[DCCP]: Fix the ACK and SEQ window variables settings

This is from a first audit, more eyeballs are more than welcome.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 41 insertions, 10 deletions

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index aab72b8d0703..33968a9422f2 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -340,13 +340,11 @@ static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
 {
         struct dccp_sock *dp = dccp_sk(sk);
-        u64 tmp_gsr;
 
-        dccp_set_seqno(&tmp_gsr,
+        dp->dccps_gsr = seq;
+        dccp_set_seqno(&dp->dccps_swl,
                        (dp->dccps_gsr + 1 -
                         (dp->dccps_options.dccpo_sequence_window / 4)));
-        dp->dccps_gsr = seq;
-        dccp_set_seqno(&dp->dccps_swl, max48(tmp_gsr, dp->dccps_isr));
         dccp_set_seqno(&dp->dccps_swh,
                        (dp->dccps_gsr +
                         (3 * dp->dccps_options.dccpo_sequence_window) / 4));
@@ -355,13 +353,11 @@ static inline void dccp_update_gsr(struct sock *sk, u64 seq)
 static inline void dccp_update_gss(struct sock *sk, u64 seq)
 {
         struct dccp_sock *dp = dccp_sk(sk);
-        u64 tmp_gss;
 
-        dccp_set_seqno(&tmp_gss,
+        dp->dccps_awh = dp->dccps_gss = seq;
+        dccp_set_seqno(&dp->dccps_awl,
                        (dp->dccps_gss -
                         dp->dccps_options.dccpo_sequence_window + 1));
-        dp->dccps_awl = max48(tmp_gss, dp->dccps_iss);
-        dp->dccps_awh = dp->dccps_gss = seq;
 }
 
 extern void dccp_insert_options(struct sock *sk, struct sk_buff *skb);
diff --git a/net/dccp/input.c b/net/dccp/input.c
index ce8396b126d2..5847cf454e26 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -314,7 +314,19 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
                 }
 
                 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
-                dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
+                dccp_update_gsr(sk, dp->dccps_isr);
+                /*
+                 * 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.
+                 *
+                 * AWL was adjusted in dccp_v4_connect -acme
+                 */
+                dccp_set_seqno(&dp->dccps_swl,
+                               max48(dp->dccps_swl, dp->dccps_isr));
 
                 if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
                     ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 02ebf1f39f38..647e669a1266 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -309,6 +309,16 @@ static int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
                                                             usin->sin_port);
         dccp_update_gss(sk, dp->dccps_iss);
 
+        /*
+         * 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_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
+
         inet->id = dp->dccps_iss ^ jiffies;
 
         err = dccp_connect(sk);
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
index b8e67207e97e..ce5dff4ac22e 100644
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -146,6 +146,19 @@ out_free:
                 newdp->dccps_iss = dreq->dreq_iss;
                 dccp_update_gss(newsk, dreq->dreq_iss);
 
+                /*
+                 * 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_set_seqno(&newdp->dccps_swl,
+                               max48(newdp->dccps_swl, newdp->dccps_isr));
+                dccp_set_seqno(&newdp->dccps_awl,
+                               max48(newdp->dccps_awl, newdp->dccps_iss));
+
                 dccp_init_xmit_timers(newsk);
 
                 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
diff --git a/net/dccp/timer.c b/net/dccp/timer.c
index 47b1616e6189..aa34b576e228 100644
--- a/net/dccp/timer.c
+++ b/net/dccp/timer.c
@@ -144,7 +144,7 @@ static void dccp_retransmit_timer(struct sock *sk)
         /*
          * sk->sk_send_head has to have one skb with
          * DCCP_SKB_CB(skb)->dccpd_type set to one of the retransmittable DCCP
-         * packet types (REQUEST, RESPONSE, the ACK in the 3way hanshake
+         * packet types (REQUEST, RESPONSE, the ACK in the 3way handshake
          * (PARTOPEN timer), etc).
          */
         BUG_TRAP(sk->sk_send_head != NULL);