Merge branch 'bindtodevice_tw_rst'

Florian Westphal says:

====================
tcp: honour SO_BINDTODEVICE for TW_RST case too

This is V2, this time as a small series since I followed Erics advice
to split this into smaller chunks, I hope this makes it easier to
review.

First patch adds inet_sk_transparent helper.
Second patch contains an if/else swap that I split from the
original TW_RST v1 one.
Third patch is the actual change without the superfluous sock_net change.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/request_sock.h

@@ -68,7 +68,7 @@ struct request_sock {
 	u32				peer_secid;
 };
 
-static inline struct request_sock *inet_reqsk(struct sock *sk)
+static inline struct request_sock *inet_reqsk(const struct sock *sk)
 {
 	return (struct request_sock *)sk;
 }

include/net/tcp.h

@@ -1620,6 +1620,18 @@ static inline void tcp_highest_sack_combine(struct sock *sk,
 		tcp_sk(sk)->highest_sack = new;
 }
 
+/* This helper checks if socket has IP_TRANSPARENT set */
+static inline bool inet_sk_transparent(const struct sock *sk)
+{
+	switch (sk->sk_state) {
+	case TCP_TIME_WAIT:
+		return inet_twsk(sk)->tw_transparent;
+	case TCP_NEW_SYN_RECV:
+		return inet_rsk(inet_reqsk(sk))->no_srccheck;
+	}
+	return inet_sk(sk)->transparent;
+}
+
 /* Determines whether this is a thin stream (which may suffer from
  * increased latency). Used to trigger latency-reducing mechanisms.
  */

net/ipv4/tcp_ipv4.c

@@ -587,7 +587,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 	} rep;
 	struct ip_reply_arg arg;
 #ifdef CONFIG_TCP_MD5SIG
-	struct tcp_md5sig_key *key;
+	struct tcp_md5sig_key *key = NULL;
 	const __u8 *hash_location = NULL;
 	unsigned char newhash[16];
 	int genhash;
@@ -627,7 +627,10 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 #ifdef CONFIG_TCP_MD5SIG
 	hash_location = tcp_parse_md5sig_option(th);
-	if (!sk && hash_location) {
+	if (sk && sk_fullsock(sk)) {
+		key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
+					&ip_hdr(skb)->saddr, AF_INET);
+	} else if (hash_location) {
 		/*
 		 * active side is lost. Try to find listening socket through
 		 * source port, and then find md5 key through listening socket.
@@ -651,10 +654,6 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 		genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
 			goto release_sk1;
-	} else {
-		key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
-					     &ip_hdr(skb)->saddr,
-					     AF_INET) : NULL;
 	}
 
 	if (key) {
@@ -675,7 +674,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 				      ip_hdr(skb)->saddr, /* XXX */
 				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
 	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
-	arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
+	arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
+
 	/* When socket is gone, all binding information is lost.
 	 * routing might fail in this case. No choice here, if we choose to force
 	 * input interface, we will misroute in case of asymmetric route.
@@ -683,6 +683,9 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 	if (sk)
 		arg.bound_dev_if = sk->sk_bound_dev_if;
 
+	BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
+		     offsetof(struct inet_timewait_sock, tw_bound_dev_if));
+
 	arg.tos = ip_hdr(skb)->tos;
 	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
 			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
@@ -1706,7 +1709,9 @@ int tcp_v4_rcv(struct sk_buff *skb)
 		tcp_v4_timewait_ack(sk, skb);
 		break;
 	case TCP_TW_RST:
-		goto no_tcp_socket;
+		tcp_v4_send_reset(sk, skb);
+		inet_twsk_deschedule_put(inet_twsk(sk));
+		goto discard_it;
 	case TCP_TW_SUCCESS:;
 	}
 	goto discard_it;

net/ipv4/tcp_minisocks.c

@@ -131,7 +131,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
 			goto kill;
 
 		if (th->syn && !before(TCP_SKB_CB(skb)->seq, tcptw->tw_rcv_nxt))
-			goto kill_with_rst;
+			return TCP_TW_RST;
 
 		/* Dup ACK? */
 		if (!th->ack ||
@@ -145,11 +145,8 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
 		 * reset.
 		 */
 		if (!th->fin ||
-		    TCP_SKB_CB(skb)->end_seq != tcptw->tw_rcv_nxt + 1) {
-kill_with_rst:
-			inet_twsk_deschedule_put(tw);
+		    TCP_SKB_CB(skb)->end_seq != tcptw->tw_rcv_nxt + 1)
 			return TCP_TW_RST;
-		}
 
 		/* FIN arrived, enter true time-wait state. */
 		tw->tw_substate	  = TCP_TIME_WAIT;

net/ipv6/tcp_ipv6.c

@@ -854,7 +854,9 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 
 #ifdef CONFIG_TCP_MD5SIG
 	hash_location = tcp_parse_md5sig_option(th);
-	if (!sk && hash_location) {
+	if (sk && sk_fullsock(sk)) {
+		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
+	} else if (hash_location) {
 		/*
 		 * active side is lost. Try to find listening socket through
 		 * source port, and then find md5 key through listening socket.
@@ -877,8 +879,6 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
 			goto release_sk1;
-	} else {
-		key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 	}
 #endif
 
@@ -1516,7 +1516,9 @@ static int tcp_v6_rcv(struct sk_buff *skb)
 		break;
 	case TCP_TW_RST:
 		tcp_v6_restore_cb(skb);
-		goto no_tcp_socket;
+		tcp_v6_send_reset(sk, skb);
+		inet_twsk_deschedule_put(inet_twsk(sk));
+		goto discard_it;
 	case TCP_TW_SUCCESS:
 		;
 	}