1 files changed, 54 insertions, 16 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 6d88219c5e2..7cda24b53f6 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -328,26 +328,29 @@ static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
  *
  */
 
-void tcp_v4_err(struct sk_buff *skb, u32 info)
+void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 {
-	struct iphdr *iph = (struct iphdr *)skb->data;
-	struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
+	struct iphdr *iph = (struct iphdr *)icmp_skb->data;
+	struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
+	struct inet_connection_sock *icsk;
 	struct tcp_sock *tp;
 	struct inet_sock *inet;
-	const int type = icmp_hdr(skb)->type;
-	const int code = icmp_hdr(skb)->code;
+	const int type = icmp_hdr(icmp_skb)->type;
+	const int code = icmp_hdr(icmp_skb)->code;
 	struct sock *sk;
+	struct sk_buff *skb;
 	__u32 seq;
+	__u32 remaining;
 	int err;
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net(icmp_skb->dev);
 
-	if (skb->len < (iph->ihl << 2) + 8) {
+	if (icmp_skb->len < (iph->ihl << 2) + 8) {
 		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 		return;
 	}
 
 	sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
-			iph->saddr, th->source, inet_iif(skb));
+			iph->saddr, th->source, inet_iif(icmp_skb));
 	if (!sk) {
 		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 		return;
@@ -367,6 +370,7 @@ void tcp_v4_err(struct sk_buff *skb, u32 info)
 	if (sk->sk_state == TCP_CLOSE)
 		goto out;
 
+	icsk = inet_csk(sk);
 	tp = tcp_sk(sk);
 	seq = ntohl(th->seq);
 	if (sk->sk_state != TCP_LISTEN &&
@@ -393,6 +397,39 @@ void tcp_v4_err(struct sk_buff *skb, u32 info)
 		}
 
 		err = icmp_err_convert[code].errno;
+		/* check if icmp_skb allows revert of backoff
+		 * (see draft-zimmermann-tcp-lcd) */
+		if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
+			break;
+		if (seq != tp->snd_una  || !icsk->icsk_retransmits ||
+		    !icsk->icsk_backoff)
+			break;
+
+		icsk->icsk_backoff--;
+		inet_csk(sk)->icsk_rto = __tcp_set_rto(tp) <<
+					 icsk->icsk_backoff;
+		tcp_bound_rto(sk);
+
+		skb = tcp_write_queue_head(sk);
+		BUG_ON(!skb);
+
+		remaining = icsk->icsk_rto - min(icsk->icsk_rto,
+				tcp_time_stamp - TCP_SKB_CB(skb)->when);
+
+		if (remaining) {
+			inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+						  remaining, TCP_RTO_MAX);
+		} else if (sock_owned_by_user(sk)) {
+			/* RTO revert clocked out retransmission,
+			 * but socket is locked. Will defer. */
+			inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+						  HZ/20, TCP_RTO_MAX);
+		} else {
+			/* RTO revert clocked out retransmission.
+			 * Will retransmit now */
+			tcp_retransmit_timer(sk);
+		}
+
 		break;
 	case ICMP_TIME_EXCEEDED:
 		err = EHOSTUNREACH;
@@ -849,7 +886,7 @@ int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
 			}
 			sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
 		}
-		if (tcp_alloc_md5sig_pool() == NULL) {
+		if (tcp_alloc_md5sig_pool(sk) == NULL) {
 			kfree(newkey);
 			return -ENOMEM;
 		}
@@ -970,8 +1007,9 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
 
 	if (!tcp_sk(sk)->md5sig_info) {
 		struct tcp_sock *tp = tcp_sk(sk);
-		struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
+		struct tcp_md5sig_info *p;
 
+		p = kzalloc(sizeof(*p), sk->sk_allocation);
 		if (!p)
 			return -EINVAL;
 
@@ -979,7 +1017,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
 		sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
 	}
 
-	newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
+	newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
 	if (!newkey)
 		return -ENOMEM;
 	return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
@@ -1158,7 +1196,7 @@ struct request_sock_ops tcp_request_sock_ops __read_mostly = {
 };
 
 #ifdef CONFIG_TCP_MD5SIG
-static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
+static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
 	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
 };
@@ -1717,7 +1755,7 @@ int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
 	return 0;
 }
 
-struct inet_connection_sock_af_ops ipv4_specific = {
+const struct inet_connection_sock_af_ops ipv4_specific = {
 	.queue_xmit	   = ip_queue_xmit,
 	.send_check	   = tcp_v4_send_check,
 	.rebuild_header	   = inet_sk_rebuild_header,
@@ -1737,7 +1775,7 @@ struct inet_connection_sock_af_ops ipv4_specific = {
 };
 
 #ifdef CONFIG_TCP_MD5SIG
-static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
+static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
 	.md5_lookup		= tcp_v4_md5_lookup,
 	.calc_md5_hash		= tcp_v4_md5_hash_skb,
 	.md5_add		= tcp_v4_md5_add_func,
@@ -1770,7 +1808,7 @@ static int tcp_v4_init_sock(struct sock *sk)
 	/* See draft-stevens-tcpca-spec-01 for discussion of the
 	 * initialization of these values.
 	 */
-	tp->snd_ssthresh = 0x7fffffff;	/* Infinity */
+	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 	tp->snd_cwnd_clamp = ~0;
 	tp->mss_cache = 536;
 
@@ -2246,7 +2284,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
 		jiffies_to_clock_t(icsk->icsk_ack.ato),
 		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
 		tp->snd_cwnd,
-		tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
+		tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
 		len);
 }