1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * xfrm4_policy.c 4 * 5 * Changes: 6 * Kazunori MIYAZAWA @USAGI 7 * YOSHIFUJI Hideaki @USAGI 8 * Split up af-specific portion 9 * 10 */ 11 12 #include <linux/err.h> 13 #include <linux/kernel.h> 14 #include <linux/inetdevice.h> 15 #include <linux/if_tunnel.h> 16 #include <net/dst.h> 17 #include <net/xfrm.h> 18 #include <net/ip.h> 19 #include <net/l3mdev.h> 20 21 static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4, 22 int tos, int oif, 23 const xfrm_address_t *saddr, 24 const xfrm_address_t *daddr, 25 u32 mark) 26 { 27 struct rtable *rt; 28 29 memset(fl4, 0, sizeof(*fl4)); 30 fl4->daddr = daddr->a4; 31 fl4->flowi4_tos = tos; 32 fl4->flowi4_oif = l3mdev_master_ifindex_by_index(net, oif); 33 fl4->flowi4_mark = mark; 34 if (saddr) 35 fl4->saddr = saddr->a4; 36 37 fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF; 38 39 rt = __ip_route_output_key(net, fl4); 40 if (!IS_ERR(rt)) 41 return &rt->dst; 42 43 return ERR_CAST(rt); 44 } 45 46 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif, 47 const xfrm_address_t *saddr, 48 const xfrm_address_t *daddr, 49 u32 mark) 50 { 51 struct flowi4 fl4; 52 53 return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark); 54 } 55 56 static int xfrm4_get_saddr(struct net *net, int oif, 57 xfrm_address_t *saddr, xfrm_address_t *daddr, 58 u32 mark) 59 { 60 struct dst_entry *dst; 61 struct flowi4 fl4; 62 63 dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark); 64 if (IS_ERR(dst)) 65 return -EHOSTUNREACH; 66 67 saddr->a4 = fl4.saddr; 68 dst_release(dst); 69 return 0; 70 } 71 72 static int xfrm4_get_tos(const struct flowi *fl) 73 { 74 return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */ 75 } 76 77 static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst, 78 int nfheader_len) 79 { 80 return 0; 81 } 82 83 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 84 const struct flowi *fl) 85 { 86 struct rtable *rt = (struct rtable *)xdst->route; 87 const struct flowi4 *fl4 = &fl->u.ip4; 88 89 xdst->u.rt.rt_iif = fl4->flowi4_iif; 90 91 xdst->u.dst.dev = dev; 92 dev_hold(dev); 93 94 /* Sheit... I remember I did this right. Apparently, 95 * it was magically lost, so this code needs audit */ 96 xdst->u.rt.rt_is_input = rt->rt_is_input; 97 xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | 98 RTCF_LOCAL); 99 xdst->u.rt.rt_type = rt->rt_type; 100 xdst->u.rt.rt_gateway = rt->rt_gateway; 101 xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway; 102 xdst->u.rt.rt_pmtu = rt->rt_pmtu; 103 xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked; 104 INIT_LIST_HEAD(&xdst->u.rt.rt_uncached); 105 rt_add_uncached_list(&xdst->u.rt); 106 107 return 0; 108 } 109 110 static void 111 _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse) 112 { 113 const struct iphdr *iph = ip_hdr(skb); 114 int ihl = iph->ihl; 115 u8 *xprth = skb_network_header(skb) + ihl * 4; 116 struct flowi4 *fl4 = &fl->u.ip4; 117 int oif = 0; 118 119 if (skb_dst(skb)) 120 oif = skb_dst(skb)->dev->ifindex; 121 122 memset(fl4, 0, sizeof(struct flowi4)); 123 fl4->flowi4_mark = skb->mark; 124 fl4->flowi4_oif = reverse ? skb->skb_iif : oif; 125 126 fl4->flowi4_proto = iph->protocol; 127 fl4->daddr = reverse ? iph->saddr : iph->daddr; 128 fl4->saddr = reverse ? iph->daddr : iph->saddr; 129 fl4->flowi4_tos = iph->tos; 130 131 if (!ip_is_fragment(iph)) { 132 switch (iph->protocol) { 133 case IPPROTO_UDP: 134 case IPPROTO_UDPLITE: 135 case IPPROTO_TCP: 136 case IPPROTO_SCTP: 137 case IPPROTO_DCCP: 138 if (xprth + 4 < skb->data || 139 pskb_may_pull(skb, xprth + 4 - skb->data)) { 140 __be16 *ports; 141 142 xprth = skb_network_header(skb) + ihl * 4; 143 ports = (__be16 *)xprth; 144 145 fl4->fl4_sport = ports[!!reverse]; 146 fl4->fl4_dport = ports[!reverse]; 147 } 148 break; 149 150 case IPPROTO_ICMP: 151 if (xprth + 2 < skb->data || 152 pskb_may_pull(skb, xprth + 2 - skb->data)) { 153 u8 *icmp; 154 155 xprth = skb_network_header(skb) + ihl * 4; 156 icmp = xprth; 157 158 fl4->fl4_icmp_type = icmp[0]; 159 fl4->fl4_icmp_code = icmp[1]; 160 } 161 break; 162 163 case IPPROTO_ESP: 164 if (xprth + 4 < skb->data || 165 pskb_may_pull(skb, xprth + 4 - skb->data)) { 166 __be32 *ehdr; 167 168 xprth = skb_network_header(skb) + ihl * 4; 169 ehdr = (__be32 *)xprth; 170 171 fl4->fl4_ipsec_spi = ehdr[0]; 172 } 173 break; 174 175 case IPPROTO_AH: 176 if (xprth + 8 < skb->data || 177 pskb_may_pull(skb, xprth + 8 - skb->data)) { 178 __be32 *ah_hdr; 179 180 xprth = skb_network_header(skb) + ihl * 4; 181 ah_hdr = (__be32 *)xprth; 182 183 fl4->fl4_ipsec_spi = ah_hdr[1]; 184 } 185 break; 186 187 case IPPROTO_COMP: 188 if (xprth + 4 < skb->data || 189 pskb_may_pull(skb, xprth + 4 - skb->data)) { 190 __be16 *ipcomp_hdr; 191 192 xprth = skb_network_header(skb) + ihl * 4; 193 ipcomp_hdr = (__be16 *)xprth; 194 195 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); 196 } 197 break; 198 199 case IPPROTO_GRE: 200 if (xprth + 12 < skb->data || 201 pskb_may_pull(skb, xprth + 12 - skb->data)) { 202 __be16 *greflags; 203 __be32 *gre_hdr; 204 205 xprth = skb_network_header(skb) + ihl * 4; 206 greflags = (__be16 *)xprth; 207 gre_hdr = (__be32 *)xprth; 208 209 if (greflags[0] & GRE_KEY) { 210 if (greflags[0] & GRE_CSUM) 211 gre_hdr++; 212 fl4->fl4_gre_key = gre_hdr[1]; 213 } 214 } 215 break; 216 217 default: 218 fl4->fl4_ipsec_spi = 0; 219 break; 220 } 221 } 222 } 223 224 static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk, 225 struct sk_buff *skb, u32 mtu) 226 { 227 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 228 struct dst_entry *path = xdst->route; 229 230 path->ops->update_pmtu(path, sk, skb, mtu); 231 } 232 233 static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk, 234 struct sk_buff *skb) 235 { 236 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 237 struct dst_entry *path = xdst->route; 238 239 path->ops->redirect(path, sk, skb); 240 } 241 242 static void xfrm4_dst_destroy(struct dst_entry *dst) 243 { 244 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 245 246 dst_destroy_metrics_generic(dst); 247 if (xdst->u.rt.rt_uncached_list) 248 rt_del_uncached_list(&xdst->u.rt); 249 xfrm_dst_destroy(xdst); 250 } 251 252 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 253 int unregister) 254 { 255 if (!unregister) 256 return; 257 258 xfrm_dst_ifdown(dst, dev); 259 } 260 261 static struct dst_ops xfrm4_dst_ops_template = { 262 .family = AF_INET, 263 .update_pmtu = xfrm4_update_pmtu, 264 .redirect = xfrm4_redirect, 265 .cow_metrics = dst_cow_metrics_generic, 266 .destroy = xfrm4_dst_destroy, 267 .ifdown = xfrm4_dst_ifdown, 268 .local_out = __ip_local_out, 269 .gc_thresh = 32768, 270 }; 271 272 static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 273 .dst_ops = &xfrm4_dst_ops_template, 274 .dst_lookup = xfrm4_dst_lookup, 275 .get_saddr = xfrm4_get_saddr, 276 .decode_session = _decode_session4, 277 .get_tos = xfrm4_get_tos, 278 .init_path = xfrm4_init_path, 279 .fill_dst = xfrm4_fill_dst, 280 .blackhole_route = ipv4_blackhole_route, 281 }; 282 283 #ifdef CONFIG_SYSCTL 284 static struct ctl_table xfrm4_policy_table[] = { 285 { 286 .procname = "xfrm4_gc_thresh", 287 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh, 288 .maxlen = sizeof(int), 289 .mode = 0644, 290 .proc_handler = proc_dointvec, 291 }, 292 { } 293 }; 294 295 static __net_init int xfrm4_net_sysctl_init(struct net *net) 296 { 297 struct ctl_table *table; 298 struct ctl_table_header *hdr; 299 300 table = xfrm4_policy_table; 301 if (!net_eq(net, &init_net)) { 302 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL); 303 if (!table) 304 goto err_alloc; 305 306 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh; 307 } 308 309 hdr = register_net_sysctl(net, "net/ipv4", table); 310 if (!hdr) 311 goto err_reg; 312 313 net->ipv4.xfrm4_hdr = hdr; 314 return 0; 315 316 err_reg: 317 if (!net_eq(net, &init_net)) 318 kfree(table); 319 err_alloc: 320 return -ENOMEM; 321 } 322 323 static __net_exit void xfrm4_net_sysctl_exit(struct net *net) 324 { 325 struct ctl_table *table; 326 327 if (!net->ipv4.xfrm4_hdr) 328 return; 329 330 table = net->ipv4.xfrm4_hdr->ctl_table_arg; 331 unregister_net_sysctl_table(net->ipv4.xfrm4_hdr); 332 if (!net_eq(net, &init_net)) 333 kfree(table); 334 } 335 #else /* CONFIG_SYSCTL */ 336 static inline int xfrm4_net_sysctl_init(struct net *net) 337 { 338 return 0; 339 } 340 341 static inline void xfrm4_net_sysctl_exit(struct net *net) 342 { 343 } 344 #endif 345 346 static int __net_init xfrm4_net_init(struct net *net) 347 { 348 int ret; 349 350 memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template, 351 sizeof(xfrm4_dst_ops_template)); 352 ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops); 353 if (ret) 354 return ret; 355 356 ret = xfrm4_net_sysctl_init(net); 357 if (ret) 358 dst_entries_destroy(&net->xfrm.xfrm4_dst_ops); 359 360 return ret; 361 } 362 363 static void __net_exit xfrm4_net_exit(struct net *net) 364 { 365 xfrm4_net_sysctl_exit(net); 366 dst_entries_destroy(&net->xfrm.xfrm4_dst_ops); 367 } 368 369 static struct pernet_operations __net_initdata xfrm4_net_ops = { 370 .init = xfrm4_net_init, 371 .exit = xfrm4_net_exit, 372 }; 373 374 static void __init xfrm4_policy_init(void) 375 { 376 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET); 377 } 378 379 void __init xfrm4_init(void) 380 { 381 xfrm4_state_init(); 382 xfrm4_policy_init(); 383 xfrm4_protocol_init(); 384 register_pernet_subsys(&xfrm4_net_ops); 385 } 386