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net/ipv6/xfrm6_protocol.c 6.41 KB
7e14ea152   Steffen Klassert   xfrm6: Add IPsec ...
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  /* xfrm6_protocol.c - Generic xfrm protocol multiplexer for ipv6.
   *
   * Copyright (C) 2013 secunet Security Networks AG
   *
   * Author:
   * Steffen Klassert <steffen.klassert@secunet.com>
   *
   * Based on:
   * net/ipv4/xfrm4_protocol.c
   *
   *	This program is free software; you can redistribute it and/or
   *	modify it under the terms of the GNU General Public License
   *	as published by the Free Software Foundation; either version
   *	2 of the License, or (at your option) any later version.
   */
  
  #include <linux/init.h>
  #include <linux/mutex.h>
  #include <linux/skbuff.h>
  #include <linux/icmpv6.h>
  #include <net/ipv6.h>
  #include <net/protocol.h>
  #include <net/xfrm.h>
  
  static struct xfrm6_protocol __rcu *esp6_handlers __read_mostly;
  static struct xfrm6_protocol __rcu *ah6_handlers __read_mostly;
  static struct xfrm6_protocol __rcu *ipcomp6_handlers __read_mostly;
  static DEFINE_MUTEX(xfrm6_protocol_mutex);
  
  static inline struct xfrm6_protocol __rcu **proto_handlers(u8 protocol)
  {
  	switch (protocol) {
  	case IPPROTO_ESP:
  		return &esp6_handlers;
  	case IPPROTO_AH:
  		return &ah6_handlers;
  	case IPPROTO_COMP:
  		return &ipcomp6_handlers;
  	}
  
  	return NULL;
  }
  
  #define for_each_protocol_rcu(head, handler)		\
  	for (handler = rcu_dereference(head);		\
  	     handler != NULL;				\
  	     handler = rcu_dereference(handler->next))	\
  
  int xfrm6_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
  {
  	int ret;
  	struct xfrm6_protocol *handler;
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  	struct xfrm6_protocol __rcu **head = proto_handlers(protocol);
  
  	if (!head)
  		return 0;
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  	for_each_protocol_rcu(*proto_handlers(protocol), handler)
  		if ((ret = handler->cb_handler(skb, err)) <= 0)
  			return ret;
  
  	return 0;
  }
  EXPORT_SYMBOL(xfrm6_rcv_cb);
  
  static int xfrm6_esp_rcv(struct sk_buff *skb)
  {
  	int ret;
  	struct xfrm6_protocol *handler;
  
  	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
  
  	for_each_protocol_rcu(esp6_handlers, handler)
  		if ((ret = handler->handler(skb)) != -EINVAL)
  			return ret;
  
  	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
  
  	kfree_skb(skb);
  	return 0;
  }
  
  static void xfrm6_esp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  			  u8 type, u8 code, int offset, __be32 info)
  {
  	struct xfrm6_protocol *handler;
  
  	for_each_protocol_rcu(esp6_handlers, handler)
  		if (!handler->err_handler(skb, opt, type, code, offset, info))
  			break;
  }
  
  static int xfrm6_ah_rcv(struct sk_buff *skb)
  {
  	int ret;
  	struct xfrm6_protocol *handler;
  
  	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
  
  	for_each_protocol_rcu(ah6_handlers, handler)
  		if ((ret = handler->handler(skb)) != -EINVAL)
  			return ret;
  
  	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
  
  	kfree_skb(skb);
  	return 0;
  }
  
  static void xfrm6_ah_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  			 u8 type, u8 code, int offset, __be32 info)
  {
  	struct xfrm6_protocol *handler;
  
  	for_each_protocol_rcu(ah6_handlers, handler)
  		if (!handler->err_handler(skb, opt, type, code, offset, info))
  			break;
  }
  
  static int xfrm6_ipcomp_rcv(struct sk_buff *skb)
  {
  	int ret;
  	struct xfrm6_protocol *handler;
  
  	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
  
  	for_each_protocol_rcu(ipcomp6_handlers, handler)
  		if ((ret = handler->handler(skb)) != -EINVAL)
  			return ret;
  
  	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
  
  	kfree_skb(skb);
  	return 0;
  }
  
  static void xfrm6_ipcomp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  			     u8 type, u8 code, int offset, __be32 info)
  {
  	struct xfrm6_protocol *handler;
  
  	for_each_protocol_rcu(ipcomp6_handlers, handler)
  		if (!handler->err_handler(skb, opt, type, code, offset, info))
  			break;
  }
  
  static const struct inet6_protocol esp6_protocol = {
  	.handler	=	xfrm6_esp_rcv,
  	.err_handler	=	xfrm6_esp_err,
  	.flags		=	INET6_PROTO_NOPOLICY,
  };
  
  static const struct inet6_protocol ah6_protocol = {
  	.handler	=	xfrm6_ah_rcv,
  	.err_handler	=	xfrm6_ah_err,
  	.flags		=	INET6_PROTO_NOPOLICY,
  };
  
  static const struct inet6_protocol ipcomp6_protocol = {
  	.handler	=	xfrm6_ipcomp_rcv,
  	.err_handler	=	xfrm6_ipcomp_err,
  	.flags		=	INET6_PROTO_NOPOLICY,
  };
960fdfdeb   Florian Westphal   xfrm: input: cons...
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  static const struct xfrm_input_afinfo xfrm6_input_afinfo = {
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  	.family		=	AF_INET6,
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  	.callback	=	xfrm6_rcv_cb,
  };
  
  static inline const struct inet6_protocol *netproto(unsigned char protocol)
  {
  	switch (protocol) {
  	case IPPROTO_ESP:
  		return &esp6_protocol;
  	case IPPROTO_AH:
  		return &ah6_protocol;
  	case IPPROTO_COMP:
  		return &ipcomp6_protocol;
  	}
  
  	return NULL;
  }
  
  int xfrm6_protocol_register(struct xfrm6_protocol *handler,
  			    unsigned char protocol)
  {
  	struct xfrm6_protocol __rcu **pprev;
  	struct xfrm6_protocol *t;
  	bool add_netproto = false;
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  	int ret = -EEXIST;
  	int priority = handler->priority;
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  	if (!proto_handlers(protocol) || !netproto(protocol))
  		return -EINVAL;
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  	mutex_lock(&xfrm6_protocol_mutex);
  
  	if (!rcu_dereference_protected(*proto_handlers(protocol),
  				       lockdep_is_held(&xfrm6_protocol_mutex)))
  		add_netproto = true;
  
  	for (pprev = proto_handlers(protocol);
  	     (t = rcu_dereference_protected(*pprev,
  			lockdep_is_held(&xfrm6_protocol_mutex))) != NULL;
  	     pprev = &t->next) {
  		if (t->priority < priority)
  			break;
  		if (t->priority == priority)
  			goto err;
  	}
  
  	handler->next = *pprev;
  	rcu_assign_pointer(*pprev, handler);
  
  	ret = 0;
  
  err:
  	mutex_unlock(&xfrm6_protocol_mutex);
  
  	if (add_netproto) {
  		if (inet6_add_protocol(netproto(protocol), protocol)) {
  			pr_err("%s: can't add protocol
  ", __func__);
  			ret = -EAGAIN;
  		}
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL(xfrm6_protocol_register);
  
  int xfrm6_protocol_deregister(struct xfrm6_protocol *handler,
  			      unsigned char protocol)
  {
  	struct xfrm6_protocol __rcu **pprev;
  	struct xfrm6_protocol *t;
  	int ret = -ENOENT;
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  	if (!proto_handlers(protocol) || !netproto(protocol))
  		return -EINVAL;
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  	mutex_lock(&xfrm6_protocol_mutex);
  
  	for (pprev = proto_handlers(protocol);
  	     (t = rcu_dereference_protected(*pprev,
  			lockdep_is_held(&xfrm6_protocol_mutex))) != NULL;
  	     pprev = &t->next) {
  		if (t == handler) {
  			*pprev = handler->next;
  			ret = 0;
  			break;
  		}
  	}
  
  	if (!rcu_dereference_protected(*proto_handlers(protocol),
  				       lockdep_is_held(&xfrm6_protocol_mutex))) {
  		if (inet6_del_protocol(netproto(protocol), protocol) < 0) {
  			pr_err("%s: can't remove protocol
  ", __func__);
  			ret = -EAGAIN;
  		}
  	}
  
  	mutex_unlock(&xfrm6_protocol_mutex);
  
  	synchronize_net();
  
  	return ret;
  }
  EXPORT_SYMBOL(xfrm6_protocol_deregister);
  
  int __init xfrm6_protocol_init(void)
  {
  	return xfrm_input_register_afinfo(&xfrm6_input_afinfo);
  }
  
  void xfrm6_protocol_fini(void)
  {
  	xfrm_input_unregister_afinfo(&xfrm6_input_afinfo);
  }