diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2012-03-10 09:20:21 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-03-11 15:52:12 -0700 |
| commit | dfd25ffffc132c00070eed64200e8950da5d7e9d (patch) | |
| tree | fbce07add57f0ab7a16792b4af461d2f9e265fb6 | |
| parent | 4e50391968849860dff1aacde358b4eb14aa5127 (diff) | |
tcp: fix syncookie regression
commit ea4fc0d619 (ipv4: Don't use rt->rt_{src,dst} in ip_queue_xmit())
added a serious regression on synflood handling.
Simon Kirby discovered a successful connection was delayed by 20 seconds
before being responsive.
In my tests, I discovered that xmit frames were lost, and needed ~4
retransmits and a socket dst rebuild before being really sent.
In case of syncookie initiated connection, we use a different path to
initialize the socket dst, and inet->cork.fl.u.ip4 is left cleared.
As ip_queue_xmit() now depends on inet flow being setup, fix this by
copying the temp flowi4 we use in cookie_v4_check().
Reported-by: Simon Kirby <sim@netnation.com>
Bisected-by: Simon Kirby <sim@netnation.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/syncookies.c | 30 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 10 |
2 files changed, 23 insertions, 17 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 51fdbb49043..eab2a7fb15d 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -278,6 +278,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, struct rtable *rt; __u8 rcv_wscale; bool ecn_ok = false; + struct flowi4 fl4; if (!sysctl_tcp_syncookies || !th->ack || th->rst) goto out; @@ -346,20 +347,16 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, * hasn't changed since we received the original syn, but I see * no easy way to do this. */ - { - struct flowi4 fl4; - - flowi4_init_output(&fl4, 0, sk->sk_mark, RT_CONN_FLAGS(sk), - RT_SCOPE_UNIVERSE, IPPROTO_TCP, - inet_sk_flowi_flags(sk), - (opt && opt->srr) ? opt->faddr : ireq->rmt_addr, - ireq->loc_addr, th->source, th->dest); - security_req_classify_flow(req, flowi4_to_flowi(&fl4)); - rt = ip_route_output_key(sock_net(sk), &fl4); - if (IS_ERR(rt)) { - reqsk_free(req); - goto out; - } + flowi4_init_output(&fl4, 0, sk->sk_mark, RT_CONN_FLAGS(sk), + RT_SCOPE_UNIVERSE, IPPROTO_TCP, + inet_sk_flowi_flags(sk), + (opt && opt->srr) ? opt->faddr : ireq->rmt_addr, + ireq->loc_addr, th->source, th->dest); + security_req_classify_flow(req, flowi4_to_flowi(&fl4)); + rt = ip_route_output_key(sock_net(sk), &fl4); + if (IS_ERR(rt)) { + reqsk_free(req); + goto out; } /* Try to redo what tcp_v4_send_synack did. */ @@ -373,5 +370,10 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, ireq->rcv_wscale = rcv_wscale; ret = get_cookie_sock(sk, skb, req, &rt->dst); + /* ip_queue_xmit() depends on our flow being setup + * Normal sockets get it right from inet_csk_route_child_sock() + */ + if (ret) + inet_sk(ret)->cork.fl.u.ip4 = fl4; out: return ret; } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 94d683a61cb..fd54c5f8a25 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1466,9 +1466,13 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; newinet->inet_id = newtp->write_seq ^ jiffies; - if (!dst && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL) - goto put_and_exit; - + if (!dst) { + dst = inet_csk_route_child_sock(sk, newsk, req); + if (!dst) + goto put_and_exit; + } else { + /* syncookie case : see end of cookie_v4_check() */ + } sk_setup_caps(newsk, dst); tcp_mtup_init(newsk); |