[PATCH stable 4.4 1/9] Revert "tcp: detect malicious patterns in tcp_collapse_ofo_queue()"

[Mao Wenan]

This reverts commit dc6ae4dffd656811dee7151b19545e4cd839d378.
---
 net/ipv4/tcp_input.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4a261e0..995b2bc 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4791,7 +4791,6 @@ restart:
 static void tcp_collapse_ofo_queue(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
-       u32 range_truesize, sum_tiny = 0;
        struct sk_buff *skb = skb_peek(&tp->out_of_order_queue);
        struct sk_buff *head;
        u32 start, end;
@@ -4801,7 +4800,6 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
 
        start = TCP_SKB_CB(skb)->seq;
        end = TCP_SKB_CB(skb)->end_seq;
-       range_truesize = skb->truesize;
        head = skb;
 
        for (;;) {
@@ -4816,24 +4814,14 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
                if (!skb ||
                    after(TCP_SKB_CB(skb)->seq, end) ||
                    before(TCP_SKB_CB(skb)->end_seq, start)) {
-                       /* Do not attempt collapsing tiny skbs */
-                       if (range_truesize != head->truesize ||
-                           end - start >= SKB_WITH_OVERHEAD(SK_MEM_QUANTUM)) {
-                               tcp_collapse(sk, &tp->out_of_order_queue,
-                                            head, skb, start, end);
-                       } else {
-                               sum_tiny += range_truesize;
-                               if (sum_tiny > sk->sk_rcvbuf >> 3)
-                                       return;
-                       }
-
+                       tcp_collapse(sk, &tp->out_of_order_queue,
+                                    head, skb, start, end);
                        head = skb;
                        if (!skb)
                                break;
                        /* Start new segment */
                        start = TCP_SKB_CB(skb)->seq;
                        end = TCP_SKB_CB(skb)->end_seq;
-                       range_truesize = skb->truesize;
                } else {
                        if (before(TCP_SKB_CB(skb)->seq, start))
                                start = TCP_SKB_CB(skb)->seq;
-- 
1.8.3.1