[DCCP]: Combine allocating & zeroing header space on skb

This is a code simplification:
it combines three often recurring operations into one inline function,

        * allocate `len' bytes header space in skb
        * fill these `len' bytes with zeroes
        * cast the start of this header space as dccp_hdr

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

4 files changed, 14 insertions, 24 deletions

diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 53553c99cad6..90d04ffddae8 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -256,6 +256,13 @@ static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb)
         return (struct dccp_hdr *)skb->h.raw;
 }
 
+static inline struct dccp_hdr *dccp_zeroed_hdr(struct sk_buff *skb, int headlen)
+{
+        skb->h.raw = skb_push(skb, headlen);
+        memset(skb->h.raw, 0, headlen);
+        return dccp_hdr(skb);
+}
+
 static inline struct dccp_hdr_ext *dccp_hdrx(const struct sk_buff *skb)
 {
         return (struct dccp_hdr_ext *)(skb->h.raw + sizeof(struct dccp_hdr));
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index de64e6c7f93d..ce8eed32dbeb 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -212,12 +212,9 @@ static void dccp_v4_reqsk_send_ack(struct sk_buff *rxskb,
 
         /* Reserve space for headers. */
         skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header);
-
         skb->dst = dst_clone(rxskb->dst);
 
-        skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
-        dh = dccp_hdr(skb);
-        memset(dh, 0, dccp_hdr_ack_len);
+        dh = dccp_zeroed_hdr(skb, dccp_hdr_ack_len);
 
         /* Build DCCP header and checksum it. */
         dh->dccph_type     = DCCP_PKT_ACK;
@@ -720,9 +717,7 @@ static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
         skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header);
         skb->dst = dst_clone(dst);
 
-        skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
-        dh = dccp_hdr(skb);
-        memset(dh, 0, dccp_hdr_reset_len);
+        dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
 
         /* Build DCCP header and checksum it. */
         dh->dccph_type     = DCCP_PKT_RESET;
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 6f1c2ad88608..116bddb64b80 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -537,9 +537,7 @@ static void dccp_v6_ctl_send_reset(struct sk_buff *rxskb)
 
         skb_reserve(skb, dccp_v6_ctl_socket->sk->sk_prot->max_header);
 
-        skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
-        dh = dccp_hdr(skb);
-        memset(dh, 0, dccp_hdr_reset_len);
+        dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
 
         /* Swap the send and the receive. */
         dh->dccph_type  = DCCP_PKT_RESET;
@@ -601,9 +599,7 @@ static void dccp_v6_reqsk_send_ack(struct sk_buff *rxskb,
 
         skb_reserve(skb, dccp_v6_ctl_socket->sk->sk_prot->max_header);
 
-        skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
-        dh = dccp_hdr(skb);
-        memset(dh, 0, dccp_hdr_ack_len);
+        dh = dccp_zeroed_hdr(skb, dccp_hdr_ack_len);
 
         /* Build DCCP header and checksum it. */
         dh->dccph_type  = DCCP_PKT_ACK;
diff --git a/net/dccp/output.c b/net/dccp/output.c
index 2cc4f4b2a9dd..1ae2248557c6 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -88,11 +88,9 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
                         return -EPROTO;
                 }
                 
-                skb->h.raw = skb_push(skb, dccp_header_size);
-                dh = dccp_hdr(skb);
 
                 /* Build DCCP header and checksum it. */
-                memset(dh, 0, dccp_header_size);
+                dh = dccp_zeroed_hdr(skb, dccp_header_size);
                 dh->dccph_type  = dcb->dccpd_type;
                 dh->dccph_sport = inet->sport;
                 dh->dccph_dport = inet->dport;
@@ -340,10 +338,7 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
                 return NULL;
         }
 
-        skb->h.raw = skb_push(skb, dccp_header_size);
-
-        dh = dccp_hdr(skb);
-        memset(dh, 0, dccp_header_size);
+        dh = dccp_zeroed_hdr(skb, dccp_header_size);
 
         dh->dccph_sport = inet_sk(sk)->sport;
         dh->dccph_dport = inet_rsk(req)->rmt_port;
@@ -392,10 +387,7 @@ static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
                 return NULL;
         }
 
-        skb->h.raw = skb_push(skb, dccp_header_size);
-
-        dh = dccp_hdr(skb);
-        memset(dh, 0, dccp_header_size);
+        dh = dccp_zeroed_hdr(skb, dccp_header_size);
 
         dh->dccph_sport = inet_sk(sk)->sport;
         dh->dccph_dport = inet_sk(sk)->dport;