Commit 2ca7b0ac authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

[NETFILTER]: Avoid skb_copy/pskb_copy/skb_realloc_headroom



This patch replaces unnecessary uses of skb_copy, pskb_copy and
skb_realloc_headroom by functions such as skb_make_writable and
pskb_expand_head.

This allows us to remove the double pointers later.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent af1e1cf0
......@@ -8,6 +8,7 @@
*
*/
#include <linux/netfilter.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_nat.h>
#include <linux/module.h>
......@@ -19,17 +20,9 @@ static int ebt_target_dnat(struct sk_buff **pskb, unsigned int hooknr,
{
struct ebt_nat_info *info = (struct ebt_nat_info *)data;
if (skb_shared(*pskb) || skb_cloned(*pskb)) {
struct sk_buff *nskb;
if (skb_make_writable(*pskb, 0))
return NF_DROP;
nskb = skb_copy(*pskb, GFP_ATOMIC);
if (!nskb)
return NF_DROP;
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
}
memcpy(eth_hdr(*pskb)->h_dest, info->mac, ETH_ALEN);
return info->target;
}
......
......@@ -8,6 +8,7 @@
*
*/
#include <linux/netfilter.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_redirect.h>
#include <linux/module.h>
......@@ -20,17 +21,9 @@ static int ebt_target_redirect(struct sk_buff **pskb, unsigned int hooknr,
{
struct ebt_redirect_info *info = (struct ebt_redirect_info *)data;
if (skb_shared(*pskb) || skb_cloned(*pskb)) {
struct sk_buff *nskb;
if (skb_make_writable(*pskb, 0))
return NF_DROP;
nskb = skb_copy(*pskb, GFP_ATOMIC);
if (!nskb)
return NF_DROP;
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
}
if (hooknr != NF_BR_BROUTING)
memcpy(eth_hdr(*pskb)->h_dest,
in->br_port->br->dev->dev_addr, ETH_ALEN);
......
......@@ -8,6 +8,7 @@
*
*/
#include <linux/netfilter.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_nat.h>
#include <linux/module.h>
......@@ -21,17 +22,9 @@ static int ebt_target_snat(struct sk_buff **pskb, unsigned int hooknr,
{
struct ebt_nat_info *info = (struct ebt_nat_info *) data;
if (skb_shared(*pskb) || skb_cloned(*pskb)) {
struct sk_buff *nskb;
if (skb_make_writable(*pskb, 0))
return NF_DROP;
nskb = skb_copy(*pskb, GFP_ATOMIC);
if (!nskb)
return NF_DROP;
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
}
memcpy(eth_hdr(*pskb)->h_source, info->mac, ETH_ALEN);
if (!(info->target & NAT_ARP_BIT) &&
eth_hdr(*pskb)->h_proto == htons(ETH_P_ARP)) {
......
......@@ -3,6 +3,7 @@
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <net/route.h>
#include <net/xfrm.h>
#include <net/ip.h>
......@@ -66,17 +67,10 @@ int ip_route_me_harder(struct sk_buff **pskb, unsigned addr_type)
/* Change in oif may mean change in hh_len. */
hh_len = (*pskb)->dst->dev->hard_header_len;
if (skb_headroom(*pskb) < hh_len) {
struct sk_buff *nskb;
nskb = skb_realloc_headroom(*pskb, hh_len);
if (!nskb)
return -1;
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
}
if (skb_headroom(*pskb) < hh_len &&
pskb_expand_head(*pskb, hh_len - skb_headroom(*pskb), 0,
GFP_ATOMIC))
return -1;
return 0;
}
......@@ -107,17 +101,10 @@ int ip_xfrm_me_harder(struct sk_buff **pskb)
/* Change in oif may mean change in hh_len. */
hh_len = (*pskb)->dst->dev->hard_header_len;
if (skb_headroom(*pskb) < hh_len) {
struct sk_buff *nskb;
nskb = skb_realloc_headroom(*pskb, hh_len);
if (!nskb)
return -1;
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
}
if (skb_headroom(*pskb) < hh_len &&
pskb_expand_head(*pskb, hh_len - skb_headroom(*pskb), 0,
GFP_ATOMIC))
return -1;
return 0;
}
EXPORT_SYMBOL(ip_xfrm_me_harder);
......
/* module that allows mangling of the arp payload */
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/netfilter_arp/arpt_mangle.h>
#include <net/sock.h>
......@@ -18,17 +19,8 @@ target(struct sk_buff **pskb,
unsigned char *arpptr;
int pln, hln;
if (skb_shared(*pskb) || skb_cloned(*pskb)) {
struct sk_buff *nskb;
nskb = skb_copy(*pskb, GFP_ATOMIC);
if (!nskb)
return NF_DROP;
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
}
if (skb_make_writable(*pskb, (*pskb)->len))
return NF_DROP;
arp = arp_hdr(*pskb);
arpptr = skb_network_header(*pskb) + sizeof(*arp);
......
......@@ -335,6 +335,7 @@ static int
ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
{
int diff;
int err;
struct iphdr *user_iph = (struct iphdr *)v->payload;
if (v->data_len < sizeof(*user_iph))
......@@ -347,21 +348,14 @@ ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
if (v->data_len > 0xFFFF)
return -EINVAL;
if (diff > skb_tailroom(e->skb)) {
struct sk_buff *newskb;
newskb = skb_copy_expand(e->skb,
skb_headroom(e->skb),
diff,
GFP_ATOMIC);
if (newskb == NULL) {
printk(KERN_WARNING "ip_queue: OOM "
"in mangle, dropping packet\n");
return -ENOMEM;
err = pskb_expand_head(e->skb, 0,
diff - skb_tailroom(e->skb),
GFP_ATOMIC);
if (err) {
printk(KERN_WARNING "ip_queue: error "
"in mangle, dropping packet: %d\n", -err);
return err;
}
if (e->skb->sk)
skb_set_owner_w(newskb, e->skb->sk);
kfree_skb(e->skb);
e->skb = newskb;
}
skb_put(e->skb, diff);
}
......
......@@ -113,20 +113,12 @@ static void mangle_contents(struct sk_buff *skb,
/* Unusual, but possible case. */
static int enlarge_skb(struct sk_buff **pskb, unsigned int extra)
{
struct sk_buff *nskb;
if ((*pskb)->len + extra > 65535)
return 0;
nskb = skb_copy_expand(*pskb, skb_headroom(*pskb), extra, GFP_ATOMIC);
if (!nskb)
if (pskb_expand_head(*pskb, 0, extra - skb_tailroom(*pskb), GFP_ATOMIC))
return 0;
/* Transfer socket to new skb. */
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
return 1;
}
......
......@@ -332,6 +332,7 @@ static int
ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
{
int diff;
int err;
struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
if (v->data_len < sizeof(*user_iph))
......@@ -344,21 +345,14 @@ ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
if (v->data_len > 0xFFFF)
return -EINVAL;
if (diff > skb_tailroom(e->skb)) {
struct sk_buff *newskb;
newskb = skb_copy_expand(e->skb,
skb_headroom(e->skb),
diff,
GFP_ATOMIC);
if (newskb == NULL) {
err = pskb_expand_head(e->skb, 0,
diff - skb_tailroom(e->skb),
GFP_ATOMIC);
if (err) {
printk(KERN_WARNING "ip6_queue: OOM "
"in mangle, dropping packet\n");
return -ENOMEM;
return err;
}
if (e->skb->sk)
skb_set_owner_w(newskb, e->skb->sk);
kfree_skb(e->skb);
e->skb = newskb;
}
skb_put(e->skb, diff);
}
......
......@@ -617,6 +617,7 @@ static int
nfqnl_mangle(void *data, int data_len, struct nfqnl_queue_entry *e)
{
int diff;
int err;
diff = data_len - e->skb->len;
if (diff < 0) {
......@@ -626,21 +627,14 @@ nfqnl_mangle(void *data, int data_len, struct nfqnl_queue_entry *e)
if (data_len > 0xFFFF)
return -EINVAL;
if (diff > skb_tailroom(e->skb)) {
struct sk_buff *newskb;
newskb = skb_copy_expand(e->skb,
skb_headroom(e->skb),
diff,
GFP_ATOMIC);
if (newskb == NULL) {
err = pskb_expand_head(e->skb, 0,
diff - skb_tailroom(e->skb),
GFP_ATOMIC);
if (err) {
printk(KERN_WARNING "nf_queue: OOM "
"in mangle, dropping packet\n");
return -ENOMEM;
return err;
}
if (e->skb->sk)
skb_set_owner_w(newskb, e->skb->sk);
kfree_skb(e->skb);
e->skb = newskb;
}
skb_put(e->skb, diff);
}
......
......@@ -105,14 +105,10 @@ tcpmss_mangle_packet(struct sk_buff **pskb,
* MSS Option not found ?! add it..
*/
if (skb_tailroom((*pskb)) < TCPOLEN_MSS) {
struct sk_buff *newskb;
newskb = skb_copy_expand(*pskb, skb_headroom(*pskb),
TCPOLEN_MSS, GFP_ATOMIC);
if (!newskb)
if (pskb_expand_head(*pskb, 0,
TCPOLEN_MSS - skb_tailroom(*pskb),
GFP_ATOMIC))
return -1;
kfree_skb(*pskb);
*pskb = newskb;
tcph = (struct tcphdr *)(skb_network_header(*pskb) + tcphoff);
}
......
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