From c24b14c46bb88d844275de5c4024c8745ae89d42 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Mon, 23 Oct 2017 09:20:24 -0700 Subject: [PATCH] tcp: add tracepoint trace_tcp_send_reset New tracepoint trace_tcp_send_reset is added and called from tcp_v4_send_reset(), tcp_v6_send_reset() and tcp_send_active_reset(). Signed-off-by: Song Liu Signed-off-by: David S. Miller --- include/trace/events/tcp.h | 11 +++++++++++ net/core/net-traces.c | 2 ++ net/ipv4/tcp_ipv4.c | 6 +++++- net/ipv4/tcp_output.c | 5 +++++ net/ipv6/tcp_ipv6.c | 10 ++++++++-- 5 files changed, 31 insertions(+), 3 deletions(-) diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h index 2b6fe72c6781..3e57e1ae1c6b 100644 --- a/include/trace/events/tcp.h +++ b/include/trace/events/tcp.h @@ -77,6 +77,17 @@ DEFINE_EVENT(tcp_event_sk_skb, tcp_retransmit_skb, TP_ARGS(sk, skb) ); +/* + * skb of trace_tcp_send_reset is the skb that caused RST. In case of + * active reset, skb should be NULL + */ +DEFINE_EVENT(tcp_event_sk_skb, tcp_send_reset, + + TP_PROTO(const struct sock *sk, const struct sk_buff *skb), + + TP_ARGS(sk, skb) +); + #endif /* _TRACE_TCP_H */ /* This part must be outside protection */ diff --git a/net/core/net-traces.c b/net/core/net-traces.c index f4e4fa2db505..8dcd9b0be04a 100644 --- a/net/core/net-traces.c +++ b/net/core/net-traces.c @@ -49,3 +49,5 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(br_fdb_update); EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb); EXPORT_TRACEPOINT_SYMBOL_GPL(napi_poll); + +EXPORT_TRACEPOINT_SYMBOL_GPL(tcp_send_reset); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index e22439f05e46..eb3f3b8e1e4b 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -85,6 +85,8 @@ #include #include +#include + #ifdef CONFIG_TCP_MD5SIG static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, __be32 daddr, __be32 saddr, const struct tcphdr *th); @@ -701,8 +703,10 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) * routing might fail in this case. No choice here, if we choose to force * input interface, we will misroute in case of asymmetric route. */ - if (sk) + if (sk) { arg.bound_dev_if = sk->sk_bound_dev_if; + trace_tcp_send_reset(sk, skb); + } BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) != offsetof(struct inet_timewait_sock, tw_bound_dev_if)); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 988733f289c8..1f01f4c9c738 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3084,6 +3084,11 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority) /* Send it off. */ if (tcp_transmit_skb(sk, skb, 0, priority)) NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTFAILED); + + /* skb of trace_tcp_send_reset() keeps the skb that caused RST, + * skb here is different to the troublesome skb, so use NULL + */ + trace_tcp_send_reset(sk, NULL); } /* Send a crossed SYN-ACK during socket establishment. diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index ae83615b7f6d..0e2529958b52 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -69,6 +69,8 @@ #include #include +#include + static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb); static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, struct request_sock *req); @@ -890,7 +892,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) int genhash; struct sock *sk1 = NULL; #endif - int oif; + int oif = 0; if (th->rst) return; @@ -939,7 +941,11 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len - (th->doff << 2); - oif = sk ? sk->sk_bound_dev_if : 0; + if (sk) { + oif = sk->sk_bound_dev_if; + trace_tcp_send_reset(sk, skb); + } + tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0); #ifdef CONFIG_TCP_MD5SIG -- 2.39.5