1 files changed, 109 insertions, 48 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 19c449f62672..bbb7d88a16b4 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1367,7 +1367,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
  * a normal way
  */
 static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk,
-                                        u32 skip_to_seq)
+                                        u32 skip_to_seq, int *fack_count)
 {
         tcp_for_write_queue_from(skb, sk) {
                 if (skb == tcp_send_head(sk))
@@ -1375,6 +1375,8 @@ static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk,
 
                 if (!before(TCP_SKB_CB(skb)->end_seq, skip_to_seq))
                         break;
+
+                *fack_count += tcp_skb_pcount(skb);
         }
         return skb;
 }
@@ -1390,7 +1392,7 @@ static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb,
                 return skb;
 
         if (before(next_dup->start_seq, skip_to_seq)) {
-                skb = tcp_sacktag_skip(skb, sk, next_dup->start_seq);
+                skb = tcp_sacktag_skip(skb, sk, next_dup->start_seq, fack_count);
                 tcp_sacktag_walk(skb, sk, NULL,
                                  next_dup->start_seq, next_dup->end_seq,
                                  1, fack_count, reord, flag);
@@ -1537,7 +1539,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb,
 
                         /* Head todo? */
                         if (before(start_seq, cache->start_seq)) {
-                                skb = tcp_sacktag_skip(skb, sk, start_seq);
+                                skb = tcp_sacktag_skip(skb, sk, start_seq,
+                                                       &fack_count);
                                 skb = tcp_sacktag_walk(skb, sk, next_dup,
                                                        start_seq,
                                                        cache->start_seq,
@@ -1565,7 +1568,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb,
                                 goto walk;
                         }
 
-                        skb = tcp_sacktag_skip(skb, sk, cache->end_seq);
+                        skb = tcp_sacktag_skip(skb, sk, cache->end_seq,
+                                               &fack_count);
                         /* Check overlap against next cached too (past this one already) */
                         cache++;
                         continue;
@@ -1577,7 +1581,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb,
                                 break;
                         fack_count = tp->fackets_out;
                 }
-                skb = tcp_sacktag_skip(skb, sk, start_seq);
+                skb = tcp_sacktag_skip(skb, sk, start_seq, &fack_count);
 
 walk:
                 skb = tcp_sacktag_walk(skb, sk, next_dup, start_seq, end_seq,
@@ -1621,13 +1625,11 @@ out:
         return flag;
 }
 
-/* If we receive more dupacks than we expected counting segments
- * in assumption of absent reordering, interpret this as reordering.
- * The only another reason could be bug in receiver TCP.
+/* Limits sacked_out so that sum with lost_out isn't ever larger than
+ * packets_out. Returns zero if sacked_out adjustement wasn't necessary.
  */
-static void tcp_check_reno_reordering(struct sock *sk, const int addend)
+int tcp_limit_reno_sacked(struct tcp_sock *tp)
 {
-        struct tcp_sock *tp = tcp_sk(sk);
         u32 holes;
 
         holes = max(tp->lost_out, 1U);
@@ -1635,8 +1637,20 @@ static void tcp_check_reno_reordering(struct sock *sk, const int addend)
 
         if ((tp->sacked_out + holes) > tp->packets_out) {
                 tp->sacked_out = tp->packets_out - holes;
-                tcp_update_reordering(sk, tp->packets_out + addend, 0);
+                return 1;
         }
+        return 0;
+}
+
+/* If we receive more dupacks than we expected counting segments
+ * in assumption of absent reordering, interpret this as reordering.
+ * The only another reason could be bug in receiver TCP.
+ */
+static void tcp_check_reno_reordering(struct sock *sk, const int addend)
+{
+        struct tcp_sock *tp = tcp_sk(sk);
+        if (tcp_limit_reno_sacked(tp))
+                tcp_update_reordering(sk, tp->packets_out + addend, 0);
 }
 
 /* Emulate SACKs for SACKless connection: account for a new dupack. */
@@ -1677,11 +1691,16 @@ static inline void tcp_reset_reno_sack(struct tcp_sock *tp)
 int tcp_use_frto(struct sock *sk)
 {
         const struct tcp_sock *tp = tcp_sk(sk);
+        const struct inet_connection_sock *icsk = inet_csk(sk);
         struct sk_buff *skb;
 
         if (!sysctl_tcp_frto)
                 return 0;
 
+        /* MTU probe and F-RTO won't really play nicely along currently */
+        if (icsk->icsk_mtup.probe_size)
+                return 0;
+
         if (IsSackFrto())
                 return 1;
 
@@ -2130,11 +2149,13 @@ static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb)
 /* Mark head of queue up as lost. With RFC3517 SACK, the packets is
  * is against sacked "cnt", otherwise it's against facked "cnt"
  */
-static void tcp_mark_head_lost(struct sock *sk, int packets, int fast_rexmit)
+static void tcp_mark_head_lost(struct sock *sk, int packets)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct sk_buff *skb;
-        int cnt;
+        int cnt, oldcnt;
+        int err;
+        unsigned int mss;
 
         BUG_TRAP(packets <= tp->packets_out);
         if (tp->lost_skb_hint) {
@@ -2153,13 +2174,25 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int fast_rexmit)
                 tp->lost_skb_hint = skb;
                 tp->lost_cnt_hint = cnt;
 
+                if (after(TCP_SKB_CB(skb)->end_seq, tp->high_seq))
+                        break;
+
+                oldcnt = cnt;
                 if (tcp_is_fack(tp) || tcp_is_reno(tp) ||
                     (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
                         cnt += tcp_skb_pcount(skb);
 
-                if (((!fast_rexmit || (tp->lost_out > 0)) && (cnt > packets)) ||
-                    after(TCP_SKB_CB(skb)->end_seq, tp->high_seq))
-                        break;
+                if (cnt > packets) {
+                        if (tcp_is_sack(tp) || (oldcnt >= packets))
+                                break;
+
+                        mss = skb_shinfo(skb)->gso_size;
+                        err = tcp_fragment(sk, skb, (packets - oldcnt) * mss, mss);
+                        if (err < 0)
+                                break;
+                        cnt = packets;
+                }
+
                 if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_SACKED_ACKED|TCPCB_LOST))) {
                         TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
                         tp->lost_out += tcp_skb_pcount(skb);
@@ -2176,17 +2209,17 @@ static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit)
         struct tcp_sock *tp = tcp_sk(sk);
 
         if (tcp_is_reno(tp)) {
-                tcp_mark_head_lost(sk, 1, fast_rexmit);
+                tcp_mark_head_lost(sk, 1);
         } else if (tcp_is_fack(tp)) {
                 int lost = tp->fackets_out - tp->reordering;
                 if (lost <= 0)
                         lost = 1;
-                tcp_mark_head_lost(sk, lost, fast_rexmit);
+                tcp_mark_head_lost(sk, lost);
         } else {
                 int sacked_upto = tp->sacked_out - tp->reordering;
-                if (sacked_upto < 0)
-                        sacked_upto = 0;
-                tcp_mark_head_lost(sk, sacked_upto, fast_rexmit);
+                if (sacked_upto < fast_rexmit)
+                        sacked_upto = fast_rexmit;
+                tcp_mark_head_lost(sk, sacked_upto);
         }
 
         /* New heuristics: it is possible only after we switched
@@ -2520,7 +2553,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
             before(tp->snd_una, tp->high_seq) &&
             icsk->icsk_ca_state != TCP_CA_Open &&
             tp->fackets_out > tp->reordering) {
-                tcp_mark_head_lost(sk, tp->fackets_out - tp->reordering, 0);
+                tcp_mark_head_lost(sk, tp->fackets_out - tp->reordering);
                 NET_INC_STATS_BH(LINUX_MIB_TCPLOSS);
         }
 
@@ -2582,6 +2615,8 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
         case TCP_CA_Loss:
                 if (flag & FLAG_DATA_ACKED)
                         icsk->icsk_retransmits = 0;
+                if (tcp_is_reno(tp) && flag & FLAG_SND_UNA_ADVANCED)
+                        tcp_reset_reno_sack(tp);
                 if (!tcp_try_undo_loss(sk)) {
                         tcp_moderate_cwnd(tp);
                         tcp_xmit_retransmit_queue(sk);
@@ -3806,8 +3841,28 @@ static void tcp_ofo_queue(struct sock *sk)
         }
 }
 
+static int tcp_prune_ofo_queue(struct sock *sk);
 static int tcp_prune_queue(struct sock *sk);
 
+static inline int tcp_try_rmem_schedule(struct sock *sk, unsigned int size)
+{
+        if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
+            !sk_rmem_schedule(sk, size)) {
+
+                if (tcp_prune_queue(sk) < 0)
+                        return -1;
+
+                if (!sk_rmem_schedule(sk, size)) {
+                        if (!tcp_prune_ofo_queue(sk))
+                                return -1;
+
+                        if (!sk_rmem_schedule(sk, size))
+                                return -1;
+                }
+        }
+        return 0;
+}
+
 static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
 {
         struct tcphdr *th = tcp_hdr(skb);
@@ -3857,12 +3912,9 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
                 if (eaten <= 0) {
 queue_and_out:
                         if (eaten < 0 &&
-                            (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
-                             !sk_rmem_schedule(sk, skb->truesize))) {
-                                if (tcp_prune_queue(sk) < 0 ||
-                                    !sk_rmem_schedule(sk, skb->truesize))
-                                        goto drop;
-                        }
+                            tcp_try_rmem_schedule(sk, skb->truesize))
+                                goto drop;
+
                         skb_set_owner_r(skb, sk);
                         __skb_queue_tail(&sk->sk_receive_queue, skb);
                 }
@@ -3931,12 +3983,8 @@ drop:
 
         TCP_ECN_check_ce(tp, skb);
 
-        if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
-            !sk_rmem_schedule(sk, skb->truesize)) {
-                if (tcp_prune_queue(sk) < 0 ||
-                    !sk_rmem_schedule(sk, skb->truesize))
-                        goto drop;
-        }
+        if (tcp_try_rmem_schedule(sk, skb->truesize))
+                goto drop;
 
         /* Disable header prediction. */
         tp->pred_flags = 0;
@@ -4163,6 +4211,32 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
         }
 }
 
+/*
+ * Purge the out-of-order queue.
+ * Return true if queue was pruned.
+ */
+static int tcp_prune_ofo_queue(struct sock *sk)
+{
+        struct tcp_sock *tp = tcp_sk(sk);
+        int res = 0;
+
+        if (!skb_queue_empty(&tp->out_of_order_queue)) {
+                NET_INC_STATS_BH(LINUX_MIB_OFOPRUNED);
+                __skb_queue_purge(&tp->out_of_order_queue);
+
+                /* Reset SACK state.  A conforming SACK implementation will
+                 * do the same at a timeout based retransmit.  When a connection
+                 * is in a sad state like this, we care only about integrity
+                 * of the connection not performance.
+                 */
+                if (tp->rx_opt.sack_ok)
+                        tcp_sack_reset(&tp->rx_opt);
+                sk_mem_reclaim(sk);
+                res = 1;
+        }
+        return res;
+}
+
 /* Reduce allocated memory if we can, trying to get
  * the socket within its memory limits again.
  *
@@ -4196,20 +4270,7 @@ static int tcp_prune_queue(struct sock *sk)
         /* Collapsing did not help, destructive actions follow.
          * This must not ever occur. */
 
-        /* First, purge the out_of_order queue. */
-        if (!skb_queue_empty(&tp->out_of_order_queue)) {
-                NET_INC_STATS_BH(LINUX_MIB_OFOPRUNED);
-                __skb_queue_purge(&tp->out_of_order_queue);
-
-                /* Reset SACK state.  A conforming SACK implementation will
-                 * do the same at a timeout based retransmit.  When a connection
-                 * is in a sad state like this, we care only about integrity
-                 * of the connection not performance.
-                 */
-                if (tcp_is_sack(tp))
-                        tcp_sack_reset(&tp->rx_opt);
-                sk_mem_reclaim(sk);
-        }
+        tcp_prune_ofo_queue(sk);
 
         if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf)
                 return 0;