1 files changed, 35 insertions, 25 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1c12b8ec849d..7963e03f1068 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -808,20 +808,38 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
 	kfree(inet_rsk(req)->opt);
 }
 
-static void syn_flood_warning(const struct sk_buff *skb)
+/*
+ * Return 1 if a syncookie should be sent
+ */
+int tcp_syn_flood_action(struct sock *sk,
+			 const struct sk_buff *skb,
+			 const char *proto)
 {
-	const char *msg;
+	const char *msg = "Dropping request";
+	int want_cookie = 0;
+	struct listen_sock *lopt;
+
+
 
 #ifdef CONFIG_SYN_COOKIES
-	if (sysctl_tcp_syncookies)
+	if (sysctl_tcp_syncookies) {
 		msg = "Sending cookies";
-	else
+		want_cookie = 1;
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
+	} else
 #endif
-		msg = "Dropping request";
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
 
-	pr_info("TCP: Possible SYN flooding on port %d. %s.\n",
-				ntohs(tcp_hdr(skb)->dest), msg);
+	lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
+	if (!lopt->synflood_warned) {
+		lopt->synflood_warned = 1;
+		pr_info("%s: Possible SYN flooding on port %d. %s. "
+			" Check SNMP counters.\n",
+			proto, ntohs(tcp_hdr(skb)->dest), msg);
+	}
+	return want_cookie;
 }
+EXPORT_SYMBOL(tcp_syn_flood_action);
 
 /*
  * Save and compile IPv4 options into the request_sock if needed.
@@ -909,18 +927,21 @@ int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
 			}
 			sk_nocaps_add(sk, NETIF_F_GSO_MASK);
 		}
-		if (tcp_alloc_md5sig_pool(sk) == NULL) {
+
+		md5sig = tp->md5sig_info;
+		if (md5sig->entries4 == 0 &&
+		    tcp_alloc_md5sig_pool(sk) == NULL) {
 			kfree(newkey);
 			return -ENOMEM;
 		}
-		md5sig = tp->md5sig_info;
 
 		if (md5sig->alloced4 == md5sig->entries4) {
 			keys = kmalloc((sizeof(*keys) *
 					(md5sig->entries4 + 1)), GFP_ATOMIC);
 			if (!keys) {
 				kfree(newkey);
-				tcp_free_md5sig_pool();
+				if (md5sig->entries4 == 0)
+					tcp_free_md5sig_pool();
 				return -ENOMEM;
 			}
 
@@ -964,6 +985,7 @@ int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
 				kfree(tp->md5sig_info->keys4);
 				tp->md5sig_info->keys4 = NULL;
 				tp->md5sig_info->alloced4 = 0;
+				tcp_free_md5sig_pool();
 			} else if (tp->md5sig_info->entries4 != i) {
 				/* Need to do some manipulation */
 				memmove(&tp->md5sig_info->keys4[i],
@@ -971,7 +993,6 @@ int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
 					(tp->md5sig_info->entries4 - i) *
 					 sizeof(struct tcp4_md5sig_key));
 			}
-			tcp_free_md5sig_pool();
 			return 0;
 		}
 	}
@@ -1235,11 +1256,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	__be32 saddr = ip_hdr(skb)->saddr;
 	__be32 daddr = ip_hdr(skb)->daddr;
 	__u32 isn = TCP_SKB_CB(skb)->when;
-#ifdef CONFIG_SYN_COOKIES
 	int want_cookie = 0;
-#else
-#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
-#endif
 
 	/* Never answer to SYNs send to broadcast or multicast */
 	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
@@ -1250,14 +1267,9 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	 * evidently real one.
 	 */
 	if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
-		if (net_ratelimit())
-			syn_flood_warning(skb);
-#ifdef CONFIG_SYN_COOKIES
-		if (sysctl_tcp_syncookies) {
-			want_cookie = 1;
-		} else
-#endif
-		goto drop;
+		want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
+		if (!want_cookie)
+			goto drop;
 	}
 
 	/* Accept backlog is full. If we have already queued enough
@@ -1303,9 +1315,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 		while (l-- > 0)
 			*c++ ^= *hash_location++;
 
-#ifdef CONFIG_SYN_COOKIES
 		want_cookie = 0;	/* not our kind of cookie */
-#endif
 		tmp_ext.cookie_out_never = 0; /* false */
 		tmp_ext.cookie_plus = tmp_opt.cookie_plus;
 	} else if (!tp->rx_opt.cookie_in_always) {