X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=net%2Fipv4%2Ftcp_input.c;h=37e2aa925f62395cfb48145cd3a76b6afebb64b1;hb=3d4762639dd3;hp=2c1f59386a7bac8a8d9034ad8c64ba14d877fed2;hpb=dc25ad3fe1152559d5bbc792c1cb1f080a55f233;p=karo-tx-linux.git

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2c1f59386a7b..37e2aa925f62 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1935,6 +1935,7 @@ void tcp_enter_loss(struct sock *sk)
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct net *net = sock_net(sk);
 	struct sk_buff *skb;
+	bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery;
 	bool is_reneg;			/* is receiver reneging on SACKs? */
 	bool mark_lost;
 
@@ -1994,15 +1995,18 @@ void tcp_enter_loss(struct sock *sk)
 	tp->high_seq = tp->snd_nxt;
 	tcp_ecn_queue_cwr(tp);
 
-	/* F-RTO RFC5682 sec 3.1 step 1 mandates to disable F-RTO
-	 * if a previous recovery is underway, otherwise it may incorrectly
-	 * call a timeout spurious if some previously retransmitted packets
-	 * are s/acked (sec 3.2). We do not apply that retriction since
-	 * retransmitted skbs are permanently tagged with TCPCB_EVER_RETRANS
-	 * so FLAG_ORIG_SACK_ACKED is always correct. But we do disable F-RTO
-	 * on PTMU discovery to avoid sending new data.
+	/* F-RTO RFC5682 sec 3.1 step 1: retransmit SND.UNA if no previous
+	 * loss recovery is underway except recurring timeout(s) on
+	 * the same SND.UNA (sec 3.2). Disable F-RTO on path MTU probing
+	 *
+	 * In theory F-RTO can be used repeatedly during loss recovery.
+	 * In practice this interacts badly with broken middle-boxes that
+	 * falsely raise the receive window, which results in repeated
+	 * timeouts and stop-and-go behavior.
 	 */
-	tp->frto = sysctl_tcp_frto && !inet_csk(sk)->icsk_mtup.probe_size;
+	tp->frto = sysctl_tcp_frto &&
+		   (new_recovery || icsk->icsk_retransmits) &&
+		   !inet_csk(sk)->icsk_mtup.probe_size;
 }
 
 /* If ACK arrived pointing to a remembered SACK, it means that our
@@ -3764,11 +3768,12 @@ void tcp_parse_options(const struct sk_buff *skb,
 				    !estab && sysctl_tcp_window_scaling) {
 					__u8 snd_wscale = *(__u8 *)ptr;
 					opt_rx->wscale_ok = 1;
-					if (snd_wscale > 14) {
-						net_info_ratelimited("%s: Illegal window scaling value %d >14 received\n",
+					if (snd_wscale > TCP_MAX_WSCALE) {
+						net_info_ratelimited("%s: Illegal window scaling value %d > %u received\n",
 								     __func__,
-								     snd_wscale);
-						snd_wscale = 14;
+								     snd_wscale,
+								     TCP_MAX_WSCALE);
+						snd_wscale = TCP_MAX_WSCALE;
 					}
 					opt_rx->snd_wscale = snd_wscale;
 				}
@@ -4003,10 +4008,10 @@ void tcp_reset(struct sock *sk)
 	/* This barrier is coupled with smp_rmb() in tcp_poll() */
 	smp_wmb();
 
+	tcp_done(sk);
+
 	if (!sock_flag(sk, SOCK_DEAD))
 		sk->sk_error_report(sk);
-
-	tcp_done(sk);
 }
 
 /*
@@ -6329,36 +6334,14 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 		goto drop_and_free;
 
 	if (isn && tmp_opt.tstamp_ok)
-		af_ops->init_seq(skb, &tcp_rsk(req)->ts_off);
+		af_ops->init_seq_tsoff(skb, &tcp_rsk(req)->ts_off);
 
 	if (!want_cookie && !isn) {
-		/* VJ's idea. We save last timestamp seen
-		 * from the destination in peer table, when entering
-		 * state TIME-WAIT, and check against it before
-		 * accepting new connection request.
-		 *
-		 * If "isn" is not zero, this request hit alive
-		 * timewait bucket, so that all the necessary checks
-		 * are made in the function processing timewait state.
-		 */
-		if (net->ipv4.tcp_death_row.sysctl_tw_recycle) {
-			bool strict;
-
-			dst = af_ops->route_req(sk, &fl, req, &strict);
-
-			if (dst && strict &&
-			    !tcp_peer_is_proven(req, dst, true,
-						tmp_opt.saw_tstamp)) {
-				NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
-				goto drop_and_release;
-			}
-		}
 		/* Kill the following clause, if you dislike this way. */
-		else if (!net->ipv4.sysctl_tcp_syncookies &&
-			 (net->ipv4.sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
-			  (net->ipv4.sysctl_max_syn_backlog >> 2)) &&
-			 !tcp_peer_is_proven(req, dst, false,
-					     tmp_opt.saw_tstamp)) {
+		if (!net->ipv4.sysctl_tcp_syncookies &&
+		    (net->ipv4.sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
+		     (net->ipv4.sysctl_max_syn_backlog >> 2)) &&
+		    !tcp_peer_is_proven(req, dst)) {
 			/* Without syncookies last quarter of
 			 * backlog is filled with destinations,
 			 * proven to be alive.
@@ -6371,10 +6354,10 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 			goto drop_and_release;
 		}
 
-		isn = af_ops->init_seq(skb, &tcp_rsk(req)->ts_off);
+		isn = af_ops->init_seq_tsoff(skb, &tcp_rsk(req)->ts_off);
 	}
 	if (!dst) {
-		dst = af_ops->route_req(sk, &fl, req, NULL);
+		dst = af_ops->route_req(sk, &fl, req);
 		if (!dst)
 			goto drop_and_free;
 	}