diff options
| author | Yuchung Cheng <ycheng@google.com> | 2021-01-19 20:26:19 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-01-20 04:47:20 +0100 |
| commit | 9c30ae8398b0813e237bde387d67a7f74ab2db2d (patch) | |
| tree | d7bd663b98e76378c3a279078746b22962a30932 /net | |
| parent | net: dsa: b53: fix an off by one in checking "vlan->vid" (diff) | |
| download | linux-9c30ae8398b0813e237bde387d67a7f74ab2db2d.tar.xz linux-9c30ae8398b0813e237bde387d67a7f74ab2db2d.zip | |
tcp: fix TCP socket rehash stats mis-accounting
The previous commit 32efcc06d2a1 ("tcp: export count for rehash attempts")
would mis-account rehashing SNMP and socket stats:
a. During handshake of an active open, only counts the first
SYN timeout
b. After handshake of passive and active open, stop updating
after (roughly) TCP_RETRIES1 recurring RTOs
c. After the socket aborts, over count timeout_rehash by 1
This patch fixes this by checking the rehash result from sk_rethink_txhash.
Fixes: 32efcc06d2a1 ("tcp: export count for rehash attempts")
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Link: https://lore.kernel.org/r/20210119192619.1848270-1-ycheng@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 5 | ||||
| -rw-r--r-- | net/ipv4/tcp_timer.c | 22 |
2 files changed, 10 insertions, 17 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index bafcab75f425..a7dfca0a38cd 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4397,10 +4397,9 @@ static void tcp_rcv_spurious_retrans(struct sock *sk, const struct sk_buff *skb) * The receiver remembers and reflects via DSACKs. Leverage the * DSACK state and change the txhash to re-route speculatively. */ - if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq) { - sk_rethink_txhash(sk); + if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq && + sk_rethink_txhash(sk)) NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDUPLICATEDATAREHASH); - } } static void tcp_send_dupack(struct sock *sk, const struct sk_buff *skb) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 454732ecc8f3..faa92948441b 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -219,14 +219,8 @@ static int tcp_write_timeout(struct sock *sk) int retry_until; if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { - if (icsk->icsk_retransmits) { - dst_negative_advice(sk); - } else { - sk_rethink_txhash(sk); - tp->timeout_rehash++; - __NET_INC_STATS(sock_net(sk), - LINUX_MIB_TCPTIMEOUTREHASH); - } + if (icsk->icsk_retransmits) + __dst_negative_advice(sk); retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; expired = icsk->icsk_retransmits >= retry_until; } else { @@ -234,12 +228,7 @@ static int tcp_write_timeout(struct sock *sk) /* Black hole detection */ tcp_mtu_probing(icsk, sk); - dst_negative_advice(sk); - } else { - sk_rethink_txhash(sk); - tp->timeout_rehash++; - __NET_INC_STATS(sock_net(sk), - LINUX_MIB_TCPTIMEOUTREHASH); + __dst_negative_advice(sk); } retry_until = net->ipv4.sysctl_tcp_retries2; @@ -270,6 +259,11 @@ static int tcp_write_timeout(struct sock *sk) return 1; } + if (sk_rethink_txhash(sk)) { + tp->timeout_rehash++; + __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPTIMEOUTREHASH); + } + return 0; } |