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tcp: rate limit synflood warnings further

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Convert pr_info to net_info_ratelimited to limit the total number of
synflood warnings.

Commit 946cedccbd ("tcp: Change possible SYN flooding messages")
rate limits synflood warnings to one per listener.

Workloads that open many listener sockets can still see a high rate of
log messages. Syzkaller is one frequent example.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Willem de Bruijn 2018-09-09 19:12:12 -04:00 committed by David S. Miller
parent 2d946e5bcd
commit 0297c1c2ea
1 changed files with 2 additions and 2 deletions
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4
net/ipv4/tcp_input.c
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@ -6367,8 +6367,8 @@ static bool tcp_syn_flood_action(const struct sock *sk,
if (!queue->synflood_warned &&
net->ipv4.sysctl_tcp_syncookies != 2 &&
xchg(&queue->synflood_warned, 1) == 0)
pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
proto, ntohs(tcp_hdr(skb)->dest), msg);
net_info_ratelimited("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
proto, ntohs(tcp_hdr(skb)->dest), msg);
return want_cookie;
}