2017-12-06 15:01:49

by Yafang Shao

[permalink] [raw]
Subject: [PATCH v4 net-next] net/tcp: trace all TCP/IP state transition with tcp_set_state tracepoint

The TCP/IP transition from TCP_LISTEN to TCP_SYN_RECV and some other
transitions are not traced with tcp_set_state tracepoint.

In order to trace the whole tcp lifespans, two helpers are introduced,
void sk_set_state(struct sock *sk, int state);
void sk_state_store(struct sock *sk, int newstate);

When do TCP/IP state transition, we should use these two helpers or use
tcp_set_state() other than assigning a value to sk_state directly.

Signed-off-by: Yafang Shao <[email protected]>
Acked-by: Song Liu <[email protected]>
Reviewed-by: Marcelo Ricardo Leitner <[email protected]>
---
v3->v4: Do not trace DCCP socket
v2->v3: Per suggestion from Marcelo Ricardo Leitner, inverting __
to sk_state_store.
---
include/net/sock.h | 8 ++++++--
net/core/sock.c | 16 ++++++++++++++++
net/ipv4/inet_connection_sock.c | 5 +++--
net/ipv4/inet_hashtables.c | 2 +-
net/ipv4/tcp.c | 2 +-
5 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 79e1a2c..1cf7685 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2349,18 +2349,22 @@ static inline int sk_state_load(const struct sock *sk)
}

/**
- * sk_state_store - update sk->sk_state
+ * __sk_state_store - update sk->sk_state
* @sk: socket pointer
* @newstate: new state
*
* Paired with sk_state_load(). Should be used in contexts where
* state change might impact lockless readers.
*/
-static inline void sk_state_store(struct sock *sk, int newstate)
+static inline void __sk_state_store(struct sock *sk, int newstate)
{
smp_store_release(&sk->sk_state, newstate);
}

+/* For tcp_set_state tracepoint */
+void sk_state_store(struct sock *sk, int newstate);
+void sk_set_state(struct sock *sk, int state);
+
void sock_enable_timestamp(struct sock *sk, int flag);
int sock_get_timestamp(struct sock *, struct timeval __user *);
int sock_get_timestampns(struct sock *, struct timespec __user *);
diff --git a/net/core/sock.c b/net/core/sock.c
index c0b5b2f..5d4f6f4 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -138,6 +138,7 @@
#include <net/sock_reuseport.h>

#include <trace/events/sock.h>
+#include <trace/events/tcp.h>

#include <net/tcp.h>
#include <net/busy_poll.h>
@@ -2859,6 +2860,21 @@ int sock_get_timestampns(struct sock *sk, struct timespec __user *userstamp)
}
EXPORT_SYMBOL(sock_get_timestampns);

+void sk_state_store(struct sock *sk, int newstate)
+{
+ /* Don't trace DCCP socket */
+ if (sk->sk_type == SOCK_STREAM)
+ trace_tcp_set_state(sk, sk->sk_state, newstate);
+ __sk_state_store(sk, newstate);
+}
+
+void sk_set_state(struct sock *sk, int state)
+{
+ if (sk->sk_type == SOCK_STREAM)
+ trace_tcp_set_state(sk, sk->sk_state, state);
+ sk->sk_state = state;
+}
+
void sock_enable_timestamp(struct sock *sk, int flag)
{
if (!sock_flag(sk, flag)) {
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 4ca46dc..41f9c87 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -783,7 +783,7 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
if (newsk) {
struct inet_connection_sock *newicsk = inet_csk(newsk);

- newsk->sk_state = TCP_SYN_RECV;
+ sk_set_state(newsk, TCP_SYN_RECV);
newicsk->icsk_bind_hash = NULL;

inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
@@ -888,7 +888,8 @@ int inet_csk_listen_start(struct sock *sk, int backlog)
return 0;
}

- sk->sk_state = TCP_CLOSE;
+ sk_set_state(sk, TCP_CLOSE);
+
return err;
}
EXPORT_SYMBOL_GPL(inet_csk_listen_start);
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index f6f5810..5973693 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -544,7 +544,7 @@ bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
} else {
percpu_counter_inc(sk->sk_prot->orphan_count);
- sk->sk_state = TCP_CLOSE;
+ sk_set_state(sk, TCP_CLOSE);
sock_set_flag(sk, SOCK_DEAD);
inet_csk_destroy_sock(sk);
}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 1803116..ac98dc6 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2065,7 +2065,7 @@ void tcp_set_state(struct sock *sk, int state)
/* Change state AFTER socket is unhashed to avoid closed
* socket sitting in hash tables.
*/
- sk_state_store(sk, state);
+ __sk_state_store(sk, state);

#ifdef STATE_TRACE
SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
--
1.8.3.1


2017-12-06 20:27:21

by David Miller

[permalink] [raw]
Subject: Re: [PATCH v4 net-next] net/tcp: trace all TCP/IP state transition with tcp_set_state tracepoint

From: Yafang Shao <[email protected]>
Date: Wed, 6 Dec 2017 15:01:29 +0000

> v3->v4: Do not trace DCCP socket

This is not sufficient.

Your test will match SCTP stream sockets.