--- /dev/null
+/*
+ * Rusty Russell (C)2000 -- This code is GPL.
+ * Patrick McHardy (c) 2006-2012
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_bridge.h>
+#include <linux/seq_file.h>
+#include <linux/rcupdate.h>
+#include <net/protocol.h>
+#include <net/netfilter/nf_queue.h>
+#include <net/dst.h>
+
+#include "nf_internals.h"
+
+/*
+ * Hook for nfnetlink_queue to register its queue handler.
+ * We do this so that most of the NFQUEUE code can be modular.
+ *
+ * Once the queue is registered it must reinject all packets it
+ * receives, no matter what.
+ */
+static const struct nf_queue_handler __rcu *queue_handler __read_mostly;
+
+/* return EBUSY when somebody else is registered, return EEXIST if the
+ * same handler is registered, return 0 in case of success. */
+void nf_register_queue_handler(const struct nf_queue_handler *qh)
+{
+ /* should never happen, we only have one queueing backend in kernel */
+ WARN_ON(rcu_access_pointer(queue_handler));
+ rcu_assign_pointer(queue_handler, qh);
+}
+EXPORT_SYMBOL(nf_register_queue_handler);
+
+/* The caller must flush their queue before this */
+void nf_unregister_queue_handler(void)
+{
+ RCU_INIT_POINTER(queue_handler, NULL);
+ synchronize_rcu();
+}
+EXPORT_SYMBOL(nf_unregister_queue_handler);
+
+void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
+{
+ struct nf_hook_state *state = &entry->state;
+
+ /* Release those devices we held, or Alexey will kill me. */
+ if (state->in)
+ dev_put(state->in);
+ if (state->out)
+ dev_put(state->out);
+ if (state->sk)
+ sock_put(state->sk);
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+ if (entry->skb->nf_bridge) {
+ struct net_device *physdev;
+
+ physdev = nf_bridge_get_physindev(entry->skb);
+ if (physdev)
+ dev_put(physdev);
+ physdev = nf_bridge_get_physoutdev(entry->skb);
+ if (physdev)
+ dev_put(physdev);
+ }
+#endif
+ /* Drop reference to owner of hook which queued us. */
+ module_put(entry->elem->owner);
+}
+EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);
+
+/* Bump dev refs so they don't vanish while packet is out */
+bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
+{
+ struct nf_hook_state *state = &entry->state;
+
+ if (!try_module_get(entry->elem->owner))
+ return false;
+
+ if (state->in)
+ dev_hold(state->in);
+ if (state->out)
+ dev_hold(state->out);
+ if (state->sk)
+ sock_hold(state->sk);
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+ if (entry->skb->nf_bridge) {
+ struct net_device *physdev;
+
+ physdev = nf_bridge_get_physindev(entry->skb);
+ if (physdev)
+ dev_hold(physdev);
+ physdev = nf_bridge_get_physoutdev(entry->skb);
+ if (physdev)
+ dev_hold(physdev);
+ }
+#endif
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
+
+/*
+ * Any packet that leaves via this function must come back
+ * through nf_reinject().
+ */
+int nf_queue(struct sk_buff *skb,
+ struct nf_hook_ops *elem,
+ struct nf_hook_state *state,
+ unsigned int queuenum)
+{
+ int status = -ENOENT;
+ struct nf_queue_entry *entry = NULL;
+ const struct nf_afinfo *afinfo;
+ const struct nf_queue_handler *qh;
+
+ /* QUEUE == DROP if no one is waiting, to be safe. */
+ rcu_read_lock();
+
+ qh = rcu_dereference(queue_handler);
+ if (!qh) {
+ status = -ESRCH;
+ goto err_unlock;
+ }
+
+ afinfo = nf_get_afinfo(state->pf);
+ if (!afinfo)
+ goto err_unlock;
+
+ entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);
+ if (!entry) {
+ status = -ENOMEM;
+ goto err_unlock;
+ }
+
+ *entry = (struct nf_queue_entry) {
+ .skb = skb,
+ .elem = elem,
+ .state = *state,
+ .size = sizeof(*entry) + afinfo->route_key_size,
+ };
+
+ if (!nf_queue_entry_get_refs(entry)) {
+ status = -ECANCELED;
+ goto err_unlock;
+ }
+ skb_dst_force(skb);
+ afinfo->saveroute(skb, entry);
+ status = qh->outfn(entry, queuenum);
+
+ rcu_read_unlock();
+
+ if (status < 0) {
+ nf_queue_entry_release_refs(entry);
+ goto err;
+ }
+
+ return 0;
+
+err_unlock:
+ rcu_read_unlock();
+err:
+ kfree(entry);
+ return status;
+}
+
+void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
+{
+ struct sk_buff *skb = entry->skb;
+ struct nf_hook_ops *elem = entry->elem;
+ const struct nf_afinfo *afinfo;
+ int err;
+
+ rcu_read_lock();
+
+ nf_queue_entry_release_refs(entry);
+
+ /* Continue traversal iff userspace said ok... */
+ if (verdict == NF_REPEAT) {
+ elem = list_entry(elem->list.prev, struct nf_hook_ops, list);
+ verdict = NF_ACCEPT;
+ }
+
+ if (verdict == NF_ACCEPT) {
+ afinfo = nf_get_afinfo(entry->state.pf);
+ if (!afinfo || afinfo->reroute(skb, entry) < 0)
+ verdict = NF_DROP;
+ }
+
+ entry->state.thresh = INT_MIN;
+
+ if (verdict == NF_ACCEPT) {
+ next_hook:
+ verdict = nf_iterate(&nf_hooks[entry->state.pf][entry->state.hook],
+ skb, &entry->state, &elem);
+ }
+
+ switch (verdict & NF_VERDICT_MASK) {
+ case NF_ACCEPT:
+ case NF_STOP:
+ local_bh_disable();
+ entry->state.okfn(entry->state.sk, skb);
+ local_bh_enable();
+ break;
+ case NF_QUEUE:
+ err = nf_queue(skb, elem, &entry->state,
+ verdict >> NF_VERDICT_QBITS);
+ if (err < 0) {
+ if (err == -ECANCELED)
+ goto next_hook;
+ if (err == -ESRCH &&
+ (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
+ goto next_hook;
+ kfree_skb(skb);
+ }
+ break;
+ case NF_STOLEN:
+ break;
+ default:
+ kfree_skb(skb);
+ }
+ rcu_read_unlock();
+ kfree(entry);
+}
+EXPORT_SYMBOL(nf_reinject);
Code Review / kvmfornfv.git / blobdiff