1 #include <linux/kernel.h>
2 #include <linux/slab.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/proc_fs.h>
6 #include <linux/skbuff.h>
7 #include <linux/netfilter.h>
8 #include <linux/seq_file.h>
9 #include <linux/rcupdate.h>
10 #include <net/protocol.h>
11 #include <net/netfilter/nf_queue.h>
14 #include "nf_internals.h"
17 * Hook for nfnetlink_queue to register its queue handler.
18 * We do this so that most of the NFQUEUE code can be modular.
20 * Once the queue is registered it must reinject all packets it
21 * receives, no matter what.
23 static const struct nf_queue_handler __rcu *queue_handler __read_mostly;
25 /* return EBUSY when somebody else is registered, return EEXIST if the
26 * same handler is registered, return 0 in case of success. */
27 void nf_register_queue_handler(const struct nf_queue_handler *qh)
29 /* should never happen, we only have one queueing backend in kernel */
30 WARN_ON(rcu_access_pointer(queue_handler));
31 rcu_assign_pointer(queue_handler, qh);
33 EXPORT_SYMBOL(nf_register_queue_handler);
35 /* The caller must flush their queue before this */
36 void nf_unregister_queue_handler(void)
38 RCU_INIT_POINTER(queue_handler, NULL);
41 EXPORT_SYMBOL(nf_unregister_queue_handler);
43 static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
45 /* Release those devices we held, or Alexey will kill me. */
47 dev_put(entry->indev);
49 dev_put(entry->outdev);
50 #ifdef CONFIG_BRIDGE_NETFILTER
51 if (entry->skb->nf_bridge) {
52 struct nf_bridge_info *nf_bridge = entry->skb->nf_bridge;
54 if (nf_bridge->physindev)
55 dev_put(nf_bridge->physindev);
56 if (nf_bridge->physoutdev)
57 dev_put(nf_bridge->physoutdev);
60 /* Drop reference to owner of hook which queued us. */
61 module_put(entry->elem->owner);
65 * Any packet that leaves via this function must come back
66 * through nf_reinject().
68 static int __nf_queue(struct sk_buff *skb,
69 struct nf_hook_ops *elem,
70 u_int8_t pf, unsigned int hook,
71 struct net_device *indev,
72 struct net_device *outdev,
73 int (*okfn)(struct sk_buff *),
74 unsigned int queuenum)
77 struct nf_queue_entry *entry = NULL;
78 #ifdef CONFIG_BRIDGE_NETFILTER
79 struct net_device *physindev;
80 struct net_device *physoutdev;
82 const struct nf_afinfo *afinfo;
83 const struct nf_queue_handler *qh;
85 /* QUEUE == DROP if no one is waiting, to be safe. */
88 qh = rcu_dereference(queue_handler);
94 afinfo = nf_get_afinfo(pf);
98 entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);
104 *entry = (struct nf_queue_entry) {
114 /* If it's going away, ignore hook. */
115 if (!try_module_get(entry->elem->owner)) {
119 /* Bump dev refs so they don't vanish while packet is out */
124 #ifdef CONFIG_BRIDGE_NETFILTER
125 if (skb->nf_bridge) {
126 physindev = skb->nf_bridge->physindev;
129 physoutdev = skb->nf_bridge->physoutdev;
131 dev_hold(physoutdev);
135 afinfo->saveroute(skb, entry);
136 status = qh->outfn(entry, queuenum);
141 nf_queue_entry_release_refs(entry);
154 #ifdef CONFIG_BRIDGE_NETFILTER
155 /* When called from bridge netfilter, skb->data must point to MAC header
156 * before calling skb_gso_segment(). Else, original MAC header is lost
157 * and segmented skbs will be sent to wrong destination.
159 static void nf_bridge_adjust_skb_data(struct sk_buff *skb)
162 __skb_push(skb, skb->network_header - skb->mac_header);
165 static void nf_bridge_adjust_segmented_data(struct sk_buff *skb)
168 __skb_pull(skb, skb->network_header - skb->mac_header);
171 #define nf_bridge_adjust_skb_data(s) do {} while (0)
172 #define nf_bridge_adjust_segmented_data(s) do {} while (0)
175 int nf_queue(struct sk_buff *skb,
176 struct nf_hook_ops *elem,
177 u_int8_t pf, unsigned int hook,
178 struct net_device *indev,
179 struct net_device *outdev,
180 int (*okfn)(struct sk_buff *),
181 unsigned int queuenum)
183 struct sk_buff *segs;
187 if (!skb_is_gso(skb))
188 return __nf_queue(skb, elem, pf, hook, indev, outdev, okfn,
193 skb->protocol = htons(ETH_P_IP);
196 skb->protocol = htons(ETH_P_IPV6);
200 nf_bridge_adjust_skb_data(skb);
201 segs = skb_gso_segment(skb, 0);
202 /* Does not use PTR_ERR to limit the number of error codes that can be
203 * returned by nf_queue. For instance, callers rely on -ECANCELED to mean
204 * 'ignore this hook'.
211 struct sk_buff *nskb = segs->next;
215 nf_bridge_adjust_segmented_data(segs);
216 err = __nf_queue(segs, elem, pf, hook, indev,
217 outdev, okfn, queuenum);
231 nf_bridge_adjust_segmented_data(skb);
235 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
237 struct sk_buff *skb = entry->skb;
238 struct nf_hook_ops *elem = entry->elem;
239 const struct nf_afinfo *afinfo;
244 nf_queue_entry_release_refs(entry);
246 /* Continue traversal iff userspace said ok... */
247 if (verdict == NF_REPEAT) {
248 elem = list_entry(elem->list.prev, struct nf_hook_ops, list);
252 if (verdict == NF_ACCEPT) {
253 afinfo = nf_get_afinfo(entry->pf);
254 if (!afinfo || afinfo->reroute(skb, entry) < 0)
258 if (verdict == NF_ACCEPT) {
260 verdict = nf_iterate(&nf_hooks[entry->pf][entry->hook],
262 entry->indev, entry->outdev, &elem,
263 entry->okfn, INT_MIN);
266 switch (verdict & NF_VERDICT_MASK) {
274 err = __nf_queue(skb, elem, entry->pf, entry->hook,
275 entry->indev, entry->outdev, entry->okfn,
276 verdict >> NF_VERDICT_QBITS);
278 if (err == -ECANCELED)
281 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
294 EXPORT_SYMBOL(nf_reinject);