1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C)2003,2004 USAGI/WIDE Project 4 * 5 * Authors Mitsuru KANDA <mk@linux-ipv6.org> 6 * YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> 7 */ 8 9 #define pr_fmt(fmt) "IPv6: " fmt 10 11 #include <linux/icmpv6.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/mutex.h> 15 #include <linux/netdevice.h> 16 #include <linux/skbuff.h> 17 #include <linux/slab.h> 18 #include <net/ipv6.h> 19 #include <net/protocol.h> 20 #include <net/xfrm.h> 21 22 static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly; 23 static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly; 24 static DEFINE_MUTEX(tunnel6_mutex); 25 26 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family) 27 { 28 struct xfrm6_tunnel __rcu **pprev; 29 struct xfrm6_tunnel *t; 30 int ret = -EEXIST; 31 int priority = handler->priority; 32 33 mutex_lock(&tunnel6_mutex); 34 35 for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers; 36 (t = rcu_dereference_protected(*pprev, 37 lockdep_is_held(&tunnel6_mutex))) != NULL; 38 pprev = &t->next) { 39 if (t->priority > priority) 40 break; 41 if (t->priority == priority) 42 goto err; 43 } 44 45 handler->next = *pprev; 46 rcu_assign_pointer(*pprev, handler); 47 48 ret = 0; 49 50 err: 51 mutex_unlock(&tunnel6_mutex); 52 53 return ret; 54 } 55 EXPORT_SYMBOL(xfrm6_tunnel_register); 56 57 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family) 58 { 59 struct xfrm6_tunnel __rcu **pprev; 60 struct xfrm6_tunnel *t; 61 int ret = -ENOENT; 62 63 mutex_lock(&tunnel6_mutex); 64 65 for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers; 66 (t = rcu_dereference_protected(*pprev, 67 lockdep_is_held(&tunnel6_mutex))) != NULL; 68 pprev = &t->next) { 69 if (t == handler) { 70 *pprev = handler->next; 71 ret = 0; 72 break; 73 } 74 } 75 76 mutex_unlock(&tunnel6_mutex); 77 78 synchronize_net(); 79 80 return ret; 81 } 82 EXPORT_SYMBOL(xfrm6_tunnel_deregister); 83 84 #define for_each_tunnel_rcu(head, handler) \ 85 for (handler = rcu_dereference(head); \ 86 handler != NULL; \ 87 handler = rcu_dereference(handler->next)) \ 88 89 static int tunnel6_rcv(struct sk_buff *skb) 90 { 91 struct xfrm6_tunnel *handler; 92 93 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 94 goto drop; 95 96 for_each_tunnel_rcu(tunnel6_handlers, handler) 97 if (!handler->handler(skb)) 98 return 0; 99 100 icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0); 101 102 drop: 103 kfree_skb(skb); 104 return 0; 105 } 106 107 static int tunnel46_rcv(struct sk_buff *skb) 108 { 109 struct xfrm6_tunnel *handler; 110 111 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 112 goto drop; 113 114 for_each_tunnel_rcu(tunnel46_handlers, handler) 115 if (!handler->handler(skb)) 116 return 0; 117 118 icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0); 119 120 drop: 121 kfree_skb(skb); 122 return 0; 123 } 124 125 static int tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 126 u8 type, u8 code, int offset, __be32 info) 127 { 128 struct xfrm6_tunnel *handler; 129 130 for_each_tunnel_rcu(tunnel6_handlers, handler) 131 if (!handler->err_handler(skb, opt, type, code, offset, info)) 132 return 0; 133 134 return -ENOENT; 135 } 136 137 static int tunnel46_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 138 u8 type, u8 code, int offset, __be32 info) 139 { 140 struct xfrm6_tunnel *handler; 141 142 for_each_tunnel_rcu(tunnel46_handlers, handler) 143 if (!handler->err_handler(skb, opt, type, code, offset, info)) 144 return 0; 145 146 return -ENOENT; 147 } 148 149 static const struct inet6_protocol tunnel6_protocol = { 150 .handler = tunnel6_rcv, 151 .err_handler = tunnel6_err, 152 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, 153 }; 154 155 static const struct inet6_protocol tunnel46_protocol = { 156 .handler = tunnel46_rcv, 157 .err_handler = tunnel46_err, 158 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, 159 }; 160 161 static int __init tunnel6_init(void) 162 { 163 if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) { 164 pr_err("%s: can't add protocol\n", __func__); 165 return -EAGAIN; 166 } 167 if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) { 168 pr_err("%s: can't add protocol\n", __func__); 169 inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6); 170 return -EAGAIN; 171 } 172 return 0; 173 } 174 175 static void __exit tunnel6_fini(void) 176 { 177 if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP)) 178 pr_err("%s: can't remove protocol\n", __func__); 179 if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6)) 180 pr_err("%s: can't remove protocol\n", __func__); 181 } 182 183 module_init(tunnel6_init); 184 module_exit(tunnel6_fini); 185 MODULE_LICENSE("GPL"); 186