tcp: md5: rcu conversion

In order to be able to support proper RST messages for TCP MD5 flows, we
need to allow access to MD5 keys without locking listener socket.

This conversion is a nice cleanup, and shrinks size of timewait sockets
by 80 bytes.

IPv6 code reuses generic code found in IPv4 instead of duplicating it.

Control path uses GFP_KERNEL allocations instead of GFP_ATOMIC.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Shawn Lu <shawn.lu@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 161 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index f37769ea6375..bec41f9a6413 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -540,19 +540,7 @@ static void tcp_v6_reqsk_destructor(struct request_sock *req)
 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
 						   const struct in6_addr *addr)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
-	int i;
-
-	BUG_ON(tp == NULL);
-
-	if (!tp->md5sig_info || !tp->md5sig_info->entries6)
-		return NULL;
-
-	for (i = 0; i < tp->md5sig_info->entries6; i++) {
-		if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, addr))
-			return &tp->md5sig_info->keys6[i].base;
-	}
-	return NULL;
+	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 }
 
 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
@@ -567,129 +555,11 @@ static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
 	return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
 }
 
-static int tcp_v6_md5_do_add(struct sock *sk, const struct in6_addr *peer,
-			     char *newkey, u8 newkeylen)
-{
-	/* Add key to the list */
-	struct tcp_md5sig_key *key;
-	struct tcp_sock *tp = tcp_sk(sk);
-	struct tcp6_md5sig_key *keys;
-
-	key = tcp_v6_md5_do_lookup(sk, peer);
-	if (key) {
-		/* modify existing entry - just update that one */
-		kfree(key->key);
-		key->key = newkey;
-		key->keylen = newkeylen;
-	} else {
-		/* reallocate new list if current one is full. */
-		if (!tp->md5sig_info) {
-			tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info), GFP_ATOMIC);
-			if (!tp->md5sig_info) {
-				kfree(newkey);
-				return -ENOMEM;
-			}
-			sk_nocaps_add(sk, NETIF_F_GSO_MASK);
-		}
-		if (tp->md5sig_info->entries6 == 0 &&
-			tcp_alloc_md5sig_pool(sk) == NULL) {
-			kfree(newkey);
-			return -ENOMEM;
-		}
-		if (tp->md5sig_info->alloced6 == tp->md5sig_info->entries6) {
-			keys = kmalloc((sizeof (tp->md5sig_info->keys6[0]) *
-				       (tp->md5sig_info->entries6 + 1)), GFP_ATOMIC);
-
-			if (!keys) {
-				kfree(newkey);
-				if (tp->md5sig_info->entries6 == 0)
-					tcp_free_md5sig_pool();
-				return -ENOMEM;
-			}
-
-			if (tp->md5sig_info->entries6)
-				memmove(keys, tp->md5sig_info->keys6,
-					(sizeof (tp->md5sig_info->keys6[0]) *
-					 tp->md5sig_info->entries6));
-
-			kfree(tp->md5sig_info->keys6);
-			tp->md5sig_info->keys6 = keys;
-			tp->md5sig_info->alloced6++;
-		}
-
-		tp->md5sig_info->keys6[tp->md5sig_info->entries6].addr = *peer;
-		tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.key = newkey;
-		tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.keylen = newkeylen;
-
-		tp->md5sig_info->entries6++;
-	}
-	return 0;
-}
-
-static int tcp_v6_md5_do_del(struct sock *sk, const struct in6_addr *peer)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-	int i;
-
-	for (i = 0; i < tp->md5sig_info->entries6; i++) {
-		if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, peer)) {
-			/* Free the key */
-			kfree(tp->md5sig_info->keys6[i].base.key);
-			tp->md5sig_info->entries6--;
-
-			if (tp->md5sig_info->entries6 == 0) {
-				kfree(tp->md5sig_info->keys6);
-				tp->md5sig_info->keys6 = NULL;
-				tp->md5sig_info->alloced6 = 0;
-				tcp_free_md5sig_pool();
-			} else {
-				/* shrink the database */
-				if (tp->md5sig_info->entries6 != i)
-					memmove(&tp->md5sig_info->keys6[i],
-						&tp->md5sig_info->keys6[i+1],
-						(tp->md5sig_info->entries6 - i)
-						* sizeof (tp->md5sig_info->keys6[0]));
-			}
-			return 0;
-		}
-	}
-	return -ENOENT;
-}
-
-static void tcp_v6_clear_md5_list (struct sock *sk)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-	int i;
-
-	if (tp->md5sig_info->entries6) {
-		for (i = 0; i < tp->md5sig_info->entries6; i++)
-			kfree(tp->md5sig_info->keys6[i].base.key);
-		tp->md5sig_info->entries6 = 0;
-		tcp_free_md5sig_pool();
-	}
-
-	kfree(tp->md5sig_info->keys6);
-	tp->md5sig_info->keys6 = NULL;
-	tp->md5sig_info->alloced6 = 0;
-
-	if (tp->md5sig_info->entries4) {
-		for (i = 0; i < tp->md5sig_info->entries4; i++)
-			kfree(tp->md5sig_info->keys4[i].base.key);
-		tp->md5sig_info->entries4 = 0;
-		tcp_free_md5sig_pool();
-	}
-
-	kfree(tp->md5sig_info->keys4);
-	tp->md5sig_info->keys4 = NULL;
-	tp->md5sig_info->alloced4 = 0;
-}
-
 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
 				  int optlen)
 {
 	struct tcp_md5sig cmd;
 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
-	u8 *newkey;
 
 	if (optlen < sizeof(cmd))
 		return -EINVAL;
@@ -704,33 +574,21 @@ static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
 		if (!tcp_sk(sk)->md5sig_info)
 			return -ENOENT;
 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
-			return tcp_v4_md5_do_del(sk, sin6->sin6_addr.s6_addr32[3]);
-		return tcp_v6_md5_do_del(sk, &sin6->sin6_addr);
+			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
+					      AF_INET);
+		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
+				      AF_INET6);
 	}
 
 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 		return -EINVAL;
 
-	if (!tcp_sk(sk)->md5sig_info) {
-		struct tcp_sock *tp = tcp_sk(sk);
-		struct tcp_md5sig_info *p;
-
-		p = kzalloc(sizeof(struct tcp_md5sig_info), GFP_KERNEL);
-		if (!p)
-			return -ENOMEM;
-
-		tp->md5sig_info = p;
-		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
-	}
+	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
+		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
+				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 
-	newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
-	if (!newkey)
-		return -ENOMEM;
-	if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
-		return tcp_v4_md5_do_add(sk, sin6->sin6_addr.s6_addr32[3],
-					 newkey, cmd.tcpm_keylen);
-	}
-	return tcp_v6_md5_do_add(sk, &sin6->sin6_addr, newkey, cmd.tcpm_keylen);
+	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
+			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 }
 
 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
@@ -1503,10 +1361,8 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 		 * memory, then we end up not copying the key
 		 * across. Shucks.
 		 */
-		char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
-		if (newkey != NULL)
-			tcp_v6_md5_do_add(newsk, &newnp->daddr,
-					  newkey, key->keylen);
+		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newnp->daddr,
+			       AF_INET6, key->key, key->keylen, GFP_ATOMIC);
 	}
 #endif
 
@@ -1995,11 +1851,6 @@ static int tcp_v6_init_sock(struct sock *sk)
 
 static void tcp_v6_destroy_sock(struct sock *sk)
 {
-#ifdef CONFIG_TCP_MD5SIG
-	/* Clean up the MD5 key list */
-	if (tcp_sk(sk)->md5sig_info)
-		tcp_v6_clear_md5_list(sk);
-#endif
 	tcp_v4_destroy_sock(sk);
 	inet6_destroy_sock(sk);
 }