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"
25 * Hook for nfnetlink_queue to register its queue handler.
26 * We do this so that most of the NFQUEUE code can be modular.
28 * Once the queue is registered it must reinject all packets it
29 * receives, no matter what.
32 /* return EBUSY when somebody else is registered, return EEXIST if the
33 * same handler is registered, return 0 in case of success. */
34 void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh)
36 /* should never happen, we only have one queueing backend in kernel */
37 WARN_ON(rcu_access_pointer(net->nf.queue_handler));
38 rcu_assign_pointer(net->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(struct net *net)
45 RCU_INIT_POINTER(net->nf.queue_handler, NULL);
47 EXPORT_SYMBOL(nf_unregister_queue_handler);
49 static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
51 struct nf_hook_state *state = &entry->state;
53 /* Release those devices we held, or Alexey will kill me. */
61 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
63 dev_put(entry->physin);
65 dev_put(entry->physout);
69 void nf_queue_entry_free(struct nf_queue_entry *entry)
71 nf_queue_entry_release_refs(entry);
74 EXPORT_SYMBOL_GPL(nf_queue_entry_free);
76 static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
78 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
79 const struct sk_buff *skb = entry->skb;
80 struct nf_bridge_info *nf_bridge;
82 nf_bridge = nf_bridge_info_get(skb);
84 entry->physin = nf_bridge_get_physindev(skb);
85 entry->physout = nf_bridge_get_physoutdev(skb);
88 entry->physout = NULL;
93 /* Bump dev refs so they don't vanish while packet is out */
94 void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
96 struct nf_hook_state *state = &entry->state;
101 dev_hold(state->out);
103 sock_hold(state->sk);
105 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
107 dev_hold(entry->physin);
109 dev_hold(entry->physout);
112 EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
114 void nf_queue_nf_hook_drop(struct net *net)
116 const struct nf_queue_handler *qh;
119 qh = rcu_dereference(net->nf.queue_handler);
121 qh->nf_hook_drop(net);
124 EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
126 static void nf_ip_saveroute(const struct sk_buff *skb,
127 struct nf_queue_entry *entry)
129 struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
131 if (entry->state.hook == NF_INET_LOCAL_OUT) {
132 const struct iphdr *iph = ip_hdr(skb);
134 rt_info->tos = iph->tos;
135 rt_info->daddr = iph->daddr;
136 rt_info->saddr = iph->saddr;
137 rt_info->mark = skb->mark;
141 static void nf_ip6_saveroute(const struct sk_buff *skb,
142 struct nf_queue_entry *entry)
144 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
146 if (entry->state.hook == NF_INET_LOCAL_OUT) {
147 const struct ipv6hdr *iph = ipv6_hdr(skb);
149 rt_info->daddr = iph->daddr;
150 rt_info->saddr = iph->saddr;
151 rt_info->mark = skb->mark;
155 static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
156 unsigned int index, unsigned int queuenum)
158 struct nf_queue_entry *entry = NULL;
159 const struct nf_queue_handler *qh;
160 struct net *net = state->net;
161 unsigned int route_key_size;
164 /* QUEUE == DROP if no one is waiting, to be safe. */
165 qh = rcu_dereference(net->nf.queue_handler);
171 route_key_size = sizeof(struct ip_rt_info);
174 route_key_size = sizeof(struct ip6_rt_info);
181 entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
185 if (skb_dst(skb) && !skb_dst_force(skb)) {
190 *entry = (struct nf_queue_entry) {
194 .size = sizeof(*entry) + route_key_size,
197 __nf_queue_entry_init_physdevs(entry);
199 nf_queue_entry_get_refs(entry);
201 switch (entry->state.pf) {
203 nf_ip_saveroute(skb, entry);
206 nf_ip6_saveroute(skb, entry);
210 status = qh->outfn(entry, queuenum);
212 nf_queue_entry_free(entry);
219 /* Packets leaving via this function must come back through nf_reinject(). */
220 int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
221 unsigned int index, unsigned int verdict)
225 ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
228 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
235 EXPORT_SYMBOL_GPL(nf_queue);
237 static unsigned int nf_iterate(struct sk_buff *skb,
238 struct nf_hook_state *state,
239 const struct nf_hook_entries *hooks,
242 const struct nf_hook_entry *hook;
243 unsigned int verdict, i = *index;
245 while (i < hooks->num_hook_entries) {
246 hook = &hooks->hooks[i];
248 verdict = nf_hook_entry_hookfn(hook, skb, state);
249 if (verdict != NF_ACCEPT) {
251 if (verdict != NF_REPEAT)
262 static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
265 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
267 return rcu_dereference(net->nf.hooks_bridge[hooknum]);
270 return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
272 return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
281 /* Caller must hold rcu read-side lock */
282 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
284 const struct nf_hook_entry *hook_entry;
285 const struct nf_hook_entries *hooks;
286 struct sk_buff *skb = entry->skb;
287 const struct net *net;
292 net = entry->state.net;
293 pf = entry->state.pf;
295 hooks = nf_hook_entries_head(net, pf, entry->state.hook);
297 i = entry->hook_index;
298 if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
300 nf_queue_entry_free(entry);
304 hook_entry = &hooks->hooks[i];
306 /* Continue traversal iff userspace said ok... */
307 if (verdict == NF_REPEAT)
308 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
310 if (verdict == NF_ACCEPT) {
311 if (nf_reroute(skb, entry) < 0)
315 if (verdict == NF_ACCEPT) {
318 verdict = nf_iterate(skb, &entry->state, hooks, &i);
321 switch (verdict & NF_VERDICT_MASK) {
325 entry->state.okfn(entry->state.net, entry->state.sk, skb);
329 err = nf_queue(skb, &entry->state, i, verdict);
339 nf_queue_entry_free(entry);
341 EXPORT_SYMBOL(nf_reinject);