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tcp: tcp_syn_flood_action read port from socket 

This allows us to call this function before an SKB has been
allocated.

Signed-off-by: Petar Penkov <ppenkov@google.com>
Reviewed-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Petar Penkov 2019-07-29 09:59:13 -07:00 committed by Alexei Starovoitov
parent d340691356
commit 965112785e
1 changed files with 3 additions and 5 deletions
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8
net/ipv4/tcp_input.c
View File

@ -6422,9 +6422,7 @@ EXPORT_SYMBOL(inet_reqsk_alloc);
/* /*
* Return true if a syncookie should be sent * Return true if a syncookie should be sent
*/ */
static bool tcp_syn_flood_action(const struct sock *sk, static bool tcp_syn_flood_action(const struct sock *sk, const char *proto)
const struct sk_buff *skb,
const char *proto)
{ {
struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
const char *msg = "Dropping request"; const char *msg = "Dropping request";
@ -6444,7 +6442,7 @@ static bool tcp_syn_flood_action(const struct sock *sk,
net->ipv4.sysctl_tcp_syncookies != 2 && net->ipv4.sysctl_tcp_syncookies != 2 &&
xchg(&queue->synflood_warned, 1) == 0) xchg(&queue->synflood_warned, 1) == 0)
net_info_ratelimited("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n", net_info_ratelimited("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
proto, ntohs(tcp_hdr(skb)->dest), msg); proto, sk->sk_num, msg);
return want_cookie; return want_cookie;
} }
@ -6487,7 +6485,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
*/ */
if ((net->ipv4.sysctl_tcp_syncookies == 2 || if ((net->ipv4.sysctl_tcp_syncookies == 2 ||
inet_csk_reqsk_queue_is_full(sk)) && !isn) { inet_csk_reqsk_queue_is_full(sk)) && !isn) {
want_cookie = tcp_syn_flood_action(sk, skb, rsk_ops->slab_name); want_cookie = tcp_syn_flood_action(sk, rsk_ops->slab_name);
if (!want_cookie) if (!want_cookie)
goto drop; goto drop;
} }