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	This patch is to register a callback function tunnel6_rcv_cb with
is_ipip set in a xfrm_input_afinfo object for tunnel6 and tunnel46.
It will be called by xfrm_rcv_cb() from xfrm_input() when family
is AF_INET6 and proto is IPPROTO_IPIP or IPPROTO_IPV6.
v1->v2:
  - Fix a sparse warning caused by the missing "__rcu", as Jakub
    noticed.
  - Handle the err returned by xfrm_input_register_afinfo() in
    tunnel6_init/fini(), as Sabrina noticed.
v2->v3:
  - Add "#if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)" to fix the build error
    when xfrm is disabled, reported by kbuild test robot
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
		
	
			
		
			
				
	
	
		
			305 lines
		
	
	
	
		
			7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			305 lines
		
	
	
	
		
			7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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 * Copyright (C)2003,2004 USAGI/WIDE Project
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 *
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 * Authors	Mitsuru KANDA  <mk@linux-ipv6.org>
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 *		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
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 */
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#define pr_fmt(fmt) "IPv6: " fmt
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#include <linux/icmpv6.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <net/ipv6.h>
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#include <net/protocol.h>
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#include <net/xfrm.h>
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static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
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static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
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static struct xfrm6_tunnel __rcu *tunnelmpls6_handlers __read_mostly;
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static DEFINE_MUTEX(tunnel6_mutex);
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static inline int xfrm6_tunnel_mpls_supported(void)
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{
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	return IS_ENABLED(CONFIG_MPLS);
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}
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int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family)
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{
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	struct xfrm6_tunnel __rcu **pprev;
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	struct xfrm6_tunnel *t;
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	int ret = -EEXIST;
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	int priority = handler->priority;
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	mutex_lock(&tunnel6_mutex);
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	switch (family) {
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	case AF_INET6:
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		pprev = &tunnel6_handlers;
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		break;
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	case AF_INET:
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		pprev = &tunnel46_handlers;
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		break;
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	case AF_MPLS:
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		pprev = &tunnelmpls6_handlers;
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		break;
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	default:
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		goto err;
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	}
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	for (; (t = rcu_dereference_protected(*pprev,
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			lockdep_is_held(&tunnel6_mutex))) != NULL;
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	     pprev = &t->next) {
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		if (t->priority > priority)
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			break;
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		if (t->priority == priority)
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			goto err;
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	}
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	handler->next = *pprev;
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	rcu_assign_pointer(*pprev, handler);
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	ret = 0;
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err:
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	mutex_unlock(&tunnel6_mutex);
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	return ret;
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}
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EXPORT_SYMBOL(xfrm6_tunnel_register);
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int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
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{
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	struct xfrm6_tunnel __rcu **pprev;
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	struct xfrm6_tunnel *t;
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	int ret = -ENOENT;
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	mutex_lock(&tunnel6_mutex);
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	switch (family) {
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	case AF_INET6:
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		pprev = &tunnel6_handlers;
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		break;
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	case AF_INET:
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		pprev = &tunnel46_handlers;
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		break;
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	case AF_MPLS:
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		pprev = &tunnelmpls6_handlers;
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		break;
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	default:
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		goto err;
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	}
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	for (; (t = rcu_dereference_protected(*pprev,
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			lockdep_is_held(&tunnel6_mutex))) != NULL;
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	     pprev = &t->next) {
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		if (t == handler) {
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			*pprev = handler->next;
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			ret = 0;
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			break;
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		}
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	}
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err:
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	mutex_unlock(&tunnel6_mutex);
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	synchronize_net();
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	return ret;
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}
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EXPORT_SYMBOL(xfrm6_tunnel_deregister);
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#define for_each_tunnel_rcu(head, handler)		\
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	for (handler = rcu_dereference(head);		\
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	     handler != NULL;				\
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	     handler = rcu_dereference(handler->next))	\
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static int tunnelmpls6_rcv(struct sk_buff *skb)
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{
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	struct xfrm6_tunnel *handler;
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	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
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		goto drop;
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	for_each_tunnel_rcu(tunnelmpls6_handlers, handler)
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		if (!handler->handler(skb))
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			return 0;
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	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
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drop:
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	kfree_skb(skb);
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	return 0;
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}
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static int tunnel6_rcv(struct sk_buff *skb)
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{
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	struct xfrm6_tunnel *handler;
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	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
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		goto drop;
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	for_each_tunnel_rcu(tunnel6_handlers, handler)
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		if (!handler->handler(skb))
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			return 0;
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	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
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drop:
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	kfree_skb(skb);
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	return 0;
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}
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#if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)
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static int tunnel6_rcv_cb(struct sk_buff *skb, u8 proto, int err)
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{
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	struct xfrm6_tunnel __rcu *head;
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	struct xfrm6_tunnel *handler;
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	int ret;
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	head = (proto == IPPROTO_IPV6) ? tunnel6_handlers : tunnel46_handlers;
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	for_each_tunnel_rcu(head, handler) {
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		if (handler->cb_handler) {
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			ret = handler->cb_handler(skb, err);
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			if (ret <= 0)
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				return ret;
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		}
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	}
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	return 0;
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}
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static const struct xfrm_input_afinfo tunnel6_input_afinfo = {
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	.family		=	AF_INET6,
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	.is_ipip	=	true,
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	.callback	=	tunnel6_rcv_cb,
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};
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#endif
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static int tunnel46_rcv(struct sk_buff *skb)
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{
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	struct xfrm6_tunnel *handler;
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	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
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		goto drop;
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	for_each_tunnel_rcu(tunnel46_handlers, handler)
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		if (!handler->handler(skb))
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			return 0;
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	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
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drop:
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	kfree_skb(skb);
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	return 0;
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}
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static int tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
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			u8 type, u8 code, int offset, __be32 info)
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{
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	struct xfrm6_tunnel *handler;
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	for_each_tunnel_rcu(tunnel6_handlers, handler)
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		if (!handler->err_handler(skb, opt, type, code, offset, info))
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			return 0;
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	return -ENOENT;
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}
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static int tunnel46_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
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			 u8 type, u8 code, int offset, __be32 info)
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{
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	struct xfrm6_tunnel *handler;
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	for_each_tunnel_rcu(tunnel46_handlers, handler)
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		if (!handler->err_handler(skb, opt, type, code, offset, info))
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			return 0;
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	return -ENOENT;
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}
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static int tunnelmpls6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
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			   u8 type, u8 code, int offset, __be32 info)
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{
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	struct xfrm6_tunnel *handler;
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	for_each_tunnel_rcu(tunnelmpls6_handlers, handler)
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		if (!handler->err_handler(skb, opt, type, code, offset, info))
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			return 0;
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	return -ENOENT;
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}
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static const struct inet6_protocol tunnel6_protocol = {
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	.handler	= tunnel6_rcv,
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	.err_handler	= tunnel6_err,
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	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
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};
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static const struct inet6_protocol tunnel46_protocol = {
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	.handler	= tunnel46_rcv,
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	.err_handler	= tunnel46_err,
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	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
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};
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static const struct inet6_protocol tunnelmpls6_protocol = {
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	.handler	= tunnelmpls6_rcv,
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	.err_handler	= tunnelmpls6_err,
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	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
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};
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static int __init tunnel6_init(void)
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{
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	if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
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		pr_err("%s: can't add protocol\n", __func__);
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		return -EAGAIN;
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	}
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	if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
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		pr_err("%s: can't add protocol\n", __func__);
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		inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
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		return -EAGAIN;
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	}
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	if (xfrm6_tunnel_mpls_supported() &&
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	    inet6_add_protocol(&tunnelmpls6_protocol, IPPROTO_MPLS)) {
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		pr_err("%s: can't add protocol\n", __func__);
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		inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
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		inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP);
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		return -EAGAIN;
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	}
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#if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)
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	if (xfrm_input_register_afinfo(&tunnel6_input_afinfo)) {
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		pr_err("%s: can't add input afinfo\n", __func__);
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		inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
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		inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP);
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		if (xfrm6_tunnel_mpls_supported())
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			inet6_del_protocol(&tunnelmpls6_protocol, IPPROTO_MPLS);
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		return -EAGAIN;
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	}
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#endif
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	return 0;
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}
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static void __exit tunnel6_fini(void)
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{
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#if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)
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	if (xfrm_input_unregister_afinfo(&tunnel6_input_afinfo))
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		pr_err("%s: can't remove input afinfo\n", __func__);
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#endif
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	if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
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		pr_err("%s: can't remove protocol\n", __func__);
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	if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
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		pr_err("%s: can't remove protocol\n", __func__);
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	if (xfrm6_tunnel_mpls_supported() &&
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	    inet6_del_protocol(&tunnelmpls6_protocol, IPPROTO_MPLS))
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		pr_err("%s: can't remove protocol\n", __func__);
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}
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module_init(tunnel6_init);
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module_exit(tunnel6_fini);
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MODULE_LICENSE("GPL");
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