Merge branch 'listener_refactor_16'

Eric Dumazet says:

====================
tcp: listener refactor part 16

A CONFIG_PROVE_RCU=y build revealed an RCU splat I had to fix.

I added const qualifiers to various md5 methods, as I expect
to call them on behalf of request sock traffic even if
the listener socket is not locked. This seems ok, but adding
const makes the contract clearer. Note a good reduction
of code size thanks to request/establish sockets convergence.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 38 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 4e90217003e8..fc8995a702a6 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -648,7 +648,7 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
 		if (!key)
 			goto release_sk1;
 
-		genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb);
+		genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
 			goto release_sk1;
 	} else {
@@ -898,10 +898,10 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
 					 const union tcp_md5_addr *addr,
 					 int family)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
+	const struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_md5sig_key *key;
 	unsigned int size = sizeof(struct in_addr);
-	struct tcp_md5sig_info *md5sig;
+	const struct tcp_md5sig_info *md5sig;
 
 	/* caller either holds rcu_read_lock() or socket lock */
 	md5sig = rcu_dereference_check(tp->md5sig_info,
@@ -924,24 +924,15 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
 EXPORT_SYMBOL(tcp_md5_do_lookup);
 
 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
-					 struct sock *addr_sk)
+					 const struct sock *addr_sk)
 {
 	union tcp_md5_addr *addr;
 
-	addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr;
+	addr = (union tcp_md5_addr *)&sk->sk_daddr;
 	return tcp_md5_do_lookup(sk, addr, AF_INET);
 }
 EXPORT_SYMBOL(tcp_v4_md5_lookup);
 
-static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
-						      struct request_sock *req)
-{
-	union tcp_md5_addr *addr;
-
-	addr = (union tcp_md5_addr *)&inet_rsk(req)->ir_rmt_addr;
-	return tcp_md5_do_lookup(sk, addr, AF_INET);
-}
-
 /* This can be called on a newly created socket, from other files */
 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 		   int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
@@ -1102,8 +1093,8 @@ clear_hash_noput:
 	return 1;
 }
 
-int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
-			const struct sock *sk, const struct request_sock *req,
+int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
+			const struct sock *sk,
 			const struct sk_buff *skb)
 {
 	struct tcp_md5sig_pool *hp;
@@ -1111,12 +1102,9 @@ int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
 	const struct tcphdr *th = tcp_hdr(skb);
 	__be32 saddr, daddr;
 
-	if (sk) {
-		saddr = inet_sk(sk)->inet_saddr;
-		daddr = inet_sk(sk)->inet_daddr;
-	} else if (req) {
-		saddr = inet_rsk(req)->ir_loc_addr;
-		daddr = inet_rsk(req)->ir_rmt_addr;
+	if (sk) { /* valid for establish/request sockets */
+		saddr = sk->sk_rcv_saddr;
+		daddr = sk->sk_daddr;
 	} else {
 		const struct iphdr *iph = ip_hdr(skb);
 		saddr = iph->saddr;
@@ -1153,8 +1141,9 @@ clear_hash_noput:
 }
 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
 
-static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
-				      const struct sk_buff *skb)
+/* Called with rcu_read_lock() */
+static bool tcp_v4_inbound_md5_hash(struct sock *sk,
+				    const struct sk_buff *skb)
 {
 	/*
 	 * This gets called for each TCP segment that arrives
@@ -1194,7 +1183,7 @@ static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
 	 */
 	genhash = tcp_v4_md5_hash_skb(newhash,
 				      hash_expected,
-				      NULL, NULL, skb);
+				      NULL, skb);
 
 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 		net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
@@ -1206,18 +1195,6 @@ static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
 	}
 	return false;
 }
-
-static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
-{
-	bool ret;
-
-	rcu_read_lock();
-	ret = __tcp_v4_inbound_md5_hash(sk, skb);
-	rcu_read_unlock();
-
-	return ret;
-}
-
 #endif
 
 static void tcp_v4_init_req(struct request_sock *req, struct sock *sk_listener,
@@ -1261,7 +1238,7 @@ struct request_sock_ops tcp_request_sock_ops __read_mostly = {
 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
 	.mss_clamp	=	TCP_MSS_DEFAULT,
 #ifdef CONFIG_TCP_MD5SIG
-	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
+	.req_md5_lookup	=	tcp_v4_md5_lookup,
 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
 #endif
 	.init_req	=	tcp_v4_init_req,