1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C)2003-2006 Helsinki University of Technology 4 * Copyright (C)2003-2006 USAGI/WIDE Project 5 */ 6 /* 7 * Authors: 8 * Noriaki TAKAMIYA @USAGI 9 * Masahide NAKAMURA @USAGI 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/module.h> 15 #include <linux/skbuff.h> 16 #include <linux/time.h> 17 #include <linux/ipv6.h> 18 #include <linux/icmpv6.h> 19 #include <net/sock.h> 20 #include <net/ipv6.h> 21 #include <net/ip6_checksum.h> 22 #include <net/rawv6.h> 23 #include <net/xfrm.h> 24 #include <net/mip6.h> 25 26 static inline unsigned int calc_padlen(unsigned int len, unsigned int n) 27 { 28 return (n - len + 16) & 0x7; 29 } 30 31 static inline void *mip6_padn(__u8 *data, __u8 padlen) 32 { 33 if (!data) 34 return NULL; 35 if (padlen == 1) { 36 data[0] = IPV6_TLV_PAD1; 37 } else if (padlen > 1) { 38 data[0] = IPV6_TLV_PADN; 39 data[1] = padlen - 2; 40 if (padlen > 2) 41 memset(data+2, 0, data[1]); 42 } 43 return data + padlen; 44 } 45 46 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos) 47 { 48 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos); 49 } 50 51 static int mip6_mh_len(int type) 52 { 53 int len = 0; 54 55 switch (type) { 56 case IP6_MH_TYPE_BRR: 57 len = 0; 58 break; 59 case IP6_MH_TYPE_HOTI: 60 case IP6_MH_TYPE_COTI: 61 case IP6_MH_TYPE_BU: 62 case IP6_MH_TYPE_BACK: 63 len = 1; 64 break; 65 case IP6_MH_TYPE_HOT: 66 case IP6_MH_TYPE_COT: 67 case IP6_MH_TYPE_BERROR: 68 len = 2; 69 break; 70 } 71 return len; 72 } 73 74 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb) 75 { 76 struct ip6_mh _hdr; 77 const struct ip6_mh *mh; 78 79 mh = skb_header_pointer(skb, skb_transport_offset(skb), 80 sizeof(_hdr), &_hdr); 81 if (!mh) 82 return -1; 83 84 if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len) 85 return -1; 86 87 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { 88 net_dbg_ratelimited("mip6: MH message too short: %d vs >=%d\n", 89 mh->ip6mh_hdrlen, 90 mip6_mh_len(mh->ip6mh_type)); 91 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) + 92 skb_network_header_len(skb)); 93 return -1; 94 } 95 96 if (mh->ip6mh_proto != IPPROTO_NONE) { 97 net_dbg_ratelimited("mip6: MH invalid payload proto = %d\n", 98 mh->ip6mh_proto); 99 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) + 100 skb_network_header_len(skb)); 101 return -1; 102 } 103 104 return 0; 105 } 106 107 struct mip6_report_rate_limiter { 108 spinlock_t lock; 109 ktime_t stamp; 110 int iif; 111 struct in6_addr src; 112 struct in6_addr dst; 113 }; 114 115 static struct mip6_report_rate_limiter mip6_report_rl = { 116 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock) 117 }; 118 119 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) 120 { 121 const struct ipv6hdr *iph = ipv6_hdr(skb); 122 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; 123 int err = destopt->nexthdr; 124 125 spin_lock(&x->lock); 126 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && 127 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 128 err = -ENOENT; 129 spin_unlock(&x->lock); 130 131 return err; 132 } 133 134 /* Destination Option Header is inserted. 135 * IP Header's src address is replaced with Home Address Option in 136 * Destination Option Header. 137 */ 138 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb) 139 { 140 struct ipv6hdr *iph; 141 struct ipv6_destopt_hdr *dstopt; 142 struct ipv6_destopt_hao *hao; 143 u8 nexthdr; 144 int len; 145 146 skb_push(skb, -skb_network_offset(skb)); 147 iph = ipv6_hdr(skb); 148 149 nexthdr = *skb_mac_header(skb); 150 *skb_mac_header(skb) = IPPROTO_DSTOPTS; 151 152 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb); 153 dstopt->nexthdr = nexthdr; 154 155 hao = mip6_padn((char *)(dstopt + 1), 156 calc_padlen(sizeof(*dstopt), 6)); 157 158 hao->type = IPV6_TLV_HAO; 159 BUILD_BUG_ON(sizeof(*hao) != 18); 160 hao->length = sizeof(*hao) - 2; 161 162 len = ((char *)hao - (char *)dstopt) + sizeof(*hao); 163 164 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); 165 spin_lock_bh(&x->lock); 166 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 167 spin_unlock_bh(&x->lock); 168 169 WARN_ON(len != x->props.header_len); 170 dstopt->hdrlen = (x->props.header_len >> 3) - 1; 171 172 return 0; 173 } 174 175 static inline int mip6_report_rl_allow(ktime_t stamp, 176 const struct in6_addr *dst, 177 const struct in6_addr *src, int iif) 178 { 179 int allow = 0; 180 181 spin_lock_bh(&mip6_report_rl.lock); 182 if (mip6_report_rl.stamp != stamp || 183 mip6_report_rl.iif != iif || 184 !ipv6_addr_equal(&mip6_report_rl.src, src) || 185 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) { 186 mip6_report_rl.stamp = stamp; 187 mip6_report_rl.iif = iif; 188 mip6_report_rl.src = *src; 189 mip6_report_rl.dst = *dst; 190 allow = 1; 191 } 192 spin_unlock_bh(&mip6_report_rl.lock); 193 return allow; 194 } 195 196 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, 197 const struct flowi *fl) 198 { 199 struct net *net = xs_net(x); 200 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 201 const struct flowi6 *fl6 = &fl->u.ip6; 202 struct ipv6_destopt_hao *hao = NULL; 203 struct xfrm_selector sel; 204 int offset; 205 ktime_t stamp; 206 int err = 0; 207 208 if (unlikely(fl6->flowi6_proto == IPPROTO_MH && 209 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX)) 210 goto out; 211 212 if (likely(opt->dsthao)) { 213 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 214 if (likely(offset >= 0)) 215 hao = (struct ipv6_destopt_hao *) 216 (skb_network_header(skb) + offset); 217 } 218 219 stamp = skb_get_ktime(skb); 220 221 if (!mip6_report_rl_allow(stamp, &ipv6_hdr(skb)->daddr, 222 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 223 opt->iif)) 224 goto out; 225 226 memset(&sel, 0, sizeof(sel)); 227 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 228 sizeof(sel.daddr)); 229 sel.prefixlen_d = 128; 230 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 231 sizeof(sel.saddr)); 232 sel.prefixlen_s = 128; 233 sel.family = AF_INET6; 234 sel.proto = fl6->flowi6_proto; 235 sel.dport = xfrm_flowi_dport(fl, &fl6->uli); 236 if (sel.dport) 237 sel.dport_mask = htons(~0); 238 sel.sport = xfrm_flowi_sport(fl, &fl6->uli); 239 if (sel.sport) 240 sel.sport_mask = htons(~0); 241 sel.ifindex = fl6->flowi6_oif; 242 243 err = km_report(net, IPPROTO_DSTOPTS, &sel, 244 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 245 246 out: 247 return err; 248 } 249 250 static int mip6_destopt_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 251 { 252 if (x->id.spi) { 253 NL_SET_ERR_MSG(extack, "SPI must be 0"); 254 return -EINVAL; 255 } 256 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 257 NL_SET_ERR_MSG(extack, "XFRM mode must be XFRM_MODE_ROUTEOPTIMIZATION"); 258 return -EINVAL; 259 } 260 261 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 262 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 263 sizeof(struct ipv6_destopt_hao); 264 WARN_ON(x->props.header_len != 24); 265 266 return 0; 267 } 268 269 /* 270 * Do nothing about destroying since it has no specific operation for 271 * destination options header unlike IPsec protocols. 272 */ 273 static void mip6_destopt_destroy(struct xfrm_state *x) 274 { 275 } 276 277 static const struct xfrm_type mip6_destopt_type = { 278 .owner = THIS_MODULE, 279 .proto = IPPROTO_DSTOPTS, 280 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR, 281 .init_state = mip6_destopt_init_state, 282 .destructor = mip6_destopt_destroy, 283 .input = mip6_destopt_input, 284 .output = mip6_destopt_output, 285 .reject = mip6_destopt_reject, 286 }; 287 288 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 289 { 290 const struct ipv6hdr *iph = ipv6_hdr(skb); 291 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 292 int err = rt2->rt_hdr.nexthdr; 293 294 spin_lock(&x->lock); 295 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) && 296 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 297 err = -ENOENT; 298 spin_unlock(&x->lock); 299 300 return err; 301 } 302 303 /* Routing Header type 2 is inserted. 304 * IP Header's dst address is replaced with Routing Header's Home Address. 305 */ 306 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 307 { 308 struct ipv6hdr *iph; 309 struct rt2_hdr *rt2; 310 u8 nexthdr; 311 312 skb_push(skb, -skb_network_offset(skb)); 313 iph = ipv6_hdr(skb); 314 315 nexthdr = *skb_mac_header(skb); 316 *skb_mac_header(skb) = IPPROTO_ROUTING; 317 318 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 319 rt2->rt_hdr.nexthdr = nexthdr; 320 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 321 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 322 rt2->rt_hdr.segments_left = 1; 323 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 324 325 WARN_ON(rt2->rt_hdr.hdrlen != 2); 326 327 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 328 spin_lock_bh(&x->lock); 329 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 330 spin_unlock_bh(&x->lock); 331 332 return 0; 333 } 334 335 static int mip6_rthdr_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 336 { 337 if (x->id.spi) { 338 NL_SET_ERR_MSG(extack, "SPI must be 0"); 339 return -EINVAL; 340 } 341 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 342 NL_SET_ERR_MSG(extack, "XFRM mode must be XFRM_MODE_ROUTEOPTIMIZATION"); 343 return -EINVAL; 344 } 345 346 x->props.header_len = sizeof(struct rt2_hdr); 347 348 return 0; 349 } 350 351 /* 352 * Do nothing about destroying since it has no specific operation for routing 353 * header type 2 unlike IPsec protocols. 354 */ 355 static void mip6_rthdr_destroy(struct xfrm_state *x) 356 { 357 } 358 359 static const struct xfrm_type mip6_rthdr_type = { 360 .owner = THIS_MODULE, 361 .proto = IPPROTO_ROUTING, 362 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR, 363 .init_state = mip6_rthdr_init_state, 364 .destructor = mip6_rthdr_destroy, 365 .input = mip6_rthdr_input, 366 .output = mip6_rthdr_output, 367 }; 368 369 static int __init mip6_init(void) 370 { 371 pr_info("Mobile IPv6\n"); 372 373 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 374 pr_info("%s: can't add xfrm type(destopt)\n", __func__); 375 goto mip6_destopt_xfrm_fail; 376 } 377 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 378 pr_info("%s: can't add xfrm type(rthdr)\n", __func__); 379 goto mip6_rthdr_xfrm_fail; 380 } 381 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 382 pr_info("%s: can't add rawv6 mh filter\n", __func__); 383 goto mip6_rawv6_mh_fail; 384 } 385 386 387 return 0; 388 389 mip6_rawv6_mh_fail: 390 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 391 mip6_rthdr_xfrm_fail: 392 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 393 mip6_destopt_xfrm_fail: 394 return -EAGAIN; 395 } 396 397 static void __exit mip6_fini(void) 398 { 399 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 400 pr_info("%s: can't remove rawv6 mh filter\n", __func__); 401 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 402 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 403 } 404 405 module_init(mip6_init); 406 module_exit(mip6_fini); 407 408 MODULE_LICENSE("GPL"); 409 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 410 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 411