Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Rusty Russell (C)2000 -- This code is GPL.
3 * Patrick McHardy (c) 2006-2012
4 */
5
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_bridge.h>
14#include <linux/seq_file.h>
15#include <linux/rcupdate.h>
16#include <net/protocol.h>
17#include <net/netfilter/nf_queue.h>
18#include <net/dst.h>
19
20#include "nf_internals.h"
21
22/*
23 * Hook for nfnetlink_queue to register its queue handler.
24 * We do this so that most of the NFQUEUE code can be modular.
25 *
26 * Once the queue is registered it must reinject all packets it
27 * receives, no matter what.
28 */
29
30/* return EBUSY when somebody else is registered, return EEXIST if the
31 * same handler is registered, return 0 in case of success. */
32void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh)
33{
34 /* should never happen, we only have one queueing backend in kernel */
35 WARN_ON(rcu_access_pointer(net->nf.queue_handler));
36 rcu_assign_pointer(net->nf.queue_handler, qh);
37}
38EXPORT_SYMBOL(nf_register_queue_handler);
39
40/* The caller must flush their queue before this */
41void nf_unregister_queue_handler(struct net *net)
42{
43 RCU_INIT_POINTER(net->nf.queue_handler, NULL);
44}
45EXPORT_SYMBOL(nf_unregister_queue_handler);
46
47void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
48{
49 struct nf_hook_state *state = &entry->state;
50
51 /* Release those devices we held, or Alexey will kill me. */
52 if (state->in)
53 dev_put(state->in);
54 if (state->out)
55 dev_put(state->out);
56 if (state->sk)
57 sock_put(state->sk);
58#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
59 if (entry->skb->nf_bridge) {
60 struct net_device *physdev;
61
62 physdev = nf_bridge_get_physindev(entry->skb);
63 if (physdev)
64 dev_put(physdev);
65 physdev = nf_bridge_get_physoutdev(entry->skb);
66 if (physdev)
67 dev_put(physdev);
68 }
69#endif
70}
71EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);
72
73/* Bump dev refs so they don't vanish while packet is out */
74void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
75{
76 struct nf_hook_state *state = &entry->state;
77
78 if (state->in)
79 dev_hold(state->in);
80 if (state->out)
81 dev_hold(state->out);
82 if (state->sk)
83 sock_hold(state->sk);
84#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
85 if (entry->skb->nf_bridge) {
86 struct net_device *physdev;
87
88 physdev = nf_bridge_get_physindev(entry->skb);
89 if (physdev)
90 dev_hold(physdev);
91 physdev = nf_bridge_get_physoutdev(entry->skb);
92 if (physdev)
93 dev_hold(physdev);
94 }
95#endif
96}
97EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
98
99void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops)
100{
101 const struct nf_queue_handler *qh;
102
103 rcu_read_lock();
104 qh = rcu_dereference(net->nf.queue_handler);
105 if (qh)
106 qh->nf_hook_drop(net, ops);
107 rcu_read_unlock();
108}
109
110/*
111 * Any packet that leaves via this function must come back
112 * through nf_reinject().
113 */
114int nf_queue(struct sk_buff *skb,
115 struct nf_hook_ops *elem,
116 struct nf_hook_state *state,
117 unsigned int queuenum)
118{
119 int status = -ENOENT;
120 struct nf_queue_entry *entry = NULL;
121 const struct nf_afinfo *afinfo;
122 const struct nf_queue_handler *qh;
123 struct net *net = state->net;
124
125 /* QUEUE == DROP if no one is waiting, to be safe. */
126 qh = rcu_dereference(net->nf.queue_handler);
127 if (!qh) {
128 status = -ESRCH;
129 goto err;
130 }
131
132 afinfo = nf_get_afinfo(state->pf);
133 if (!afinfo)
134 goto err;
135
136 entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);
137 if (!entry) {
138 status = -ENOMEM;
139 goto err;
140 }
141
142 *entry = (struct nf_queue_entry) {
143 .skb = skb,
144 .elem = elem,
145 .state = *state,
146 .size = sizeof(*entry) + afinfo->route_key_size,
147 };
148
149 nf_queue_entry_get_refs(entry);
150 skb_dst_force(skb);
151 afinfo->saveroute(skb, entry);
152 status = qh->outfn(entry, queuenum);
153
154 if (status < 0) {
155 nf_queue_entry_release_refs(entry);
156 goto err;
157 }
158
159 return 0;
160
161err:
162 kfree(entry);
163 return status;
164}
165
166void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
167{
168 struct sk_buff *skb = entry->skb;
169 struct nf_hook_ops *elem = entry->elem;
170 const struct nf_afinfo *afinfo;
171 int err;
172
173 nf_queue_entry_release_refs(entry);
174
175 /* Continue traversal iff userspace said ok... */
176 if (verdict == NF_REPEAT)
177 verdict = elem->hook(elem->priv, skb, &entry->state);
178
179 if (verdict == NF_ACCEPT) {
180 afinfo = nf_get_afinfo(entry->state.pf);
181 if (!afinfo || afinfo->reroute(entry->state.net, skb, entry) < 0)
182 verdict = NF_DROP;
183 }
184
185 entry->state.thresh = INT_MIN;
186
187 if (verdict == NF_ACCEPT) {
188 next_hook:
189 verdict = nf_iterate(entry->state.hook_list,
190 skb, &entry->state, &elem);
191 }
192
193 switch (verdict & NF_VERDICT_MASK) {
194 case NF_ACCEPT:
195 case NF_STOP:
196 local_bh_disable();
197 entry->state.okfn(entry->state.net, entry->state.sk, skb);
198 local_bh_enable();
199 break;
200 case NF_QUEUE:
201 err = nf_queue(skb, elem, &entry->state,
202 verdict >> NF_VERDICT_QBITS);
203 if (err < 0) {
204 if (err == -ESRCH &&
205 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
206 goto next_hook;
207 kfree_skb(skb);
208 }
209 break;
210 case NF_STOLEN:
211 break;
212 default:
213 kfree_skb(skb);
214 }
215
216 kfree(entry);
217}
218EXPORT_SYMBOL(nf_reinject);