linux-stable/net/sched/act_nat.c
Benjamin LaHaise c1b52739e4 pkt_sched: namespace aware act_mirred
Eric Dumazet pointed out that act_mirred needs to find the current net_ns,
and struct net pointer is not provided in the call chain.  His original
patch made use of current->nsproxy->net_ns to find the network namespace,
but this fails to work correctly for userspace code that makes use of
netlink sockets in different network namespaces.  Instead, pass the
"struct net *" down along the call chain to where it is needed.

This version removes the ifb changes as Eric has submitted that patch
separately, but is otherwise identical to the previous version.

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-14 15:09:36 -05:00

330 lines
7.3 KiB
C

/*
* Stateless NAT actions
*
* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*/
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/tc_act/tc_nat.h>
#include <net/act_api.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/netlink.h>
#include <net/tc_act/tc_nat.h>
#include <net/tcp.h>
#include <net/udp.h>
#define NAT_TAB_MASK 15
static struct tcf_common *tcf_nat_ht[NAT_TAB_MASK + 1];
static u32 nat_idx_gen;
static DEFINE_RWLOCK(nat_lock);
static struct tcf_hashinfo nat_hash_info = {
.htab = tcf_nat_ht,
.hmask = NAT_TAB_MASK,
.lock = &nat_lock,
};
static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = {
[TCA_NAT_PARMS] = { .len = sizeof(struct tc_nat) },
};
static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
struct tc_action *a, int ovr, int bind)
{
struct nlattr *tb[TCA_NAT_MAX + 1];
struct tc_nat *parm;
int ret = 0, err;
struct tcf_nat *p;
struct tcf_common *pc;
if (nla == NULL)
return -EINVAL;
err = nla_parse_nested(tb, TCA_NAT_MAX, nla, nat_policy);
if (err < 0)
return err;
if (tb[TCA_NAT_PARMS] == NULL)
return -EINVAL;
parm = nla_data(tb[TCA_NAT_PARMS]);
pc = tcf_hash_check(parm->index, a, bind, &nat_hash_info);
if (!pc) {
pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
&nat_idx_gen, &nat_hash_info);
if (IS_ERR(pc))
return PTR_ERR(pc);
p = to_tcf_nat(pc);
ret = ACT_P_CREATED;
} else {
p = to_tcf_nat(pc);
if (!ovr) {
tcf_hash_release(pc, bind, &nat_hash_info);
return -EEXIST;
}
}
spin_lock_bh(&p->tcf_lock);
p->old_addr = parm->old_addr;
p->new_addr = parm->new_addr;
p->mask = parm->mask;
p->flags = parm->flags;
p->tcf_action = parm->action;
spin_unlock_bh(&p->tcf_lock);
if (ret == ACT_P_CREATED)
tcf_hash_insert(pc, &nat_hash_info);
return ret;
}
static int tcf_nat_cleanup(struct tc_action *a, int bind)
{
struct tcf_nat *p = a->priv;
return tcf_hash_release(&p->common, bind, &nat_hash_info);
}
static int tcf_nat(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_nat *p = a->priv;
struct iphdr *iph;
__be32 old_addr;
__be32 new_addr;
__be32 mask;
__be32 addr;
int egress;
int action;
int ihl;
int noff;
spin_lock(&p->tcf_lock);
p->tcf_tm.lastuse = jiffies;
old_addr = p->old_addr;
new_addr = p->new_addr;
mask = p->mask;
egress = p->flags & TCA_NAT_FLAG_EGRESS;
action = p->tcf_action;
bstats_update(&p->tcf_bstats, skb);
spin_unlock(&p->tcf_lock);
if (unlikely(action == TC_ACT_SHOT))
goto drop;
noff = skb_network_offset(skb);
if (!pskb_may_pull(skb, sizeof(*iph) + noff))
goto drop;
iph = ip_hdr(skb);
if (egress)
addr = iph->saddr;
else
addr = iph->daddr;
if (!((old_addr ^ addr) & mask)) {
if (skb_cloned(skb) &&
!skb_clone_writable(skb, sizeof(*iph) + noff) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
goto drop;
new_addr &= mask;
new_addr |= addr & ~mask;
/* Rewrite IP header */
iph = ip_hdr(skb);
if (egress)
iph->saddr = new_addr;
else
iph->daddr = new_addr;
csum_replace4(&iph->check, addr, new_addr);
} else if ((iph->frag_off & htons(IP_OFFSET)) ||
iph->protocol != IPPROTO_ICMP) {
goto out;
}
ihl = iph->ihl * 4;
/* It would be nice to share code with stateful NAT. */
switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
case IPPROTO_TCP:
{
struct tcphdr *tcph;
if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) ||
(skb_cloned(skb) &&
!skb_clone_writable(skb, ihl + sizeof(*tcph) + noff) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
goto drop;
tcph = (void *)(skb_network_header(skb) + ihl);
inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, 1);
break;
}
case IPPROTO_UDP:
{
struct udphdr *udph;
if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) ||
(skb_cloned(skb) &&
!skb_clone_writable(skb, ihl + sizeof(*udph) + noff) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
goto drop;
udph = (void *)(skb_network_header(skb) + ihl);
if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
inet_proto_csum_replace4(&udph->check, skb, addr,
new_addr, 1);
if (!udph->check)
udph->check = CSUM_MANGLED_0;
}
break;
}
case IPPROTO_ICMP:
{
struct icmphdr *icmph;
if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + noff))
goto drop;
icmph = (void *)(skb_network_header(skb) + ihl);
if ((icmph->type != ICMP_DEST_UNREACH) &&
(icmph->type != ICMP_TIME_EXCEEDED) &&
(icmph->type != ICMP_PARAMETERPROB))
break;
if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph) +
noff))
goto drop;
icmph = (void *)(skb_network_header(skb) + ihl);
iph = (void *)(icmph + 1);
if (egress)
addr = iph->daddr;
else
addr = iph->saddr;
if ((old_addr ^ addr) & mask)
break;
if (skb_cloned(skb) &&
!skb_clone_writable(skb, ihl + sizeof(*icmph) +
sizeof(*iph) + noff) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
goto drop;
icmph = (void *)(skb_network_header(skb) + ihl);
iph = (void *)(icmph + 1);
new_addr &= mask;
new_addr |= addr & ~mask;
/* XXX Fix up the inner checksums. */
if (egress)
iph->daddr = new_addr;
else
iph->saddr = new_addr;
inet_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr,
0);
break;
}
default:
break;
}
out:
return action;
drop:
spin_lock(&p->tcf_lock);
p->tcf_qstats.drops++;
spin_unlock(&p->tcf_lock);
return TC_ACT_SHOT;
}
static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a,
int bind, int ref)
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_nat *p = a->priv;
struct tc_nat opt = {
.old_addr = p->old_addr,
.new_addr = p->new_addr,
.mask = p->mask,
.flags = p->flags,
.index = p->tcf_index,
.action = p->tcf_action,
.refcnt = p->tcf_refcnt - ref,
.bindcnt = p->tcf_bindcnt - bind,
};
struct tcf_t t;
if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
if (nla_put(skb, TCA_NAT_TM, sizeof(t), &t))
goto nla_put_failure;
return skb->len;
nla_put_failure:
nlmsg_trim(skb, b);
return -1;
}
static struct tc_action_ops act_nat_ops = {
.kind = "nat",
.hinfo = &nat_hash_info,
.type = TCA_ACT_NAT,
.capab = TCA_CAP_NONE,
.owner = THIS_MODULE,
.act = tcf_nat,
.dump = tcf_nat_dump,
.cleanup = tcf_nat_cleanup,
.lookup = tcf_hash_search,
.init = tcf_nat_init,
.walk = tcf_generic_walker
};
MODULE_DESCRIPTION("Stateless NAT actions");
MODULE_LICENSE("GPL");
static int __init nat_init_module(void)
{
return tcf_register_action(&act_nat_ops);
}
static void __exit nat_cleanup_module(void)
{
tcf_unregister_action(&act_nat_ops);
}
module_init(nat_init_module);
module_exit(nat_cleanup_module);