// SPDX-License-Identifier: GPL-2.0-or-later/* * 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_ipv4.h>#include <linux/netfilter_ipv6.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" static const struct nf_queue_handler __rcu *nf_queue_handler; /* * 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. */ 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(nf_queue_handler));	rcu_assign_pointer(nf_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(nf_queue_handler, NULL);}EXPORT_SYMBOL(nf_unregister_queue_handler); static void nf_queue_sock_put(struct sock *sk){#ifdef CONFIG_INET	sock_gen_put(sk);#else	sock_put(sk);#endif} static 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. */	dev_put(entry->skb_dev);	dev_put(state->in);	dev_put(state->out);	if (state->sk)		nf_queue_sock_put(state->sk); #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)	dev_put(entry->bridge_dev);	dev_put(entry->physin);	dev_put(entry->physout);#endif} void nf_queue_entry_free(struct nf_queue_entry *entry){	nf_queue_entry_release_refs(entry);	kfree(entry);}EXPORT_SYMBOL_GPL(nf_queue_entry_free); static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry){#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)	const struct sk_buff *skb = entry->skb;	struct dst_entry *dst = skb_dst(skb);	struct net_device *dev = NULL; 	if (nf_bridge_info_exists(skb)) {		entry->physin = nf_bridge_get_physindev(skb, entry->state.net);		entry->physout = nf_bridge_get_physoutdev(skb);	} else {		entry->physin = NULL;		entry->physout = NULL;	} 	if (entry->state.pf == NFPROTO_BRIDGE &&	    dst && (dst->flags & DST_FAKE_RTABLE))		dev = dst_dev_rcu(dst); 	/* Must hold a reference on the bridge device: dst_hold() protects	 * the dst itself, but the fake rtable is embedded in bridge-private	 * storage that netdevice teardown can free independently.	 */	entry->bridge_dev = dev;#endif} /* 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 (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))		return false; 	dev_hold(entry->skb_dev);	dev_hold(state->in);	dev_hold(state->out); #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)	dev_hold(entry->bridge_dev);	dev_hold(entry->physin);	dev_hold(entry->physout);#endif	return true;}EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs); void nf_queue_nf_hook_drop(struct net *net){	const struct nf_queue_handler *qh; 	rcu_read_lock();	qh = rcu_dereference(nf_queue_handler);	if (qh)		qh->nf_hook_drop(net);	rcu_read_unlock();}EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop); static void nf_ip_saveroute(const struct sk_buff *skb,			    struct nf_queue_entry *entry){	struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); 	if (entry->state.hook == NF_INET_LOCAL_OUT) {		const struct iphdr *iph = ip_hdr(skb); 		rt_info->tos = iph->tos;		rt_info->daddr = iph->daddr;		rt_info->saddr = iph->saddr;		rt_info->mark = skb->mark;	}} static void nf_ip6_saveroute(const struct sk_buff *skb,			     struct nf_queue_entry *entry){	struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 	if (entry->state.hook == NF_INET_LOCAL_OUT) {		const struct ipv6hdr *iph = ipv6_hdr(skb); 		rt_info->daddr = iph->daddr;		rt_info->saddr = iph->saddr;		rt_info->mark = skb->mark;	}} static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,		      unsigned int index, unsigned int queuenum){	struct nf_queue_entry *entry = NULL;	const struct nf_queue_handler *qh;	unsigned int route_key_size;	int status; 	/* QUEUE == DROP if no one is waiting, to be safe. */	qh = rcu_dereference(nf_queue_handler);	if (!qh)		return -ESRCH; 	switch (state->pf) {	case AF_INET:		route_key_size = sizeof(struct ip_rt_info);		break;	case AF_INET6:		route_key_size = sizeof(struct ip6_rt_info);		break;	default:		route_key_size = 0;		break;	} 	if (skb_sk_is_prefetched(skb)) {		struct sock *sk = skb->sk; 		if (!sk_is_refcounted(sk)) {			if (!refcount_inc_not_zero(&sk->sk_refcnt))				return -ENOTCONN; 			/* drop refcount on skb_orphan */			skb->destructor = sock_edemux;		}	} 	entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);	if (!entry)		return -ENOMEM; 	if (skb_dst(skb) && !skb_dst_force(skb)) {		kfree(entry);		return -ENETDOWN;	} 	*entry = (struct nf_queue_entry) {		.skb	= skb,		.skb_dev = skb->dev,		.state	= *state,		.hook_index = index,		.size	= sizeof(*entry) + route_key_size,	};	__nf_queue_entry_init_physdevs(entry); 	if (!nf_queue_entry_get_refs(entry)) {		kfree(entry);		return -ENOTCONN;	} 	switch (entry->state.pf) {	case AF_INET:		nf_ip_saveroute(skb, entry);		break;	case AF_INET6:		nf_ip6_saveroute(skb, entry);		break;	} 	status = qh->outfn(entry, queuenum);	if (status < 0) {		nf_queue_entry_free(entry);		return status;	} 	return 0;} /* Packets leaving via this function must come back through nf_reinject(). */int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,	     unsigned int index, unsigned int verdict){	int ret; 	ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);	if (ret < 0) {		if (ret == -ESRCH &&		    (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))			return 1;		kfree_skb(skb);	} 	return 0;}EXPORT_SYMBOL_GPL(nf_queue);