1 files changed, 142 insertions, 105 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 7c83cb8bf13..f0eb4e337ec 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -363,15 +363,17 @@ static inline void TCP_ECN_send(struct sock *sk, struct sk_buff *skb,
  */
 static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags)
 {
+	struct skb_shared_info *shinfo = skb_shinfo(skb);
+
 	skb->ip_summed = CHECKSUM_PARTIAL;
 	skb->csum = 0;
 
 	TCP_SKB_CB(skb)->tcp_flags = flags;
 	TCP_SKB_CB(skb)->sacked = 0;
 
-	skb_shinfo(skb)->gso_segs = 1;
-	skb_shinfo(skb)->gso_size = 0;
-	skb_shinfo(skb)->gso_type = 0;
+	shinfo->gso_segs = 1;
+	shinfo->gso_size = 0;
+	shinfo->gso_type = 0;
 
 	TCP_SKB_CB(skb)->seq = seq;
 	if (flags & (TCPHDR_SYN | TCPHDR_FIN))
@@ -406,7 +408,7 @@ struct tcp_out_options {
  * 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
+ * inter-operability 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).
@@ -637,6 +639,8 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 	unsigned int size = 0;
 	unsigned int eff_sacks;
 
+	opts->options = 0;
+
 #ifdef CONFIG_TCP_MD5SIG
 	*md5 = tp->af_specific->md5_lookup(sk, sk);
 	if (unlikely(*md5)) {
@@ -677,7 +681,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
  *
  * Its important tcp_wfree() can be replaced by sock_wfree() in the event skb
  * needs to be reallocated in a driver.
- * The invariant being skb->truesize substracted from sk->sk_wmem_alloc
+ * The invariant being skb->truesize subtracted from sk->sk_wmem_alloc
  *
  * Since transmit from skb destructor is forbidden, we use a tasklet
  * to process all sockets that eventually need to send more skbs.
@@ -694,12 +698,13 @@ static void tcp_tsq_handler(struct sock *sk)
 	if ((1 << sk->sk_state) &
 	    (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_CLOSING |
 	     TCPF_CLOSE_WAIT  | TCPF_LAST_ACK))
-		tcp_write_xmit(sk, tcp_current_mss(sk), 0, 0, GFP_ATOMIC);
+		tcp_write_xmit(sk, tcp_current_mss(sk), tcp_sk(sk)->nonagle,
+			       0, GFP_ATOMIC);
 }
 /*
- * One tasklest per cpu tries to send more skbs.
+ * One tasklet per cpu tries to send more skbs.
  * We run in tasklet context but need to disable irqs when
- * transfering tsq->head because tcp_wfree() might
+ * transferring tsq->head because tcp_wfree() might
  * interrupt us (non NAPI drivers)
  */
 static void tcp_tasklet_func(unsigned long data)
@@ -793,7 +798,7 @@ void __init tcp_tasklet_init(void)
 
 /*
  * Write buffer destructor automatically called from kfree_skb.
- * We cant xmit new skbs from this context, as we might already
+ * We can't xmit new skbs from this context, as we might already
  * hold qdisc lock.
  */
 void tcp_wfree(struct sk_buff *skb)
@@ -848,19 +853,19 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 
 	BUG_ON(!skb || !tcp_skb_pcount(skb));
 
-	/* If congestion control is doing timestamping, we must
-	 * take such a timestamp before we potentially clone/copy.
-	 */
-	if (icsk->icsk_ca_ops->flags & TCP_CONG_RTT_STAMP)
-		__net_timestamp(skb);
-
-	if (likely(clone_it)) {
+	if (clone_it) {
 		const struct sk_buff *fclone = skb + 1;
 
+		/* If congestion control is doing timestamping, we must
+		 * take such a timestamp before we potentially clone/copy.
+		 */
+		if (icsk->icsk_ca_ops->flags & TCP_CONG_RTT_STAMP)
+			__net_timestamp(skb);
+
 		if (unlikely(skb->fclone == SKB_FCLONE_ORIG &&
 			     fclone->fclone == SKB_FCLONE_CLONE))
-			NET_INC_STATS_BH(sock_net(sk),
-					 LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES);
+			NET_INC_STATS(sock_net(sk),
+				      LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES);
 
 		if (unlikely(skb_cloned(skb)))
 			skb = pskb_copy(skb, gfp_mask);
@@ -895,8 +900,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 
 	skb_orphan(skb);
 	skb->sk = sk;
-	skb->destructor = (sysctl_tcp_limit_output_bytes > 0) ?
-			  tcp_wfree : sock_wfree;
+	skb->destructor = tcp_wfree;
 	atomic_add(skb->truesize, &sk->sk_wmem_alloc);
 
 	/* Build TCP header and checksum it. */
@@ -985,18 +989,22 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb)
 static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
 				 unsigned int mss_now)
 {
-	if (skb->len <= mss_now || !sk_can_gso(sk) ||
-	    skb->ip_summed == CHECKSUM_NONE) {
+	struct skb_shared_info *shinfo = skb_shinfo(skb);
+
+	/* Make sure we own this skb before messing gso_size/gso_segs */
+	WARN_ON_ONCE(skb_cloned(skb));
+
+	if (skb->len <= mss_now || skb->ip_summed == CHECKSUM_NONE) {
 		/* Avoid the costly divide in the normal
 		 * non-TSO case.
 		 */
-		skb_shinfo(skb)->gso_segs = 1;
-		skb_shinfo(skb)->gso_size = 0;
-		skb_shinfo(skb)->gso_type = 0;
+		shinfo->gso_segs = 1;
+		shinfo->gso_size = 0;
+		shinfo->gso_type = 0;
 	} else {
-		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss_now);
-		skb_shinfo(skb)->gso_size = mss_now;
-		skb_shinfo(skb)->gso_type = sk->sk_gso_type;
+		shinfo->gso_segs = DIV_ROUND_UP(skb->len, mss_now);
+		shinfo->gso_size = mss_now;
+		shinfo->gso_type = sk->sk_gso_type;
 	}
 }
 
@@ -1066,9 +1074,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
 	if (nsize < 0)
 		nsize = 0;
 
-	if (skb_cloned(skb) &&
-	    skb_is_nonlinear(skb) &&
-	    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+	if (skb_unclone(skb, GFP_ATOMIC))
 		return -ENOMEM;
 
 	/* Get a new skb... force flag on. */
@@ -1145,6 +1151,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
  */
 static void __pskb_trim_head(struct sk_buff *skb, int len)
 {
+	struct skb_shared_info *shinfo;
 	int i, k, eat;
 
 	eat = min_t(int, len, skb_headlen(skb));
@@ -1156,23 +1163,24 @@ static void __pskb_trim_head(struct sk_buff *skb, int len)
 	}
 	eat = len;
 	k = 0;
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
-		int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+	shinfo = skb_shinfo(skb);
+	for (i = 0; i < shinfo->nr_frags; i++) {
+		int size = skb_frag_size(&shinfo->frags[i]);
 
 		if (size <= eat) {
 			skb_frag_unref(skb, i);
 			eat -= size;
 		} else {
-			skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
+			shinfo->frags[k] = shinfo->frags[i];
 			if (eat) {
-				skb_shinfo(skb)->frags[k].page_offset += eat;
-				skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
+				shinfo->frags[k].page_offset += eat;
+				skb_frag_size_sub(&shinfo->frags[k], eat);
 				eat = 0;
 			}
 			k++;
 		}
 	}
-	skb_shinfo(skb)->nr_frags = k;
+	shinfo->nr_frags = k;
 
 	skb_reset_tail_pointer(skb);
 	skb->data_len -= len;
@@ -1377,23 +1385,51 @@ static void tcp_cwnd_validate(struct sock *sk)
 	}
 }
 
-/* Returns the portion of skb which can be sent right away without
- * introducing MSS oddities to segment boundaries. In rare cases where
- * mss_now != mss_cache, we will request caller to create a small skb
- * per input skb which could be mostly avoided here (if desired).
- *
- * We explicitly want to create a request for splitting write queue tail
- * to a small skb for Nagle purposes while avoiding unnecessary modulos,
- * thus all the complexity (cwnd_len is always MSS multiple which we
- * return whenever allowed by the other factors). Basically we need the
- * modulo only when the receiver window alone is the limiting factor or
- * when we would be allowed to send the split-due-to-Nagle skb fully.
+/* Minshall's variant of the Nagle send check. */
+static bool tcp_minshall_check(const struct tcp_sock *tp)
+{
+	return after(tp->snd_sml, tp->snd_una) &&
+		!after(tp->snd_sml, tp->snd_nxt);
+}
+
+/* Update snd_sml if this skb is under mss
+ * Note that a TSO packet might end with a sub-mss segment
+ * The test is really :
+ * if ((skb->len % mss) != 0)
+ *        tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
+ * But we can avoid doing the divide again given we already have
+ *  skb_pcount = skb->len / mss_now
  */
-static unsigned int tcp_mss_split_point(const struct sock *sk, const struct sk_buff *skb,
-					unsigned int mss_now, unsigned int max_segs)
+static void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss_now,
+				const struct sk_buff *skb)
+{
+	if (skb->len < tcp_skb_pcount(skb) * mss_now)
+		tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
+}
+
+/* Return false, if packet can be sent now without violation Nagle's rules:
+ * 1. It is full sized. (provided by caller in %partial bool)
+ * 2. Or it contains FIN. (already checked by caller)
+ * 3. Or TCP_CORK is not set, and TCP_NODELAY is set.
+ * 4. Or TCP_CORK is not set, and all sent packets are ACKed.
+ *    With Minshall's modification: all sent small packets are ACKed.
+ */
+static bool tcp_nagle_check(bool partial, const struct tcp_sock *tp,
+			    unsigned int mss_now, int nonagle)
+{
+	return partial &&
+		((nonagle & TCP_NAGLE_CORK) ||
+		 (!nonagle && tp->packets_out && tcp_minshall_check(tp)));
+}
+/* Returns the portion of skb which can be sent right away */
+static unsigned int tcp_mss_split_point(const struct sock *sk,
+					const struct sk_buff *skb,
+					unsigned int mss_now,
+					unsigned int max_segs,
+					int nonagle)
 {
 	const struct tcp_sock *tp = tcp_sk(sk);
-	u32 needed, window, max_len;
+	u32 partial, needed, window, max_len;
 
 	window = tcp_wnd_end(tp) - TCP_SKB_CB(skb)->seq;
 	max_len = mss_now * max_segs;
@@ -1406,7 +1442,15 @@ static unsigned int tcp_mss_split_point(const struct sock *sk, const struct sk_b
 	if (max_len <= needed)
 		return max_len;
 
-	return needed - needed % mss_now;
+	partial = needed % mss_now;
+	/* If last segment is not a full MSS, check if Nagle rules allow us
+	 * to include this last segment in this skb.
+	 * Otherwise, we'll split the skb at last MSS boundary
+	 */
+	if (tcp_nagle_check(partial != 0, tp, mss_now, nonagle))
+		return needed - partial;
+
+	return needed;
 }
 
 /* Can at least one segment of SKB be sent right now, according to the
@@ -1446,28 +1490,6 @@ static int tcp_init_tso_segs(const struct sock *sk, struct sk_buff *skb,
 	return tso_segs;
 }
 
-/* Minshall's variant of the Nagle send check. */
-static inline bool tcp_minshall_check(const struct tcp_sock *tp)
-{
-	return after(tp->snd_sml, tp->snd_una) &&
-		!after(tp->snd_sml, tp->snd_nxt);
-}
-
-/* Return false, if packet can be sent now without violation Nagle's rules:
- * 1. It is full sized.
- * 2. Or it contains FIN. (already checked by caller)
- * 3. Or TCP_CORK is not set, and TCP_NODELAY is set.
- * 4. Or TCP_CORK is not set, and all sent packets are ACKed.
- *    With Minshall's modification: all sent small packets are ACKed.
- */
-static inline bool tcp_nagle_check(const struct tcp_sock *tp,
-				  const struct sk_buff *skb,
-				  unsigned int mss_now, int nonagle)
-{
-	return skb->len < mss_now &&
-		((nonagle & TCP_NAGLE_CORK) ||
-		 (!nonagle && tp->packets_out && tcp_minshall_check(tp)));
-}
 
 /* Return true if the Nagle test allows this packet to be
  * sent now.
@@ -1488,7 +1510,7 @@ static inline bool tcp_nagle_test(const struct tcp_sock *tp, const struct sk_buf
 	if (tcp_urg_mode(tp) || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN))
 		return true;
 
-	if (!tcp_nagle_check(tp, skb, cur_mss, nonagle))
+	if (!tcp_nagle_check(skb->len < cur_mss, tp, cur_mss, nonagle))
 		return true;
 
 	return false;
@@ -1840,7 +1862,6 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 	while ((skb = tcp_send_head(sk))) {
 		unsigned int limit;
 
-
 		tso_segs = tcp_init_tso_segs(sk, skb, mss_now);
 		BUG_ON(!tso_segs);
 
@@ -1869,19 +1890,39 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 				break;
 		}
 
-		/* TSQ : sk_wmem_alloc accounts skb truesize,
-		 * including skb overhead. But thats OK.
+		/* TCP Small Queues :
+		 * Control number of packets in qdisc/devices to two packets / or ~1 ms.
+		 * This allows for :
+		 *  - better RTT estimation and ACK scheduling
+		 *  - faster recovery
+		 *  - high rates
+		 * Alas, some drivers / subsystems require a fair amount
+		 * of queued bytes to ensure line rate.
+		 * One example is wifi aggregation (802.11 AMPDU)
 		 */
-		if (atomic_read(&sk->sk_wmem_alloc) >= sysctl_tcp_limit_output_bytes) {
+		limit = max_t(unsigned int, sysctl_tcp_limit_output_bytes,
+			      sk->sk_pacing_rate >> 10);
+
+		if (atomic_read(&sk->sk_wmem_alloc) > limit) {
 			set_bit(TSQ_THROTTLED, &tp->tsq_flags);
-			break;
+			/* It is possible TX completion already happened
+			 * before we set TSQ_THROTTLED, so we must
+			 * test again the condition.
+			 * We abuse smp_mb__after_clear_bit() because
+			 * there is no smp_mb__after_set_bit() yet
+			 */
+			smp_mb__after_clear_bit();
+			if (atomic_read(&sk->sk_wmem_alloc) > limit)
+				break;
 		}
+
 		limit = mss_now;
 		if (tso_segs > 1 && !tcp_urg_mode(tp))
 			limit = tcp_mss_split_point(sk, skb, mss_now,
 						    min_t(unsigned int,
 							  cwnd_quota,
-							  sk->sk_gso_max_segs));
+							  sk->sk_gso_max_segs),
+						    nonagle);
 
 		if (skb->len > limit &&
 		    unlikely(tso_fragment(sk, skb, limit, mss_now, gfp)))
@@ -1945,7 +1986,7 @@ bool tcp_schedule_loss_probe(struct sock *sk)
 	/* Schedule a loss probe in 2*RTT for SACK capable connections
 	 * in Open state, that are either limited by cwnd or application.
 	 */
-	if (sysctl_tcp_early_retrans < 3 || !rtt || !tp->packets_out ||
+	if (sysctl_tcp_early_retrans < 3 || !tp->srtt || !tp->packets_out ||
 	    !tcp_is_sack(tp) || inet_csk(sk)->icsk_ca_state != TCP_CA_Open)
 		return false;
 
@@ -2296,6 +2337,7 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	unsigned int cur_mss;
+	int err;
 
 	/* Inconslusive MTU probe */
 	if (icsk->icsk_mtup.probe_size) {
@@ -2337,6 +2379,8 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 		int oldpcount = tcp_skb_pcount(skb);
 
 		if (unlikely(oldpcount > 1)) {
+			if (skb_unclone(skb, GFP_ATOMIC))
+				return -ENOMEM;
 			tcp_init_tso_segs(sk, skb, cur_mss);
 			tcp_adjust_pcount(sk, skb, oldpcount - tcp_skb_pcount(skb));
 		}
@@ -2344,21 +2388,6 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 
 	tcp_retrans_try_collapse(sk, skb, cur_mss);
 
-	/* Some Solaris stacks overoptimize and ignore the FIN on a
-	 * retransmit when old data is attached.  So strip it off
-	 * since it is cheap to do so and saves bytes on the network.
-	 */
-	if (skb->len > 0 &&
-	    (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) &&
-	    tp->snd_una == (TCP_SKB_CB(skb)->end_seq - 1)) {
-		if (!pskb_trim(skb, 0)) {
-			/* Reuse, even though it does some unnecessary work */
-			tcp_init_nondata_skb(skb, TCP_SKB_CB(skb)->end_seq - 1,
-					     TCP_SKB_CB(skb)->tcp_flags);
-			skb->ip_summed = CHECKSUM_NONE;
-		}
-	}
-
 	/* Make a copy, if the first transmission SKB clone we made
 	 * is still in somebody's hands, else make a clone.
 	 */
@@ -2372,11 +2401,15 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 		     skb_headroom(skb) >= 0xFFFF)) {
 		struct sk_buff *nskb = __pskb_copy(skb, MAX_TCP_HEADER,
 						   GFP_ATOMIC);
-		return nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
-			      -ENOBUFS;
+		err = nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
+			     -ENOBUFS;
 	} else {
-		return tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
+		err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
 	}
+
+	if (likely(!err))
+		TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS;
+	return err;
 }
 
 int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
@@ -2727,8 +2760,8 @@ 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 = ireq->loc_port;
-	th->dest = ireq->rmt_port;
+	th->source = htons(ireq->ir_num);
+	th->dest = ireq->ir_rmt_port;
 	/* Setting of flags are superfluous here for callers (and ECE is
 	 * not even correctly set)
 	 */
@@ -2758,7 +2791,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 EXPORT_SYMBOL(tcp_make_synack);
 
 /* Do all connect socket setups that can be done AF independent. */
-void tcp_connect_init(struct sock *sk)
+static void tcp_connect_init(struct sock *sk)
 {
 	const struct dst_entry *dst = __sk_dst_get(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
@@ -2880,7 +2913,12 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
 	space = __tcp_mtu_to_mss(sk, inet_csk(sk)->icsk_pmtu_cookie) -
 		MAX_TCP_OPTION_SPACE;
 
-	syn_data = skb_copy_expand(syn, skb_headroom(syn), space,
+	space = min_t(size_t, space, fo->size);
+
+	/* limit to order-0 allocations */
+	space = min_t(size_t, space, SKB_MAX_HEAD(MAX_TCP_HEADER));
+
+	syn_data = skb_copy_expand(syn, MAX_TCP_HEADER, space,
 				   sk->sk_allocation);
 	if (syn_data == NULL)
 		goto fallback;
@@ -3099,7 +3137,6 @@ void tcp_send_window_probe(struct sock *sk)
 {
 	if (sk->sk_state == TCP_ESTABLISHED) {
 		tcp_sk(sk)->snd_wl1 = tcp_sk(sk)->rcv_nxt - 1;
-		tcp_sk(sk)->snd_nxt = tcp_sk(sk)->write_seq;
 		tcp_xmit_probe_skb(sk, 0);
 	}
 }