[DCCP]: Use `unsigned' for packet lengths

This patch implements a suggestion by Ian McDonald and

 1) Avoids tests against negative packet lengths by using unsigned int
    for packet payload lengths in the CCID send_packet()/packet_sent() routines

 2) As a consequence, it removes an now unnecessary test with regard to `len > 0'
    in ccid3_hc_tx_packet_sent: that condition is always true, since
      * negative packet lengths are avoided
      * ccid3_hc_tx_send_packet flags an error whenever the payload length is 0.
        As a consequence, ccid3_hc_tx_packet_sent is never called as all errors
        returned by ccid_hc_tx_send_packet are caught in dccp_write_xmit

 3) Removes the third argument of ccid_hc_tx_send_packet (the `len' parameter),
    since it is currently always set to skb->len. The code is updated with regard
    to this parameter change.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

4 files changed, 48 insertions, 58 deletions

diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index f7eb6c613414..c7c29514dce8 100644
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -52,9 +52,9 @@ struct ccid_operations {
                                                     unsigned char len, u16 idx,
                                                     unsigned char* value);
         int             (*ccid_hc_tx_send_packet)(struct sock *sk,
-                                                  struct sk_buff *skb, int len);
-        void            (*ccid_hc_tx_packet_sent)(struct sock *sk, int more,
-                                                  int len);
+                                                  struct sk_buff *skb);
+        void            (*ccid_hc_tx_packet_sent)(struct sock *sk,
+                                                  int more, unsigned int len);
         void            (*ccid_hc_rx_get_info)(struct sock *sk,
                                                struct tcp_info *info);
         void            (*ccid_hc_tx_get_info)(struct sock *sk,
@@ -94,16 +94,16 @@ extern void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
 extern void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk);
 
 static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
-                                         struct sk_buff *skb, int len)
+                                         struct sk_buff *skb)
 {
         int rc = 0;
         if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
-                rc = ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb, len);
+                rc = ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb);
         return rc;
 }
 
 static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
-                                          int more, int len)
+                                          int more, unsigned int len)
 {
         if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
                 ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, more, len);
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 207f7f9b36ca..2555be8f4790 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -125,8 +125,7 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx, int num,
         return 0;
 }
 
-static int ccid2_hc_tx_send_packet(struct sock *sk,
-                                   struct sk_buff *skb, int len)
+static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 {
         struct ccid2_hc_tx_sock *hctx;
 
@@ -268,7 +267,7 @@ static void ccid2_start_rto_timer(struct sock *sk)
                        jiffies + hctx->ccid2hctx_rto);
 }
 
-static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len)
+static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
 {
         struct dccp_sock *dp = dccp_sk(sk);
         struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index aa5440ee20ae..70ebe705eb75 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -272,8 +272,7 @@ out:
  *   = 0: can send immediately
  *   < 0: error condition; do not send packet
  */
-static int ccid3_hc_tx_send_packet(struct sock *sk,
-                                   struct sk_buff *skb, int len)
+static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 {
         struct dccp_sock *dp = dccp_sk(sk);
         struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
@@ -288,7 +287,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk,
          * zero-sized Data(Ack)s is theoretically possible, but for congestion
          * control this case is pathological - ignore it.
          */
-        if (unlikely(len == 0))
+        if (unlikely(skb->len == 0))
                 return -EBADMSG;
 
         /* See if last packet allocated was not sent */
@@ -317,7 +316,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk,
                 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
 
                 /* Set initial sending rate to 1 packet per second */
-                ccid3_hc_tx_update_s(hctx, len);
+                ccid3_hc_tx_update_s(hctx, skb->len);
                 hctx->ccid3hctx_x     = hctx->ccid3hctx_s;
 
                 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
@@ -356,59 +355,53 @@ static int ccid3_hc_tx_send_packet(struct sock *sk,
         return 0;
 }
 
-static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
+static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
 {
         const struct dccp_sock *dp = dccp_sk(sk);
         struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
         struct timeval now;
+        unsigned long quarter_rtt;
+        struct dccp_tx_hist_entry *packet;
 
         BUG_ON(hctx == NULL);
 
         dccp_timestamp(sk, &now);
 
-        /* check if we have sent a data packet */
-        if (len > 0) {
-                unsigned long quarter_rtt;
-                struct dccp_tx_hist_entry *packet;
+        ccid3_hc_tx_update_s(hctx, len);
 
-                ccid3_hc_tx_update_s(hctx, len);
+        packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
+        if (unlikely(packet == NULL)) {
+                DCCP_WARN("packet doesn't exist in history!\n");
+                return;
+        }
+        if (unlikely(packet->dccphtx_sent)) {
+                DCCP_WARN("no unsent packet in history!\n");
+                return;
+        }
+        packet->dccphtx_tstamp = now;
+        packet->dccphtx_seqno  = dp->dccps_gss;
+        /*
+         * Check if win_count have changed
+         * Algorithm in "8.1. Window Counter Value" in RFC 4342.
+         */
+        quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
+        if (likely(hctx->ccid3hctx_rtt > 8))
+                quarter_rtt /= hctx->ccid3hctx_rtt / 4;
 
-                packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
-                if (unlikely(packet == NULL)) {
-                        DCCP_WARN("packet doesn't exist in history!\n");
-                        return;
-                }
-                if (unlikely(packet->dccphtx_sent)) {
-                        DCCP_WARN("no unsent packet in history!\n");
-                        return;
-                }
-                packet->dccphtx_tstamp = now;
-                packet->dccphtx_seqno  = dp->dccps_gss;
-                /*
-                 * Check if win_count have changed
-                 * Algorithm in "8.1. Window Counter Value" in RFC 4342.
-                 */
-                quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
-                if (likely(hctx->ccid3hctx_rtt > 8))
-                        quarter_rtt /= hctx->ccid3hctx_rtt / 4;
-
-                if (quarter_rtt > 0) {
-                        hctx->ccid3hctx_t_last_win_count = now;
-                        hctx->ccid3hctx_last_win_count   = (hctx->ccid3hctx_last_win_count +
-                                                            min_t(unsigned long, quarter_rtt, 5)) % 16;
-                        ccid3_pr_debug("%s, sk=%p, window changed from "
-                                       "%u to %u!\n",
-                                       dccp_role(sk), sk,
-                                       packet->dccphtx_ccval,
-                                       hctx->ccid3hctx_last_win_count);
-                }
+        if (quarter_rtt > 0) {
+                hctx->ccid3hctx_t_last_win_count = now;
+                hctx->ccid3hctx_last_win_count   = (hctx->ccid3hctx_last_win_count +
+                                                    min_t(unsigned long, quarter_rtt, 5)) % 16;
+                ccid3_pr_debug("%s, sk=%p, window changed from "
+                               "%u to %u!\n",
+                               dccp_role(sk), sk,
+                               packet->dccphtx_ccval,
+                               hctx->ccid3hctx_last_win_count);
+        }
 
-                hctx->ccid3hctx_idle = 0;
-                packet->dccphtx_rtt  = hctx->ccid3hctx_rtt;
-                packet->dccphtx_sent = 1;
-        } else
-                ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n",
-                               dccp_role(sk), sk, dp->dccps_gss);
+        hctx->ccid3hctx_idle = 0;
+        packet->dccphtx_rtt  = hctx->ccid3hctx_rtt;
+        packet->dccphtx_sent = 1;
 }
 
 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
diff --git a/net/dccp/output.c b/net/dccp/output.c
index bfd9c5757897..400c30b6fcae 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -195,8 +195,7 @@ static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
                 if (signal_pending(current))
                         goto do_interrupted;
 
-                rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
-                                            skb->len);
+                rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
                 if (rc <= 0)
                         break;
                 delay = msecs_to_jiffies(rc);
@@ -245,8 +244,7 @@ void dccp_write_xmit(struct sock *sk, int block)
                                            this we have other issues */
 
         while ((skb = skb_peek(&sk->sk_write_queue))) {
-                int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
-                                         skb->len);
+                int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
 
                 if (err > 0) {
                         if (!block) {