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307 lines
6.6 KiB
307 lines
6.6 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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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 <[email protected]> |
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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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#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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static 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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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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if (!skb_dst(skb)) { |
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const struct iphdr *iph = ip_hdr(skb); |
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if (ip_route_input_noref(skb, iph->daddr, iph->saddr, |
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iph->tos, skb->dev)) |
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goto drop; |
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} |
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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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drop: |
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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 int 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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return 0; |
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return -ENOENT; |
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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 int 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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return 0; |
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return -ENOENT; |
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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 int 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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return 0; |
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return -ENOENT; |
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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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}; |
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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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}; |
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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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}; |
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static const struct xfrm_input_afinfo xfrm4_input_afinfo = { |
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.family = AF_INET, |
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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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