![Harald Welte](/assets/img/avatar_default.png)
The rerouting functionality is required by the core, therefore it has to be implemented by the core and not in individual queue handlers. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
140 lines
3.2 KiB
C
140 lines
3.2 KiB
C
/* IPv4 specific functions of netfilter core */
|
|
|
|
#include <linux/config.h>
|
|
#ifdef CONFIG_NETFILTER
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/netfilter_ipv4.h>
|
|
|
|
#include <linux/tcp.h>
|
|
#include <linux/udp.h>
|
|
#include <linux/icmp.h>
|
|
#include <net/route.h>
|
|
#include <linux/ip.h>
|
|
|
|
/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
|
|
int ip_route_me_harder(struct sk_buff **pskb)
|
|
{
|
|
struct iphdr *iph = (*pskb)->nh.iph;
|
|
struct rtable *rt;
|
|
struct flowi fl = {};
|
|
struct dst_entry *odst;
|
|
unsigned int hh_len;
|
|
|
|
/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
|
|
* packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook.
|
|
*/
|
|
if (inet_addr_type(iph->saddr) == RTN_LOCAL) {
|
|
fl.nl_u.ip4_u.daddr = iph->daddr;
|
|
fl.nl_u.ip4_u.saddr = iph->saddr;
|
|
fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
|
|
fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0;
|
|
#ifdef CONFIG_IP_ROUTE_FWMARK
|
|
fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark;
|
|
#endif
|
|
fl.proto = iph->protocol;
|
|
if (ip_route_output_key(&rt, &fl) != 0)
|
|
return -1;
|
|
|
|
/* Drop old route. */
|
|
dst_release((*pskb)->dst);
|
|
(*pskb)->dst = &rt->u.dst;
|
|
} else {
|
|
/* non-local src, find valid iif to satisfy
|
|
* rp-filter when calling ip_route_input. */
|
|
fl.nl_u.ip4_u.daddr = iph->saddr;
|
|
if (ip_route_output_key(&rt, &fl) != 0)
|
|
return -1;
|
|
|
|
odst = (*pskb)->dst;
|
|
if (ip_route_input(*pskb, iph->daddr, iph->saddr,
|
|
RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
|
|
dst_release(&rt->u.dst);
|
|
return -1;
|
|
}
|
|
dst_release(&rt->u.dst);
|
|
dst_release(odst);
|
|
}
|
|
|
|
if ((*pskb)->dst->error)
|
|
return -1;
|
|
|
|
/* 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;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(ip_route_me_harder);
|
|
|
|
/*
|
|
* Extra routing may needed on local out, as the QUEUE target never
|
|
* returns control to the table.
|
|
*/
|
|
|
|
struct ip_rt_info {
|
|
u_int32_t daddr;
|
|
u_int32_t saddr;
|
|
u_int8_t tos;
|
|
};
|
|
|
|
static void queue_save(const struct sk_buff *skb, struct nf_info *info)
|
|
{
|
|
struct ip_rt_info *rt_info = nf_info_reroute(info);
|
|
|
|
if (info->hook == NF_IP_LOCAL_OUT) {
|
|
const struct iphdr *iph = skb->nh.iph;
|
|
|
|
rt_info->tos = iph->tos;
|
|
rt_info->daddr = iph->daddr;
|
|
rt_info->saddr = iph->saddr;
|
|
}
|
|
}
|
|
|
|
static int queue_reroute(struct sk_buff **pskb, const struct nf_info *info)
|
|
{
|
|
const struct ip_rt_info *rt_info = nf_info_reroute(info);
|
|
|
|
if (info->hook == NF_IP_LOCAL_OUT) {
|
|
struct iphdr *iph = (*pskb)->nh.iph;
|
|
|
|
if (!(iph->tos == rt_info->tos
|
|
&& iph->daddr == rt_info->daddr
|
|
&& iph->saddr == rt_info->saddr))
|
|
return ip_route_me_harder(pskb);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static struct nf_queue_rerouter ip_reroute = {
|
|
.rer_size = sizeof(struct ip_rt_info),
|
|
.save = queue_save,
|
|
.reroute = queue_reroute,
|
|
};
|
|
|
|
static int init(void)
|
|
{
|
|
return nf_register_queue_rerouter(PF_INET, &ip_reroute);
|
|
}
|
|
|
|
static void fini(void)
|
|
{
|
|
nf_unregister_queue_rerouter(PF_INET);
|
|
}
|
|
|
|
module_init(init);
|
|
module_exit(fini);
|
|
|
|
#endif /* CONFIG_NETFILTER */
|