Merge branch 'tcp-robust-ooo'

[linux-2.6-microblaze.git] / net / ipv4 / tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 6bade06..3bcd30a 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4358,6 +4358,23 @@ static bool tcp_try_coalesce(struct sock *sk,
        return true;
 }
 
+static bool tcp_ooo_try_coalesce(struct sock *sk,
+                            struct sk_buff *to,
+                            struct sk_buff *from,
+                            bool *fragstolen)
+{
+       bool res = tcp_try_coalesce(sk, to, from, fragstolen);
+
+       /* In case tcp_drop() is called later, update to->gso_segs */
+       if (res) {
+               u32 gso_segs = max_t(u16, 1, skb_shinfo(to)->gso_segs) +
+                              max_t(u16, 1, skb_shinfo(from)->gso_segs);
+
+               skb_shinfo(to)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
+       }
+       return res;
+}
+
 static void tcp_drop(struct sock *sk, struct sk_buff *skb)
 {
        sk_drops_add(sk, skb);
@@ -4481,8 +4498,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
        /* In the typical case, we are adding an skb to the end of the list.
         * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
         */
-       if (tcp_try_coalesce(sk, tp->ooo_last_skb,
-                            skb, &fragstolen)) {
+       if (tcp_ooo_try_coalesce(sk, tp->ooo_last_skb,
+                                skb, &fragstolen)) {
 coalesce_done:
                tcp_grow_window(sk, skb);
                kfree_skb_partial(skb, fragstolen);
@@ -4510,7 +4527,7 @@ coalesce_done:
                                /* All the bits are present. Drop. */
                                NET_INC_STATS(sock_net(sk),
                                              LINUX_MIB_TCPOFOMERGE);
-                               __kfree_skb(skb);
+                               tcp_drop(sk, skb);
                                skb = NULL;
                                tcp_dsack_set(sk, seq, end_seq);
                                goto add_sack;
@@ -4529,11 +4546,11 @@ coalesce_done:
                                                 TCP_SKB_CB(skb1)->end_seq);
                                NET_INC_STATS(sock_net(sk),
                                              LINUX_MIB_TCPOFOMERGE);
-                               __kfree_skb(skb1);
+                               tcp_drop(sk, skb1);
                                goto merge_right;
                        }
-               } else if (tcp_try_coalesce(sk, skb1,
-                                           skb, &fragstolen)) {
+               } else if (tcp_ooo_try_coalesce(sk, skb1,
+                                               skb, &fragstolen)) {
                        goto coalesce_done;
                }
                p = &parent->rb_right;
@@ -4902,6 +4919,7 @@ end:
 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, *head;
        u32 start, end;
 
@@ -4913,6 +4931,7 @@ new_range:
        }
        start = TCP_SKB_CB(skb)->seq;
        end = TCP_SKB_CB(skb)->end_seq;
+       range_truesize = skb->truesize;
 
        for (head = skb;;) {
                skb = skb_rb_next(skb);
@@ -4923,11 +4942,20 @@ new_range:
                if (!skb ||
                    after(TCP_SKB_CB(skb)->seq, end) ||
                    before(TCP_SKB_CB(skb)->end_seq, start)) {
-                       tcp_collapse(sk, NULL, &tp->out_of_order_queue,
-                                    head, skb, start, end);
+                       /* Do not attempt collapsing tiny skbs */
+                       if (range_truesize != head->truesize ||
+                           end - start >= SKB_WITH_OVERHEAD(SK_MEM_QUANTUM)) {
+                               tcp_collapse(sk, NULL, &tp->out_of_order_queue,
+                                            head, skb, start, end);
+                       } else {
+                               sum_tiny += range_truesize;
+                               if (sum_tiny > sk->sk_rcvbuf >> 3)
+                                       return;
+                       }
                        goto new_range;
                }
 
+               range_truesize += skb->truesize;
                if (unlikely(before(TCP_SKB_CB(skb)->seq, start)))
                        start = TCP_SKB_CB(skb)->seq;
                if (after(TCP_SKB_CB(skb)->end_seq, end))
@@ -4942,6 +4970,7 @@ new_range:
  * 2) not add too big latencies if thousands of packets sit there.
  *    (But if application shrinks SO_RCVBUF, we could still end up
  *     freeing whole queue here)
+ * 3) Drop at least 12.5 % of sk_rcvbuf to avoid malicious attacks.
  *
  * Return true if queue has shrunk.
  */
@@ -4949,20 +4978,26 @@ static bool tcp_prune_ofo_queue(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct rb_node *node, *prev;
+       int goal;
 
        if (RB_EMPTY_ROOT(&tp->out_of_order_queue))
                return false;
 
        NET_INC_STATS(sock_net(sk), LINUX_MIB_OFOPRUNED);
+       goal = sk->sk_rcvbuf >> 3;
        node = &tp->ooo_last_skb->rbnode;
        do {
                prev = rb_prev(node);
                rb_erase(node, &tp->out_of_order_queue);
+               goal -= rb_to_skb(node)->truesize;
                tcp_drop(sk, rb_to_skb(node));
-               sk_mem_reclaim(sk);
-               if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
-                   !tcp_under_memory_pressure(sk))
-                       break;
+               if (!prev || goal <= 0) {
+                       sk_mem_reclaim(sk);
+                       if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
+                           !tcp_under_memory_pressure(sk))
+                               break;
+                       goal = sk->sk_rcvbuf >> 3;
+               }
                node = prev;
        } while (node);
        tp->ooo_last_skb = rb_to_skb(prev);
@@ -4997,6 +5032,9 @@ static int tcp_prune_queue(struct sock *sk)
        else if (tcp_under_memory_pressure(sk))
                tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
 
+       if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf)
+               return 0;
+
        tcp_collapse_ofo_queue(sk);
        if (!skb_queue_empty(&sk->sk_receive_queue))
                tcp_collapse(sk, &sk->sk_receive_queue, NULL,