networking: introduce and use skb_put_data()

A common pattern with skb_put() is to just want to memcpy()
some data into the new space, introduce skb_put_data() for
this.

An spatch similar to the one for skb_put_zero() converts many
of the places using it:

    @@
    identifier p, p2;
    expression len, skb, data;
    type t, t2;
    @@
    (
    -p = skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    |
    -p = (t)skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, len);
    |
    -memcpy(p, data, len);
    )

    @@
    type t, t2;
    identifier p, p2;
    expression skb, data;
    @@
    t *p;
    ...
    (
    -p = skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    |
    -p = (t *)skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, sizeof(*p));
    |
    -memcpy(p, data, sizeof(*p));
    )

    @@
    expression skb, len, data;
    @@
    -memcpy(skb_put(skb, len), data, len);
    +skb_put_data(skb, data, len);

(again, manually post-processed to retain some comments)

Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 4 deletions

diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c
index bb6ed8e..15bf0c5 100644
--- a/net/bridge/netfilter/nft_reject_bridge.c
+++ b/net/bridge/netfilter/nft_reject_bridge.c
@@ -151,8 +151,7 @@ static void nft_reject_br_send_v4_unreach(struct net *net,
 	icmph->type     = ICMP_DEST_UNREACH;
 	icmph->code	= code;
 
-	payload = skb_put(nskb, len);
-	memcpy(payload, skb_network_header(oldskb), len);
+	payload = skb_put_data(nskb, skb_network_header(oldskb), len);
 
 	csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
 	icmph->checksum = csum_fold(csum);
@@ -278,8 +277,7 @@ static void nft_reject_br_send_v6_unreach(struct net *net,
 	icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
 	icmp6h->icmp6_code = code;
 
-	payload = skb_put(nskb, len);
-	memcpy(payload, skb_network_header(oldskb), len);
+	payload = skb_put_data(nskb, skb_network_header(oldskb), len);
 	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
 
 	icmp6h->icmp6_cksum =