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 <mhiramat@xxxxxxxxxx>
---
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);
--
To unsubscribe from this list: send the line "unsubscribe dccp" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
