1 files changed, 31 insertions, 22 deletions

diff --git a/net/dccp/output.c b/net/dccp/output.c
index fe20068c5d8e..d06945c7d3df 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -53,8 +53,11 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
                                           dccp_packet_hdr_len(dcb->dccpd_type);
                 int err, set_ack = 1;
                 u64 ackno = dp->dccps_gsr;
-
-                dccp_inc_seqno(&dp->dccps_gss);
+                /*
+                 * Increment GSS here already in case the option code needs it.
+                 * Update GSS for real only if option processing below succeeds.
+                 */
+                dcb->dccpd_seq = ADD48(dp->dccps_gss, 1);
 
                 switch (dcb->dccpd_type) {
                 case DCCP_PKT_DATA:
@@ -66,6 +69,9 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 
                 case DCCP_PKT_REQUEST:
                         set_ack = 0;
+                        /* Use ISS on the first (non-retransmitted) Request. */
+                        if (icsk->icsk_retransmits == 0)
+                                dcb->dccpd_seq = dp->dccps_iss;
                         /* fall through */
 
                 case DCCP_PKT_SYNC:
@@ -84,8 +90,6 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
                         break;
                 }
 
-                dcb->dccpd_seq = dp->dccps_gss;
-
                 if (dccp_insert_options(sk, skb)) {
                         kfree_skb(skb);
                         return -EPROTO;
@@ -103,7 +107,7 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
                 /* XXX For now we're using only 48 bits sequence numbers */
                 dh->dccph_x     = 1;
 
-                dp->dccps_awh = dp->dccps_gss;
+                dccp_update_gss(sk, dcb->dccpd_seq);
                 dccp_hdr_set_seq(dh, dp->dccps_gss);
                 if (set_ack)
                         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
@@ -112,6 +116,11 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
                 case DCCP_PKT_REQUEST:
                         dccp_hdr_request(skb)->dccph_req_service =
                                                         dp->dccps_service;
+                        /*
+                         * Limit Ack window to ISS <= P.ackno <= GSS, so that
+                         * only Responses to Requests we sent are considered.
+                         */
+                        dp->dccps_awl = dp->dccps_iss;
                         break;
                 case DCCP_PKT_RESET:
                         dccp_hdr_reset(skb)->dccph_reset_code =
@@ -284,14 +293,26 @@ void dccp_write_xmit(struct sock *sk, int block)
         }
 }
 
-int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
+/**
+ * dccp_retransmit_skb  -  Retransmit Request, Close, or CloseReq packets
+ * There are only four retransmittable packet types in DCCP:
+ * - Request  in client-REQUEST  state (sec. 8.1.1),
+ * - CloseReq in server-CLOSEREQ state (sec. 8.3),
+ * - Close    in   node-CLOSING  state (sec. 8.3),
+ * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()).
+ * This function expects sk->sk_send_head to contain the original skb.
+ */
+int dccp_retransmit_skb(struct sock *sk)
 {
+        WARN_ON(sk->sk_send_head == NULL);
+
         if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
                 return -EHOSTUNREACH; /* Routing failure or similar. */
 
-        return dccp_transmit_skb(sk, (skb_cloned(skb) ?
-                                      pskb_copy(skb, GFP_ATOMIC):
-                                      skb_clone(skb, GFP_ATOMIC)));
+        /* this count is used to distinguish original and retransmitted skb */
+        inet_csk(sk)->icsk_retransmits++;
+
+        return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));
 }
 
 struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
@@ -437,19 +458,7 @@ static inline void dccp_connect_init(struct sock *sk)
 
         dccp_sync_mss(sk, dst_mtu(dst));
 
-        /*
-         * SWL and AWL are initially adjusted so that they are not less than
-         * the initial Sequence Numbers received and sent, respectively:
-         *      SWL := max(GSR + 1 - floor(W/4), ISR),
-         *      AWL := max(GSS - W' + 1, ISS).
-         * These adjustments MUST be applied only at the beginning of the
-         * connection.
-         */
-        dccp_update_gss(sk, dp->dccps_iss);
-        dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
-
-        /* S.GAR - greatest valid acknowledgement number received on a non-Sync;
-         *         initialized to S.ISS (sec. 8.5)                            */
+        /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */
         dp->dccps_gar = dp->dccps_iss;
 
         icsk->icsk_retransmits = 0;