1 /* 2 * xfrm4_policy.c 3 * 4 * Changes: 5 * Kazunori MIYAZAWA @USAGI 6 * YOSHIFUJI Hideaki @USAGI 7 * Split up af-specific portion 8 * 9 */ 10 11 #include <linux/err.h> 12 #include <linux/kernel.h> 13 #include <linux/inetdevice.h> 14 #include <linux/if_tunnel.h> 15 #include <net/dst.h> 16 #include <net/xfrm.h> 17 #include <net/ip.h> 18 #include <net/l3mdev.h> 19 20 static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4, 21 int tos, int oif, 22 const xfrm_address_t *saddr, 23 const xfrm_address_t *daddr) 24 { 25 struct rtable *rt; 26 27 memset(fl4, 0, sizeof(*fl4)); 28 fl4->daddr = daddr->a4; 29 fl4->flowi4_tos = tos; 30 fl4->flowi4_oif = l3mdev_master_ifindex_by_index(net, oif); 31 if (saddr) 32 fl4->saddr = saddr->a4; 33 34 fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF; 35 36 rt = __ip_route_output_key(net, fl4); 37 if (!IS_ERR(rt)) 38 return &rt->dst; 39 40 return ERR_CAST(rt); 41 } 42 43 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif, 44 const xfrm_address_t *saddr, 45 const xfrm_address_t *daddr) 46 { 47 struct flowi4 fl4; 48 49 return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr); 50 } 51 52 static int xfrm4_get_saddr(struct net *net, int oif, 53 xfrm_address_t *saddr, xfrm_address_t *daddr) 54 { 55 struct dst_entry *dst; 56 struct flowi4 fl4; 57 58 dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr); 59 if (IS_ERR(dst)) 60 return -EHOSTUNREACH; 61 62 saddr->a4 = fl4.saddr; 63 dst_release(dst); 64 return 0; 65 } 66 67 static int xfrm4_get_tos(const struct flowi *fl) 68 { 69 return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */ 70 } 71 72 static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst, 73 int nfheader_len) 74 { 75 return 0; 76 } 77 78 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 79 const struct flowi *fl) 80 { 81 struct rtable *rt = (struct rtable *)xdst->route; 82 const struct flowi4 *fl4 = &fl->u.ip4; 83 84 xdst->u.rt.rt_iif = fl4->flowi4_iif; 85 86 xdst->u.dst.dev = dev; 87 dev_hold(dev); 88 89 /* Sheit... I remember I did this right. Apparently, 90 * it was magically lost, so this code needs audit */ 91 xdst->u.rt.rt_is_input = rt->rt_is_input; 92 xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | 93 RTCF_LOCAL); 94 xdst->u.rt.rt_type = rt->rt_type; 95 xdst->u.rt.rt_gateway = rt->rt_gateway; 96 xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway; 97 xdst->u.rt.rt_pmtu = rt->rt_pmtu; 98 xdst->u.rt.rt_table_id = rt->rt_table_id; 99 INIT_LIST_HEAD(&xdst->u.rt.rt_uncached); 100 101 return 0; 102 } 103 104 static void 105 _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse) 106 { 107 const struct iphdr *iph = ip_hdr(skb); 108 u8 *xprth = skb_network_header(skb) + iph->ihl * 4; 109 struct flowi4 *fl4 = &fl->u.ip4; 110 int oif = 0; 111 112 if (skb_dst(skb)) 113 oif = skb_dst(skb)->dev->ifindex; 114 115 memset(fl4, 0, sizeof(struct flowi4)); 116 fl4->flowi4_mark = skb->mark; 117 fl4->flowi4_oif = reverse ? skb->skb_iif : oif; 118 119 if (!ip_is_fragment(iph)) { 120 switch (iph->protocol) { 121 case IPPROTO_UDP: 122 case IPPROTO_UDPLITE: 123 case IPPROTO_TCP: 124 case IPPROTO_SCTP: 125 case IPPROTO_DCCP: 126 if (xprth + 4 < skb->data || 127 pskb_may_pull(skb, xprth + 4 - skb->data)) { 128 __be16 *ports; 129 130 xprth = skb_network_header(skb) + iph->ihl * 4; 131 ports = (__be16 *)xprth; 132 133 fl4->fl4_sport = ports[!!reverse]; 134 fl4->fl4_dport = ports[!reverse]; 135 } 136 break; 137 138 case IPPROTO_ICMP: 139 if (xprth + 2 < skb->data || 140 pskb_may_pull(skb, xprth + 2 - skb->data)) { 141 u8 *icmp; 142 143 xprth = skb_network_header(skb) + iph->ihl * 4; 144 icmp = xprth; 145 146 fl4->fl4_icmp_type = icmp[0]; 147 fl4->fl4_icmp_code = icmp[1]; 148 } 149 break; 150 151 case IPPROTO_ESP: 152 if (xprth + 4 < skb->data || 153 pskb_may_pull(skb, xprth + 4 - skb->data)) { 154 __be32 *ehdr; 155 156 xprth = skb_network_header(skb) + iph->ihl * 4; 157 ehdr = (__be32 *)xprth; 158 159 fl4->fl4_ipsec_spi = ehdr[0]; 160 } 161 break; 162 163 case IPPROTO_AH: 164 if (xprth + 8 < skb->data || 165 pskb_may_pull(skb, xprth + 8 - skb->data)) { 166 __be32 *ah_hdr; 167 168 xprth = skb_network_header(skb) + iph->ihl * 4; 169 ah_hdr = (__be32 *)xprth; 170 171 fl4->fl4_ipsec_spi = ah_hdr[1]; 172 } 173 break; 174 175 case IPPROTO_COMP: 176 if (xprth + 4 < skb->data || 177 pskb_may_pull(skb, xprth + 4 - skb->data)) { 178 __be16 *ipcomp_hdr; 179 180 xprth = skb_network_header(skb) + iph->ihl * 4; 181 ipcomp_hdr = (__be16 *)xprth; 182 183 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); 184 } 185 break; 186 187 case IPPROTO_GRE: 188 if (xprth + 12 < skb->data || 189 pskb_may_pull(skb, xprth + 12 - skb->data)) { 190 __be16 *greflags; 191 __be32 *gre_hdr; 192 193 xprth = skb_network_header(skb) + iph->ihl * 4; 194 greflags = (__be16 *)xprth; 195 gre_hdr = (__be32 *)xprth; 196 197 if (greflags[0] & GRE_KEY) { 198 if (greflags[0] & GRE_CSUM) 199 gre_hdr++; 200 fl4->fl4_gre_key = gre_hdr[1]; 201 } 202 } 203 break; 204 205 default: 206 fl4->fl4_ipsec_spi = 0; 207 break; 208 } 209 } 210 fl4->flowi4_proto = iph->protocol; 211 fl4->daddr = reverse ? iph->saddr : iph->daddr; 212 fl4->saddr = reverse ? iph->daddr : iph->saddr; 213 fl4->flowi4_tos = iph->tos; 214 } 215 216 static inline int xfrm4_garbage_collect(struct dst_ops *ops) 217 { 218 struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops); 219 220 xfrm_garbage_collect_deferred(net); 221 return (dst_entries_get_slow(ops) > ops->gc_thresh * 2); 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); 247 248 xfrm_dst_destroy(xdst); 249 } 250 251 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 252 int unregister) 253 { 254 if (!unregister) 255 return; 256 257 xfrm_dst_ifdown(dst, dev); 258 } 259 260 static struct dst_ops xfrm4_dst_ops_template = { 261 .family = AF_INET, 262 .gc = xfrm4_garbage_collect, 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 = INT_MAX, 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 } 386 387