Linux 6.10-rc3
[linux-block.git] / net / netfilter / nf_queue.c
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f229f6ce
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1/*
2 * Rusty Russell (C)2000 -- This code is GPL.
3 * Patrick McHardy (c) 2006-2012
4 */
5
f6ebe77f 6#include <linux/kernel.h>
5a0e3ad6 7#include <linux/slab.h>
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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>
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13#include <linux/netfilter_ipv4.h>
14#include <linux/netfilter_ipv6.h>
c737b7c4 15#include <linux/netfilter_bridge.h>
bbd86b9f 16#include <linux/seq_file.h>
7a11b984 17#include <linux/rcupdate.h>
f6ebe77f 18#include <net/protocol.h>
c01cd429 19#include <net/netfilter/nf_queue.h>
7fee226a 20#include <net/dst.h>
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21
22#include "nf_internals.h"
23
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24static const struct nf_queue_handler __rcu *nf_queue_handler;
25
601e68e1 26/*
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27 * Hook for nfnetlink_queue to register its queue handler.
28 * We do this so that most of the NFQUEUE code can be modular.
29 *
30 * Once the queue is registered it must reinject all packets it
31 * receives, no matter what.
f6ebe77f 32 */
f6ebe77f 33
87029970 34void nf_register_queue_handler(const struct nf_queue_handler *qh)
601e68e1 35{
0360ae41 36 /* should never happen, we only have one queueing backend in kernel */
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37 WARN_ON(rcu_access_pointer(nf_queue_handler));
38 rcu_assign_pointer(nf_queue_handler, qh);
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39}
40EXPORT_SYMBOL(nf_register_queue_handler);
41
42/* The caller must flush their queue before this */
87029970 43void nf_unregister_queue_handler(void)
f6ebe77f 44{
87029970 45 RCU_INIT_POINTER(nf_queue_handler, NULL);
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46}
47EXPORT_SYMBOL(nf_unregister_queue_handler);
48
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49static void nf_queue_sock_put(struct sock *sk)
50{
51#ifdef CONFIG_INET
52 sock_gen_put(sk);
53#else
54 sock_put(sk);
55#endif
56}
57
dd3cc111 58static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
daaa8be2 59{
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60 struct nf_hook_state *state = &entry->state;
61
daaa8be2 62 /* Release those devices we held, or Alexey will kill me. */
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63 dev_put(state->in);
64 dev_put(state->out);
1c984f8a 65 if (state->sk)
747670fd 66 nf_queue_sock_put(state->sk);
c4b0e771 67
119e52e6 68#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
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69 dev_put(entry->physin);
70 dev_put(entry->physout);
119e52e6 71#endif
c4b0e771 72}
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73
74void nf_queue_entry_free(struct nf_queue_entry *entry)
75{
76 nf_queue_entry_release_refs(entry);
77 kfree(entry);
78}
79EXPORT_SYMBOL_GPL(nf_queue_entry_free);
c4b0e771 80
119e52e6 81static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
c4b0e771 82{
1109a90c 83#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
119e52e6 84 const struct sk_buff *skb = entry->skb;
c4b0e771 85
aeaa4407 86 if (nf_bridge_info_exists(skb)) {
a54e7219 87 entry->physin = nf_bridge_get_physindev(skb, entry->state.net);
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88 entry->physout = nf_bridge_get_physoutdev(skb);
89 } else {
90 entry->physin = NULL;
91 entry->physout = NULL;
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92 }
93#endif
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94}
95
4bd60443 96/* Bump dev refs so they don't vanish while packet is out */
c3873070 97bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
4bd60443 98{
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99 struct nf_hook_state *state = &entry->state;
100
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101 if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))
102 return false;
103
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104 dev_hold(state->in);
105 dev_hold(state->out);
4bd60443 106
119e52e6 107#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
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108 dev_hold(entry->physin);
109 dev_hold(entry->physout);
119e52e6 110#endif
c3873070 111 return true;
4bd60443 112}
a5fedd43 113EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
4bd60443 114
26888dfd 115void nf_queue_nf_hook_drop(struct net *net)
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116{
117 const struct nf_queue_handler *qh;
8405a8ff 118
8405a8ff 119 rcu_read_lock();
87029970 120 qh = rcu_dereference(nf_queue_handler);
2385eb0c 121 if (qh)
26888dfd 122 qh->nf_hook_drop(net);
8405a8ff 123 rcu_read_unlock();
8405a8ff 124}
e2a75007 125EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
8405a8ff 126
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127static void nf_ip_saveroute(const struct sk_buff *skb,
128 struct nf_queue_entry *entry)
129{
130 struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
131
132 if (entry->state.hook == NF_INET_LOCAL_OUT) {
133 const struct iphdr *iph = ip_hdr(skb);
134
135 rt_info->tos = iph->tos;
136 rt_info->daddr = iph->daddr;
137 rt_info->saddr = iph->saddr;
138 rt_info->mark = skb->mark;
139 }
140}
141
142static void nf_ip6_saveroute(const struct sk_buff *skb,
143 struct nf_queue_entry *entry)
144{
145 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
146
147 if (entry->state.hook == NF_INET_LOCAL_OUT) {
148 const struct ipv6hdr *iph = ipv6_hdr(skb);
149
150 rt_info->daddr = iph->daddr;
151 rt_info->saddr = iph->saddr;
152 rt_info->mark = skb->mark;
153 }
154}
155
7034b566 156static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
960632ec 157 unsigned int index, unsigned int queuenum)
f6ebe77f 158{
daaa8be2 159 struct nf_queue_entry *entry = NULL;
e3ac5298 160 const struct nf_queue_handler *qh;
46435623 161 unsigned int route_key_size;
28f715b9 162 int status;
f6ebe77f 163
25985edc 164 /* QUEUE == DROP if no one is waiting, to be safe. */
87029970 165 qh = rcu_dereference(nf_queue_handler);
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166 if (!qh)
167 return -ESRCH;
f6ebe77f 168
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169 switch (state->pf) {
170 case AF_INET:
171 route_key_size = sizeof(struct ip_rt_info);
172 break;
173 case AF_INET6:
174 route_key_size = sizeof(struct ip6_rt_info);
175 break;
176 default:
177 route_key_size = 0;
178 break;
179 }
bce8032e 180
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181 if (skb_sk_is_prefetched(skb)) {
182 struct sock *sk = skb->sk;
183
184 if (!sk_is_refcounted(sk)) {
185 if (!refcount_inc_not_zero(&sk->sk_refcnt))
186 return -ENOTCONN;
187
188 /* drop refcount on skb_orphan */
189 skb->destructor = sock_edemux;
190 }
191 }
192
46435623 193 entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
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194 if (!entry)
195 return -ENOMEM;
f6ebe77f 196
0b9173f4 197 if (skb_dst(skb) && !skb_dst_force(skb)) {
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198 kfree(entry);
199 return -ENETDOWN;
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200 }
201
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202 *entry = (struct nf_queue_entry) {
203 .skb = skb,
1d1de89b 204 .state = *state,
960632ec 205 .hook_index = index,
46435623 206 .size = sizeof(*entry) + route_key_size,
02f014d8 207 };
f6ebe77f 208
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209 __nf_queue_entry_init_physdevs(entry);
210
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211 if (!nf_queue_entry_get_refs(entry)) {
212 kfree(entry);
213 return -ENOTCONN;
214 }
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215
216 switch (entry->state.pf) {
217 case AF_INET:
218 nf_ip_saveroute(skb, entry);
219 break;
220 case AF_INET6:
221 nf_ip6_saveroute(skb, entry);
222 break;
223 }
224
02f014d8 225 status = qh->outfn(entry, queuenum);
f6ebe77f 226 if (status < 0) {
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227 nf_queue_entry_free(entry);
228 return status;
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229 }
230
f1585086 231 return 0;
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232}
233
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234/* Packets leaving via this function must come back through nf_reinject(). */
235int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
0d9cb300 236 unsigned int index, unsigned int verdict)
7034b566 237{
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238 int ret;
239
0d9cb300 240 ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
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241 if (ret < 0) {
242 if (ret == -ESRCH &&
960632ec 243 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
7034b566 244 return 1;
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245 kfree_skb(skb);
246 }
247
248 return 0;
249}
971502d7 250EXPORT_SYMBOL_GPL(nf_queue);