/* * 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" /* * 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. */ /* 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(struct net *net, const struct nf_queue_handler *qh){	/* should never happen, we only have one queueing backend in kernel */	WARN_ON(rcu_access_pointer(net->nf.queue_handler));	rcu_assign_pointer(net->nf.queue_handler, qh);}EXPORT_SYMBOL(nf_register_queue_handler); /* The caller must flush their queue before this */void nf_unregister_queue_handler(struct net *net){	RCU_INIT_POINTER(net->nf.queue_handler, NULL);}EXPORT_SYMBOL(nf_unregister_queue_handler); 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. */	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->physin)		dev_put(entry->physin);	if (entry->physout)		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 nf_bridge_info *nf_bridge; 	nf_bridge = nf_bridge_info_get(skb);	if (nf_bridge) {		entry->physin = nf_bridge_get_physindev(skb);		entry->physout = nf_bridge_get_physoutdev(skb);	} else {		entry->physin = NULL;		entry->physout = NULL;	}#endif} /* Bump dev refs so they don't vanish while packet is out */void nf_queue_entry_get_refs(struct nf_queue_entry *entry){	struct nf_hook_state *state = &entry->state; 	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->physin)		dev_hold(entry->physin);	if (entry->physout)		dev_hold(entry->physout);#endif}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(net->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;	struct net *net = state->net;	unsigned int route_key_size;	int status; 	/* QUEUE == DROP if no one is waiting, to be safe. */	qh = rcu_dereference(net->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;	} 	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,		.state	= *state,		.hook_index = index,		.size	= sizeof(*entry) + route_key_size,	}; 	__nf_queue_entry_init_physdevs(entry); 	nf_queue_entry_get_refs(entry); 	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); static unsigned int nf_iterate(struct sk_buff *skb,			       struct nf_hook_state *state,			       const struct nf_hook_entries *hooks,			       unsigned int *index){	const struct nf_hook_entry *hook;	unsigned int verdict, i = *index; 	while (i < hooks->num_hook_entries) {		hook = &hooks->hooks[i];repeat:		verdict = nf_hook_entry_hookfn(hook, skb, state);		if (verdict != NF_ACCEPT) {			*index = i;			if (verdict != NF_REPEAT)				return verdict;			goto repeat;		}		i++;	} 	*index = i;	return NF_ACCEPT;} static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum){	switch (pf) {#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE	case NFPROTO_BRIDGE:		return rcu_dereference(net->nf.hooks_bridge[hooknum]);#endif	case NFPROTO_IPV4:		return rcu_dereference(net->nf.hooks_ipv4[hooknum]);	case NFPROTO_IPV6:		return rcu_dereference(net->nf.hooks_ipv6[hooknum]);	default:		WARN_ON_ONCE(1);		return NULL;	} 	return NULL;} /* Caller must hold rcu read-side lock */void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict){	const struct nf_hook_entry *hook_entry;	const struct nf_hook_entries *hooks;	struct sk_buff *skb = entry->skb;	const struct net *net;	unsigned int i;	int err;	u8 pf; 	net = entry->state.net;	pf = entry->state.pf; 	hooks = nf_hook_entries_head(net, pf, entry->state.hook); 	i = entry->hook_index;	if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {		kfree_skb(skb);		nf_queue_entry_free(entry);		return;	} 	hook_entry = &hooks->hooks[i]; 	/* Continue traversal iff userspace said ok... */	if (verdict == NF_REPEAT)		verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state); 	if (verdict == NF_ACCEPT) {		if (nf_reroute(skb, entry) < 0)			verdict = NF_DROP;	} 	if (verdict == NF_ACCEPT) {next_hook:		++i;		verdict = nf_iterate(skb, &entry->state, hooks, &i);	} 	switch (verdict & NF_VERDICT_MASK) {	case NF_ACCEPT:	case NF_STOP:		local_bh_disable();		entry->state.okfn(entry->state.net, entry->state.sk, skb);		local_bh_enable();		break;	case NF_QUEUE:		err = nf_queue(skb, &entry->state, i, verdict);		if (err == 1)			goto next_hook;		break;	case NF_STOLEN:		break;	default:		kfree_skb(skb);	} 	nf_queue_entry_free(entry);}EXPORT_SYMBOL(nf_reinject);