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-rw-r--r--net/dccp/output.c53
1 files changed, 31 insertions, 22 deletions
diff --git a/net/dccp/output.c b/net/dccp/output.c
index fe20068..d06945c 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;
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