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AJvYcCW0WSQkbTEg+HobPJOyKz2KMjxTGbhNoqKbO8MWNrprmcLeq92NiJm0NtUz4Da4MzJfais/RMGdxEG17Md9CQc7Gfq6osiABlYHXACYDKiRZmBd X-Gm-Message-State: AOJu0Yx8vApFcn4GMRNx3jXoyzNKTQ8FsF6FWRVMUhtvu5O34XnXyQK8 lT3HYBBFyIUvyexogpIv7K0cIx1YfU+DhMM8nDoQdHVE1F1iUfDz X-Google-Smtp-Source: AGHT+IEtTBKIvCkExk6lBXtM3X3usjWQBYXzXQPkQ6sXjJy5YkdzJDYhixfLZSgbRiSrD5+CQ3B9BA== X-Received: by 2002:a81:dc09:0:b0:614:42b1:edd8 with SMTP id h9-20020a81dc09000000b0061442b1edd8mr513720ywj.2.1711683782953; Thu, 28 Mar 2024 20:43:02 -0700 (PDT) Received: from KERNELXING-MB0.tencent.com ([43.132.141.25]) by smtp.gmail.com with ESMTPSA id a18-20020aa78e92000000b006e6c0080466sm2201854pfr.176.2024.03.28.20.43.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Mar 2024 20:43:02 -0700 (PDT) From: Jason Xing To: edumazet@google.com, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, rostedt@goodmis.org, kuba@kernel.org, pabeni@redhat.com, davem@davemloft.net Cc: netdev@vger.kernel.org, linux-trace-kernel@vger.kernel.org, kerneljasonxing@gmail.com, Jason Xing Subject: [PATCH net-next v3 2/3] trace: tcp: fully support trace_tcp_send_reset Date: Fri, 29 Mar 2024 11:42:42 +0800 Message-Id: <20240329034243.7929-3-kerneljasonxing@gmail.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20240329034243.7929-1-kerneljasonxing@gmail.com> References: <20240329034243.7929-1-kerneljasonxing@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jason Xing Prior to this patch, what we can see by enabling trace_tcp_send is only happening under two circumstances: 1) active rst mode 2) non-active rst mode and based on the full socket That means the inconsistency occurs if we use tcpdump and trace simultaneously to see how rst happens. It's necessary that we should take into other cases into considerations, say: 1) time-wait socket 2) no socket ... By parsing the incoming skb and reversing its 4-tuple can we know the exact 'flow' which might not exist. Samples after applied this patch: 1. tcp_send_reset: skbaddr=XXX skaddr=XXX src=ip:port dest=ip:port state=TCP_ESTABLISHED 2. tcp_send_reset: skbaddr=000...000 skaddr=XXX src=ip:port dest=ip:port state=UNKNOWN Note: 1) UNKNOWN means we cannot extract the right information from skb. 2) skbaddr/skaddr could be 0 Signed-off-by: Jason Xing --- include/trace/events/tcp.h | 39 ++++++++++++++++++++++++++++++++++++-- net/ipv4/tcp_ipv4.c | 4 ++-- net/ipv6/tcp_ipv6.c | 3 ++- 3 files changed, 41 insertions(+), 5 deletions(-) diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h index 194425f69642..289438c54227 100644 --- a/include/trace/events/tcp.h +++ b/include/trace/events/tcp.h @@ -78,11 +78,46 @@ DEFINE_EVENT(tcp_event_sk_skb, tcp_retransmit_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, +TRACE_EVENT(tcp_send_reset, TP_PROTO(const struct sock *sk, const struct sk_buff *skb), - TP_ARGS(sk, skb) + TP_ARGS(sk, skb), + + TP_STRUCT__entry( + __field(const void *, skbaddr) + __field(const void *, skaddr) + __field(int, state) + __array(__u8, saddr, sizeof(struct sockaddr_in6)) + __array(__u8, daddr, sizeof(struct sockaddr_in6)) + ), + + TP_fast_assign( + __entry->skbaddr = skb; + __entry->skaddr = sk; + /* Zero means unknown state. */ + __entry->state = sk ? sk->sk_state : 0; + + memset(__entry->saddr, 0, sizeof(struct sockaddr_in6)); + memset(__entry->daddr, 0, sizeof(struct sockaddr_in6)); + + if (sk && sk_fullsock(sk)) { + const struct inet_sock *inet = inet_sk(sk); + + TP_STORE_ADDR_PORTS(__entry, inet, sk); + } else { + /* + * We should reverse the 4-tuple of skb, so later + * it can print the right flow direction of rst. + */ + TP_STORE_ADDR_PORTS_SKB(skb, entry->daddr, entry->saddr); + } + ), + + TP_printk("skbaddr=%p skaddr=%p src=%pISpc dest=%pISpc state=%s", + __entry->skbaddr, __entry->skaddr, + __entry->saddr, __entry->daddr, + __entry->state ? show_tcp_state_name(__entry->state) : "UNKNOWN") ); /* diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a22ee5838751..d5c4a969c066 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -868,10 +868,10 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) */ if (sk) { arg.bound_dev_if = sk->sk_bound_dev_if; - if (sk_fullsock(sk)) - trace_tcp_send_reset(sk, skb); } + 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/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 3f4cba49e9ee..8e9c59b6c00c 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1113,7 +1113,6 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) if (sk) { oif = sk->sk_bound_dev_if; if (sk_fullsock(sk)) { - trace_tcp_send_reset(sk, skb); if (inet6_test_bit(REPFLOW, sk)) label = ip6_flowlabel(ipv6h); priority = READ_ONCE(sk->sk_priority); @@ -1129,6 +1128,8 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) label = ip6_flowlabel(ipv6h); } + trace_tcp_send_reset(sk, skb); + tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, 1, ipv6_get_dsfield(ipv6h), label, priority, txhash, &key); -- 2.37.3