From cf34ce3da1e41579296364509266c7dac573822a Mon Sep 17 00:00:00 2001 From: Song Liu Date: Mon, 30 Oct 2017 14:41:35 -0700 Subject: [PATCH] tcp: add tracepoint trace_tcp_retransmit_synack() This tracepoint can be used to trace synack retransmits. It maintains pointer to struct request_sock. We cannot simply reuse trace_tcp_retransmit_skb() here, because the sk here is the LISTEN socket. The IP addresses and ports should be extracted from struct request_sock. Note that, like many other tracepoints, this patch uses IS_ENABLED in TP_fast_assign macro, which triggers sparse warning like: ./include/trace/events/tcp.h:274:1: error: directive in argument list ./include/trace/events/tcp.h:281:1: error: directive in argument list However, there is no good solution to avoid these warnings. To the best of our knowledge, these warnings are harmless. Signed-off-by: Song Liu Acked-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- include/trace/events/tcp.h | 56 ++++++++++++++++++++++++++++++++++++++ net/ipv4/tcp_output.c | 1 + 2 files changed, 57 insertions(+) diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h index 03699ba71623..07cccca6cbf1 100644 --- a/include/trace/events/tcp.h +++ b/include/trace/events/tcp.h @@ -237,6 +237,62 @@ TRACE_EVENT(tcp_set_state, show_tcp_state_name(__entry->newstate)) ); +TRACE_EVENT(tcp_retransmit_synack, + + TP_PROTO(const struct sock *sk, const struct request_sock *req), + + TP_ARGS(sk, req), + + TP_STRUCT__entry( + __field(const void *, skaddr) + __field(const void *, req) + __field(__u16, sport) + __field(__u16, dport) + __array(__u8, saddr, 4) + __array(__u8, daddr, 4) + __array(__u8, saddr_v6, 16) + __array(__u8, daddr_v6, 16) + ), + + TP_fast_assign( + struct inet_request_sock *ireq = inet_rsk(req); + struct in6_addr *pin6; + __be32 *p32; + + __entry->skaddr = sk; + __entry->req = req; + + __entry->sport = ireq->ir_num; + __entry->dport = ntohs(ireq->ir_rmt_port); + + p32 = (__be32 *) __entry->saddr; + *p32 = ireq->ir_loc_addr; + + p32 = (__be32 *) __entry->daddr; + *p32 = ireq->ir_rmt_addr; + +#if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family == AF_INET6) { + pin6 = (struct in6_addr *)__entry->saddr_v6; + *pin6 = ireq->ir_v6_loc_addr; + pin6 = (struct in6_addr *)__entry->daddr_v6; + *pin6 = ireq->ir_v6_rmt_addr; + } else +#endif + { + pin6 = (struct in6_addr *)__entry->saddr_v6; + ipv6_addr_set_v4mapped(ireq->ir_loc_addr, pin6); + pin6 = (struct in6_addr *)__entry->daddr_v6; + ipv6_addr_set_v4mapped(ireq->ir_rmt_addr, pin6); + } + ), + + TP_printk("sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c", + __entry->sport, __entry->dport, + __entry->saddr, __entry->daddr, + __entry->saddr_v6, __entry->daddr_v6) +); + #endif /* _TRACE_TCP_H */ /* This part must be outside protection */ diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index a85e8a282d17..06a0c89ffe40 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3782,6 +3782,7 @@ int tcp_rtx_synack(const struct sock *sk, struct request_sock *req) __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNRETRANS); if (unlikely(tcp_passive_fastopen(sk))) tcp_sk(sk)->total_retrans++; + trace_tcp_retransmit_synack(sk, req); } return res; }