This adds an event to trace TCP stat variables with slightly intrusive trace-event. This uses ftrace/perf event log buffer to trace those state, no needs to prepare own ring-buffer, nor custom user apps.
User can use ftrace to trace this event as below; # cd /sys/kernel/debug/tracing # echo 1 > events/tcp/tcp_probe/enable (run workloads) # cat trace Signed-off-by: Masami Hiramatsu <[email protected]> --- include/trace/events/tcp.h | 96 ++++++++++++++++++++++++++++++++++++++++++++ net/core/net-traces.c | 1 net/ipv4/tcp_input.c | 4 ++ 3 files changed, 101 insertions(+) create mode 100644 include/trace/events/tcp.h diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h new file mode 100644 index 000000000000..b8969bbceb38 --- /dev/null +++ b/include/trace/events/tcp.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM tcp + +#if !defined(_TRACE_TCP_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_TCP_H + +#include <net/tcp.h> +#include <linux/tcp.h> +#include <linux/ipv6.h> +#include <uapi/linux/in.h> +#include <uapi/linux/in6.h> +#include <linux/tracepoint.h> + +TRACE_EVENT(tcp_probe, + + TP_PROTO(struct sock *sk, struct sk_buff *skb), + + TP_ARGS(sk, skb), + + TP_STRUCT__entry( + /* sockaddr_in6 is always bigger than sockaddr_in */ + __array(__u8, saddr, sizeof(struct sockaddr_in6)) + __array(__u8, daddr, sizeof(struct sockaddr_in6)) + __field(__u16, sport) + __field(__u16, dport) + __field(__u32, mark) + __field(__u16, length) + __field(__u32, snd_nxt) + __field(__u32, snd_una) + __field(__u32, snd_cwnd) + __field(__u32, ssthresh) + __field(__u32, snd_wnd) + __field(__u32, srtt) + __field(__u32, rcv_wnd) + ), + + TP_fast_assign( + const struct tcp_sock *tp = tcp_sk(sk); + const struct inet_sock *inet = inet_sk(sk); + + memset(__entry->saddr, 0, sizeof(struct sockaddr_in6)); + memset(__entry->daddr, 0, sizeof(struct sockaddr_in6)); + + if (sk->sk_family == AF_INET) { + struct sockaddr_in *v4 = (void *)__entry->saddr; + + v4->sin_family = AF_INET; + v4->sin_port = inet->inet_sport; + v4->sin_addr.s_addr = inet->inet_saddr; + v4 = (void *)__entry->daddr; + v4->sin_family = AF_INET; + v4->sin_port = inet->inet_dport; + v4->sin_addr.s_addr = inet->inet_daddr; +#if IS_ENABLED(CONFIG_IPV6) + } else if (sk->sk_family == AF_INET6) { + struct sockaddr_in6 *v6 = (void *)__entry->saddr; + + v6->sin6_family = AF_INET6; + v6->sin6_port = inet->inet_sport; + v6->sin6_addr = inet6_sk(sk)->saddr; + v6 = (void *)__entry->daddr; + v6->sin6_family = AF_INET6; + v6->sin6_port = inet->inet_dport; + v6->sin6_addr = sk->sk_v6_daddr; +#endif + } + + /* For filtering use */ + __entry->sport = ntohs(inet->inet_sport); + __entry->dport = ntohs(inet->inet_dport); + __entry->mark = skb->mark; + + __entry->length = skb->len; + __entry->snd_nxt = tp->snd_nxt; + __entry->snd_una = tp->snd_una; + __entry->snd_cwnd = tp->snd_cwnd; + __entry->snd_wnd = tp->snd_wnd; + __entry->rcv_wnd = tp->rcv_wnd; + __entry->ssthresh = tcp_current_ssthresh(sk); + __entry->srtt = tp->srtt_us >> 3; + ), + + TP_printk("src=%pISpc dest=%pISpc mark=%#x length=%d snd_nxt=%#x " + "snd_una=%#x snd_cwnd=%u ssthresh=%u snd_wnd=%u srtt=%u " + "rcv_wnd=%u", + __entry->saddr, __entry->daddr, __entry->mark, + __entry->length, __entry->snd_nxt, __entry->snd_una, + __entry->snd_cwnd, __entry->ssthresh, __entry->snd_wnd, + __entry->srtt, __entry->rcv_wnd) +); + +#endif /* _TRACE_TCP_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/net/core/net-traces.c b/net/core/net-traces.c index 71f209542364..2e84d642c03f 100644 --- a/net/core/net-traces.c +++ b/net/core/net-traces.c @@ -31,6 +31,7 @@ #include <trace/events/net.h> #include <trace/events/napi.h> #include <trace/events/sock.h> +#include <trace/events/tcp.h> #include <trace/events/udp.h> #include <trace/events/fib.h> #include <trace/events/qdisc.h> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 9a0b3c5ffa46..da8b342b95ce 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -76,6 +76,7 @@ #include <linux/ipsec.h> #include <asm/unaligned.h> #include <linux/errqueue.h> +#include <trace/events/tcp.h> int sysctl_tcp_fack __read_mostly; int sysctl_tcp_max_reordering __read_mostly = 300; @@ -5356,6 +5357,9 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb, unsigned int len = skb->len; struct tcp_sock *tp = tcp_sk(sk); + /* TCP congestion window tracking */ + trace_tcp_probe(sk, skb); + tcp_mstamp_refresh(tp); if (unlikely(!sk->sk_rx_dst)) inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb);
