[PATCH net-next 02/15] ipv6: add dev->gso_ipv6_max_size

[Eric Dumazet <eric.dumazet@gmail.com>]

From: Eric Dumazet <edumazet@google.com>

This enable TCP stack to build TSO packets bigger than
64KB if the driver is LSOv2 compatible.

This patch introduces new variable gso_ipv6_max_size
that is modifiable through ip link.

ip link set dev eth0 gso_ipv6_max_size 185000

User input is capped by driver limit.

Signed-off-by: Coco Li <lixiaoyan@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/linux/netdevice.h          | 12 ++++++++++++
 include/uapi/linux/if_link.h       |  1 +
 net/core/dev.c                     |  1 +
 net/core/rtnetlink.c               | 15 +++++++++++++++
 net/core/sock.c                    |  6 ++++++
 tools/include/uapi/linux/if_link.h |  1 +
 6 files changed, 36 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index b1f68df2b37bc4b623f61cc2c6f0c02ba2afbe02..2a563869ba44f7d48095d36b1395e3fbd8cfff87 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1949,6 +1949,7 @@ enum netdev_ml_priv_type {
  *	@linkwatch_dev_tracker:	refcount tracker used by linkwatch.
  *	@watchdog_dev_tracker:	refcount tracker used by watchdog.
  *	@tso_ipv6_max_size:	Maximum size of IPv6 TSO packets (driver/NIC limit)
+ *	@gso_ipv6_max_size:	Maximum size of IPv6 GSO packets (user/admin limit)
  *
  *	FIXME: cleanup struct net_device such that network protocol info
  *	moves out.
@@ -2284,6 +2285,7 @@ struct net_device {
 	netdevice_tracker	linkwatch_dev_tracker;
 	netdevice_tracker	watchdog_dev_tracker;
 	unsigned int		tso_ipv6_max_size;
+	unsigned int		gso_ipv6_max_size;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 
@@ -4804,6 +4806,10 @@ static inline void netif_set_gso_max_size(struct net_device *dev,
 {
 	/* dev->gso_max_size is read locklessly from sk_setup_caps() */
 	WRITE_ONCE(dev->gso_max_size, size);
+
+	/* legacy drivers want to lower gso_max_size, regardless of family. */
+	size = min(size, dev->gso_ipv6_max_size);
+	WRITE_ONCE(dev->gso_ipv6_max_size, size);
 }
 
 static inline void netif_set_gso_max_segs(struct net_device *dev,
@@ -4827,6 +4833,12 @@ static inline void netif_set_tso_ipv6_max_size(struct net_device *dev,
 	dev->tso_ipv6_max_size = size;
 }
 
+static inline void netif_set_gso_ipv6_max_size(struct net_device *dev,
+					       unsigned int size)
+{
+	size = min(size, dev->tso_ipv6_max_size);
+	WRITE_ONCE(dev->gso_ipv6_max_size, size);
+}
 
 static inline void skb_gso_error_unwind(struct sk_buff *skb, __be16 protocol,
 					int pulled_hlen, u16 mac_offset,
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 79b9d399cd297a1f79dca5ce89762800c38ed4a8..024b3bd0467e1360917001dba6bcfd1f30391894 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -349,6 +349,7 @@ enum {
 	IFLA_PARENT_DEV_BUS_NAME,
 	IFLA_GRO_MAX_SIZE,
 	IFLA_TSO_IPV6_MAX_SIZE,
+	IFLA_GSO_IPV6_MAX_SIZE,
 
 	__IFLA_MAX
 };
diff --git a/net/core/dev.c b/net/core/dev.c
index b6ca3c348d41a097baf210f2a5d966b71308c69b..53c947e6fdb7c47e6cc92fd4e38b71e9b90d921c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10189,6 +10189,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	dev->gso_max_segs = GSO_MAX_SEGS;
 	dev->gro_max_size = GRO_MAX_SIZE;
 	dev->tso_ipv6_max_size = GSO_MAX_SIZE;
+	dev->gso_ipv6_max_size = GSO_MAX_SIZE;
 
 	dev->upper_level = 1;
 	dev->lower_level = 1;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 4cefa07195ba3b67e7b724194b5d729d395ba466..0a0b26261f6d9e4e40bf9cfbda31a29c1f2e3aaa 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1028,6 +1028,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + nla_total_size(4) /* IFLA_GSO_MAX_SIZE */
 	       + nla_total_size(4) /* IFLA_GRO_MAX_SIZE */
 	       + nla_total_size(4) /* IFLA_TSO_IPV6_MAX_SIZE */
+	       + nla_total_size(4) /* IFLA_GSO_IPV6_MAX_SIZE */
 	       + nla_total_size(1) /* IFLA_OPERSTATE */
 	       + nla_total_size(1) /* IFLA_LINKMODE */
 	       + nla_total_size(4) /* IFLA_CARRIER_CHANGES */
@@ -1732,6 +1733,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
 	    nla_put_u32(skb, IFLA_GSO_MAX_SIZE, dev->gso_max_size) ||
 	    nla_put_u32(skb, IFLA_GRO_MAX_SIZE, dev->gro_max_size) ||
 	    nla_put_u32(skb, IFLA_TSO_IPV6_MAX_SIZE, dev->tso_ipv6_max_size) ||
+	    nla_put_u32(skb, IFLA_GSO_IPV6_MAX_SIZE, dev->gso_ipv6_max_size) ||
 #ifdef CONFIG_RPS
 	    nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) ||
 #endif
@@ -1886,6 +1888,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_PARENT_DEV_NAME]	= { .type = NLA_NUL_STRING },
 	[IFLA_GRO_MAX_SIZE]	= { .type = NLA_U32 },
 	[IFLA_TSO_IPV6_MAX_SIZE]	= { .type = NLA_U32 },
+	[IFLA_GSO_IPV6_MAX_SIZE]	= { .type = NLA_U32 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -2772,6 +2775,15 @@ static int do_setlink(const struct sk_buff *skb,
 		}
 	}
 
+	if (tb[IFLA_GSO_IPV6_MAX_SIZE]) {
+		u32 max_size = nla_get_u32(tb[IFLA_GSO_IPV6_MAX_SIZE]);
+
+		if (dev->gso_ipv6_max_size ^ max_size) {
+			netif_set_gso_ipv6_max_size(dev, max_size);
+			status |= DO_SETLINK_MODIFIED;
+		}
+	}
+
 	if (tb[IFLA_GSO_MAX_SEGS]) {
 		u32 max_segs = nla_get_u32(tb[IFLA_GSO_MAX_SEGS]);
 
@@ -3247,6 +3259,9 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname,
 		netif_set_gso_max_segs(dev, nla_get_u32(tb[IFLA_GSO_MAX_SEGS]));
 	if (tb[IFLA_GRO_MAX_SIZE])
 		netif_set_gro_max_size(dev, nla_get_u32(tb[IFLA_GRO_MAX_SIZE]));
+	if (tb[IFLA_GSO_IPV6_MAX_SIZE])
+		netif_set_gso_ipv6_max_size(dev,
+			nla_get_u32(tb[IFLA_GSO_IPV6_MAX_SIZE]));
 
 	return dev;
 }
diff --git a/net/core/sock.c b/net/core/sock.c
index 09d31a7dc68f88af42f75f3f445818fe273b04fb..aec1e156548ea0818f025fd8f448f5e353f79a3b 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2279,6 +2279,12 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
 			sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
 			/* pairs with the WRITE_ONCE() in netif_set_gso_max_size() */
 			sk->sk_gso_max_size = READ_ONCE(dst->dev->gso_max_size);
+#if IS_ENABLED(CONFIG_IPV6)
+			if (sk->sk_family == AF_INET6 &&
+			    sk_is_tcp(sk) &&
+			    !ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
+				sk->sk_gso_max_size = READ_ONCE(dst->dev->gso_ipv6_max_size);
+#endif
 			sk->sk_gso_max_size -= (MAX_TCP_HEADER + 1);
 			/* pairs with the WRITE_ONCE() in netif_set_gso_max_segs() */
 			max_segs = max_t(u32, READ_ONCE(dst->dev->gso_max_segs), 1);
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index 79b9d399cd297a1f79dca5ce89762800c38ed4a8..024b3bd0467e1360917001dba6bcfd1f30391894 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h
@@ -349,6 +349,7 @@ enum {
 	IFLA_PARENT_DEV_BUS_NAME,
 	IFLA_GRO_MAX_SIZE,
 	IFLA_TSO_IPV6_MAX_SIZE,
+	IFLA_GSO_IPV6_MAX_SIZE,
 
 	__IFLA_MAX
 };
-- 
2.35.0.rc2.247.g8bbb082509-goog