302 lines
6.7 KiB
C
302 lines
6.7 KiB
C
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/* xfrm4_protocol.c - Generic xfrm protocol multiplexer.
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*
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* Copyright (C) 2013 secunet Security Networks AG
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*
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* Author:
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* Steffen Klassert <steffen.klassert@secunet.com>
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*
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* Based on:
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* net/ipv4/tunnel4.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/mutex.h>
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#include <linux/skbuff.h>
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#include <net/icmp.h>
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#include <net/ip.h>
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#include <net/protocol.h>
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#include <net/xfrm.h>
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static struct xfrm4_protocol __rcu *esp4_handlers __read_mostly;
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static struct xfrm4_protocol __rcu *ah4_handlers __read_mostly;
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static struct xfrm4_protocol __rcu *ipcomp4_handlers __read_mostly;
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static DEFINE_MUTEX(xfrm4_protocol_mutex);
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static inline struct xfrm4_protocol __rcu **proto_handlers(u8 protocol)
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{
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switch (protocol) {
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case IPPROTO_ESP:
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return &esp4_handlers;
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case IPPROTO_AH:
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return &ah4_handlers;
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case IPPROTO_COMP:
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return &ipcomp4_handlers;
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}
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return NULL;
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}
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#define for_each_protocol_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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int xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
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{
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int ret;
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struct xfrm4_protocol *handler;
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struct xfrm4_protocol __rcu **head = proto_handlers(protocol);
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if (!head)
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return 0;
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for_each_protocol_rcu(*head, handler)
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if ((ret = handler->cb_handler(skb, err)) <= 0)
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return ret;
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return 0;
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}
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EXPORT_SYMBOL(xfrm4_rcv_cb);
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int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
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int encap_type)
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{
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int ret;
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struct xfrm4_protocol *handler;
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struct xfrm4_protocol __rcu **head = proto_handlers(nexthdr);
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XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
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XFRM_SPI_SKB_CB(skb)->family = AF_INET;
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XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
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if (!head)
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goto out;
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for_each_protocol_rcu(*head, handler)
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if ((ret = handler->input_handler(skb, nexthdr, spi, encap_type)) != -EINVAL)
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return ret;
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out:
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
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kfree_skb(skb);
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return 0;
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}
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EXPORT_SYMBOL(xfrm4_rcv_encap);
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static int xfrm4_esp_rcv(struct sk_buff *skb)
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{
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int ret;
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struct xfrm4_protocol *handler;
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XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
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for_each_protocol_rcu(esp4_handlers, handler)
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if ((ret = handler->handler(skb)) != -EINVAL)
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return ret;
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
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kfree_skb(skb);
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return 0;
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}
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static void xfrm4_esp_err(struct sk_buff *skb, u32 info)
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{
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struct xfrm4_protocol *handler;
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for_each_protocol_rcu(esp4_handlers, handler)
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if (!handler->err_handler(skb, info))
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break;
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}
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static int xfrm4_ah_rcv(struct sk_buff *skb)
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{
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int ret;
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struct xfrm4_protocol *handler;
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XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
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for_each_protocol_rcu(ah4_handlers, handler)
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if ((ret = handler->handler(skb)) != -EINVAL)
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return ret;
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
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kfree_skb(skb);
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return 0;
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}
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static void xfrm4_ah_err(struct sk_buff *skb, u32 info)
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{
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struct xfrm4_protocol *handler;
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for_each_protocol_rcu(ah4_handlers, handler)
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if (!handler->err_handler(skb, info))
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break;
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}
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static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
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{
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int ret;
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struct xfrm4_protocol *handler;
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XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
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for_each_protocol_rcu(ipcomp4_handlers, handler)
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if ((ret = handler->handler(skb)) != -EINVAL)
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return ret;
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icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
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kfree_skb(skb);
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return 0;
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}
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static void xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
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{
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struct xfrm4_protocol *handler;
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for_each_protocol_rcu(ipcomp4_handlers, handler)
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if (!handler->err_handler(skb, info))
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break;
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}
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static const struct net_protocol esp4_protocol = {
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.handler = xfrm4_esp_rcv,
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.err_handler = xfrm4_esp_err,
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.no_policy = 1,
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.netns_ok = 1,
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};
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static const struct net_protocol ah4_protocol = {
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.handler = xfrm4_ah_rcv,
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.err_handler = xfrm4_ah_err,
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.no_policy = 1,
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.netns_ok = 1,
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};
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static const struct net_protocol ipcomp4_protocol = {
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.handler = xfrm4_ipcomp_rcv,
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.err_handler = xfrm4_ipcomp_err,
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.no_policy = 1,
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.netns_ok = 1,
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};
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static struct xfrm_input_afinfo xfrm4_input_afinfo = {
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.family = AF_INET,
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.owner = THIS_MODULE,
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.callback = xfrm4_rcv_cb,
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};
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static inline const struct net_protocol *netproto(unsigned char protocol)
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{
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switch (protocol) {
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case IPPROTO_ESP:
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return &esp4_protocol;
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case IPPROTO_AH:
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return &ah4_protocol;
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case IPPROTO_COMP:
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return &ipcomp4_protocol;
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}
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return NULL;
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}
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int xfrm4_protocol_register(struct xfrm4_protocol *handler,
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unsigned char protocol)
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{
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struct xfrm4_protocol __rcu **pprev;
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struct xfrm4_protocol *t;
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bool add_netproto = false;
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int ret = -EEXIST;
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int priority = handler->priority;
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if (!proto_handlers(protocol) || !netproto(protocol))
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return -EINVAL;
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mutex_lock(&xfrm4_protocol_mutex);
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if (!rcu_dereference_protected(*proto_handlers(protocol),
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lockdep_is_held(&xfrm4_protocol_mutex)))
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add_netproto = true;
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for (pprev = proto_handlers(protocol);
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(t = rcu_dereference_protected(*pprev,
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lockdep_is_held(&xfrm4_protocol_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(&xfrm4_protocol_mutex);
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if (add_netproto) {
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if (inet_add_protocol(netproto(protocol), protocol)) {
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pr_err("%s: can't add protocol\n", __func__);
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ret = -EAGAIN;
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}
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}
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return ret;
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}
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EXPORT_SYMBOL(xfrm4_protocol_register);
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int xfrm4_protocol_deregister(struct xfrm4_protocol *handler,
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unsigned char protocol)
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{
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struct xfrm4_protocol __rcu **pprev;
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struct xfrm4_protocol *t;
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int ret = -ENOENT;
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if (!proto_handlers(protocol) || !netproto(protocol))
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return -EINVAL;
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mutex_lock(&xfrm4_protocol_mutex);
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for (pprev = proto_handlers(protocol);
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(t = rcu_dereference_protected(*pprev,
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lockdep_is_held(&xfrm4_protocol_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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if (!rcu_dereference_protected(*proto_handlers(protocol),
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lockdep_is_held(&xfrm4_protocol_mutex))) {
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if (inet_del_protocol(netproto(protocol), protocol) < 0) {
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pr_err("%s: can't remove protocol\n", __func__);
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ret = -EAGAIN;
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}
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}
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mutex_unlock(&xfrm4_protocol_mutex);
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synchronize_net();
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return ret;
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}
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EXPORT_SYMBOL(xfrm4_protocol_deregister);
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void __init xfrm4_protocol_init(void)
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{
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xfrm_input_register_afinfo(&xfrm4_input_afinfo);
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}
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EXPORT_SYMBOL(xfrm4_protocol_init);
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