[NETFILTER]: Do not copy skb in skb_make_writable
Now that all callers of netfilter can guarantee that the skb is not shared,
we no longer have to copy the skb in skb_make_writable.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 1dd075e..2505348c 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -287,7 +287,7 @@
/* Call this before modifying an existing packet: ensures it is
modifiable and linear to the point you care about (writable_len).
Returns true or false. */
-extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
+extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to)
{
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index 23cbfc7..62d8867 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -365,7 +365,7 @@
}
skb_put(e->skb, diff);
}
- if (!skb_make_writable(&e->skb, v->data_len))
+ if (!skb_make_writable(e->skb, v->data_len))
return -ENOMEM;
skb_copy_to_linear_data(e->skb, v->payload, v->data_len);
e->skb->ip_summed = CHECKSUM_NONE;
diff --git a/net/ipv4/netfilter/ipt_ECN.c b/net/ipv4/netfilter/ipt_ECN.c
index f1253bd..92744be 100644
--- a/net/ipv4/netfilter/ipt_ECN.c
+++ b/net/ipv4/netfilter/ipt_ECN.c
@@ -32,7 +32,7 @@
if ((iph->tos & IPT_ECN_IP_MASK) != (einfo->ip_ect & IPT_ECN_IP_MASK)) {
__u8 oldtos;
- if (!skb_make_writable(pskb, sizeof(struct iphdr)))
+ if (!skb_make_writable(*pskb, sizeof(struct iphdr)))
return false;
iph = ip_hdr(*pskb);
oldtos = iph->tos;
@@ -62,7 +62,7 @@
tcph->cwr == einfo->proto.tcp.cwr))
return true;
- if (!skb_make_writable(pskb, ip_hdrlen(*pskb) + sizeof(*tcph)))
+ if (!skb_make_writable(*pskb, ip_hdrlen(*pskb) + sizeof(*tcph)))
return false;
tcph = (void *)ip_hdr(*pskb) + ip_hdrlen(*pskb);
diff --git a/net/ipv4/netfilter/ipt_TOS.c b/net/ipv4/netfilter/ipt_TOS.c
index 25f5d0b..87b689a 100644
--- a/net/ipv4/netfilter/ipt_TOS.c
+++ b/net/ipv4/netfilter/ipt_TOS.c
@@ -33,7 +33,7 @@
if ((iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) {
__u8 oldtos;
- if (!skb_make_writable(pskb, sizeof(struct iphdr)))
+ if (!skb_make_writable(*pskb, sizeof(struct iphdr)))
return NF_DROP;
iph = ip_hdr(*pskb);
oldtos = iph->tos;
diff --git a/net/ipv4/netfilter/ipt_TTL.c b/net/ipv4/netfilter/ipt_TTL.c
index 2b54e7b..3dd4676 100644
--- a/net/ipv4/netfilter/ipt_TTL.c
+++ b/net/ipv4/netfilter/ipt_TTL.c
@@ -29,7 +29,7 @@
const struct ipt_TTL_info *info = targinfo;
int new_ttl;
- if (!skb_make_writable(pskb, (*pskb)->len))
+ if (!skb_make_writable(*pskb, (*pskb)->len))
return NF_DROP;
iph = ip_hdr(*pskb);
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index 7221aa2..3b5eb7c 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -357,7 +357,7 @@
struct iphdr *iph;
struct nf_nat_protocol *p;
- if (!skb_make_writable(pskb, iphdroff + sizeof(*iph)))
+ if (!skb_make_writable(*pskb, iphdroff + sizeof(*iph)))
return 0;
iph = (void *)(*pskb)->data + iphdroff;
@@ -431,7 +431,7 @@
unsigned long statusbit;
enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
- if (!skb_make_writable(pskb, hdrlen + sizeof(*inside)))
+ if (!skb_make_writable(*pskb, hdrlen + sizeof(*inside)))
return 0;
inside = (void *)(*pskb)->data + ip_hdrlen(*pskb);
diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c
index 93d8a0a..6e81f76 100644
--- a/net/ipv4/netfilter/nf_nat_helper.c
+++ b/net/ipv4/netfilter/nf_nat_helper.c
@@ -152,7 +152,7 @@
struct tcphdr *tcph;
int oldlen, datalen;
- if (!skb_make_writable(pskb, (*pskb)->len))
+ if (!skb_make_writable(*pskb, (*pskb)->len))
return 0;
if (rep_len > match_len &&
@@ -234,7 +234,7 @@
match_offset + match_len)
return 0;
- if (!skb_make_writable(pskb, (*pskb)->len))
+ if (!skb_make_writable(*pskb, (*pskb)->len))
return 0;
if (rep_len > match_len &&
@@ -341,7 +341,7 @@
optoff = ip_hdrlen(*pskb) + sizeof(struct tcphdr);
optend = ip_hdrlen(*pskb) + tcph->doff * 4;
- if (!skb_make_writable(pskb, optend))
+ if (!skb_make_writable(*pskb, optend))
return 0;
dir = CTINFO2DIR(ctinfo);
@@ -390,7 +390,7 @@
this_way = &nat->seq[dir];
other_way = &nat->seq[!dir];
- if (!skb_make_writable(pskb, ip_hdrlen(*pskb) + sizeof(*tcph)))
+ if (!skb_make_writable(*pskb, ip_hdrlen(*pskb) + sizeof(*tcph)))
return 0;
tcph = (void *)(*pskb)->data + ip_hdrlen(*pskb);
diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c
index d562290..e7a2aaf 100644
--- a/net/ipv4/netfilter/nf_nat_proto_gre.c
+++ b/net/ipv4/netfilter/nf_nat_proto_gre.c
@@ -109,7 +109,7 @@
/* pgreh includes two optional 32bit fields which are not required
* to be there. That's where the magic '8' comes from */
- if (!skb_make_writable(pskb, hdroff + sizeof(*pgreh) - 8))
+ if (!skb_make_writable(*pskb, hdroff + sizeof(*pgreh) - 8))
return 0;
greh = (void *)(*pskb)->data + hdroff;
diff --git a/net/ipv4/netfilter/nf_nat_proto_icmp.c b/net/ipv4/netfilter/nf_nat_proto_icmp.c
index 898d737..4087f4f 100644
--- a/net/ipv4/netfilter/nf_nat_proto_icmp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_icmp.c
@@ -61,7 +61,7 @@
struct icmphdr *hdr;
unsigned int hdroff = iphdroff + iph->ihl*4;
- if (!skb_make_writable(pskb, hdroff + sizeof(*hdr)))
+ if (!skb_make_writable(*pskb, hdroff + sizeof(*hdr)))
return 0;
hdr = (struct icmphdr *)((*pskb)->data + hdroff);
diff --git a/net/ipv4/netfilter/nf_nat_proto_tcp.c b/net/ipv4/netfilter/nf_nat_proto_tcp.c
index 5bbbb2a..e544125 100644
--- a/net/ipv4/netfilter/nf_nat_proto_tcp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_tcp.c
@@ -106,7 +106,7 @@
if ((*pskb)->len >= hdroff + sizeof(struct tcphdr))
hdrsize = sizeof(struct tcphdr);
- if (!skb_make_writable(pskb, hdroff + hdrsize))
+ if (!skb_make_writable(*pskb, hdroff + hdrsize))
return 0;
iph = (struct iphdr *)((*pskb)->data + iphdroff);
diff --git a/net/ipv4/netfilter/nf_nat_proto_udp.c b/net/ipv4/netfilter/nf_nat_proto_udp.c
index a0af4fd..ebe9b42 100644
--- a/net/ipv4/netfilter/nf_nat_proto_udp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_udp.c
@@ -97,7 +97,7 @@
__be32 oldip, newip;
__be16 *portptr, newport;
- if (!skb_make_writable(pskb, hdroff + sizeof(*hdr)))
+ if (!skb_make_writable(*pskb, hdroff + sizeof(*hdr)))
return 0;
iph = (struct iphdr *)((*pskb)->data + iphdroff);
diff --git a/net/ipv4/netfilter/nf_nat_snmp_basic.c b/net/ipv4/netfilter/nf_nat_snmp_basic.c
index 6bfcd3a..87011fe 100644
--- a/net/ipv4/netfilter/nf_nat_snmp_basic.c
+++ b/net/ipv4/netfilter/nf_nat_snmp_basic.c
@@ -1258,7 +1258,7 @@
return NF_DROP;
}
- if (!skb_make_writable(pskb, (*pskb)->len))
+ if (!skb_make_writable(*pskb, (*pskb)->len))
return NF_DROP;
spin_lock_bh(&snmp_lock);
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index 0473145..d7080dd 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -362,7 +362,7 @@
}
skb_put(e->skb, diff);
}
- if (!skb_make_writable(&e->skb, v->data_len))
+ if (!skb_make_writable(e->skb, v->data_len))
return -ENOMEM;
skb_copy_to_linear_data(e->skb, v->payload, v->data_len);
e->skb->ip_summed = CHECKSUM_NONE;
diff --git a/net/ipv6/netfilter/ip6t_HL.c b/net/ipv6/netfilter/ip6t_HL.c
index ad4d943..f76197f 100644
--- a/net/ipv6/netfilter/ip6t_HL.c
+++ b/net/ipv6/netfilter/ip6t_HL.c
@@ -29,7 +29,7 @@
const struct ip6t_HL_info *info = targinfo;
int new_hl;
- if (!skb_make_writable(pskb, (*pskb)->len))
+ if (!skb_make_writable(*pskb, (*pskb)->len))
return NF_DROP;
ip6h = ipv6_hdr(*pskb);
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index a523fa4..2c9e8e36 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -196,34 +196,24 @@
EXPORT_SYMBOL(nf_hook_slow);
-int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len)
+int skb_make_writable(struct sk_buff *skb, unsigned int writable_len)
{
- struct sk_buff *nskb;
-
- if (writable_len > (*pskb)->len)
+ if (writable_len > skb->len)
return 0;
/* Not exclusive use of packet? Must copy. */
- if (skb_cloned(*pskb) && !skb_clone_writable(*pskb, writable_len))
- goto copy_skb;
- if (skb_shared(*pskb))
- goto copy_skb;
+ if (!skb_cloned(skb)) {
+ if (writable_len <= skb_headlen(skb))
+ return 1;
+ } else if (skb_clone_writable(skb, writable_len))
+ return 1;
- return pskb_may_pull(*pskb, writable_len);
+ if (writable_len <= skb_headlen(skb))
+ writable_len = 0;
+ else
+ writable_len -= skb_headlen(skb);
-copy_skb:
- nskb = skb_copy(*pskb, GFP_ATOMIC);
- if (!nskb)
- return 0;
- BUG_ON(skb_is_nonlinear(nskb));
-
- /* Rest of kernel will get very unhappy if we pass it a
- suddenly-orphaned skbuff */
- if ((*pskb)->sk)
- skb_set_owner_w(nskb, (*pskb)->sk);
- kfree_skb(*pskb);
- *pskb = nskb;
- return 1;
+ return !!__pskb_pull_tail(skb, writable_len);
}
EXPORT_SYMBOL(skb_make_writable);
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 49f0480..6ba98ac 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -644,7 +644,7 @@
}
skb_put(e->skb, diff);
}
- if (!skb_make_writable(&e->skb, data_len))
+ if (!skb_make_writable(e->skb, data_len))
return -ENOMEM;
skb_copy_to_linear_data(e->skb, data, data_len);
e->skb->ip_summed = CHECKSUM_NONE;
diff --git a/net/netfilter/xt_DSCP.c b/net/netfilter/xt_DSCP.c
index 798ab73..1706616 100644
--- a/net/netfilter/xt_DSCP.c
+++ b/net/netfilter/xt_DSCP.c
@@ -36,7 +36,7 @@
u_int8_t dscp = ipv4_get_dsfield(ip_hdr(*pskb)) >> XT_DSCP_SHIFT;
if (dscp != dinfo->dscp) {
- if (!skb_make_writable(pskb, sizeof(struct iphdr)))
+ if (!skb_make_writable(*pskb, sizeof(struct iphdr)))
return NF_DROP;
ipv4_change_dsfield(ip_hdr(*pskb), (__u8)(~XT_DSCP_MASK),
@@ -57,7 +57,7 @@
u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(*pskb)) >> XT_DSCP_SHIFT;
if (dscp != dinfo->dscp) {
- if (!skb_make_writable(pskb, sizeof(struct ipv6hdr)))
+ if (!skb_make_writable(*pskb, sizeof(struct ipv6hdr)))
return NF_DROP;
ipv6_change_dsfield(ipv6_hdr(*pskb), (__u8)(~XT_DSCP_MASK),
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index d40f7e4..31b6f9d 100644
--- a/net/netfilter/xt_TCPMSS.c
+++ b/net/netfilter/xt_TCPMSS.c
@@ -50,7 +50,7 @@
u16 newmss;
u8 *opt;
- if (!skb_make_writable(pskb, (*pskb)->len))
+ if (!skb_make_writable(*pskb, (*pskb)->len))
return -1;
tcplen = (*pskb)->len - tcphoff;