* [MPTCP] [RFC PATCH 04/16] mptcp: Handle MPTCP TCP options
@ 2018-03-28 23:18 Mat Martineau
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From: Mat Martineau @ 2018-03-28 23:18 UTC (permalink / raw)
To: mptcp
[-- Attachment #1: Type: text/plain, Size: 14516 bytes --]
From: Peter Krystad <peter.krystad(a)intel.com>
Signed-off-by: Peter Krystad <peter.krystad(a)intel.com>
---
include/linux/tcp.h | 14 ++++
include/net/mptcp.h | 49 ++++++++++++++
include/net/tcp.h | 2 +
net/ipv4/tcp_input.c | 15 +++++
net/ipv4/tcp_output.c | 72 ++++++++++++++++++++
net/mptcp/Makefile | 2 +-
net/mptcp/options.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++++++
7 files changed, 330 insertions(+), 1 deletion(-)
create mode 100644 net/mptcp/options.c
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 8f4c54986f97..af175306d78c 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -104,6 +104,16 @@ struct tcp_options_received {
u8 num_sacks; /* Number of SACK blocks */
u16 user_mss; /* mss requested by user in ioctl */
u16 mss_clamp; /* Maximal mss, negotiated at connection setup */
+ struct {
+ u8 mp_capable : 1,
+ mp_join : 1,
+ dss : 1,
+ version : 4;
+ u8 flags;
+ u64 sndr_key;
+ u64 rcvr_key;
+ } mptcp;
+
};
static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
@@ -113,6 +123,7 @@ static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
#if IS_ENABLED(CONFIG_SMC)
rx_opt->smc_ok = 0;
#endif
+ rx_opt->mptcp.mp_capable = rx_opt->mptcp.mp_join = rx_opt->mptcp.dss = 0;
}
/* This is the max number of SACKS that we'll generate and process. It's safe
@@ -137,6 +148,7 @@ struct tcp_request_sock {
* FastOpen it's the seq#
* after data-in-SYN.
*/
+ bool is_mptcp;
};
static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
@@ -384,6 +396,8 @@ struct tcp_sock {
*/
struct request_sock *fastopen_rsk;
u32 *saved_syn;
+
+ bool is_mptcp;
};
enum tsq_enum {
diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index d66dbff5aa73..01f4f56f8886 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -16,6 +16,23 @@
#ifndef __NET_MPTCP_H
#define __NET_MPTCP_H
+/* MPTCP option subtypes */
+
+#define MPTCPOPT_MP_CAPABLE 0
+#define MPTCPOPT_MP_JOIN 1
+#define MPTCPOPT_DSS 2
+#define MPTCPOPT_ADD_ADDR 3
+#define MPTCPOPT_REMOVE_ADDR 4
+#define MPTCPOPT_MP_PRIO 5
+#define MPTCPOPT_MP_FAIL 6
+#define MPTCPOPT_MP_FASTCLOSE 7
+
+/* MPTCP handshake flags */
+
+#define MPTCP_CAP_CHECKSUM_REQD (1 << 7)
+#define MPTCP_CAP_EXTENSIBILITY (1 << 6)
+#define MPTCP_CAP_HMAC_SHA1 (1 << 0)
+
/* MPTCP connection sock */
struct mptcp_sock {
/* inet_connection_sock must be the first member */
@@ -28,4 +45,36 @@ static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
return (struct mptcp_sock *)sk;
}
+#ifdef CONFIG_MPTCP
+
+void mptcp_parse_option(const unsigned char *ptr, int opsize,
+ struct tcp_options_received *opt_rx);
+unsigned int mptcp_syn_options(struct sock *sk, u64 *local_key);
+unsigned int mptcp_synack_options(struct request_sock *req,
+ u64 *local_key, u64 *remote_key);
+
+void mptcp_get_options(const struct sk_buff *skb,
+ struct tcp_options_received *options);
+
+#else
+
+static inline void mptcp_parse_option(const unsigned char *ptr, int opsize,
+ struct tcp_options_received *opt_rx)
+{
+}
+
+static inline unsigned int mptcp_syn_options(struct sock *sk, u64 *local_key)
+{
+ return 0;
+}
+static inline unsigned int mptcp_synack_options(struct request_sock *sk,
+ u64 *local_key,
+ u64 *remote_key)
+{
+ return 0;
+}
+
+
+
+#endif /* CONFIG_MPTCP */
#endif /* __NET_MPTCP_H */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index c474f5478f76..58f33b024411 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -214,6 +214,8 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
#define TCPOLEN_MD5SIG_ALIGNED 20
#define TCPOLEN_MSS_ALIGNED 4
#define TCPOLEN_EXP_SMC_BASE_ALIGNED 8
+#define TCPOLEN_MPTCP_MPC_SYN 12
+#define TCPOLEN_MPTCP_MPC_SYNACK 20
/* Flags in tp->nonagle */
#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 451ef3012636..61462ea52aed 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -78,6 +78,7 @@
#include <linux/errqueue.h>
#include <trace/events/tcp.h>
#include <linux/static_key.h>
+#include <net/mptcp.h>
int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
@@ -3785,6 +3786,10 @@ void tcp_parse_options(const struct net *net,
*/
break;
#endif
+ case TCPOPT_MPTCP:
+ mptcp_parse_option(ptr, opsize, opt_rx);
+ break;
+
case TCPOPT_FASTOPEN:
tcp_parse_fastopen_option(
opsize - TCPOLEN_FASTOPEN_BASE,
@@ -5670,6 +5675,15 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
tcp_initialize_rcv_mss(sk);
+ // @@ could use a callout here
+ if (tp->is_mptcp) {
+ struct subflow_sock *subflow = subflow_sk(sk);
+ if (subflow->request_mptcp && tp->rx_opt.mptcp.mp_capable) {
+ subflow->mp_capable = 1;
+ subflow->remote_key = tp->rx_opt.mptcp.sndr_key;
+ }
+ }
+
/* Remember, tcp_poll() does not lock socket!
* Change state from SYN-SENT only after copied_seq
* is initialized. */
@@ -6245,6 +6259,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
tcp_rsk(req)->af_specific = af_ops;
tcp_rsk(req)->ts_off = 0;
+ tcp_rsk(req)->is_mptcp = 0;
tcp_clear_options(&tmp_opt);
tmp_opt.mss_clamp = af_ops->mss_clamp;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 383cac0ff0ec..2c28e8d60a4a 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -37,6 +37,7 @@
#define pr_fmt(fmt) "TCP: " fmt
#include <net/tcp.h>
+#include <net/mptcp.h>
#include <linux/compiler.h>
#include <linux/gfp.h>
@@ -404,6 +405,8 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp)
#define OPTION_WSCALE (1 << 3)
#define OPTION_FAST_OPEN_COOKIE (1 << 8)
#define OPTION_SMC (1 << 9)
+#define OPTION_MPTCP (1 << 10)
+#define OPTION_MPTCP_ACK (1 << 11)
static void smc_options_write(__be32 *ptr, u16 *options)
{
@@ -429,6 +432,8 @@ struct tcp_out_options {
__u8 *hash_location; /* temporary pointer, overloaded */
__u32 tsval, tsecr; /* need to include OPTION_TS */
struct tcp_fastopen_cookie *fastopen_cookie; /* Fast open cookie */
+ u64 sndr_key;
+ u64 rcvr_key;
};
/* Write previously computed TCP options to the packet.
@@ -539,6 +544,29 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
}
smc_options_write(ptr, &options);
+
+ if (OPTION_MPTCP & options) {
+ u8 *p = (u8 *)ptr;
+ *p++ = 0x1e; // TCP option: Multipath TCP
+ *p++ = 12; // length
+ *p++ = 0; // subtype=MP_CAPABLE | version=0
+ *p++ = 0x1; // flags=HMAC-SHA1
+ memcpy(p, &opts->sndr_key, 8);
+ pr_debug("tcp_options_write: opts->sndr_key=%llu", opts->sndr_key);
+ }
+
+ if (OPTION_MPTCP_ACK & options) {
+ u8 *p = (u8 *)ptr;
+ *p++ = 0x1e; // TCP option: Multipath TCP
+ *p++ = 20; // length
+ *p++ = 0; // subtype=MP_CAPABLE | version=0
+ *p++ = 0x1; // flags=HMAC-SHA1
+ memcpy(p, &opts->sndr_key, 8);
+ pr_debug("tcp_options_write: opts->sndr_key=%llu", opts->sndr_key);
+ p += 8;
+ memcpy(p, &opts->rcvr_key, 8);
+ pr_debug("tcp_options_write: opts->rcvr_key=%llu", opts->rcvr_key);
+ }
}
static void smc_set_option(const struct tcp_sock *tp,
@@ -641,6 +669,15 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
smc_set_option(tp, opts, &remaining);
+ if (tp->is_mptcp) {
+ u64 local_key;
+ if (mptcp_syn_options(sk, &local_key)) {
+ opts->options |= OPTION_MPTCP;
+ opts->sndr_key = local_key;
+ remaining -= TCPOLEN_MPTCP_MPC_SYN;
+ }
+ }
+
return MAX_TCP_OPTION_SPACE - remaining;
}
@@ -701,6 +738,18 @@ static unsigned int tcp_synack_options(const struct sock *sk,
remaining -= need;
}
}
+ if (tcp_rsk(req)->is_mptcp) {
+ u64 local_key;
+ u64 remote_key;
+ if (mptcp_synack_options(req, &local_key, &remote_key)) {
+ if (remaining >= TCPOLEN_MPTCP_MPC_SYNACK) {
+ opts->options |= OPTION_MPTCP_ACK;
+ opts->sndr_key = local_key;
+ opts->rcvr_key = remote_key;
+ remaining -= TCPOLEN_MPTCP_MPC_SYNACK;
+ }
+ }
+ }
smc_set_option_cond(tcp_sk(sk), ireq, opts, &remaining);
@@ -748,6 +797,29 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
}
+ if (tp->is_mptcp) {
+ struct subflow_sock *subflow = subflow_sk(sk);
+ pr_debug("tcp_established_options: subflow=%p", subflow);
+ if (subflow->mp_capable) {
+ const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
+ pr_debug("tcp_established_options: remaining=%d", remaining);
+ if (!subflow->fourth_ack) {
+ pr_debug("tcp_established_options: OPTION_MPTCP_ACK");
+ if (remaining >= 20) {
+ opts->options |= OPTION_MPTCP_ACK;
+ opts->sndr_key = subflow->local_key;
+ opts->rcvr_key = subflow->remote_key;
+ size += 20;
+ }
+ subflow->fourth_ack = 1;
+ // @@ also this is where first DSS goes in?
+ }
+ else {
+ pr_debug("tcp_established_options: OPTION_MPTCP_DSS");
+ // @@ send DSS based on remaining
+ }
+ }
+ }
return size;
}
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index 5624e7d51d48..2bd18e3b9fda 100644
--- a/net/mptcp/Makefile
+++ b/net/mptcp/Makefile
@@ -1,3 +1,3 @@
obj-$(CONFIG_MPTCP) += mptcp.o
-mptcp-y := protocol.o
+mptcp-y := protocol.o options.o
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
new file mode 100644
index 000000000000..a44283d6a0d7
--- /dev/null
+++ b/net/mptcp/options.c
@@ -0,0 +1,177 @@
+/*
+ * Multipath TCP
+ *
+ * Copyright (c) 2017, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/tcp.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+
+void mptcp_parse_option(const unsigned char *ptr, int opsize,
+ struct tcp_options_received *opt_rx)
+{
+ u8 subtype;
+ u64 *p;
+
+ opsize -= 2;
+ subtype = *ptr++;
+
+ /* MPTCPOPT_MP_CAPABLE
+ * 0: 4MSB=subtype, 4LSB=version
+ * 1: Handshake flags
+ * 2-9: Sender key
+ * 10-17: Receiver key (optional)
+ */
+ switch (subtype & 0xF0) {
+ case 0x00:
+ pr_debug("MP_CAPABLE");
+ pr_debug("flags=%02x", *ptr);
+ opt_rx->mptcp.mp_capable = 1;
+ opt_rx->mptcp.version = subtype & 0x0F;
+ opt_rx->mptcp.flags = *ptr++;
+ p = (u64 *)ptr;
+ pr_debug("sndr_key=%llu", *p);
+ opt_rx->mptcp.sndr_key = *p++;
+ if (opsize > 10) {
+ pr_debug("rcvr_key=%llu", *p);
+ opt_rx->mptcp.rcvr_key = *p++;
+ }
+ break;
+
+ /* MPTCPOPT_MP_JOIN
+ *
+ * Initial SYN
+ * 0: 4MSB=subtype, 000, 1LSB=Backup
+ * 1: Address ID
+ * 2-5: Receiver token
+ * 6-9: Sender random number
+ *
+ * SYN/ACK response
+ * 0: 4MSB=subtype, 000, 1LSB=Backup
+ * 1: Address ID
+ * 2-9: Sender truncated HMAC
+ * 10-13: Sender random number
+ *
+ * Third ACK
+ * 0: 4MSB=subtype, 0000
+ * 1: 0 (Reserved)
+ * 2-21: Sender HMAC
+ */
+
+ /* MPTCPOPT_DSS
+ * 0: 4MSB=subtype, 0000
+ * 1: 3MSB=0, F=Data FIN, m=DSN length, M=has DSN/SSN/DLL/checksum,
+ * a=DACK length, A=has DACK
+ * 0, 4, or 8 bytes of DACK (depending on A/a)
+ * 0, 4, or 8 bytes of DSN (depending on M/m)
+ * 0 or 4 bytes of SSN (depending on M)
+ * 0 or 2 bytes of DLL (depending on M)
+ * 0 or 2 bytes of checksum (depending on M)
+ */
+ case 0x20:
+ pr_debug("DSS");
+ opt_rx->mptcp.dss = 1;
+ break;
+
+ /* MPTCPOPT_ADD_ADDR
+ * 0: 4MSB=subtype, 4LSB=IP version (4 or 6)
+ * 1: Address ID
+ * 4 or 16 bytes of address (depending on ip version)
+ * 0 or 2 bytes of port (depending on length)
+ */
+
+ /* MPTCPOPT_REMOVE_ADDR
+ * 0: 4MSB=subtype, 0000
+ * 1: Address ID
+ * Additional bytes: More address IDs (depending on length)
+ */
+
+ /* MPTCPOPT_MP_PRIO
+ * 0: 4MSB=subtype, 000, 1LSB=Backup
+ * 1: Address ID (optional, current addr implied if not present)
+ */
+
+ /* MPTCPOPT_MP_FAIL
+ * 0: 4MSB=subtype, 0000
+ * 1: 0 (Reserved)
+ * 2-9: DSN
+ */
+
+ /* MPTCPOPT_MP_FASTCLOSE
+ * 0: 4MSB=subtype, 0000
+ * 1: 0 (Reserved)
+ * 2-9: Receiver key
+ */
+ default:
+ break;
+ }
+}
+
+void mptcp_get_options(const struct sk_buff *skb,
+ struct tcp_options_received *opt_rx)
+{
+ const unsigned char *ptr;
+ const struct tcphdr *th = tcp_hdr(skb);
+ int length = (th->doff * 4) - sizeof(struct tcphdr);
+
+ ptr = (const unsigned char *)(th + 1);
+
+ while (length > 0) {
+ int opcode = *ptr++;
+ int opsize;
+
+ switch (opcode) {
+ case TCPOPT_EOL:
+ return;
+ case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
+ length--;
+ continue;
+ default:
+ opsize = *ptr++;
+ if (opsize < 2) /* "silly options" */
+ return;
+ if (opsize > length)
+ return; /* don't parse partial options */
+ if (opcode == TCPOPT_MPTCP)
+ mptcp_parse_option(ptr, opsize, opt_rx);
+ ptr += opsize - 2;
+ length -= opsize;
+ }
+ }
+}
+
+unsigned int mptcp_syn_options(struct sock *sk, u64 *local_key)
+{
+ struct subflow_sock *subflow = subflow_sk(sk);
+
+ if (subflow->request_mptcp) {
+ pr_debug("local_key=%llu", subflow->local_key);
+ *local_key = subflow->local_key;
+ }
+ return subflow->request_mptcp;
+}
+
+unsigned int mptcp_synack_options(struct request_sock *req, u64 *local_key,
+ u64 *remote_key)
+{
+ struct subflow_request_sock *subflow_req = subflow_rsk(req);
+
+ if (subflow_req->mp_capable) {
+ *local_key = subflow_req->local_key;
+ *remote_key = subflow_req->remote_key;
+ pr_debug("local_key=%llu", *local_key);
+ pr_debug("remote_key=%llu", *remote_key);
+ }
+ return subflow_req->mp_capable;
+}
--
2.16.3
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2018-03-28 23:18 [MPTCP] [RFC PATCH 04/16] mptcp: Handle MPTCP TCP options Mat Martineau
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