Merge commit 'v2.6.28-rc2' into x86/pci-ioapic-boot-irq-quirks

1 files changed, 368 insertions, 315 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ad993ecb481..e4c5ac9fe89 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -5,8 +5,6 @@
  *
  *		Implementation of the Transmission Control Protocol(TCP).
  *
- * Version:	$Id: tcp_output.c,v 1.146 2002/02/01 22:01:04 davem Exp $
- *
  * Authors:	Ross Biro
  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  *		Mark Evans, <evansmp@uhura.aston.ac.uk>
@@ -347,112 +345,240 @@ static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags)
 	TCP_SKB_CB(skb)->end_seq = seq;
 }
 
-static void tcp_build_and_update_options(__be32 *ptr, struct tcp_sock *tp,
-					 __u32 tstamp, __u8 **md5_hash)
+static inline int tcp_urg_mode(const struct tcp_sock *tp)
 {
-	if (tp->rx_opt.tstamp_ok) {
-		*ptr++ = htonl((TCPOPT_NOP << 24) |
-			       (TCPOPT_NOP << 16) |
-			       (TCPOPT_TIMESTAMP << 8) |
-			       TCPOLEN_TIMESTAMP);
-		*ptr++ = htonl(tstamp);
-		*ptr++ = htonl(tp->rx_opt.ts_recent);
-	}
-	if (tp->rx_opt.eff_sacks) {
-		struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks;
-		int this_sack;
-
-		*ptr++ = htonl((TCPOPT_NOP  << 24) |
-			       (TCPOPT_NOP  << 16) |
-			       (TCPOPT_SACK <<  8) |
-			       (TCPOLEN_SACK_BASE + (tp->rx_opt.eff_sacks *
-						     TCPOLEN_SACK_PERBLOCK)));
-
-		for (this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) {
-			*ptr++ = htonl(sp[this_sack].start_seq);
-			*ptr++ = htonl(sp[this_sack].end_seq);
-		}
+	return tp->snd_una != tp->snd_up;
+}
 
-		if (tp->rx_opt.dsack) {
-			tp->rx_opt.dsack = 0;
-			tp->rx_opt.eff_sacks--;
-		}
-	}
-#ifdef CONFIG_TCP_MD5SIG
-	if (md5_hash) {
+#define OPTION_SACK_ADVERTISE	(1 << 0)
+#define OPTION_TS		(1 << 1)
+#define OPTION_MD5		(1 << 2)
+
+struct tcp_out_options {
+	u8 options;		/* bit field of OPTION_* */
+	u8 ws;			/* window scale, 0 to disable */
+	u8 num_sack_blocks;	/* number of SACK blocks to include */
+	u16 mss;		/* 0 to disable */
+	__u32 tsval, tsecr;	/* need to include OPTION_TS */
+};
+
+/* Beware: Something in the Internet is very sensitive to the ordering of
+ * TCP options, we learned this through the hard way, so be careful here.
+ * Luckily we can at least blame others for their non-compliance but from
+ * inter-operatibility perspective it seems that we're somewhat stuck with
+ * the ordering which we have been using if we want to keep working with
+ * those broken things (not that it currently hurts anybody as there isn't
+ * particular reason why the ordering would need to be changed).
+ *
+ * At least SACK_PERM as the first option is known to lead to a disaster
+ * (but it may well be that other scenarios fail similarly).
+ */
+static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
+			      const struct tcp_out_options *opts,
+			      __u8 **md5_hash) {
+	if (unlikely(OPTION_MD5 & opts->options)) {
 		*ptr++ = htonl((TCPOPT_NOP << 24) |
 			       (TCPOPT_NOP << 16) |
 			       (TCPOPT_MD5SIG << 8) |
 			       TCPOLEN_MD5SIG);
 		*md5_hash = (__u8 *)ptr;
+		ptr += 4;
+	} else {
+		*md5_hash = NULL;
 	}
-#endif
-}
 
-/* Construct a tcp options header for a SYN or SYN_ACK packet.
- * If this is every changed make sure to change the definition of
- * MAX_SYN_SIZE to match the new maximum number of options that you
- * can generate.
- *
- * Note - that with the RFC2385 TCP option, we make room for the
- * 16 byte MD5 hash. This will be filled in later, so the pointer for the
- * location to be filled is passed back up.
- */
-static void tcp_syn_build_options(__be32 *ptr, int mss, int ts, int sack,
-				  int offer_wscale, int wscale, __u32 tstamp,
-				  __u32 ts_recent, __u8 **md5_hash)
-{
-	/* We always get an MSS option.
-	 * The option bytes which will be seen in normal data
-	 * packets should timestamps be used, must be in the MSS
-	 * advertised.  But we subtract them from tp->mss_cache so
-	 * that calculations in tcp_sendmsg are simpler etc.
-	 * So account for this fact here if necessary.  If we
-	 * don't do this correctly, as a receiver we won't
-	 * recognize data packets as being full sized when we
-	 * should, and thus we won't abide by the delayed ACK
-	 * rules correctly.
-	 * SACKs don't matter, we never delay an ACK when we
-	 * have any of those going out.
-	 */
-	*ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss);
-	if (ts) {
-		if (sack)
+	if (unlikely(opts->mss)) {
+		*ptr++ = htonl((TCPOPT_MSS << 24) |
+			       (TCPOLEN_MSS << 16) |
+			       opts->mss);
+	}
+
+	if (likely(OPTION_TS & opts->options)) {
+		if (unlikely(OPTION_SACK_ADVERTISE & opts->options)) {
 			*ptr++ = htonl((TCPOPT_SACK_PERM << 24) |
 				       (TCPOLEN_SACK_PERM << 16) |
 				       (TCPOPT_TIMESTAMP << 8) |
 				       TCPOLEN_TIMESTAMP);
-		else
+		} else {
 			*ptr++ = htonl((TCPOPT_NOP << 24) |
 				       (TCPOPT_NOP << 16) |
 				       (TCPOPT_TIMESTAMP << 8) |
 				       TCPOLEN_TIMESTAMP);
-		*ptr++ = htonl(tstamp);		/* TSVAL */
-		*ptr++ = htonl(ts_recent);	/* TSECR */
-	} else if (sack)
+		}
+		*ptr++ = htonl(opts->tsval);
+		*ptr++ = htonl(opts->tsecr);
+	}
+
+	if (unlikely(OPTION_SACK_ADVERTISE & opts->options &&
+		     !(OPTION_TS & opts->options))) {
 		*ptr++ = htonl((TCPOPT_NOP << 24) |
 			       (TCPOPT_NOP << 16) |
 			       (TCPOPT_SACK_PERM << 8) |
 			       TCPOLEN_SACK_PERM);
-	if (offer_wscale)
+	}
+
+	if (unlikely(opts->ws)) {
 		*ptr++ = htonl((TCPOPT_NOP << 24) |
 			       (TCPOPT_WINDOW << 16) |
 			       (TCPOLEN_WINDOW << 8) |
-			       (wscale));
+			       opts->ws);
+	}
+
+	if (unlikely(opts->num_sack_blocks)) {
+		struct tcp_sack_block *sp = tp->rx_opt.dsack ?
+			tp->duplicate_sack : tp->selective_acks;
+		int this_sack;
+
+		*ptr++ = htonl((TCPOPT_NOP  << 24) |
+			       (TCPOPT_NOP  << 16) |
+			       (TCPOPT_SACK <<  8) |
+			       (TCPOLEN_SACK_BASE + (opts->num_sack_blocks *
+						     TCPOLEN_SACK_PERBLOCK)));
+
+		for (this_sack = 0; this_sack < opts->num_sack_blocks;
+		     ++this_sack) {
+			*ptr++ = htonl(sp[this_sack].start_seq);
+			*ptr++ = htonl(sp[this_sack].end_seq);
+		}
+
+		if (tp->rx_opt.dsack) {
+			tp->rx_opt.dsack = 0;
+			tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks;
+		}
+	}
+}
+
+static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb,
+				struct tcp_out_options *opts,
+				struct tcp_md5sig_key **md5) {
+	struct tcp_sock *tp = tcp_sk(sk);
+	unsigned size = 0;
+
 #ifdef CONFIG_TCP_MD5SIG
-	/*
-	 * If MD5 is enabled, then we set the option, and include the size
-	 * (always 18). The actual MD5 hash is added just before the
-	 * packet is sent.
-	 */
-	if (md5_hash) {
-		*ptr++ = htonl((TCPOPT_NOP << 24) |
-			       (TCPOPT_NOP << 16) |
-			       (TCPOPT_MD5SIG << 8) |
-			       TCPOLEN_MD5SIG);
-		*md5_hash = (__u8 *)ptr;
+	*md5 = tp->af_specific->md5_lookup(sk, sk);
+	if (*md5) {
+		opts->options |= OPTION_MD5;
+		size += TCPOLEN_MD5SIG_ALIGNED;
+	}
+#else
+	*md5 = NULL;
+#endif
+
+	/* We always get an MSS option.  The option bytes which will be seen in
+	 * normal data packets should timestamps be used, must be in the MSS
+	 * advertised.  But we subtract them from tp->mss_cache so that
+	 * calculations in tcp_sendmsg are simpler etc.  So account for this
+	 * fact here if necessary.  If we don't do this correctly, as a
+	 * receiver we won't recognize data packets as being full sized when we
+	 * should, and thus we won't abide by the delayed ACK rules correctly.
+	 * SACKs don't matter, we never delay an ACK when we have any of those
+	 * going out.  */
+	opts->mss = tcp_advertise_mss(sk);
+	size += TCPOLEN_MSS_ALIGNED;
+
+	if (likely(sysctl_tcp_timestamps && *md5 == NULL)) {
+		opts->options |= OPTION_TS;
+		opts->tsval = TCP_SKB_CB(skb)->when;
+		opts->tsecr = tp->rx_opt.ts_recent;
+		size += TCPOLEN_TSTAMP_ALIGNED;
+	}
+	if (likely(sysctl_tcp_window_scaling)) {
+		opts->ws = tp->rx_opt.rcv_wscale;
+		if(likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
+	}
+	if (likely(sysctl_tcp_sack)) {
+		opts->options |= OPTION_SACK_ADVERTISE;
+		if (unlikely(!(OPTION_TS & opts->options)))
+			size += TCPOLEN_SACKPERM_ALIGNED;
+	}
+
+	return size;
+}
+
+static unsigned tcp_synack_options(struct sock *sk,
+				   struct request_sock *req,
+				   unsigned mss, struct sk_buff *skb,
+				   struct tcp_out_options *opts,
+				   struct tcp_md5sig_key **md5) {
+	unsigned size = 0;
+	struct inet_request_sock *ireq = inet_rsk(req);
+	char doing_ts;
+
+#ifdef CONFIG_TCP_MD5SIG
+	*md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req);
+	if (*md5) {
+		opts->options |= OPTION_MD5;
+		size += TCPOLEN_MD5SIG_ALIGNED;
+	}
+#else
+	*md5 = NULL;
+#endif
+
+	/* we can't fit any SACK blocks in a packet with MD5 + TS
+	   options. There was discussion about disabling SACK rather than TS in
+	   order to fit in better with old, buggy kernels, but that was deemed
+	   to be unnecessary. */
+	doing_ts = ireq->tstamp_ok && !(*md5 && ireq->sack_ok);
+
+	opts->mss = mss;
+	size += TCPOLEN_MSS_ALIGNED;
+
+	if (likely(ireq->wscale_ok)) {
+		opts->ws = ireq->rcv_wscale;
+		if(likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
+	}
+	if (likely(doing_ts)) {
+		opts->options |= OPTION_TS;
+		opts->tsval = TCP_SKB_CB(skb)->when;
+		opts->tsecr = req->ts_recent;
+		size += TCPOLEN_TSTAMP_ALIGNED;
+	}
+	if (likely(ireq->sack_ok)) {
+		opts->options |= OPTION_SACK_ADVERTISE;
+		if (unlikely(!doing_ts))
+			size += TCPOLEN_SACKPERM_ALIGNED;
+	}
+
+	return size;
+}
+
+static unsigned tcp_established_options(struct sock *sk, struct sk_buff *skb,
+					struct tcp_out_options *opts,
+					struct tcp_md5sig_key **md5) {
+	struct tcp_skb_cb *tcb = skb ? TCP_SKB_CB(skb) : NULL;
+	struct tcp_sock *tp = tcp_sk(sk);
+	unsigned size = 0;
+
+#ifdef CONFIG_TCP_MD5SIG
+	*md5 = tp->af_specific->md5_lookup(sk, sk);
+	if (unlikely(*md5)) {
+		opts->options |= OPTION_MD5;
+		size += TCPOLEN_MD5SIG_ALIGNED;
 	}
+#else
+	*md5 = NULL;
 #endif
+
+	if (likely(tp->rx_opt.tstamp_ok)) {
+		opts->options |= OPTION_TS;
+		opts->tsval = tcb ? tcb->when : 0;
+		opts->tsecr = tp->rx_opt.ts_recent;
+		size += TCPOLEN_TSTAMP_ALIGNED;
+	}
+
+	if (unlikely(tp->rx_opt.eff_sacks)) {
+		const unsigned remaining = MAX_TCP_OPTION_SPACE - size;
+		opts->num_sack_blocks =
+			min_t(unsigned, tp->rx_opt.eff_sacks,
+			      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
+			      TCPOLEN_SACK_PERBLOCK);
+		size += TCPOLEN_SACK_BASE_ALIGNED +
+			opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
+	}
+
+	return size;
 }
 
 /* This routine actually transmits TCP packets queued in by
@@ -473,13 +599,11 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 	struct inet_sock *inet;
 	struct tcp_sock *tp;
 	struct tcp_skb_cb *tcb;
-	int tcp_header_size;
-#ifdef CONFIG_TCP_MD5SIG
+	struct tcp_out_options opts;
+	unsigned tcp_options_size, tcp_header_size;
 	struct tcp_md5sig_key *md5;
 	__u8 *md5_hash_location;
-#endif
 	struct tcphdr *th;
-	int sysctl_flags;
 	int err;
 
 	BUG_ON(!skb || !tcp_skb_pcount(skb));
@@ -502,50 +626,18 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 	inet = inet_sk(sk);
 	tp = tcp_sk(sk);
 	tcb = TCP_SKB_CB(skb);
-	tcp_header_size = tp->tcp_header_len;
-
-#define SYSCTL_FLAG_TSTAMPS	0x1
-#define SYSCTL_FLAG_WSCALE	0x2
-#define SYSCTL_FLAG_SACK	0x4
+	memset(&opts, 0, sizeof(opts));
 
-	sysctl_flags = 0;
-	if (unlikely(tcb->flags & TCPCB_FLAG_SYN)) {
-		tcp_header_size = sizeof(struct tcphdr) + TCPOLEN_MSS;
-		if (sysctl_tcp_timestamps) {
-			tcp_header_size += TCPOLEN_TSTAMP_ALIGNED;
-			sysctl_flags |= SYSCTL_FLAG_TSTAMPS;
-		}
-		if (sysctl_tcp_window_scaling) {
-			tcp_header_size += TCPOLEN_WSCALE_ALIGNED;
-			sysctl_flags |= SYSCTL_FLAG_WSCALE;
-		}
-		if (sysctl_tcp_sack) {
-			sysctl_flags |= SYSCTL_FLAG_SACK;
-			if (!(sysctl_flags & SYSCTL_FLAG_TSTAMPS))
-				tcp_header_size += TCPOLEN_SACKPERM_ALIGNED;
-		}
-	} else if (unlikely(tp->rx_opt.eff_sacks)) {
-		/* A SACK is 2 pad bytes, a 2 byte header, plus
-		 * 2 32-bit sequence numbers for each SACK block.
-		 */
-		tcp_header_size += (TCPOLEN_SACK_BASE_ALIGNED +
-				    (tp->rx_opt.eff_sacks *
-				     TCPOLEN_SACK_PERBLOCK));
-	}
+	if (unlikely(tcb->flags & TCPCB_FLAG_SYN))
+		tcp_options_size = tcp_syn_options(sk, skb, &opts, &md5);
+	else
+		tcp_options_size = tcp_established_options(sk, skb, &opts,
+							   &md5);
+	tcp_header_size = tcp_options_size + sizeof(struct tcphdr);
 
 	if (tcp_packets_in_flight(tp) == 0)
 		tcp_ca_event(sk, CA_EVENT_TX_START);
 
-#ifdef CONFIG_TCP_MD5SIG
-	/*
-	 * Are we doing MD5 on this segment? If so - make
-	 * room for it.
-	 */
-	md5 = tp->af_specific->md5_lookup(sk, sk);
-	if (md5)
-		tcp_header_size += TCPOLEN_MD5SIG_ALIGNED;
-#endif
-
 	skb_push(skb, tcp_header_size);
 	skb_reset_transport_header(skb);
 	skb_set_owner_w(skb, sk);
@@ -570,45 +662,23 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 	th->check		= 0;
 	th->urg_ptr		= 0;
 
-	if (unlikely(tp->urg_mode &&
+	/* The urg_mode check is necessary during a below snd_una win probe */
+	if (unlikely(tcp_urg_mode(tp) &&
 		     between(tp->snd_up, tcb->seq + 1, tcb->seq + 0xFFFF))) {
 		th->urg_ptr		= htons(tp->snd_up - tcb->seq);
 		th->urg			= 1;
 	}
 
-	if (unlikely(tcb->flags & TCPCB_FLAG_SYN)) {
-		tcp_syn_build_options((__be32 *)(th + 1),
-				      tcp_advertise_mss(sk),
-				      (sysctl_flags & SYSCTL_FLAG_TSTAMPS),
-				      (sysctl_flags & SYSCTL_FLAG_SACK),
-				      (sysctl_flags & SYSCTL_FLAG_WSCALE),
-				      tp->rx_opt.rcv_wscale,
-				      tcb->when,
-				      tp->rx_opt.ts_recent,
-
-#ifdef CONFIG_TCP_MD5SIG
-				      md5 ? &md5_hash_location :
-#endif
-				      NULL);
-	} else {
-		tcp_build_and_update_options((__be32 *)(th + 1),
-					     tp, tcb->when,
-#ifdef CONFIG_TCP_MD5SIG
-					     md5 ? &md5_hash_location :
-#endif
-					     NULL);
+	tcp_options_write((__be32 *)(th + 1), tp, &opts, &md5_hash_location);
+	if (likely((tcb->flags & TCPCB_FLAG_SYN) == 0))
 		TCP_ECN_send(sk, skb, tcp_header_size);
-	}
 
 #ifdef CONFIG_TCP_MD5SIG
 	/* Calculate the MD5 hash, as we have all we need now */
 	if (md5) {
+		sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
 		tp->af_specific->calc_md5_hash(md5_hash_location,
-					       md5,
-					       sk, NULL, NULL,
-					       tcp_hdr(skb),
-					       sk->sk_protocol,
-					       skb->len);
+					       md5, sk, NULL, skb);
 	}
 #endif
 
@@ -621,7 +691,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 		tcp_event_data_sent(tp, skb, sk);
 
 	if (after(tcb->end_seq, tp->snd_nxt) || tcb->seq == tcb->end_seq)
-		TCP_INC_STATS(TCP_MIB_OUTSEGS);
+		TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS);
 
 	err = icsk->icsk_af_ops->queue_xmit(skb, 0);
 	if (likely(err <= 0))
@@ -630,10 +700,6 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 	tcp_enter_cwr(sk, 1);
 
 	return net_xmit_eval(err);
-
-#undef SYSCTL_FLAG_TSTAMPS
-#undef SYSCTL_FLAG_WSCALE
-#undef SYSCTL_FLAG_SACK
 }
 
 /* This routine just queue's the buffer
@@ -963,7 +1029,7 @@ unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu)
 /* Compute the current effective MSS, taking SACKs and IP options,
  * and even PMTU discovery events into account.
  *
- * LARGESEND note: !urg_mode is overkill, only frames up to snd_up
+ * LARGESEND note: !tcp_urg_mode is overkill, only frames up to snd_up
  * cannot be large. However, taking into account rare use of URG, this
  * is not a big flaw.
  */
@@ -974,10 +1040,13 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
 	u32 mss_now;
 	u16 xmit_size_goal;
 	int doing_tso = 0;
+	unsigned header_len;
+	struct tcp_out_options opts;
+	struct tcp_md5sig_key *md5;
 
 	mss_now = tp->mss_cache;
 
-	if (large_allowed && sk_can_gso(sk) && !tp->urg_mode)
+	if (large_allowed && sk_can_gso(sk) && !tcp_urg_mode(tp))
 		doing_tso = 1;
 
 	if (dst) {
@@ -986,14 +1055,16 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
 			mss_now = tcp_sync_mss(sk, mtu);
 	}
 
-	if (tp->rx_opt.eff_sacks)
-		mss_now -= (TCPOLEN_SACK_BASE_ALIGNED +
-			    (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK));
-
-#ifdef CONFIG_TCP_MD5SIG
-	if (tp->af_specific->md5_lookup(sk, sk))
-		mss_now -= TCPOLEN_MD5SIG_ALIGNED;
-#endif
+	header_len = tcp_established_options(sk, NULL, &opts, &md5) +
+		     sizeof(struct tcphdr);
+	/* The mss_cache is sized based on tp->tcp_header_len, which assumes
+	 * some common options. If this is an odd packet (because we have SACK
+	 * blocks etc) then our calculated header_len will be different, and
+	 * we have to adjust mss_now correspondingly */
+	if (header_len != tp->tcp_header_len) {
+		int delta = (int) header_len - tp->tcp_header_len;
+		mss_now -= delta;
+	}
 
 	xmit_size_goal = mss_now;
 
@@ -1139,7 +1210,7 @@ static inline int tcp_nagle_test(struct tcp_sock *tp, struct sk_buff *skb,
 	/* Don't use the nagle rule for urgent data (or for the final FIN).
 	 * Nagle can be ignored during F-RTO too (see RFC4138).
 	 */
-	if (tp->urg_mode || (tp->frto_counter == 2) ||
+	if (tcp_urg_mode(tp) || (tp->frto_counter == 2) ||
 	    (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN))
 		return 1;
 
@@ -1770,6 +1841,8 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb,
 
 	/* changed transmit queue under us so clear hints */
 	tcp_clear_retrans_hints_partial(tp);
+	if (next_skb == tp->retransmit_skb_hint)
+		tp->retransmit_skb_hint = skb;
 
 	sk_wmem_free_skb(sk, next_skb);
 }
@@ -1784,7 +1857,7 @@ void tcp_simple_retransmit(struct sock *sk)
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *skb;
 	unsigned int mss = tcp_current_mss(sk, 0);
-	int lost = 0;
+	u32 prior_lost = tp->lost_out;
 
 	tcp_for_write_queue(skb, sk) {
 		if (skb == tcp_send_head(sk))
@@ -1795,17 +1868,13 @@ void tcp_simple_retransmit(struct sock *sk)
 				TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
 				tp->retrans_out -= tcp_skb_pcount(skb);
 			}
-			if (!(TCP_SKB_CB(skb)->sacked & TCPCB_LOST)) {
-				TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
-				tp->lost_out += tcp_skb_pcount(skb);
-				lost = 1;
-			}
+			tcp_skb_mark_lost_uncond_verify(tp, skb);
 		}
 	}
 
-	tcp_clear_all_retrans_hints(tp);
+	tcp_clear_retrans_hints_partial(tp);
 
-	if (!lost)
+	if (prior_lost == tp->lost_out)
 		return;
 
 	if (tcp_is_reno(tp))
@@ -1880,8 +1949,8 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	/* Collapse two adjacent packets if worthwhile and we can. */
 	if (!(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_SYN) &&
 	    (skb->len < (cur_mss >> 1)) &&
-	    (tcp_write_queue_next(sk, skb) != tcp_send_head(sk)) &&
 	    (!tcp_skb_is_last(sk, skb)) &&
+	    (tcp_write_queue_next(sk, skb) != tcp_send_head(sk)) &&
 	    (skb_shinfo(skb)->nr_frags == 0 &&
 	     skb_shinfo(tcp_write_queue_next(sk, skb))->nr_frags == 0) &&
 	    (tcp_skb_pcount(skb) == 1 &&
@@ -1913,7 +1982,7 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 
 	if (err == 0) {
 		/* Update global TCP statistics. */
-		TCP_INC_STATS(TCP_MIB_RETRANSSEGS);
+		TCP_INC_STATS(sock_net(sk), TCP_MIB_RETRANSSEGS);
 
 		tp->total_retrans++;
 
@@ -1942,83 +2011,18 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	return err;
 }
 
-/* This gets called after a retransmit timeout, and the initially
- * retransmitted data is acknowledged.  It tries to continue
- * resending the rest of the retransmit queue, until either
- * we've sent it all or the congestion window limit is reached.
- * If doing SACK, the first ACK which comes back for a timeout
- * based retransmit packet might feed us FACK information again.
- * If so, we use it to avoid unnecessarily retransmissions.
- */
-void tcp_xmit_retransmit_queue(struct sock *sk)
+static int tcp_can_forward_retransmit(struct sock *sk)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
-	struct sk_buff *skb;
-	int packet_cnt;
-
-	if (tp->retransmit_skb_hint) {
-		skb = tp->retransmit_skb_hint;
-		packet_cnt = tp->retransmit_cnt_hint;
-	} else {
-		skb = tcp_write_queue_head(sk);
-		packet_cnt = 0;
-	}
-
-	/* First pass: retransmit lost packets. */
-	if (tp->lost_out) {
-		tcp_for_write_queue_from(skb, sk) {
-			__u8 sacked = TCP_SKB_CB(skb)->sacked;
-
-			if (skb == tcp_send_head(sk))
-				break;
-			/* we could do better than to assign each time */
-			tp->retransmit_skb_hint = skb;
-			tp->retransmit_cnt_hint = packet_cnt;
-
-			/* Assume this retransmit will generate
-			 * only one packet for congestion window
-			 * calculation purposes.  This works because
-			 * tcp_retransmit_skb() will chop up the
-			 * packet to be MSS sized and all the
-			 * packet counting works out.
-			 */
-			if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
-				return;
-
-			if (sacked & TCPCB_LOST) {
-				if (!(sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))) {
-					if (tcp_retransmit_skb(sk, skb)) {
-						tp->retransmit_skb_hint = NULL;
-						return;
-					}
-					if (icsk->icsk_ca_state != TCP_CA_Loss)
-						NET_INC_STATS_BH(LINUX_MIB_TCPFASTRETRANS);
-					else
-						NET_INC_STATS_BH(LINUX_MIB_TCPSLOWSTARTRETRANS);
-
-					if (skb == tcp_write_queue_head(sk))
-						inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
-									  inet_csk(sk)->icsk_rto,
-									  TCP_RTO_MAX);
-				}
-
-				packet_cnt += tcp_skb_pcount(skb);
-				if (packet_cnt >= tp->lost_out)
-					break;
-			}
-		}
-	}
-
-	/* OK, demanded retransmission is finished. */
 
 	/* Forward retransmissions are possible only during Recovery. */
 	if (icsk->icsk_ca_state != TCP_CA_Recovery)
-		return;
+		return 0;
 
 	/* No forward retransmissions in Reno are possible. */
 	if (tcp_is_reno(tp))
-		return;
+		return 0;
 
 	/* Yeah, we have to make difficult choice between forward transmission
 	 * and retransmission... Both ways have their merits...
@@ -2029,43 +2033,104 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
 	 */
 
 	if (tcp_may_send_now(sk))
-		return;
+		return 0;
 
-	/* If nothing is SACKed, highest_sack in the loop won't be valid */
-	if (!tp->sacked_out)
-		return;
+	return 1;
+}
 
-	if (tp->forward_skb_hint)
-		skb = tp->forward_skb_hint;
-	else
+/* This gets called after a retransmit timeout, and the initially
+ * retransmitted data is acknowledged.  It tries to continue
+ * resending the rest of the retransmit queue, until either
+ * we've sent it all or the congestion window limit is reached.
+ * If doing SACK, the first ACK which comes back for a timeout
+ * based retransmit packet might feed us FACK information again.
+ * If so, we use it to avoid unnecessarily retransmissions.
+ */
+void tcp_xmit_retransmit_queue(struct sock *sk)
+{
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct sk_buff *skb;
+	struct sk_buff *hole = NULL;
+	u32 last_lost;
+	int mib_idx;
+	int fwd_rexmitting = 0;
+
+	if (!tp->lost_out)
+		tp->retransmit_high = tp->snd_una;
+
+	if (tp->retransmit_skb_hint) {
+		skb = tp->retransmit_skb_hint;
+		last_lost = TCP_SKB_CB(skb)->end_seq;
+		if (after(last_lost, tp->retransmit_high))
+			last_lost = tp->retransmit_high;
+	} else {
 		skb = tcp_write_queue_head(sk);
+		last_lost = tp->snd_una;
+	}
 
+	/* First pass: retransmit lost packets. */
 	tcp_for_write_queue_from(skb, sk) {
-		if (skb == tcp_send_head(sk))
-			break;
-		tp->forward_skb_hint = skb;
+		__u8 sacked = TCP_SKB_CB(skb)->sacked;
 
-		if (!before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
+		if (skb == tcp_send_head(sk))
 			break;
+		/* we could do better than to assign each time */
+		if (hole == NULL)
+			tp->retransmit_skb_hint = skb;
 
+		/* Assume this retransmit will generate
+		 * only one packet for congestion window
+		 * calculation purposes.  This works because
+		 * tcp_retransmit_skb() will chop up the
+		 * packet to be MSS sized and all the
+		 * packet counting works out.
+		 */
 		if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
-			break;
+			return;
+
+		if (fwd_rexmitting) {
+begin_fwd:
+			if (!before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
+				break;
+			mib_idx = LINUX_MIB_TCPFORWARDRETRANS;
+
+		} else if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high)) {
+			tp->retransmit_high = last_lost;
+			if (!tcp_can_forward_retransmit(sk))
+				break;
+			/* Backtrack if necessary to non-L'ed skb */
+			if (hole != NULL) {
+				skb = hole;
+				hole = NULL;
+			}
+			fwd_rexmitting = 1;
+			goto begin_fwd;
 
-		if (TCP_SKB_CB(skb)->sacked & TCPCB_TAGBITS)
+		} else if (!(sacked & TCPCB_LOST)) {
+			if (hole == NULL && !(sacked & TCPCB_SACKED_RETRANS))
+				hole = skb;
 			continue;
 
-		/* Ok, retransmit it. */
-		if (tcp_retransmit_skb(sk, skb)) {
-			tp->forward_skb_hint = NULL;
-			break;
+		} else {
+			last_lost = TCP_SKB_CB(skb)->end_seq;
+			if (icsk->icsk_ca_state != TCP_CA_Loss)
+				mib_idx = LINUX_MIB_TCPFASTRETRANS;
+			else
+				mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS;
 		}
 
+		if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))
+			continue;
+
+		if (tcp_retransmit_skb(sk, skb))
+			return;
+		NET_INC_STATS_BH(sock_net(sk), mib_idx);
+
 		if (skb == tcp_write_queue_head(sk))
 			inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
 						  inet_csk(sk)->icsk_rto,
 						  TCP_RTO_MAX);
-
-		NET_INC_STATS_BH(LINUX_MIB_TCPFORWARDRETRANS);
 	}
 }
 
@@ -2119,7 +2184,7 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority)
 	/* NOTE: No TCP options attached and we never retransmit this. */
 	skb = alloc_skb(MAX_TCP_HEADER, priority);
 	if (!skb) {
-		NET_INC_STATS(LINUX_MIB_TCPABORTFAILED);
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTFAILED);
 		return;
 	}
 
@@ -2130,9 +2195,9 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority)
 	/* Send it off. */
 	TCP_SKB_CB(skb)->when = tcp_time_stamp;
 	if (tcp_transmit_skb(sk, skb, 0, priority))
-		NET_INC_STATS(LINUX_MIB_TCPABORTFAILED);
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTFAILED);
 
-	TCP_INC_STATS(TCP_MIB_OUTRSTS);
+	TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTRSTS);
 }
 
 /* WARNING: This routine must only be called when we have already sent
@@ -2180,11 +2245,11 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcphdr *th;
 	int tcp_header_size;
+	struct tcp_out_options opts;
 	struct sk_buff *skb;
-#ifdef CONFIG_TCP_MD5SIG
 	struct tcp_md5sig_key *md5;
 	__u8 *md5_hash_location;
-#endif
+	int mss;
 
 	skb = sock_wmalloc(sk, MAX_TCP_HEADER + 15, 1, GFP_ATOMIC);
 	if (skb == NULL)
@@ -2195,18 +2260,30 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 
 	skb->dst = dst_clone(dst);
 
-	tcp_header_size = (sizeof(struct tcphdr) + TCPOLEN_MSS +
-			   (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0) +
-			   (ireq->wscale_ok ? TCPOLEN_WSCALE_ALIGNED : 0) +
-			   /* SACK_PERM is in the place of NOP NOP of TS */
-			   ((ireq->sack_ok && !ireq->tstamp_ok) ? TCPOLEN_SACKPERM_ALIGNED : 0));
+	mss = dst_metric(dst, RTAX_ADVMSS);
+	if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss)
+		mss = tp->rx_opt.user_mss;
+
+	if (req->rcv_wnd == 0) { /* ignored for retransmitted syns */
+		__u8 rcv_wscale;
+		/* Set this up on the first call only */
+		req->window_clamp = tp->window_clamp ? : dst_metric(dst, RTAX_WINDOW);
+		/* tcp_full_space because it is guaranteed to be the first packet */
+		tcp_select_initial_window(tcp_full_space(sk),
+			mss - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0),
+			&req->rcv_wnd,
+			&req->window_clamp,
+			ireq->wscale_ok,
+			&rcv_wscale);
+		ireq->rcv_wscale = rcv_wscale;
+	}
+
+	memset(&opts, 0, sizeof(opts));
+	TCP_SKB_CB(skb)->when = tcp_time_stamp;
+	tcp_header_size = tcp_synack_options(sk, req, mss,
+					     skb, &opts, &md5) +
+			  sizeof(struct tcphdr);
 
-#ifdef CONFIG_TCP_MD5SIG
-	/* Are we doing MD5 on this segment? If so - make room for it */
-	md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req);
-	if (md5)
-		tcp_header_size += TCPOLEN_MD5SIG_ALIGNED;
-#endif
 	skb_push(skb, tcp_header_size);
 	skb_reset_transport_header(skb);
 
@@ -2215,7 +2292,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 	th->syn = 1;
 	th->ack = 1;
 	TCP_ECN_make_synack(req, th);
-	th->source = inet_sk(sk)->sport;
+	th->source = ireq->loc_port;
 	th->dest = ireq->rmt_port;
 	/* Setting of flags are superfluous here for callers (and ECE is
 	 * not even correctly set)
@@ -2224,19 +2301,6 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 			     TCPCB_FLAG_SYN | TCPCB_FLAG_ACK);
 	th->seq = htonl(TCP_SKB_CB(skb)->seq);
 	th->ack_seq = htonl(tcp_rsk(req)->rcv_isn + 1);
-	if (req->rcv_wnd == 0) { /* ignored for retransmitted syns */
-		__u8 rcv_wscale;
-		/* Set this up on the first call only */
-		req->window_clamp = tp->window_clamp ? : dst_metric(dst, RTAX_WINDOW);
-		/* tcp_full_space because it is guaranteed to be the first packet */
-		tcp_select_initial_window(tcp_full_space(sk),
-			dst_metric(dst, RTAX_ADVMSS) - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0),
-			&req->rcv_wnd,
-			&req->window_clamp,
-			ireq->wscale_ok,
-			&rcv_wscale);
-		ireq->rcv_wscale = rcv_wscale;
-	}
 
 	/* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */
 	th->window = htons(min(req->rcv_wnd, 65535U));
@@ -2245,29 +2309,15 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 		TCP_SKB_CB(skb)->when = cookie_init_timestamp(req);
 	else
 #endif
-	TCP_SKB_CB(skb)->when = tcp_time_stamp;
-	tcp_syn_build_options((__be32 *)(th + 1), dst_metric(dst, RTAX_ADVMSS), ireq->tstamp_ok,
-			      ireq->sack_ok, ireq->wscale_ok, ireq->rcv_wscale,
-			      TCP_SKB_CB(skb)->when,
-			      req->ts_recent,
-			      (
-#ifdef CONFIG_TCP_MD5SIG
-			       md5 ? &md5_hash_location :
-#endif
-			       NULL)
-			      );
-
+	tcp_options_write((__be32 *)(th + 1), tp, &opts, &md5_hash_location);
 	th->doff = (tcp_header_size >> 2);
-	TCP_INC_STATS(TCP_MIB_OUTSEGS);
+	TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS);
 
 #ifdef CONFIG_TCP_MD5SIG
 	/* Okay, we have all we need - do the md5 hash if needed */
 	if (md5) {
 		tp->af_specific->calc_md5_hash(md5_hash_location,
-					       md5,
-					       NULL, dst, req,
-					       tcp_hdr(skb), sk->sk_protocol,
-					       skb->len);
+					       md5, NULL, req, skb);
 	}
 #endif
 
@@ -2304,6 +2354,9 @@ static void tcp_connect_init(struct sock *sk)
 	if (!tp->window_clamp)
 		tp->window_clamp = dst_metric(dst, RTAX_WINDOW);
 	tp->advmss = dst_metric(dst, RTAX_ADVMSS);
+	if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < tp->advmss)
+		tp->advmss = tp->rx_opt.user_mss;
+
 	tcp_initialize_rcv_mss(sk);
 
 	tcp_select_initial_window(tcp_full_space(sk),
@@ -2322,6 +2375,7 @@ static void tcp_connect_init(struct sock *sk)
 	tcp_init_wl(tp, tp->write_seq, 0);
 	tp->snd_una = tp->write_seq;
 	tp->snd_sml = tp->write_seq;
+	tp->snd_up = tp->write_seq;
 	tp->rcv_nxt = 0;
 	tp->rcv_wup = 0;
 	tp->copied_seq = 0;
@@ -2367,7 +2421,7 @@ int tcp_connect(struct sock *sk)
 	 */
 	tp->snd_nxt = tp->write_seq;
 	tp->pushed_seq = tp->write_seq;
-	TCP_INC_STATS(TCP_MIB_ACTIVEOPENS);
+	TCP_INC_STATS(sock_net(sk), TCP_MIB_ACTIVEOPENS);
 
 	/* Timer for repeating the SYN until an answer. */
 	inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
@@ -2531,8 +2585,7 @@ int tcp_write_wakeup(struct sock *sk)
 			tcp_event_new_data_sent(sk, skb);
 		return err;
 	} else {
-		if (tp->urg_mode &&
-		    between(tp->snd_up, tp->snd_una + 1, tp->snd_una + 0xFFFF))
+		if (between(tp->snd_up, tp->snd_una + 1, tp->snd_una + 0xFFFF))
 			tcp_xmit_probe_skb(sk, 1);
 		return tcp_xmit_probe_skb(sk, 0);
 	}