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authorMartin Townsend <mtownsend1973@gmail.com>2014-10-13 11:00:56 +0100
committerMarcel Holtmann <marcel@holtmann.org>2014-10-25 07:56:25 +0200
commit11e3ff7072789ad4585870cbdde1be10c45f1cc4 (patch)
tree0a8e62cbf7eaeb33ac5931f9cea2321abf730ce5 /net/6lowpan
parent4456c50d23d44352f4174a9a0cb75313d3150907 (diff)
downloadlinux-11e3ff7072789ad4585870cbdde1be10c45f1cc4.tar.bz2
6lowpan: Use skb_cow in IPHC decompression.
Currently there are potentially 2 skb_copy_expand calls in IPHC decompression. This patch replaces this with one call to skb_cow which will check to see if there is enough headroom first to ensure it's only done if necessary and will handle alignment issues for cache. As skb_cow uses pskb_expand_head we ensure the skb isn't shared from bluetooth and ieee802.15.4 code that use the IPHC decompression. Signed-off-by: Martin Townsend <martin.townsend@xsilon.com> Acked-by: Alexander Aring <alex.aring@gmail.com> Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'net/6lowpan')
-rw-r--r--net/6lowpan/iphc.c47
1 files changed, 21 insertions, 26 deletions
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 142eef55c9e2..747b3ccfc4f8 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -174,30 +174,22 @@ static int uncompress_context_based_src_addr(struct sk_buff *skb,
static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
struct net_device *dev, skb_delivery_cb deliver_skb)
{
- struct sk_buff *new;
int stat;
- new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
- GFP_ATOMIC);
- kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
-
- skb_push(new, sizeof(struct ipv6hdr));
- skb_reset_network_header(new);
- skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
+ skb_push(skb, sizeof(struct ipv6hdr));
+ skb_reset_network_header(skb);
+ skb_copy_to_linear_data(skb, hdr, sizeof(struct ipv6hdr));
- new->protocol = htons(ETH_P_IPV6);
- new->pkt_type = PACKET_HOST;
- new->dev = dev;
+ skb->protocol = htons(ETH_P_IPV6);
+ skb->pkt_type = PACKET_HOST;
+ skb->dev = dev;
raw_dump_table(__func__, "raw skb data dump before receiving",
- new->data, new->len);
+ skb->data, skb->len);
- stat = deliver_skb(new, dev);
+ stat = deliver_skb(skb, dev);
- kfree_skb(new);
+ consume_skb(skb);
return stat;
}
@@ -460,7 +452,7 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
/* UDP data uncompression */
if (iphc0 & LOWPAN_IPHC_NH_C) {
struct udphdr uh;
- struct sk_buff *new;
+ const int needed = sizeof(struct udphdr) + sizeof(hdr);
if (uncompress_udp_header(skb, &uh))
goto drop;
@@ -468,14 +460,11 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
/* replace the compressed UDP head by the uncompressed UDP
* header
*/
- new = skb_copy_expand(skb, sizeof(struct udphdr),
- skb_tailroom(skb), GFP_ATOMIC);
- kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
-
- skb = new;
+ err = skb_cow(skb, needed);
+ if (unlikely(err)) {
+ kfree_skb(skb);
+ return err;
+ }
skb_push(skb, sizeof(struct udphdr));
skb_reset_transport_header(skb);
@@ -485,6 +474,12 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
(u8 *)&uh, sizeof(uh));
hdr.nexthdr = UIP_PROTO_UDP;
+ } else {
+ err = skb_cow(skb, sizeof(hdr));
+ if (unlikely(err)) {
+ kfree_skb(skb);
+ return err;
+ }
}
hdr.payload_len = htons(skb->len);