Launchtime is not enabled for any SR queues anymore,
+		 * then clear DataTranTIM on TQAVCTRL and clear fetchtime delta,
+		 * effectively disabling Launchtime.
+		 */
+		if (!is_any_txtime_enabled(adapter)) {
+			tqavctrl = rd32(E1000_I210_TQAVCTRL);
+			tqavctrl &= ~E1000_TQAVCTRL_DATATRANTIM;
+			tqavctrl &= ~E1000_TQAVCTRL_FETCHTIME_DELTA;
+			wr32(E1000_I210_TQAVCTRL, tqavctrl);
+		}
+	}
+
 	/* XXX: In i210 controller the sendSlope and loCredit parameters from
 	 * CBS are not configurable by software so we don't do any 'controller
 	 * configuration' in respect to these parameters.
 	 */
 
-	netdev_dbg(netdev, "CBS %s: queue %d idleslope %d sendslope %d hiCredit %d locredit %d\n",
-		   (ring->cbs_enable) ? "enabled" : "disabled", queue,
+	netdev_dbg(netdev, "Qav Tx mode: cbs %s, launchtime %s, queue %d \
+			    idleslope %d sendslope %d hiCredit %d \
+			    locredit %d\n",
+		   (ring->cbs_enable) ? "enabled" : "disabled",
+		   (ring->launchtime_enable) ? "enabled" : "disabled", queue,
 		   ring->idleslope, ring->sendslope, ring->hicredit,
 		   ring->locredit);
 }
 
+static int igb_save_txtime_params(struct igb_adapter *adapter, int queue,
+				  bool enable)
+{
+	struct igb_ring *ring;
+
+	if (queue < 0 || queue > adapter->num_tx_queues)
+		return -EINVAL;
+
+	ring = adapter->tx_ring[queue];
+	ring->launchtime_enable = enable;
+
+	return 0;
+}
+
 static int igb_save_cbs_params(struct igb_adapter *adapter, int queue,
 			       bool enable, int idleslope, int sendslope,
 			       int hicredit, int locredit)
@@ -1856,10 +1921,11 @@ static void igb_setup_tx_mode(struct igb_adapter *adapter)
 		int i, max_queue;
 
 		/* Configure TQAVCTRL register: set transmit mode to 'Qav',
-		 * set data fetch arbitration to 'round robin'.
+		 * set data fetch arbitration to 'round robin', set SP_WAIT_SR
+		 * so SP queues wait for SR ones.
 		 */
 		val = rd32(E1000_I210_TQAVCTRL);
-		val |= E1000_TQAVCTRL_XMIT_MODE;
+		val |= E1000_TQAVCTRL_XMIT_MODE | E1000_TQAVCTRL_SP_WAIT_SR;
 		val &= ~E1000_TQAVCTRL_DATAFETCHARB;
 		wr32(E1000_I210_TQAVCTRL, val);
 
@@ -2483,7 +2549,7 @@ static void igb_offload_apply(struct igb_adapter *adapter, s32 queue)
 
 	igb_config_tx_modes(adapter, queue);
 
-	if (!is_any_cbs_enabled(adapter))
+	if (!is_any_cbs_enabled(adapter) && !is_any_txtime_enabled(adapter))
 		enable_fqtss(adapter, false);
 }
 
@@ -2756,6 +2822,29 @@ static int igb_setup_tc_block(struct igb_adapter *adapter,
 	}
 }
 
+static int igb_offload_txtime(struct igb_adapter *adapter,
+			      struct tc_etf_qopt_offload *qopt)
+{
+	struct e1000_hw *hw = &adapter->hw;
+	int err;
+
+	/* Launchtime offloading is only supported by i210 controller. */
+	if (hw->mac.type != e1000_i210)
+		return -EOPNOTSUPP;
+
+	/* Launchtime offloading is only supported by queues 0 and 1. */
+	if (qopt->queue < 0 || qopt->queue > 1)
+		return -EINVAL;
+
+	err = igb_save_txtime_params(adapter, qopt->queue, qopt->enable);
+	if (err)
+		return err;
+
+	igb_offload_apply(adapter, qopt->queue);
+
+	return 0;
+}
+
 static int igb_setup_tc(struct net_device *dev, enum tc_setup_type type,
 			void *type_data)
 {
@@ -2766,6 +2855,8 @@ static int igb_setup_tc(struct net_device *dev, enum tc_setup_type type,
 		return igb_offload_cbs(adapter, type_data);
 	case TC_SETUP_BLOCK:
 		return igb_setup_tc_block(adapter, type_data);
+	case TC_SETUP_QDISC_ETF:
+		return igb_offload_txtime(adapter, type_data);
 
 	default:
 		return -EOPNOTSUPP;
@@ -5586,11 +5677,14 @@ static void igb_set_itr(struct igb_q_vector *q_vector)
 	}
 }
 
-static void igb_tx_ctxtdesc(struct igb_ring *tx_ring, u32 vlan_macip_lens,
-			    u32 type_tucmd, u32 mss_l4len_idx)
+static void igb_tx_ctxtdesc(struct igb_ring *tx_ring,
+			    struct igb_tx_buffer *first,
+			    u32 vlan_macip_lens, u32 type_tucmd,
+			    u32 mss_l4len_idx)
 {
 	struct e1000_adv_tx_context_desc *context_desc;
 	u16 i = tx_ring->next_to_use;
+	struct timespec64 ts;
 
 	context_desc = IGB_TX_CTXTDESC(tx_ring, i);
 
@@ -5605,9 +5699,18 @@ static void igb_tx_ctxtdesc(struct igb_ring *tx_ring, u32 vlan_macip_lens,
 		mss_l4len_idx |= tx_ring->reg_idx << 4;
 
 	context_desc->vlan_macip_lens	= cpu_to_le32(vlan_macip_lens);
-	context_desc->seqnum_seed	= 0;
 	context_desc->type_tucmd_mlhl	= cpu_to_le32(type_tucmd);
 	context_desc->mss_l4len_idx	= cpu_to_le32(mss_l4len_idx);
+
+	/* We assume there is always a valid tx time available. Invalid times
+	 * should have been handled by the upper layers.
+	 */
+	if (tx_ring->launchtime_enable) {
+		ts = ns_to_timespec64(first->skb->tstamp);
+		context_desc->seqnum_seed = cpu_to_le32(ts.tv_nsec / 32);
+	} else {
+		context_desc->seqnum_seed = 0;
+	}
 }
 
 static int igb_tso(struct igb_ring *tx_ring,
@@ -5690,7 +5793,8 @@ static int igb_tso(struct igb_ring *tx_ring,
 	vlan_macip_lens |= (ip.hdr - skb->data) << E1000_ADVTXD_MACLEN_SHIFT;
 	vlan_macip_lens |= first->tx_flags & IGB_TX_FLAGS_VLAN_MASK;
 
-	igb_tx_ctxtdesc(tx_ring, vlan_macip_lens, type_tucmd, mss_l4len_idx);
+	igb_tx_ctxtdesc(tx_ring, first, vlan_macip_lens,
+			type_tucmd, mss_l4len_idx);
 
 	return 1;
 }
@@ -5745,7 +5849,7 @@ static void igb_tx_csum(struct igb_ring *tx_ring, struct igb_tx_buffer *first)
 	vlan_macip_lens |= skb_network_offset(skb) << E1000_ADVTXD_MACLEN_SHIFT;
 	vlan_macip_lens |= first->tx_flags & IGB_TX_FLAGS_VLAN_MASK;
 
-	igb_tx_ctxtdesc(tx_ring, vlan_macip_lens, type_tucmd, 0);
+	igb_tx_ctxtdesc(tx_ring, first, vlan_macip_lens, type_tucmd, 0);
 }
 
 #define IGB_SET_FLAG(_input, _flag, _result) \
-- 
2.18.0

[PATCH v2 net-next 14/14] net/sched: Make etf report drops on error_queue

[Jesus Sanchez-Palencia]

Use the socket error queue for reporting dropped packets if the
socket has enabled that feature through the SO_TXTIME API.

Packets are dropped either on enqueue() if they aren't accepted by the
qdisc or on dequeue() if the system misses their deadline. Those are
reported as different errors so applications can react accordingly.

Userspace can retrieve the errors through the socket error queue and the
corresponding cmsg interfaces. A struct sock_extended_err* is used for
returning the error data, and the packet's timestamp can be retrieved by
adding both ee_data and ee_info fields as e.g.:

    ((__u64) serr->ee_data << 32) + serr->ee_info

This feature is disabled by default and must be explicitly enabled by
applications. Enabling it can bring some overhead for the Tx cycles
of the application.

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 include/net/sock.h              |  3 ++-
 include/uapi/linux/errqueue.h   |  4 ++++
 include/uapi/linux/net_tstamp.h |  5 ++++-
 net/core/sock.c                 |  4 ++++
 net/sched/sch_etf.c             | 35 +++++++++++++++++++++++++++++++--
 5 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 68347b9821c6..e0eac9ef44b5 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -481,7 +481,8 @@ struct sock {
 
 	u8			sk_clockid;
 	u8			sk_txtime_deadline_mode : 1,
-				sk_txtime_unused : 7;
+				sk_txtime_report_errors : 1,
+				sk_txtime_unused : 6;
 
 	struct socket		*sk_socket;
 	void			*sk_user_data;
diff --git a/include/uapi/linux/errqueue.h b/include/uapi/linux/errqueue.h
index dc64cfaf13da..c0151200f7d1 100644
--- a/include/uapi/linux/errqueue.h
+++ b/include/uapi/linux/errqueue.h
@@ -20,12 +20,16 @@ struct sock_extended_err {
 #define SO_EE_ORIGIN_ICMP6	3
 #define SO_EE_ORIGIN_TXSTATUS	4
 #define SO_EE_ORIGIN_ZEROCOPY	5
+#define SO_EE_ORIGIN_TXTIME	6
 #define SO_EE_ORIGIN_TIMESTAMPING SO_EE_ORIGIN_TXSTATUS
 
 #define SO_EE_OFFENDER(ee)	((struct sockaddr*)((ee)+1))
 
 #define SO_EE_CODE_ZEROCOPY_COPIED	1
 
+#define SO_EE_CODE_TXTIME_INVALID_PARAM	1
+#define SO_EE_CODE_TXTIME_MISSED	2
+
 /**
  *	struct scm_timestamping - timestamps exposed through cmsg
  *
diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
index c9a77c353b98..f8f4539f1135 100644
--- a/include/uapi/linux/net_tstamp.h
+++ b/include/uapi/linux/net_tstamp.h
@@ -147,8 +147,11 @@ struct scm_ts_pktinfo {
  */
 enum txtime_flags {
 	SOF_TXTIME_DEADLINE_MODE = (1 << 0),
+	SOF_TXTIME_REPORT_ERRORS = (1 << 1),
 
-	SOF_TXTIME_FLAGS_MASK = (SOF_TXTIME_DEADLINE_MODE)
+	SOF_TXTIME_FLAGS_LAST = SOF_TXTIME_REPORT_ERRORS,
+	SOF_TXTIME_FLAGS_MASK = (SOF_TXTIME_FLAGS_LAST - 1) |
+				 SOF_TXTIME_FLAGS_LAST
 };
 
 struct sock_txtime {
diff --git a/net/core/sock.c b/net/core/sock.c
index fe64b839f1b2..03fdea5b0f57 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1087,6 +1087,8 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 			sk->sk_clockid = sk_txtime.clockid;
 			sk->sk_txtime_deadline_mode =
 				!!(sk_txtime.flags & SOF_TXTIME_DEADLINE_MODE);
+			sk->sk_txtime_report_errors =
+				!!(sk_txtime.flags & SOF_TXTIME_REPORT_ERRORS);
 		}
 		break;
 
@@ -1429,6 +1431,8 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.txtime.clockid = sk->sk_clockid;
 		v.txtime.flags |= sk->sk_txtime_deadline_mode ?
 				  SOF_TXTIME_DEADLINE_MODE : 0;
+		v.txtime.flags |= sk->sk_txtime_report_errors ?
+				  SOF_TXTIME_REPORT_ERRORS : 0;
 		break;
 
 	default:
diff --git a/net/sched/sch_etf.c b/net/sched/sch_etf.c
index 932a136db568..1538d6fa8165 100644
--- a/net/sched/sch_etf.c
+++ b/net/sched/sch_etf.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/errno.h>
+#include <linux/errqueue.h>
 #include <linux/rbtree.h>
 #include <linux/skbuff.h>
 #include <linux/posix-timers.h>
@@ -123,6 +124,32 @@ static void reset_watchdog(struct Qdisc *sch)
 	qdisc_watchdog_schedule_ns(&q->watchdog, ktime_to_ns(next));
 }
 
+static void report_sock_error(struct sk_buff *skb, u32 err, u8 code)
+{
+	struct sock_exterr_skb *serr;
+	struct sk_buff *clone;
+	ktime_t txtime = skb->tstamp;
+
+	if (!skb->sk || !(skb->sk->sk_txtime_report_errors))
+		return;
+
+	clone = skb_clone(skb, GFP_ATOMIC);
+	if (!clone)
+		return;
+
+	serr = SKB_EXT_ERR(clone);
+	serr->ee.ee_errno = err;
+	serr->ee.ee_origin = SO_EE_ORIGIN_TXTIME;
+	serr->ee.ee_type = 0;
+	serr->ee.ee_code = code;
+	serr->ee.ee_pad = 0;
+	serr->ee.ee_data = (txtime >> 32); /* high part of tstamp */
+	serr->ee.ee_info = txtime; /* low part of tstamp */
+
+	if (sock_queue_err_skb(skb->sk, clone))
+		kfree_skb(clone);
+}
+
 static int etf_enqueue_timesortedlist(struct sk_buff *nskb, struct Qdisc *sch,
 				      struct sk_buff **to_free)
 {
@@ -130,8 +157,11 @@ static int etf_enqueue_timesortedlist(struct sk_buff *nskb, struct Qdisc *sch,
 	struct rb_node **p = &q->head.rb_node, *parent = NULL;
 	ktime_t txtime = nskb->tstamp;
 
-	if (!is_packet_valid(sch, nskb))
+	if (!is_packet_valid(sch, nskb)) {
+		report_sock_error(nskb, EINVAL,
+				  SO_EE_CODE_TXTIME_INVALID_PARAM);
 		return qdisc_drop(nskb, sch, to_free);
+	}
 
 	while (*p) {
 		struct sk_buff *skb;
@@ -174,6 +204,8 @@ static void timesortedlist_erase(struct Qdisc *sch, struct sk_buff *skb,
 	if (drop) {
 		struct sk_buff *to_free = NULL;
 
+		report_sock_error(skb, ECANCELED, SO_EE_CODE_TXTIME_MISSED);
+
 		qdisc_drop(skb, sch, &to_free);
 		kfree_skb_list(to_free);
 		qdisc_qstats_overlimit(sch);
@@ -199,7 +231,6 @@ static struct sk_buff *etf_dequeue_timesortedlist(struct Qdisc *sch)
 	now = q->get_time();
 
 	/* Drop if packet has expired while in queue. */
-	/* FIXME: Must return error on the socket's error queue */
 	if (ktime_before(skb->tstamp, now)) {
 		timesortedlist_erase(sch, skb, true);
 		skb = NULL;
-- 
2.18.0

Re: [PATCH v2 net-next 00/14] Scheduled packet Transmission: ETF

[David Miller]

From: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
Date: Tue,  3 Jul 2018 15:42:46 -0700

> Overview
> ========
> 
> This work consists of a set of kernel interfaces that can be used by
> applications that require (time-based) Scheduled Tx of packets.
> It is comprised by 3 new components to the kernel:
> 
>   - SO_TXTIME: socket option + cmsg programming interfaces.
> 
>   - etf: the "earliest txtime first" qdisc, that provides per-queue
> 	 TxTime-based scheduling. This has been renamed from 'tbs' to
> 	 'etf' to better describe its functionality.
> 
>   - taprio: the "time-aware priority scheduler" qdisc, that provides
> 	    per-port Time-Aware scheduling;
> 
> This patchset is providing the first 2 components, which have been
> developed for longer. The taprio qdisc will be shared as an RFC separately
> (shortly).
 ...

I don't have any problems with this, series applied, thanks.

Re: [PATCH v2 net-next 00/14] Scheduled packet Transmission: ETF

[Stephen Hemminger]

On Tue,  3 Jul 2018 15:42:46 -0700
Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com> wrote:

> Changes since v1:
>   - moved struct sock_txtime from socket.h to uapi net_tstamp.h;
>   - sk_clockid was changed from u16 to u8;
>   - sk_txtime_flags was changed from u16 to a u8 bit field in struct sock;
>   - the socket option flags are now validated in sock_setsockopt();
>   - added SO_EE_ORIGIN_TXTIME;
>   - sockc.transmit_time is now initialized from all IPv4 Tx paths;
>   - added support for the IPv6 Tx path;
> 
> 
> Overview
> ========
> 
> This work consists of a set of kernel interfaces that can be used by
> applications that require (time-based) Scheduled Tx of packets.
> It is comprised by 3 new components to the kernel:
> 
>   - SO_TXTIME: socket option + cmsg programming interfaces.
> 
>   - etf: the "earliest txtime first" qdisc, that provides per-queue
> 	 TxTime-based scheduling. This has been renamed from 'tbs' to
> 	 'etf' to better describe its functionality.
> 
>   - taprio: the "time-aware priority scheduler" qdisc, that provides
> 	    per-port Time-Aware scheduling;
> 
> This patchset is providing the first 2 components, which have been
> developed for longer. The taprio qdisc will be shared as an RFC separately
> (shortly).
> 
> Note that this series is a follow up of the "Time based packet
> transmission" RFCv3 [1].
> 
> 
> 
> etf (formerly known as 'tbs')
> =============================
> 
> For applications/systems that the concept of time slices isn't precise
> enough, the etf qdisc allows applications to control the instant when
> a packet should leave the network controller. When used in conjunction
> with taprio, it can also be used in case the application needs to
> control with greater guarantee the offset into each time slice a packet
> will be sent. Another use case of etf, is when only a small number of
> applications on a system are time sensitive, so it can then be used
> with a more traditional root qdisc (like mqprio).
> 
> The etf qdisc is designed so it buffers packets until a configurable
> time before their deadline (Tx time). The qdisc uses a rbtree internally
> so the buffered packets are always 'ordered' by their txtime (deadline)
> and will be dequeued following the earliest txtime first.
> 
> It relies on the SO_TXTIME API set for receiving the per-packet timestamp
> (txtime) as well as the config flags for each socket: the clockid to be
> used as a reference, if the expected mode of txtime for that socket is
> deadline or strict mode, and if packet drops should be reported on the
> socket's error queue or not.
> 
> The qdisc will drop any packets with a Tx time in the past, or if a
> packet expires while waiting for being dequeued. Drops can be reported
> as errors back to userspace through the socket's error queue.
> 
> Example configuration:
> 
> $ tc qdisc add dev enp2s0 parent 100:1 etf offload delta 200000 \
>             clockid CLOCK_TAI
> 
> Here, the Qdisc will use HW offload for the txtime control.
> Packets will be dequeued by the qdisc "delta" (200000) nanoseconds before
> their transmission time. Because this will be using HW offload and
> since dynamic clocks are not supported by hrtimers, the system clock
> and the PHC clock must be synchronized for this mode to behave as expected.
> 
> A more complete example can be found here, with instructions of how to
> test it:
> 
> https://gist.github.com/jeez/bd3afeff081ba64a695008dd8215866f [2]
> 
> 
> Note that we haven't modified the qdisc so it uses a timerqueue because
> the modification needed was increasing the number of cachelines of a sk_buff.
> 
> 
> 
> This series is also hosted on github and can be found at [3].
> The companion iproute2 patches can be found at [4].
> 
> 
> [1] https://patchwork.ozlabs.org/cover/882342/
> 
> [2] github doesn't make it clear, but the gist can be cloned like this:
> $ git clone https://gist.github.com/jeez/bd3afeff081ba64a695008dd8215866f scheduled-tx-tests
> 
> [3] https://github.com/jeez/linux/tree/etf-v2
> 
> [4] https://github.com/jeez/iproute2/tree/etf-v2
> 
> 
> 
> Jesus Sanchez-Palencia (10):
>   net: Clear skb->tstamp only on the forwarding path
>   net: ipv4: Hook into time based transmission
>   net: ipv6: Hook into time based transmission
>   net/sched: Add HW offloading capability to ETF
>   igb: Refactor igb_configure_cbs()
>   igb: Only change Tx arbitration when CBS is on
>   igb: Refactor igb_offload_cbs()
>   igb: Only call skb_tx_timestamp after descriptors are ready
>   igb: Add support for ETF offload
>   net/sched: Make etf report drops on error_queue
> 
> Richard Cochran (2):
>   net: Add a new socket option for a future transmit time.
>   net: packet: Hook into time based transmission.
> 
> Vinicius Costa Gomes (2):
>   net/sched: Allow creating a Qdisc watchdog with other clocks
>   net/sched: Introduce the ETF Qdisc
> 
>  arch/alpha/include/uapi/asm/socket.h          |   3 +
>  arch/ia64/include/uapi/asm/socket.h           |   3 +
>  arch/mips/include/uapi/asm/socket.h           |   3 +
>  arch/parisc/include/uapi/asm/socket.h         |   3 +
>  arch/s390/include/uapi/asm/socket.h           |   3 +
>  arch/sparc/include/uapi/asm/socket.h          |   3 +
>  arch/xtensa/include/uapi/asm/socket.h         |   3 +
>  .../net/ethernet/intel/igb/e1000_defines.h    |  16 +
>  drivers/net/ethernet/intel/igb/igb.h          |   1 +
>  drivers/net/ethernet/intel/igb/igb_main.c     | 256 ++++++---
>  include/linux/netdevice.h                     |   1 +
>  include/net/inet_sock.h                       |   1 +
>  include/net/pkt_sched.h                       |   7 +
>  include/net/sock.h                            |  11 +
>  include/uapi/asm-generic/socket.h             |   3 +
>  include/uapi/linux/errqueue.h                 |   4 +
>  include/uapi/linux/net_tstamp.h               |  18 +
>  include/uapi/linux/pkt_sched.h                |  18 +
>  net/core/skbuff.c                             |   2 +-
>  net/core/sock.c                               |  39 ++
>  net/ipv4/icmp.c                               |   2 +
>  net/ipv4/ip_output.c                          |   3 +
>  net/ipv4/ping.c                               |   1 +
>  net/ipv4/raw.c                                |   2 +
>  net/ipv4/udp.c                                |   1 +
>  net/ipv6/ip6_output.c                         |  11 +-
>  net/ipv6/raw.c                                |   7 +-
>  net/ipv6/udp.c                                |   1 +
>  net/packet/af_packet.c                        |   6 +
>  net/sched/Kconfig                             |  11 +
>  net/sched/Makefile                            |   1 +
>  net/sched/sch_api.c                           |  11 +-
>  net/sched/sch_etf.c                           | 484 ++++++++++++++++++
>  33 files changed, 864 insertions(+), 75 deletions(-)
>  create mode 100644 net/sched/sch_etf.c
> 

Why support different clockid's in the API? 
I think the clock used in API should be either nanoseconds or USER_HZ (ie 100)
and the kernel components should use ktime. If you need to translate that to some
other value in the hardware driver,  then let the device driver do it.

Exposing multiple choices in userspace API, leads to more error paths and does
not provide direct benefits.

Re: [PATCH v2 net-next 02/14] net: Add a new socket option for a future transmit time.

[Eric Dumazet]

On 07/03/2018 03:42 PM, Jesus Sanchez-Palencia wrote:
> From: Richard Cochran <rcochran@linutronix.de>
> 
> This patch introduces SO_TXTIME. User space enables this option in
> order to pass a desired future transmit time in a CMSG when calling
> sendmsg(2). The argument to this socket option is a 8-bytes long struct
> provided by the uapi header net_tstamp.h defined as:
> 
> struct sock_txtime {
> 	clockid_t 	clockid;
> 	u32		flags;
> };
> 
> Note that new fields were added to struct sock by filling a 2-bytes
> hole found in the struct. For that reason, neither the struct size or
> number of cachelines were altered.


> diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
> index 4fe104b2411f..c9a77c353b98 100644
> --- a/include/uapi/linux/net_tstamp.h
> +++ b/include/uapi/linux/net_tstamp.h
> @@ -141,4 +141,19 @@ struct scm_ts_pktinfo {
>  	__u32 reserved[2];
>  };
>  
> +/*
> + * SO_TXTIME gets a struct sock_txtime with flags being an integer bit
> + * field comprised of these values.
> + */
> +enum txtime_flags {
> +	SOF_TXTIME_DEADLINE_MODE = (1 << 0),
> +
> +	SOF_TXTIME_FLAGS_MASK = (SOF_TXTIME_DEADLINE_MODE)
> +};
> +
> +struct sock_txtime {
> +	clockid_t       clockid;        /* reference clockid */
> +	u32             flags;          /* flags defined by enum txtime_flags */
> +};
> +

I was under the impression that we could not use 'u32' type in include/uapi/linux/* file

This must be replaced by __u32, right ?

Re: [PATCH v2 net-next 00/14] Scheduled packet Transmission: ETF

[Jesus Sanchez-Palencia]

Hi Stephen,


On 07/06/2018 02:38 PM, Stephen Hemminger wrote:
> On Tue,  3 Jul 2018 15:42:46 -0700
> Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com> wrote:
> 
>> Changes since v1:
>>   - moved struct sock_txtime from socket.h to uapi net_tstamp.h;
>>   - sk_clockid was changed from u16 to u8;
>>   - sk_txtime_flags was changed from u16 to a u8 bit field in struct sock;
>>   - the socket option flags are now validated in sock_setsockopt();
>>   - added SO_EE_ORIGIN_TXTIME;
>>   - sockc.transmit_time is now initialized from all IPv4 Tx paths;
>>   - added support for the IPv6 Tx path;
>>
>>
>> Overview
>> ========
>>
>> This work consists of a set of kernel interfaces that can be used by
>> applications that require (time-based) Scheduled Tx of packets.
>> It is comprised by 3 new components to the kernel:
>>
>>   - SO_TXTIME: socket option + cmsg programming interfaces.
>>
>>   - etf: the "earliest txtime first" qdisc, that provides per-queue
>> 	 TxTime-based scheduling. This has been renamed from 'tbs' to
>> 	 'etf' to better describe its functionality.
>>
>>   - taprio: the "time-aware priority scheduler" qdisc, that provides
>> 	    per-port Time-Aware scheduling;
>>
>> This patchset is providing the first 2 components, which have been
>> developed for longer. The taprio qdisc will be shared as an RFC separately
>> (shortly).
>>
>> Note that this series is a follow up of the "Time based packet
>> transmission" RFCv3 [1].
>>
>>
>>
>> etf (formerly known as 'tbs')
>> =============================
>>
>> For applications/systems that the concept of time slices isn't precise
>> enough, the etf qdisc allows applications to control the instant when
>> a packet should leave the network controller. When used in conjunction
>> with taprio, it can also be used in case the application needs to
>> control with greater guarantee the offset into each time slice a packet
>> will be sent. Another use case of etf, is when only a small number of
>> applications on a system are time sensitive, so it can then be used
>> with a more traditional root qdisc (like mqprio).
>>
>> The etf qdisc is designed so it buffers packets until a configurable
>> time before their deadline (Tx time). The qdisc uses a rbtree internally
>> so the buffered packets are always 'ordered' by their txtime (deadline)
>> and will be dequeued following the earliest txtime first.
>>
>> It relies on the SO_TXTIME API set for receiving the per-packet timestamp
>> (txtime) as well as the config flags for each socket: the clockid to be
>> used as a reference, if the expected mode of txtime for that socket is
>> deadline or strict mode, and if packet drops should be reported on the
>> socket's error queue or not.
>>
>> The qdisc will drop any packets with a Tx time in the past, or if a
>> packet expires while waiting for being dequeued. Drops can be reported
>> as errors back to userspace through the socket's error queue.
>>
>> Example configuration:
>>
>> $ tc qdisc add dev enp2s0 parent 100:1 etf offload delta 200000 \
>>             clockid CLOCK_TAI
>>
>> Here, the Qdisc will use HW offload for the txtime control.
>> Packets will be dequeued by the qdisc "delta" (200000) nanoseconds before
>> their transmission time. Because this will be using HW offload and
>> since dynamic clocks are not supported by hrtimers, the system clock
>> and the PHC clock must be synchronized for this mode to behave as expected.
>>
>> A more complete example can be found here, with instructions of how to
>> test it:
>>
>> https://gist.github.com/jeez/bd3afeff081ba64a695008dd8215866f [2]
>>
>>
>> Note that we haven't modified the qdisc so it uses a timerqueue because
>> the modification needed was increasing the number of cachelines of a sk_buff.
>>
>>
>>
>> This series is also hosted on github and can be found at [3].
>> The companion iproute2 patches can be found at [4].
>>
>>
>> [1] https://patchwork.ozlabs.org/cover/882342/
>>
>> [2] github doesn't make it clear, but the gist can be cloned like this:
>> $ git clone https://gist.github.com/jeez/bd3afeff081ba64a695008dd8215866f scheduled-tx-tests
>>
>> [3] https://github.com/jeez/linux/tree/etf-v2
>>
>> [4] https://github.com/jeez/iproute2/tree/etf-v2
>>
>>
>>
>> Jesus Sanchez-Palencia (10):
>>   net: Clear skb->tstamp only on the forwarding path
>>   net: ipv4: Hook into time based transmission
>>   net: ipv6: Hook into time based transmission
>>   net/sched: Add HW offloading capability to ETF
>>   igb: Refactor igb_configure_cbs()
>>   igb: Only change Tx arbitration when CBS is on
>>   igb: Refactor igb_offload_cbs()
>>   igb: Only call skb_tx_timestamp after descriptors are ready
>>   igb: Add support for ETF offload
>>   net/sched: Make etf report drops on error_queue
>>
>> Richard Cochran (2):
>>   net: Add a new socket option for a future transmit time.
>>   net: packet: Hook into time based transmission.
>>
>> Vinicius Costa Gomes (2):
>>   net/sched: Allow creating a Qdisc watchdog with other clocks
>>   net/sched: Introduce the ETF Qdisc
>>
>>  arch/alpha/include/uapi/asm/socket.h          |   3 +
>>  arch/ia64/include/uapi/asm/socket.h           |   3 +
>>  arch/mips/include/uapi/asm/socket.h           |   3 +
>>  arch/parisc/include/uapi/asm/socket.h         |   3 +
>>  arch/s390/include/uapi/asm/socket.h           |   3 +
>>  arch/sparc/include/uapi/asm/socket.h          |   3 +
>>  arch/xtensa/include/uapi/asm/socket.h         |   3 +
>>  .../net/ethernet/intel/igb/e1000_defines.h    |  16 +
>>  drivers/net/ethernet/intel/igb/igb.h          |   1 +
>>  drivers/net/ethernet/intel/igb/igb_main.c     | 256 ++++++---
>>  include/linux/netdevice.h                     |   1 +
>>  include/net/inet_sock.h                       |   1 +
>>  include/net/pkt_sched.h                       |   7 +
>>  include/net/sock.h                            |  11 +
>>  include/uapi/asm-generic/socket.h             |   3 +
>>  include/uapi/linux/errqueue.h                 |   4 +
>>  include/uapi/linux/net_tstamp.h               |  18 +
>>  include/uapi/linux/pkt_sched.h                |  18 +
>>  net/core/skbuff.c                             |   2 +-
>>  net/core/sock.c                               |  39 ++
>>  net/ipv4/icmp.c                               |   2 +
>>  net/ipv4/ip_output.c                          |   3 +
>>  net/ipv4/ping.c                               |   1 +
>>  net/ipv4/raw.c                                |   2 +
>>  net/ipv4/udp.c                                |   1 +
>>  net/ipv6/ip6_output.c                         |  11 +-
>>  net/ipv6/raw.c                                |   7 +-
>>  net/ipv6/udp.c                                |   1 +
>>  net/packet/af_packet.c                        |   6 +
>>  net/sched/Kconfig                             |  11 +
>>  net/sched/Makefile                            |   1 +
>>  net/sched/sch_api.c                           |  11 +-
>>  net/sched/sch_etf.c                           | 484 ++++++++++++++++++
>>  33 files changed, 864 insertions(+), 75 deletions(-)
>>  create mode 100644 net/sched/sch_etf.c
>>
> 
> Why support different clockid's in the API? 
> I think the clock used in API should be either nanoseconds or USER_HZ (ie 100)
> and the kernel components should use ktime. If you need to translate that to some
> other value in the hardware driver,  then let the device driver do it.
> 
> Exposing multiple choices in userspace API, leads to more error paths and does
> not provide direct benefits.


The kernel components already use ktime_t. The clockid_t here is to define the
time source (i.e. which clock must be used to read the ktime from) and not the
unit of time.

I hope that clarifies.

Regards,
Jesus

Re: [PATCH v2 net-next 02/14] net: Add a new socket option for a future transmit time.

[Jesus Sanchez-Palencia]

On 07/07/2018 05:44 PM, Eric Dumazet wrote:
> 
> 
> On 07/03/2018 03:42 PM, Jesus Sanchez-Palencia wrote:
>> From: Richard Cochran <rcochran@linutronix.de>
>>
>> This patch introduces SO_TXTIME. User space enables this option in
>> order to pass a desired future transmit time in a CMSG when calling
>> sendmsg(2). The argument to this socket option is a 8-bytes long struct
>> provided by the uapi header net_tstamp.h defined as:
>>
>> struct sock_txtime {
>> 	clockid_t 	clockid;
>> 	u32		flags;
>> };
>>
>> Note that new fields were added to struct sock by filling a 2-bytes
>> hole found in the struct. For that reason, neither the struct size or
>> number of cachelines were altered.
> 
> 
>> diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
>> index 4fe104b2411f..c9a77c353b98 100644
>> --- a/include/uapi/linux/net_tstamp.h
>> +++ b/include/uapi/linux/net_tstamp.h
>> @@ -141,4 +141,19 @@ struct scm_ts_pktinfo {
>>  	__u32 reserved[2];
>>  };
>>  
>> +/*
>> + * SO_TXTIME gets a struct sock_txtime with flags being an integer bit
>> + * field comprised of these values.
>> + */
>> +enum txtime_flags {
>> +	SOF_TXTIME_DEADLINE_MODE = (1 << 0),
>> +
>> +	SOF_TXTIME_FLAGS_MASK = (SOF_TXTIME_DEADLINE_MODE)
>> +};
>> +
>> +struct sock_txtime {
>> +	clockid_t       clockid;        /* reference clockid */
>> +	u32             flags;          /* flags defined by enum txtime_flags */
>> +};
>> +
> 
> I was under the impression that we could not use 'u32' type in include/uapi/linux/* file
> 
> This must be replaced by __u32, right ?


I'm sending a patch fixing that now, thanks.

Re: [PATCH v2 net-next 01/14] net: Clear skb->tstamp only on the forwarding path

[Eric Dumazet]

On 07/03/2018 03:42 PM, Jesus Sanchez-Palencia wrote:
> This is done in preparation for the upcoming time based transmission
> patchset. Now that skb->tstamp will be used to hold packet's txtime,
> we must ensure that it is being cleared when traversing namespaces.
> Also, doing that from skb_scrub_packet() before the early return would
> break our feature when tunnels are used.
> 
> Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
> ---
>  net/core/skbuff.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 1357f36c8a5e..c4e24ac27464 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -4898,7 +4898,6 @@ EXPORT_SYMBOL(skb_try_coalesce);
>   */
>  void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>  {
> -	skb->tstamp = 0;
>  	skb->pkt_type = PACKET_HOST;
>  	skb->skb_iif = 0;
>  	skb->ignore_df = 0;
> @@ -4912,6 +4911,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>  
>  	ipvs_reset(skb);
>  	skb->mark = 0;
> +	skb->tstamp = 0;
>  }
>  EXPORT_SYMBOL_GPL(skb_scrub_packet);
>  
> 



I believe we had some misunderstanding here.

What I meant by forwarding is the following case :

- We receive a packet.
- netstamp_wanted is >0 (because at least one packet capture is active)
- __net_timestamp() is called and does :
    skb->tstamp = ktime_get_real();

Then this skb is forwarded into an interface where EDT is taken into
consideration by either a qdisc or a device.

Since CLOCK_TAI is a different base than CLOCK_REALTIME, we might have a problem.


Solutions for this problem :

1) Convert all our skb->tstamp usages to CLOCK_TAI base.

or

2) clear skb->tstamp in forwarding paths, including the ones not scrubbing the packet.

My preference is 1), even if it is a bit more work.

Re: [PATCH v2 net-next 01/14] net: Clear skb->tstamp only on the forwarding path

[Jesus Sanchez-Palencia]

Hi Eric,



On 07/13/2018 10:35 AM, Eric Dumazet wrote:
> 
> 
> On 07/03/2018 03:42 PM, Jesus Sanchez-Palencia wrote:
>> This is done in preparation for the upcoming time based transmission
>> patchset. Now that skb->tstamp will be used to hold packet's txtime,
>> we must ensure that it is being cleared when traversing namespaces.
>> Also, doing that from skb_scrub_packet() before the early return would
>> break our feature when tunnels are used.
>>
>> Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
>> ---
>>  net/core/skbuff.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
>> index 1357f36c8a5e..c4e24ac27464 100644
>> --- a/net/core/skbuff.c
>> +++ b/net/core/skbuff.c
>> @@ -4898,7 +4898,6 @@ EXPORT_SYMBOL(skb_try_coalesce);
>>   */
>>  void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>>  {
>> -	skb->tstamp = 0;
>>  	skb->pkt_type = PACKET_HOST;
>>  	skb->skb_iif = 0;
>>  	skb->ignore_df = 0;
>> @@ -4912,6 +4911,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>>  
>>  	ipvs_reset(skb);
>>  	skb->mark = 0;
>> +	skb->tstamp = 0;
>>  }
>>  EXPORT_SYMBOL_GPL(skb_scrub_packet);
>>  
>>
> 
> 
> 
> I believe we had some misunderstanding here.
> 
> What I meant by forwarding is the following case :
> 
> - We receive a packet.
> - netstamp_wanted is >0 (because at least one packet capture is active)
> - __net_timestamp() is called and does :
>     skb->tstamp = ktime_get_real();
> 
> Then this skb is forwarded into an interface where EDT is taken into
> consideration by either a qdisc or a device.
> 
> Since CLOCK_TAI is a different base than CLOCK_REALTIME, we might have a problem.


I'm not sure we have a problem here. For the Tx path I only see
net_timestamp_set() being called from dev_queue_xmit_nit(). And even there, it's
a clone of the skb that gets timestamped.

I believe the original skb, which had the valid txtime copied into skb->tstamp,
is not modified anywhere along that path.

What am I missing, please?

Thanks,
Jesus



> 
> 
> Solutions for this problem :
> 
> 1) Convert all our skb->tstamp usages to CLOCK_TAI base.
> 
> or
> 
> 2) clear skb->tstamp in forwarding paths, including the ones not scrubbing the packet.
> 
> My preference is 1), even if it is a bit more work.
> 

Re: [PATCH v2 net-next 01/14] net: Clear skb->tstamp only on the forwarding path

[Eric Dumazet]

On 07/16/2018 02:52 PM, Jesus Sanchez-Palencia wrote:
> Hi Eric,
> 
> 
> 
> On 07/13/2018 10:35 AM, Eric Dumazet wrote:
>>
>>
>> On 07/03/2018 03:42 PM, Jesus Sanchez-Palencia wrote:
>>> This is done in preparation for the upcoming time based transmission
>>> patchset. Now that skb->tstamp will be used to hold packet's txtime,
>>> we must ensure that it is being cleared when traversing namespaces.
>>> Also, doing that from skb_scrub_packet() before the early return would
>>> break our feature when tunnels are used.
>>>
>>> Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
>>> ---
>>>  net/core/skbuff.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
>>> index 1357f36c8a5e..c4e24ac27464 100644
>>> --- a/net/core/skbuff.c
>>> +++ b/net/core/skbuff.c
>>> @@ -4898,7 +4898,6 @@ EXPORT_SYMBOL(skb_try_coalesce);
>>>   */
>>>  void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>>>  {
>>> -	skb->tstamp = 0;
>>>  	skb->pkt_type = PACKET_HOST;
>>>  	skb->skb_iif = 0;
>>>  	skb->ignore_df = 0;
>>> @@ -4912,6 +4911,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>>>  
>>>  	ipvs_reset(skb);
>>>  	skb->mark = 0;
>>> +	skb->tstamp = 0;
>>>  }
>>>  EXPORT_SYMBOL_GPL(skb_scrub_packet);
>>>  
>>>
>>
>>
>>
>> I believe we had some misunderstanding here.
>>
>> What I meant by forwarding is the following case :
>>
>> - We receive a packet.
>> - netstamp_wanted is >0 (because at least one packet capture is active)
>> - __net_timestamp() is called and does :
>>     skb->tstamp = ktime_get_real();
>>
>> Then this skb is forwarded into an interface where EDT is taken into
>> consideration by either a qdisc or a device.
>>
>> Since CLOCK_TAI is a different base than CLOCK_REALTIME, we might have a problem.
> 
> 
> I'm not sure we have a problem here. For the Tx path I only see
> net_timestamp_set() being called from dev_queue_xmit_nit(). And even there, it's
> a clone of the skb that gets timestamped.
> 
> I believe the original skb, which had the valid txtime copied into skb->tstamp,
> is not modified anywhere along that path.
> 
> What am I missing, please?
> 
> Thanks,
> Jesus
> 


I am simply stating that a linux router, receiving packet on ethX and forwarding
them on ethY, could have a problem if ethY has a qdisc looking at skb->tstamp
assuming a timestamp in CLOCK_TAI base.

In this case, skb->tstamp would have been set at ingress (not using CLOCK_TAI
but CLOCK_REALTIME), and would be read at egress (assuming CLOCK_TAI)

Normal IPV4 routing path would be in net/ipv4/ip_forward.c, no scrubbing ever happens,
and no cloning either.

Your patch  (Clear skb->tstamp only on the forwarding path) is not handling the
typical forward path, only the cases where 'scrubbing' is used.



> 
> 
>>
>>
>> Solutions for this problem :
>>
>> 1) Convert all our skb->tstamp usages to CLOCK_TAI base.
>>
>> or
>>
>> 2) clear skb->tstamp in forwarding paths, including the ones not scrubbing the packet.
>>
>> My preference is 1), even if it is a bit more work.
>>

Re: [PATCH v2 net-next 01/14] net: Clear skb->tstamp only on the forwarding path

[Jesus Sanchez-Palencia]

Hi Eric,


On 07/16/2018 04:15 PM, Eric Dumazet wrote:
> 
> 
> On 07/16/2018 02:52 PM, Jesus Sanchez-Palencia wrote:
>> Hi Eric,
>>
>>
>>
>> On 07/13/2018 10:35 AM, Eric Dumazet wrote:
>>>
>>>
>>> On 07/03/2018 03:42 PM, Jesus Sanchez-Palencia wrote:
>>>> This is done in preparation for the upcoming time based transmission
>>>> patchset. Now that skb->tstamp will be used to hold packet's txtime,
>>>> we must ensure that it is being cleared when traversing namespaces.
>>>> Also, doing that from skb_scrub_packet() before the early return would
>>>> break our feature when tunnels are used.
>>>>
>>>> Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
>>>> ---
>>>>  net/core/skbuff.c | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
>>>> index 1357f36c8a5e..c4e24ac27464 100644
>>>> --- a/net/core/skbuff.c
>>>> +++ b/net/core/skbuff.c
>>>> @@ -4898,7 +4898,6 @@ EXPORT_SYMBOL(skb_try_coalesce);
>>>>   */
>>>>  void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>>>>  {
>>>> -	skb->tstamp = 0;
>>>>  	skb->pkt_type = PACKET_HOST;
>>>>  	skb->skb_iif = 0;
>>>>  	skb->ignore_df = 0;
>>>> @@ -4912,6 +4911,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>>>>  
>>>>  	ipvs_reset(skb);
>>>>  	skb->mark = 0;
>>>> +	skb->tstamp = 0;
>>>>  }
>>>>  EXPORT_SYMBOL_GPL(skb_scrub_packet);
>>>>  
>>>>
>>>
>>>
>>>
>>> I believe we had some misunderstanding here.
>>>
>>> What I meant by forwarding is the following case :
>>>
>>> - We receive a packet.
>>> - netstamp_wanted is >0 (because at least one packet capture is active)
>>> - __net_timestamp() is called and does :
>>>     skb->tstamp = ktime_get_real();
>>>
>>> Then this skb is forwarded into an interface where EDT is taken into
>>> consideration by either a qdisc or a device.
>>>
>>> Since CLOCK_TAI is a different base than CLOCK_REALTIME, we might have a problem.
>>
>>
>> I'm not sure we have a problem here. For the Tx path I only see
>> net_timestamp_set() being called from dev_queue_xmit_nit(). And even there, it's
>> a clone of the skb that gets timestamped.
>>
>> I believe the original skb, which had the valid txtime copied into skb->tstamp,
>> is not modified anywhere along that path.
>>
>> What am I missing, please?
>>
>> Thanks,
>> Jesus
>>
> 
> 
> I am simply stating that a linux router, receiving packet on ethX and forwarding
> them on ethY, could have a problem if ethY has a qdisc looking at skb->tstamp
> assuming a timestamp in CLOCK_TAI base.
> 
> In this case, skb->tstamp would have been set at ingress (not using CLOCK_TAI
> but CLOCK_REALTIME), and would be read at egress (assuming CLOCK_TAI)
> 
> Normal IPV4 routing path would be in net/ipv4/ip_forward.c, no scrubbing ever happens,
> and no cloning either.
> 
> Your patch  (Clear skb->tstamp only on the forwarding path) is not handling the
> typical forward path, only the cases where 'scrubbing' is used.


Thanks for the clarification, I wasn't following you before.

I believe we're fine with what we have *today*, because the qdisc will drop skbs
that don't have a valid skb->sk, or if the SO_TXTIME flags is not set.

This is a problem, however, if another qdisc is developed tomorrow and uses the
same information but do not perform the same checks. Or, if the packet somehow
gets to the controller and the HW has the "launch time" feature enabled and the
driver uses the tstamp information the same way we do.

If we want to protect from that now, I think we should go with the most
immediate solution and clear skb->tstamp somewhere in ip_forward(), as you've
pointed before. It seems to me this wouldn't break any other feature that might
be re-using the tstamp information.

This is also a more correct fix for the problem you raised before:

>>> - We receive a packet.
>>> - netstamp_wanted is >0 (because at least one packet capture is active)
>>> - __net_timestamp() is called and does :
>>>     skb->tstamp = ktime_get_real();
>>>
>>> Then this skb is forwarded into an interface where EDT is taken into
>>> consideration by either a qdisc or a device.


IMHO this Rx tstamp should never be forwarded to the Tx path as a valid txtime,
regardless if the time base used was UTC or TAI.


What do you think?

Jesus






> 
> 
> 
>>
>>
>>>
>>>
>>> Solutions for this problem :
>>>
>>> 1) Convert all our skb->tstamp usages to CLOCK_TAI base.
>>>
>>> or
>>>
>>> 2) clear skb->tstamp in forwarding paths, including the ones not scrubbing the packet.
>>>
>>> My preference is 1), even if it is a bit more work.
>>>

Re: [PATCH v2 net-next 01/14] net: Clear skb->tstamp only on the forwarding path

[Dave Taht]

In my dreamworld, a packet with a timestamp achieved at rx time on
ethX, or via local traffic, would be consistent with the right clock
throughout the system and reliably still be there when it goes to
ethY.

This would save having to timestamp (again) inside the cb block in
fq_codel, cake, etc, and more importantly, measure total system delay
from entrance to egress, (e.g tc filters, firewall rules, routing
table lookups), not just queuing delay at the qdisc, thus detecting
when a system was overloaded and reducing queue size and throughput
appropriately as a result to cope.