[DCCP]: Miscellaneous code tidy-ups

This patch does not change code; it performs some trivial clean/tidy-ups:

  * removal of a `debug_prefix' string in favour of the
    already existing dccp_role(sk)

  * add documentation of structures and constants

  * separated out the cases for invalid packets (step 1
    of the packet validation)

  * removing duplicate statements

  * combining declaration & initialisation

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

6 files changed, 37 insertions, 62 deletions

diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
index f8208874ac7d..0c54b89a4e9b 100644
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -67,10 +67,6 @@ static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
 int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
 {
         struct dccp_sock *dp = dccp_sk(sk);
-#ifdef CONFIG_IP_DCCP_DEBUG
-        const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                "CLIENT tx: " : "server tx: ";
-#endif
         struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
         int len = av->dccpav_vec_len + 2;
         struct timeval now;
@@ -129,9 +125,9 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
 
         dccp_ackvec_insert_avr(av, avr);
 
-        dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
+        dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "
                       "ack_ackno=%llu\n",
-                      debug_prefix, avr->dccpavr_sent_len,
+                      dccp_role(sk), avr->dccpavr_sent_len,
                       (unsigned long long)avr->dccpavr_ack_seqno,
                       (unsigned long long)avr->dccpavr_ack_ackno);
         return 0;
@@ -380,14 +376,9 @@ void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
          */
         list_for_each_entry_reverse(avr, &av->dccpav_records, dccpavr_node) {
                 if (ackno == avr->dccpavr_ack_seqno) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-                        struct dccp_sock *dp = dccp_sk(sk);
-                        const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                                "CLIENT rx ack: " : "server rx ack: ";
-#endif
-                        dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
+                        dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, "
                                       "ack_ackno=%llu, ACKED!\n",
-                                      debug_prefix, 1,
+                                      dccp_role(sk), 1,
                                       (unsigned long long)avr->dccpavr_ack_seqno,
                                       (unsigned long long)avr->dccpavr_ack_ackno);
                         dccp_ackvec_throw_record(av, avr);
@@ -437,16 +428,10 @@ found:
                 if (between48(avr->dccpavr_ack_seqno, ackno_end_rl, ackno)) {
                         const u8 state = *vector & DCCP_ACKVEC_STATE_MASK;
                         if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-                                struct dccp_sock *dp = dccp_sk(sk);
-                                const char *debug_prefix =
-                                        dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                        "CLIENT rx ack: " : "server rx ack: ";
-#endif
-                                dccp_pr_debug("%sACK vector 0, len=%d, "
+                                dccp_pr_debug("%s ACK vector 0, len=%d, "
                                               "ack_seqno=%llu, ack_ackno=%llu, "
                                               "ACKED!\n",
-                                              debug_prefix, len,
+                                              dccp_role(sk), len,
                                               (unsigned long long)
                                               avr->dccpavr_ack_seqno,
                                               (unsigned long long)
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 61c09014dade..34d6d197c3b2 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -518,7 +518,7 @@ static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
                                        sizeof(struct dccp_hdr_reset);
         struct sk_buff *skb;
         struct dst_entry *dst;
-        u64 seqno;
+        u64 seqno = 0;
 
         /* Never send a reset in response to a reset. */
         if (rxdh->dccph_type == DCCP_PKT_RESET)
@@ -552,13 +552,11 @@ static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
                                 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
 
         /* See "8.3.1. Abnormal Termination" in RFC 4340 */
-        seqno = 0;
         if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
                 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
 
         dccp_hdr_set_seq(dh, seqno);
-        dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
-                         DCCP_SKB_CB(rxskb)->dccpd_seq);
+        dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), DCCP_SKB_CB(rxskb)->dccpd_seq);
 
         dccp_csum_outgoing(skb);
         dh->dccph_checksum = dccp_v4_csum_finish(skb, rxskb->nh.iph->saddr,
@@ -734,6 +732,11 @@ discard:
 
 EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
 
+/**
+ *      dccp_invalid_packet  -  check for malformed packets
+ *      Implements RFC 4340, 8.5:  Step 1: Check header basics
+ *      Packets that fail these checks are ignored and do not receive Resets.
+ */
 int dccp_invalid_packet(struct sk_buff *skb)
 {
         const struct dccp_hdr *dh;
@@ -742,6 +745,7 @@ int dccp_invalid_packet(struct sk_buff *skb)
         if (skb->pkt_type != PACKET_HOST)
                 return 1;
 
+        /* If the packet is shorter than 12 bytes, drop packet and return */
         if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
                 return 1;
@@ -749,42 +753,37 @@ int dccp_invalid_packet(struct sk_buff *skb)
 
         dh = dccp_hdr(skb);
 
-        /* If the packet type is not understood, drop packet and return */
+        /* If P.type is not understood, drop packet and return */
         if (dh->dccph_type >= DCCP_PKT_INVALID) {
                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
                 return 1;
         }
 
         /*
-         * If P.Data Offset is too small for packet type, or too large for
-         * packet, drop packet and return
+         * If P.Data Offset is too small for packet type, drop packet and return
          */
         if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
-                                            "too small 1\n",
-                               dh->dccph_doff);
+                                            "too small\n", dh->dccph_doff);
                 return 1;
         }
-
+        /*
+         * If P.Data Offset is too too large for packet, drop packet and return
+         */
         if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
-                                            "too small 2\n",
-                               dh->dccph_doff);
+                                            "too large\n", dh->dccph_doff);
                 return 1;
         }
 
-        dh = dccp_hdr(skb);
-
         /*
          * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
          * has short sequence numbers), drop packet and return
          */
-        if (dh->dccph_x == 0 &&
-            dh->dccph_type != DCCP_PKT_DATA &&
-            dh->dccph_type != DCCP_PKT_ACK &&
-            dh->dccph_type != DCCP_PKT_DATAACK) {
-                LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
-                                            "nor DataAck and P.X == 0\n",
+        if (dh->dccph_type >= DCCP_PKT_DATA    &&
+            dh->dccph_type <= DCCP_PKT_DATAACK && dh->dccph_x == 0)  {
+                LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data||Ack||"
+                                            "DataAck, while P.X == 0\n",
                                dccp_packet_name(dh->dccph_type));
                 return 1;
         }
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 2165b1740c7c..fc326173c215 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -318,7 +318,7 @@ static void dccp_v6_ctl_send_reset(struct sk_buff *rxskb)
                                        sizeof(struct dccp_hdr_reset);
         struct sk_buff *skb;
         struct flowi fl;
-        u64 seqno;
+        u64 seqno = 0;
 
         if (rxdh->dccph_type == DCCP_PKT_RESET)
                 return;
@@ -345,13 +345,11 @@ static void dccp_v6_ctl_send_reset(struct sk_buff *rxskb)
                                 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
 
         /* See "8.3.1. Abnormal Termination" in RFC 4340 */
-        seqno = 0;
         if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
                 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
 
         dccp_hdr_set_seq(dh, seqno);
-        dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
-                         DCCP_SKB_CB(rxskb)->dccpd_seq);
+        dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), DCCP_SKB_CB(rxskb)->dccpd_seq);
 
         dccp_csum_outgoing(skb);
         dh->dccph_checksum = dccp_v6_csum_finish(skb, &rxskb->nh.ipv6h->saddr,
diff --git a/net/dccp/options.c b/net/dccp/options.c
index 2d0ef27f4ab9..7e50678e2471 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -60,10 +60,6 @@ static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 {
         struct dccp_sock *dp = dccp_sk(sk);
-#ifdef CONFIG_IP_DCCP_DEBUG
-        const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-                                        "CLIENT rx opt: " : "server rx opt: ";
-#endif
         const struct dccp_hdr *dh = dccp_hdr(skb);
         const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
         unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
@@ -119,7 +115,7 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                                 goto out_invalid_option;
 
                         opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
-                        dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
+                        dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk),
                                       opt_recv->dccpor_ndp);
                         break;
                 case DCCPO_CHANGE_L:
@@ -165,8 +161,8 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                         dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
                         dccp_timestamp(sk, &dp->dccps_timestamp_time);
 
-                        dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
-                                      debug_prefix, opt_recv->dccpor_timestamp,
+                        dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
+                                      dccp_role(sk), opt_recv->dccpor_timestamp,
                                       (unsigned long long)
                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
                         break;
@@ -176,8 +172,8 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 
                         opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
 
-                        dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
-                                      debug_prefix,
+                        dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
+                                      "ackno=%llu, ",  dccp_role(sk),
                                       opt_recv->dccpor_timestamp_echo,
                                       len + 2,
                                       (unsigned long long)
@@ -211,8 +207,8 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
                                 opt_recv->dccpor_elapsed_time = elapsed_time;
 
-                        dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
-                                      elapsed_time);
+                        dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
+                                      dccp_role(sk), elapsed_time);
                         break;
                         /*
                          * From RFC 4340, sec. 10.3:
diff --git a/net/dccp/output.c b/net/dccp/output.c
index ef22f3cc791a..c34eada7f025 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -333,6 +333,7 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
                 return NULL;
         }
 
+        /* Build and checksum header */
         dh = dccp_zeroed_hdr(skb, dccp_header_size);
 
         dh->dccph_sport = inet_sk(sk)->sport;
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 9c9c08cffdaf..0225bdacd3b1 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -452,9 +452,8 @@ out_free_val:
 static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
                 char __user *optval, int optlen)
 {
-        struct dccp_sock *dp;
-        int err;
-        int val;
+        struct dccp_sock *dp = dccp_sk(sk);
+        int val, err = 0;
 
         if (optlen < sizeof(int))
                 return -EINVAL;
@@ -466,9 +465,6 @@ static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
                 return dccp_setsockopt_service(sk, val, optval, optlen);
 
         lock_sock(sk);
-        dp = dccp_sk(sk);
-        err = 0;
-
         switch (optname) {
         case DCCP_SOCKOPT_PACKET_SIZE:
                 dp->dccps_packet_size = val;