2 * Rusty Russell (C)2000 -- This code is GPL.
3 * Patrick McHardy (c) 2006-2012
6 #include <linux/kernel.h>
7 #include <linux/slab.h>
8 #include <linux/init.h>
9 #include <linux/module.h>
10 #include <linux/proc_fs.h>
11 #include <linux/skbuff.h>
12 #include <linux/netfilter.h>
13 #include <linux/netfilter_ipv4.h>
14 #include <linux/netfilter_ipv6.h>
15 #include <linux/netfilter_bridge.h>
16 #include <linux/seq_file.h>
17 #include <linux/rcupdate.h>
18 #include <net/protocol.h>
19 #include <net/netfilter/nf_queue.h>
22 #include "nf_internals.h"
24 static const struct nf_queue_handler __rcu *nf_queue_handler;
27 * Hook for nfnetlink_queue to register its queue handler.
28 * We do this so that most of the NFQUEUE code can be modular.
30 * Once the queue is registered it must reinject all packets it
31 * receives, no matter what.
34 void nf_register_queue_handler(const struct nf_queue_handler *qh)
36 /* should never happen, we only have one queueing backend in kernel */
37 WARN_ON(rcu_access_pointer(nf_queue_handler));
38 rcu_assign_pointer(nf_queue_handler, qh);
40 EXPORT_SYMBOL(nf_register_queue_handler);
42 /* The caller must flush their queue before this */
43 void nf_unregister_queue_handler(void)
45 RCU_INIT_POINTER(nf_queue_handler, NULL);
47 EXPORT_SYMBOL(nf_unregister_queue_handler);
49 static void nf_queue_sock_put(struct sock *sk)
58 static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
60 struct nf_hook_state *state = &entry->state;
62 /* Release those devices we held, or Alexey will kill me. */
66 nf_queue_sock_put(state->sk);
68 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
69 dev_put(entry->physin);
70 dev_put(entry->physout);
74 void nf_queue_entry_free(struct nf_queue_entry *entry)
76 nf_queue_entry_release_refs(entry);
79 EXPORT_SYMBOL_GPL(nf_queue_entry_free);
81 static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
83 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
84 const struct sk_buff *skb = entry->skb;
86 if (nf_bridge_info_exists(skb)) {
87 entry->physin = nf_bridge_get_physindev(skb, entry->state.net);
88 entry->physout = nf_bridge_get_physoutdev(skb);
91 entry->physout = NULL;
96 /* Bump dev refs so they don't vanish while packet is out */
97 bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
99 struct nf_hook_state *state = &entry->state;
101 if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))
105 dev_hold(state->out);
107 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
108 dev_hold(entry->physin);
109 dev_hold(entry->physout);
113 EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
115 void nf_queue_nf_hook_drop(struct net *net)
117 const struct nf_queue_handler *qh;
120 qh = rcu_dereference(nf_queue_handler);
122 qh->nf_hook_drop(net);
125 EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
127 static void nf_ip_saveroute(const struct sk_buff *skb,
128 struct nf_queue_entry *entry)
130 struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
132 if (entry->state.hook == NF_INET_LOCAL_OUT) {
133 const struct iphdr *iph = ip_hdr(skb);
135 rt_info->tos = iph->tos;
136 rt_info->daddr = iph->daddr;
137 rt_info->saddr = iph->saddr;
138 rt_info->mark = skb->mark;
142 static void nf_ip6_saveroute(const struct sk_buff *skb,
143 struct nf_queue_entry *entry)
145 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
147 if (entry->state.hook == NF_INET_LOCAL_OUT) {
148 const struct ipv6hdr *iph = ipv6_hdr(skb);
150 rt_info->daddr = iph->daddr;
151 rt_info->saddr = iph->saddr;
152 rt_info->mark = skb->mark;
156 static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
157 unsigned int index, unsigned int queuenum)
159 struct nf_queue_entry *entry = NULL;
160 const struct nf_queue_handler *qh;
161 unsigned int route_key_size;
164 /* QUEUE == DROP if no one is waiting, to be safe. */
165 qh = rcu_dereference(nf_queue_handler);
171 route_key_size = sizeof(struct ip_rt_info);
174 route_key_size = sizeof(struct ip6_rt_info);
181 if (skb_sk_is_prefetched(skb)) {
182 struct sock *sk = skb->sk;
184 if (!sk_is_refcounted(sk)) {
185 if (!refcount_inc_not_zero(&sk->sk_refcnt))
188 /* drop refcount on skb_orphan */
189 skb->destructor = sock_edemux;
193 entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
197 if (skb_dst(skb) && !skb_dst_force(skb)) {
202 *entry = (struct nf_queue_entry) {
206 .size = sizeof(*entry) + route_key_size,
209 __nf_queue_entry_init_physdevs(entry);
211 if (!nf_queue_entry_get_refs(entry)) {
216 switch (entry->state.pf) {
218 nf_ip_saveroute(skb, entry);
221 nf_ip6_saveroute(skb, entry);
225 status = qh->outfn(entry, queuenum);
227 nf_queue_entry_free(entry);
234 /* Packets leaving via this function must come back through nf_reinject(). */
235 int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
236 unsigned int index, unsigned int verdict)
240 ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
243 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
250 EXPORT_SYMBOL_GPL(nf_queue);
252 static unsigned int nf_iterate(struct sk_buff *skb,
253 struct nf_hook_state *state,
254 const struct nf_hook_entries *hooks,
257 const struct nf_hook_entry *hook;
258 unsigned int verdict, i = *index;
260 while (i < hooks->num_hook_entries) {
261 hook = &hooks->hooks[i];
263 verdict = nf_hook_entry_hookfn(hook, skb, state);
264 if (verdict != NF_ACCEPT) {
266 if (verdict != NF_REPEAT)
277 static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
280 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
282 return rcu_dereference(net->nf.hooks_bridge[hooknum]);
285 return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
287 return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
296 /* Caller must hold rcu read-side lock */
297 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
299 const struct nf_hook_entry *hook_entry;
300 const struct nf_hook_entries *hooks;
301 struct sk_buff *skb = entry->skb;
302 const struct net *net;
307 net = entry->state.net;
308 pf = entry->state.pf;
310 hooks = nf_hook_entries_head(net, pf, entry->state.hook);
312 i = entry->hook_index;
313 if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
315 nf_queue_entry_free(entry);
319 hook_entry = &hooks->hooks[i];
321 /* Continue traversal iff userspace said ok... */
322 if (verdict == NF_REPEAT)
323 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
325 if (verdict == NF_ACCEPT) {
326 if (nf_reroute(skb, entry) < 0)
330 if (verdict == NF_ACCEPT) {
333 verdict = nf_iterate(skb, &entry->state, hooks, &i);
336 switch (verdict & NF_VERDICT_MASK) {
340 entry->state.okfn(entry->state.net, entry->state.sk, skb);
344 err = nf_queue(skb, &entry->state, i, verdict);
354 nf_queue_entry_free(entry);
356 EXPORT_SYMBOL(nf_reinject);