1 files changed, 48 insertions, 17 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 7facdb0f6960..5119856017ab 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1625,13 +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);
@@ -1639,8 +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. */
@@ -1681,11 +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;
 
@@ -2134,11 +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) {
@@ -2157,13 +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);
@@ -2180,17 +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
@@ -2524,7 +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);
         }
 
@@ -2586,6 +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);