From 4bdc3d66147b3a623b32216a45431d0cff005f50 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 13 Oct 2015 17:12:54 -0700 Subject: tcp/dccp: fix behavior of stale SYN_RECV request sockets When a TCP/DCCP listener is closed, its pending SYN_RECV request sockets become stale, meaning 3WHS can not complete. But current behavior is wrong : incoming packets finding such stale sockets are dropped. We need instead to cleanup the request socket and perform another lookup : - Incoming ACK will give a RST answer, - SYN rtx might find another listener if available. - We expedite cleanup of request sockets and old listener socket. Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/dccp/ipv4.c | 15 +++++++-------- net/dccp/ipv6.c | 15 +++++++-------- 2 files changed, 14 insertions(+), 16 deletions(-) (limited to 'net/dccp') diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 8e99681..0dcf196 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -799,15 +799,10 @@ static int dccp_v4_rcv(struct sk_buff *skb) DCCP_SKB_CB(skb)->dccpd_ack_seq); } - /* Step 2: - * Look up flow ID in table and get corresponding socket */ +lookup: sk = __inet_lookup_skb(&dccp_hashinfo, skb, dh->dccph_sport, dh->dccph_dport); - /* - * Step 2: - * If no socket ... - */ - if (sk == NULL) { + if (!sk) { dccp_pr_debug("failed to look up flow ID in table and " "get corresponding socket\n"); goto no_dccp_socket; @@ -830,8 +825,12 @@ static int dccp_v4_rcv(struct sk_buff *skb) struct sock *nsk = NULL; sk = req->rsk_listener; - if (sk->sk_state == DCCP_LISTEN) + if (likely(sk->sk_state == DCCP_LISTEN)) { nsk = dccp_check_req(sk, skb, req); + } else { + inet_csk_reqsk_queue_drop(sk, req); + goto lookup; + } if (!nsk) { reqsk_put(req); goto discard_it; diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index aed314f..6883193 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -656,16 +656,11 @@ static int dccp_v6_rcv(struct sk_buff *skb) else DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); - /* Step 2: - * Look up flow ID in table and get corresponding socket */ +lookup: sk = __inet6_lookup_skb(&dccp_hashinfo, skb, dh->dccph_sport, dh->dccph_dport, inet6_iif(skb)); - /* - * Step 2: - * If no socket ... - */ - if (sk == NULL) { + if (!sk) { dccp_pr_debug("failed to look up flow ID in table and " "get corresponding socket\n"); goto no_dccp_socket; @@ -688,8 +683,12 @@ static int dccp_v6_rcv(struct sk_buff *skb) struct sock *nsk = NULL; sk = req->rsk_listener; - if (sk->sk_state == DCCP_LISTEN) + if (likely(sk->sk_state == DCCP_LISTEN)) { nsk = dccp_check_req(sk, skb, req); + } else { + inet_csk_reqsk_queue_drop(sk, req); + goto lookup; + } if (!nsk) { reqsk_put(req); goto discard_it; -- cgit v1.1