dccp: Do not let initial option overhead shrink the MPS

[pandora-kernel.git] / net / dccp / output.c

diff --git a/net/dccp/output.c b/net/dccp/output.c
index 27c79bc..36bcc00 100644 (file)
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -276,7 +276,20 @@ void dccp_write_xmit(struct sock *sk, int block)
                        const int len = skb->len;
 
                        if (sk->sk_state == DCCP_PARTOPEN) {
-                               /* See 8.1.5.  Handshake Completion */
+                               const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD;
+                               /*
+                                * See 8.1.5 - Handshake Completion.
+                                *
+                                * For robustness we resend Confirm options until the client has
+                                * entered OPEN. During the initial feature negotiation, the MPS
+                                * is smaller than usual, reduced by the Change/Confirm options.
+                                */
+                               if (!list_empty(&dp->dccps_featneg) && len > cur_mps) {
+                                       DCCP_WARN("Payload too large (%d) for featneg.\n", len);
+                                       dccp_send_ack(sk);
+                                       dccp_feat_list_purge(&dp->dccps_featneg);
+                               }
+
                                inet_csk_schedule_ack(sk);
                                inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
                                                  inet_csk(sk)->icsk_rto,