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[NETFILTER]: Call POST_ROUTING hook before fragmentation

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Call POST_ROUTING hook before fragmentation to get rid of the okfn use
in ip_refrag and save the useless fragmentation/defragmentation step
when NAT is used.

The patch introduces one user-visible change, the POSTROUTING chain
in the mangle table gets entire packets, not fragments, which should
simplify use of the MARK and CLASSIFY targets for queueing as a nice
side-effect.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2006-01-05 12:20:59 -08:00 committed by David S. Miller
parent abbcc73982
commit 1bd9bef6f9
5 changed files with 16 additions and 84 deletions
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1
include/net/ip.h
View file

@ -317,7 +317,6 @@ enum ip_defrag_users
IP_DEFRAG_CALL_RA_CHAIN,
IP_DEFRAG_CONNTRACK_IN,
IP_DEFRAG_CONNTRACK_OUT,
IP_DEFRAG_NAT_OUT,
IP_DEFRAG_VS_IN,
IP_DEFRAG_VS_OUT,
IP_DEFRAG_VS_FWD

30
net/ipv4/ip_output.c
View file

@ -202,13 +202,11 @@ static inline int ip_finish_output2(struct sk_buff *skb)
static inline int ip_finish_output(struct sk_buff *skb)
{
struct net_device *dev = skb->dst->dev;
skb->dev = dev;
skb->protocol = htons(ETH_P_IP);
return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev,
ip_finish_output2);
if (skb->len > dst_mtu(skb->dst) &&
!(skb_shinfo(skb)->ufo_size || skb_shinfo(skb)->tso_size))
return ip_fragment(skb, ip_finish_output2);
else
return ip_finish_output2(skb);
}
int ip_mc_output(struct sk_buff *skb)
@ -265,21 +263,21 @@ int ip_mc_output(struct sk_buff *skb)
newskb->dev, ip_dev_loopback_xmit);
}
if (skb->len > dst_mtu(&rt->u.dst))
return ip_fragment(skb, ip_finish_output);
else
return ip_finish_output(skb);
return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev,
ip_finish_output);
}
int ip_output(struct sk_buff *skb)
{
struct net_device *dev = skb->dst->dev;
IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
if (skb->len > dst_mtu(skb->dst) &&
!(skb_shinfo(skb)->ufo_size || skb_shinfo(skb)->tso_size))
return ip_fragment(skb, ip_finish_output);
else
return ip_finish_output(skb);
skb->dev = dev;
skb->protocol = htons(ETH_P_IP);
return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev,
ip_finish_output);
}
int ip_queue_xmit(struct sk_buff *skb, int ipfragok)

26
net/ipv4/netfilter/ip_conntrack_standalone.c
View file

@ -451,30 +451,6 @@ static unsigned int ip_conntrack_defrag(unsigned int hooknum,
return NF_ACCEPT;
}
static unsigned int ip_refrag(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct rtable *rt = (struct rtable *)(*pskb)->dst;
/* We've seen it coming out the other side: confirm */
if (ip_confirm(hooknum, pskb, in, out, okfn) != NF_ACCEPT)
return NF_DROP;
/* Local packets are never produced too large for their
interface. We degfragment them at LOCAL_OUT, however,
so we have to refragment them here. */
if ((*pskb)->len > dst_mtu(&rt->u.dst) &&
!skb_shinfo(*pskb)->tso_size) {
/* No hook can be after us, so this should be OK. */
ip_fragment(*pskb, okfn);
return NF_STOLEN;
}
return NF_ACCEPT;
}
static unsigned int ip_conntrack_local(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
@ -544,7 +520,7 @@ static struct nf_hook_ops ip_conntrack_helper_in_ops = {
/* Refragmenter; last chance. */
static struct nf_hook_ops ip_conntrack_out_ops = {
.hook = ip_refrag,
.hook = ip_confirm,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_POST_ROUTING,

17
net/ipv4/netfilter/ip_nat_standalone.c
View file

@ -190,23 +190,6 @@ ip_nat_out(unsigned int hooknum,
|| (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr))
return NF_ACCEPT;
/* We can hit fragment here; forwarded packets get
defragmented by connection tracking coming in, then
fragmented (grr) by the forward code.
In future: If we have nfct != NULL, AND we have NAT
initialized, AND there is no helper, then we can do full
NAPT on the head, and IP-address-only NAT on the rest.
I'm starting to have nightmares about fragments. */
if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
*pskb = ip_ct_gather_frags(*pskb, IP_DEFRAG_NAT_OUT);
if (!*pskb)
return NF_STOLEN;
}
return ip_nat_fn(hooknum, pskb, in, out, okfn);
}

26
net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
View file

@ -180,30 +180,6 @@ static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
return NF_ACCEPT;
}
static unsigned int ipv4_refrag(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct rtable *rt = (struct rtable *)(*pskb)->dst;
/* We've seen it coming out the other side: confirm */
if (ipv4_confirm(hooknum, pskb, in, out, okfn) != NF_ACCEPT)
return NF_DROP;
/* Local packets are never produced too large for their
interface. We degfragment them at LOCAL_OUT, however,
so we have to refragment them here. */
if ((*pskb)->len > dst_mtu(&rt->u.dst) &&
!skb_shinfo(*pskb)->tso_size) {
/* No hook can be after us, so this should be OK. */
ip_fragment(*pskb, okfn);
return NF_STOLEN;
}
return NF_ACCEPT;
}
static unsigned int ipv4_conntrack_in(unsigned int hooknum,
struct sk_buff **pskb,
const struct net_device *in,
@ -283,7 +259,7 @@ static struct nf_hook_ops ipv4_conntrack_helper_in_ops = {
/* Refragmenter; last chance. */
static struct nf_hook_ops ipv4_conntrack_out_ops = {
.hook = ipv4_refrag,
.hook = ipv4_confirm,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_POST_ROUTING,