ipv4: tcp: handle ICMP messages on TCP_NEW_SYN_RECV request sockets
tcp_v4_err() can restrict lookups to ehash table, and not to listeners.
Note this patch creates the infrastructure, but this means that ICMP
messages for request sockets are ignored until complete conversion.
New tcp_req_err() helper is exported so that we can use it in IPv6
in following patch.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 8028ad5..a576150 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -310,6 +310,34 @@
dst->ops->redirect(dst, sk, skb);
}
+
+/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
+void tcp_req_err(struct sock *sk, u32 seq)
+{
+ struct request_sock *req = inet_reqsk(sk);
+ struct net *net = sock_net(sk);
+
+ /* ICMPs are not backlogged, hence we cannot get
+ * an established socket here.
+ */
+ WARN_ON(req->sk);
+
+ if (seq != tcp_rsk(req)->snt_isn) {
+ NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
+ } else {
+ /*
+ * Still in SYN_RECV, just remove it silently.
+ * There is no good way to pass the error to the newly
+ * created socket, and POSIX does not want network
+ * errors returned from accept().
+ */
+ inet_csk_reqsk_queue_drop(req->rsk_listener, req);
+ NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
+ }
+ reqsk_put(req);
+}
+EXPORT_SYMBOL(tcp_req_err);
+
/*
* This routine is called by the ICMP module when it gets some
* sort of error condition. If err < 0 then the socket should
@@ -343,8 +371,9 @@
int err;
struct net *net = dev_net(icmp_skb->dev);
- sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
- iph->saddr, th->source, inet_iif(icmp_skb));
+ sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
+ th->dest, iph->saddr, ntohs(th->source),
+ inet_iif(icmp_skb));
if (!sk) {
ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
return;
@@ -353,6 +382,9 @@
inet_twsk_put(inet_twsk(sk));
return;
}
+ seq = ntohl(th->seq);
+ if (sk->sk_state == TCP_NEW_SYN_RECV)
+ return tcp_req_err(sk, seq);
bh_lock_sock(sk);
/* If too many ICMPs get dropped on busy
@@ -374,7 +406,6 @@
icsk = inet_csk(sk);
tp = tcp_sk(sk);
- seq = ntohl(th->seq);
/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
fastopen = tp->fastopen_rsk;
snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
@@ -458,38 +489,6 @@
}
switch (sk->sk_state) {
- struct request_sock *req;
- case TCP_LISTEN:
- if (sock_owned_by_user(sk))
- goto out;
-
- req = inet_csk_search_req(sk, th->dest,
- iph->daddr, iph->saddr);
- if (!req)
- goto out;
-
- /* ICMPs are not backlogged, hence we cannot get
- an established socket here.
- */
- WARN_ON(req->sk);
-
- if (seq != tcp_rsk(req)->snt_isn) {
- NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
- reqsk_put(req);
- goto out;
- }
-
- /*
- * Still in SYN_RECV, just remove it silently.
- * There is no good way to pass the error to the newly
- * created socket, and POSIX does not want network
- * errors returned from accept().
- */
- inet_csk_reqsk_queue_drop(sk, req);
- NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
- reqsk_put(req);
- goto out;
-
case TCP_SYN_SENT:
case TCP_SYN_RECV:
/* Only in fast or simultaneous open. If a fast open socket is