/*
|
* Rusty Russell (C)2000 -- This code is GPL.
|
* Patrick McHardy (c) 2006-2012
|
*/
|
|
#include <linux/kernel.h>
|
#include <linux/slab.h>
|
#include <linux/init.h>
|
#include <linux/module.h>
|
#include <linux/proc_fs.h>
|
#include <linux/skbuff.h>
|
#include <linux/netfilter.h>
|
#include <linux/netfilter_ipv4.h>
|
#include <linux/netfilter_ipv6.h>
|
#include <linux/netfilter_bridge.h>
|
#include <linux/seq_file.h>
|
#include <linux/rcupdate.h>
|
#include <net/protocol.h>
|
#include <net/netfilter/nf_queue.h>
|
#include <net/dst.h>
|
|
#include "nf_internals.h"
|
|
/*
|
* Hook for nfnetlink_queue to register its queue handler.
|
* We do this so that most of the NFQUEUE code can be modular.
|
*
|
* Once the queue is registered it must reinject all packets it
|
* receives, no matter what.
|
*/
|
|
/* return EBUSY when somebody else is registered, return EEXIST if the
|
* same handler is registered, return 0 in case of success. */
|
void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh)
|
{
|
/* should never happen, we only have one queueing backend in kernel */
|
WARN_ON(rcu_access_pointer(net->nf.queue_handler));
|
rcu_assign_pointer(net->nf.queue_handler, qh);
|
}
|
EXPORT_SYMBOL(nf_register_queue_handler);
|
|
/* The caller must flush their queue before this */
|
void nf_unregister_queue_handler(struct net *net)
|
{
|
RCU_INIT_POINTER(net->nf.queue_handler, NULL);
|
}
|
EXPORT_SYMBOL(nf_unregister_queue_handler);
|
|
static void nf_queue_sock_put(struct sock *sk)
|
{
|
#ifdef CONFIG_INET
|
sock_gen_put(sk);
|
#else
|
sock_put(sk);
|
#endif
|
}
|
|
static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
|
{
|
struct nf_hook_state *state = &entry->state;
|
|
/* Release those devices we held, or Alexey will kill me. */
|
if (state->in)
|
dev_put(state->in);
|
if (state->out)
|
dev_put(state->out);
|
if (state->sk)
|
nf_queue_sock_put(state->sk);
|
|
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
|
if (entry->physin)
|
dev_put(entry->physin);
|
if (entry->physout)
|
dev_put(entry->physout);
|
#endif
|
}
|
|
void nf_queue_entry_free(struct nf_queue_entry *entry)
|
{
|
nf_queue_entry_release_refs(entry);
|
kfree(entry);
|
}
|
EXPORT_SYMBOL_GPL(nf_queue_entry_free);
|
|
static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
|
{
|
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
|
const struct sk_buff *skb = entry->skb;
|
struct nf_bridge_info *nf_bridge;
|
|
nf_bridge = nf_bridge_info_get(skb);
|
if (nf_bridge) {
|
entry->physin = nf_bridge_get_physindev(skb);
|
entry->physout = nf_bridge_get_physoutdev(skb);
|
} else {
|
entry->physin = NULL;
|
entry->physout = NULL;
|
}
|
#endif
|
}
|
|
/* Bump dev refs so they don't vanish while packet is out */
|
bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
|
{
|
struct nf_hook_state *state = &entry->state;
|
|
if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))
|
return false;
|
|
if (state->in)
|
dev_hold(state->in);
|
if (state->out)
|
dev_hold(state->out);
|
|
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
|
if (entry->physin)
|
dev_hold(entry->physin);
|
if (entry->physout)
|
dev_hold(entry->physout);
|
#endif
|
return true;
|
}
|
EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
|
|
void nf_queue_nf_hook_drop(struct net *net)
|
{
|
const struct nf_queue_handler *qh;
|
|
rcu_read_lock();
|
qh = rcu_dereference(net->nf.queue_handler);
|
if (qh)
|
qh->nf_hook_drop(net);
|
rcu_read_unlock();
|
}
|
EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
|
|
static void nf_ip_saveroute(const struct sk_buff *skb,
|
struct nf_queue_entry *entry)
|
{
|
struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
|
|
if (entry->state.hook == NF_INET_LOCAL_OUT) {
|
const struct iphdr *iph = ip_hdr(skb);
|
|
rt_info->tos = iph->tos;
|
rt_info->daddr = iph->daddr;
|
rt_info->saddr = iph->saddr;
|
rt_info->mark = skb->mark;
|
}
|
}
|
|
static void nf_ip6_saveroute(const struct sk_buff *skb,
|
struct nf_queue_entry *entry)
|
{
|
struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
|
|
if (entry->state.hook == NF_INET_LOCAL_OUT) {
|
const struct ipv6hdr *iph = ipv6_hdr(skb);
|
|
rt_info->daddr = iph->daddr;
|
rt_info->saddr = iph->saddr;
|
rt_info->mark = skb->mark;
|
}
|
}
|
|
static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
|
unsigned int index, unsigned int queuenum)
|
{
|
struct nf_queue_entry *entry = NULL;
|
const struct nf_queue_handler *qh;
|
struct net *net = state->net;
|
unsigned int route_key_size;
|
int status;
|
|
/* QUEUE == DROP if no one is waiting, to be safe. */
|
qh = rcu_dereference(net->nf.queue_handler);
|
if (!qh)
|
return -ESRCH;
|
|
switch (state->pf) {
|
case AF_INET:
|
route_key_size = sizeof(struct ip_rt_info);
|
break;
|
case AF_INET6:
|
route_key_size = sizeof(struct ip6_rt_info);
|
break;
|
default:
|
route_key_size = 0;
|
break;
|
}
|
|
if (skb_sk_is_prefetched(skb)) {
|
struct sock *sk = skb->sk;
|
|
if (!sk_is_refcounted(sk)) {
|
if (!refcount_inc_not_zero(&sk->sk_refcnt))
|
return -ENOTCONN;
|
|
/* drop refcount on skb_orphan */
|
skb->destructor = sock_edemux;
|
}
|
}
|
|
entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
|
if (!entry)
|
return -ENOMEM;
|
|
if (skb_dst(skb) && !skb_dst_force(skb)) {
|
kfree(entry);
|
return -ENETDOWN;
|
}
|
|
*entry = (struct nf_queue_entry) {
|
.skb = skb,
|
.state = *state,
|
.hook_index = index,
|
.size = sizeof(*entry) + route_key_size,
|
};
|
|
__nf_queue_entry_init_physdevs(entry);
|
|
if (!nf_queue_entry_get_refs(entry)) {
|
kfree(entry);
|
return -ENOTCONN;
|
}
|
|
switch (entry->state.pf) {
|
case AF_INET:
|
nf_ip_saveroute(skb, entry);
|
break;
|
case AF_INET6:
|
nf_ip6_saveroute(skb, entry);
|
break;
|
}
|
|
status = qh->outfn(entry, queuenum);
|
if (status < 0) {
|
nf_queue_entry_free(entry);
|
return status;
|
}
|
|
return 0;
|
}
|
|
/* Packets leaving via this function must come back through nf_reinject(). */
|
int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
|
unsigned int index, unsigned int verdict)
|
{
|
int ret;
|
|
ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
|
if (ret < 0) {
|
if (ret == -ESRCH &&
|
(verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
|
return 1;
|
kfree_skb(skb);
|
}
|
|
return 0;
|
}
|
EXPORT_SYMBOL_GPL(nf_queue);
|
|
static unsigned int nf_iterate(struct sk_buff *skb,
|
struct nf_hook_state *state,
|
const struct nf_hook_entries *hooks,
|
unsigned int *index)
|
{
|
const struct nf_hook_entry *hook;
|
unsigned int verdict, i = *index;
|
|
while (i < hooks->num_hook_entries) {
|
hook = &hooks->hooks[i];
|
repeat:
|
verdict = nf_hook_entry_hookfn(hook, skb, state);
|
if (verdict != NF_ACCEPT) {
|
*index = i;
|
if (verdict != NF_REPEAT)
|
return verdict;
|
goto repeat;
|
}
|
i++;
|
}
|
|
*index = i;
|
return NF_ACCEPT;
|
}
|
|
static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
|
{
|
switch (pf) {
|
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
|
case NFPROTO_BRIDGE:
|
return rcu_dereference(net->nf.hooks_bridge[hooknum]);
|
#endif
|
case NFPROTO_IPV4:
|
return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
|
case NFPROTO_IPV6:
|
return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
|
default:
|
WARN_ON_ONCE(1);
|
return NULL;
|
}
|
|
return NULL;
|
}
|
|
/* Caller must hold rcu read-side lock */
|
void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
|
{
|
const struct nf_hook_entry *hook_entry;
|
const struct nf_hook_entries *hooks;
|
struct sk_buff *skb = entry->skb;
|
const struct net *net;
|
unsigned int i;
|
int err;
|
u8 pf;
|
|
net = entry->state.net;
|
pf = entry->state.pf;
|
|
hooks = nf_hook_entries_head(net, pf, entry->state.hook);
|
|
i = entry->hook_index;
|
if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
|
kfree_skb(skb);
|
nf_queue_entry_free(entry);
|
return;
|
}
|
|
hook_entry = &hooks->hooks[i];
|
|
/* Continue traversal iff userspace said ok... */
|
if (verdict == NF_REPEAT)
|
verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
|
|
if (verdict == NF_ACCEPT) {
|
if (nf_reroute(skb, entry) < 0)
|
verdict = NF_DROP;
|
}
|
|
if (verdict == NF_ACCEPT) {
|
next_hook:
|
++i;
|
verdict = nf_iterate(skb, &entry->state, hooks, &i);
|
}
|
|
switch (verdict & NF_VERDICT_MASK) {
|
case NF_ACCEPT:
|
case NF_STOP:
|
local_bh_disable();
|
entry->state.okfn(entry->state.net, entry->state.sk, skb);
|
local_bh_enable();
|
break;
|
case NF_QUEUE:
|
err = nf_queue(skb, &entry->state, i, verdict);
|
if (err == 1)
|
goto next_hook;
|
break;
|
case NF_STOLEN:
|
break;
|
default:
|
kfree_skb(skb);
|
}
|
|
nf_queue_entry_free(entry);
|
}
|
EXPORT_SYMBOL(nf_reinject);
|
