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/compiler.h> 12#include <linux/inetdevice.h> 13#include <net/xfrm.h> 14#include <net/ip.h> 15 16static struct dst_ops xfrm4_dst_ops; 17static struct xfrm_policy_afinfo xfrm4_policy_afinfo; 18 19static int xfrm4_dst_lookup(struct xfrm_dst **dst, struct flowi *fl) 20{ 21 return __ip_route_output_key((struct rtable**)dst, fl); 22} 23 24static int xfrm4_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr) 25{ 26 struct rtable *rt; 27 struct flowi fl_tunnel = { 28 .nl_u = { 29 .ip4_u = { 30 .daddr = daddr->a4, 31 }, 32 }, 33 }; 34 35 if (!xfrm4_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) { 36 saddr->a4 = rt->rt_src; 37 dst_release(&rt->u.dst); 38 return 0; 39 } 40 return -EHOSTUNREACH; 41} 42 43static struct dst_entry * 44__xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy) 45{ 46 struct dst_entry *dst; 47 48 read_lock_bh(&policy->lock); 49 for (dst = policy->bundles; dst; dst = dst->next) { 50 struct xfrm_dst *xdst = (struct xfrm_dst*)dst; 51 if (xdst->u.rt.fl.oif == fl->oif && 52 xdst->u.rt.fl.fl4_dst == fl->fl4_dst && 53 xdst->u.rt.fl.fl4_src == fl->fl4_src && 54 xdst->u.rt.fl.fl4_tos == fl->fl4_tos && 55 xfrm_bundle_ok(policy, xdst, fl, AF_INET, 0)) { 56 dst_clone(dst); 57 break; 58 } 59 } 60 read_unlock_bh(&policy->lock); 61 return dst; 62} 63 64/* Allocate chain of dst_entry's, attach known xfrm's, calculate 65 * all the metrics... Shortly, bundle a bundle. 66 */ 67 68static int 69__xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx, 70 struct flowi *fl, struct dst_entry **dst_p) 71{ 72 struct dst_entry *dst, *dst_prev; 73 struct rtable *rt0 = (struct rtable*)(*dst_p); 74 struct rtable *rt = rt0; 75 struct flowi fl_tunnel = { 76 .nl_u = { 77 .ip4_u = { 78 .saddr = fl->fl4_src, 79 .daddr = fl->fl4_dst, 80 .tos = fl->fl4_tos 81 } 82 } 83 }; 84 int i; 85 int err; 86 int header_len = 0; 87 int trailer_len = 0; 88 89 dst = dst_prev = NULL; 90 dst_hold(&rt->u.dst); 91 92 for (i = 0; i < nx; i++) { 93 struct dst_entry *dst1 = dst_alloc(&xfrm4_dst_ops); 94 struct xfrm_dst *xdst; 95 96 if (unlikely(dst1 == NULL)) { 97 err = -ENOBUFS; 98 dst_release(&rt->u.dst); 99 goto error; 100 } 101 102 if (!dst) 103 dst = dst1; 104 else { 105 dst_prev->child = dst1; 106 dst1->flags |= DST_NOHASH; 107 dst_clone(dst1); 108 } 109 110 xdst = (struct xfrm_dst *)dst1; 111 xdst->route = &rt->u.dst; 112 xdst->genid = xfrm[i]->genid; 113 114 dst1->next = dst_prev; 115 dst_prev = dst1; 116 117 header_len += xfrm[i]->props.header_len; 118 trailer_len += xfrm[i]->props.trailer_len; 119 120 if (xfrm[i]->props.mode == XFRM_MODE_TUNNEL) { 121 unsigned short encap_family = xfrm[i]->props.family; 122 switch (encap_family) { 123 case AF_INET: 124 fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4; 125 fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4; 126 break; 127#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 128 case AF_INET6: 129 ipv6_addr_copy(&fl_tunnel.fl6_dst, (struct in6_addr*)&xfrm[i]->id.daddr.a6); 130 ipv6_addr_copy(&fl_tunnel.fl6_src, (struct in6_addr*)&xfrm[i]->props.saddr.a6); 131 break; 132#endif 133 default: 134 BUG_ON(1); 135 } 136 err = xfrm_dst_lookup((struct xfrm_dst **)&rt, 137 &fl_tunnel, encap_family); 138 if (err) 139 goto error; 140 } else 141 dst_hold(&rt->u.dst); 142 } 143 144 dst_prev->child = &rt->u.dst; 145 dst->path = &rt->u.dst; 146 147 *dst_p = dst; 148 dst = dst_prev; 149 150 dst_prev = *dst_p; 151 i = 0; 152 for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) { 153 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev; 154 struct xfrm_state_afinfo *afinfo; 155 x->u.rt.fl = *fl; 156 157 dst_prev->xfrm = xfrm[i++]; 158 dst_prev->dev = rt->u.dst.dev; 159 if (rt->u.dst.dev) 160 dev_hold(rt->u.dst.dev); 161 dst_prev->obsolete = -1; 162 dst_prev->flags |= DST_HOST; 163 dst_prev->lastuse = jiffies; 164 dst_prev->header_len = header_len; 165 dst_prev->nfheader_len = 0; 166 dst_prev->trailer_len = trailer_len; 167 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics)); 168 169 /* Copy neighbout for reachability confirmation */ 170 dst_prev->neighbour = neigh_clone(rt->u.dst.neighbour); 171 dst_prev->input = rt->u.dst.input; 172 afinfo = xfrm_state_get_afinfo(dst_prev->xfrm->props.family); 173 if (!afinfo) { 174 dst = *dst_p; 175 err = -EAFNOSUPPORT; 176 goto error; 177 } 178 dst_prev->output = afinfo->output; 179 xfrm_state_put_afinfo(afinfo); 180 if (dst_prev->xfrm->props.family == AF_INET && rt->peer) 181 atomic_inc(&rt->peer->refcnt); 182 x->u.rt.peer = rt->peer; 183 /* Sheit... I remember I did this right. Apparently, 184 * it was magically lost, so this code needs audit */ 185 x->u.rt.rt_flags = rt0->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL); 186 x->u.rt.rt_type = rt->rt_type; 187 x->u.rt.rt_src = rt0->rt_src; 188 x->u.rt.rt_dst = rt0->rt_dst; 189 x->u.rt.rt_gateway = rt->rt_gateway; 190 x->u.rt.rt_spec_dst = rt0->rt_spec_dst; 191 x->u.rt.idev = rt0->idev; 192 in_dev_hold(rt0->idev); 193 header_len -= x->u.dst.xfrm->props.header_len; 194 trailer_len -= x->u.dst.xfrm->props.trailer_len; 195 } 196 197 xfrm_init_pmtu(dst); 198 return 0; 199 200error: 201 if (dst) 202 dst_free(dst); 203 return err; 204} 205 206static void 207_decode_session4(struct sk_buff *skb, struct flowi *fl) 208{ 209 struct iphdr *iph = ip_hdr(skb); 210 u8 *xprth = skb_network_header(skb) + iph->ihl * 4; 211 212 memset(fl, 0, sizeof(struct flowi)); 213 if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) { 214 switch (iph->protocol) { 215 case IPPROTO_UDP: 216 case IPPROTO_UDPLITE: 217 case IPPROTO_TCP: 218 case IPPROTO_SCTP: 219 case IPPROTO_DCCP: 220 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 221 __be16 *ports = (__be16 *)xprth; 222 223 fl->fl_ip_sport = ports[0]; 224 fl->fl_ip_dport = ports[1]; 225 } 226 break; 227 228 case IPPROTO_ICMP: 229 if (pskb_may_pull(skb, xprth + 2 - skb->data)) { 230 u8 *icmp = xprth; 231 232 fl->fl_icmp_type = icmp[0]; 233 fl->fl_icmp_code = icmp[1]; 234 } 235 break; 236 237 case IPPROTO_ESP: 238 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 239 __be32 *ehdr = (__be32 *)xprth; 240 241 fl->fl_ipsec_spi = ehdr[0]; 242 } 243 break; 244 245 case IPPROTO_AH: 246 if (pskb_may_pull(skb, xprth + 8 - skb->data)) { 247 __be32 *ah_hdr = (__be32*)xprth; 248 249 fl->fl_ipsec_spi = ah_hdr[1]; 250 } 251 break; 252 253 case IPPROTO_COMP: 254 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 255 __be16 *ipcomp_hdr = (__be16 *)xprth; 256 257 fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); 258 } 259 break; 260 default: 261 fl->fl_ipsec_spi = 0; 262 break; 263 } 264 } 265 fl->proto = iph->protocol; 266 fl->fl4_dst = iph->daddr; 267 fl->fl4_src = iph->saddr; 268 fl->fl4_tos = iph->tos; 269} 270 271static inline int xfrm4_garbage_collect(void) 272{ 273 xfrm4_policy_afinfo.garbage_collect(); 274 return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2); 275} 276 277static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu) 278{ 279 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 280 struct dst_entry *path = xdst->route; 281 282 path->ops->update_pmtu(path, mtu); 283} 284 285static void xfrm4_dst_destroy(struct dst_entry *dst) 286{ 287 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 288 289 if (likely(xdst->u.rt.idev)) 290 in_dev_put(xdst->u.rt.idev); 291 if (dst->xfrm && dst->xfrm->props.family == AF_INET && likely(xdst->u.rt.peer)) 292 inet_putpeer(xdst->u.rt.peer); 293 xfrm_dst_destroy(xdst); 294} 295 296static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 297 int unregister) 298{ 299 struct xfrm_dst *xdst; 300 301 if (!unregister) 302 return; 303 304 xdst = (struct xfrm_dst *)dst; 305 if (xdst->u.rt.idev->dev == dev) { 306 struct in_device *loopback_idev = in_dev_get(&loopback_dev); 307 BUG_ON(!loopback_idev); 308 309 do { 310 in_dev_put(xdst->u.rt.idev); 311 xdst->u.rt.idev = loopback_idev; 312 in_dev_hold(loopback_idev); 313 xdst = (struct xfrm_dst *)xdst->u.dst.child; 314 } while (xdst->u.dst.xfrm); 315 316 __in_dev_put(loopback_idev); 317 } 318 319 xfrm_dst_ifdown(dst, dev); 320} 321 322static struct dst_ops xfrm4_dst_ops = { 323 .family = AF_INET, 324 .protocol = __constant_htons(ETH_P_IP), 325 .gc = xfrm4_garbage_collect, 326 .update_pmtu = xfrm4_update_pmtu, 327 .destroy = xfrm4_dst_destroy, 328 .ifdown = xfrm4_dst_ifdown, 329 .gc_thresh = 1024, 330 .entry_size = sizeof(struct xfrm_dst), 331}; 332 333static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 334 .family = AF_INET, 335 .dst_ops = &xfrm4_dst_ops, 336 .dst_lookup = xfrm4_dst_lookup, 337 .get_saddr = xfrm4_get_saddr, 338 .find_bundle = __xfrm4_find_bundle, 339 .bundle_create = __xfrm4_bundle_create, 340 .decode_session = _decode_session4, 341}; 342 343static void __init xfrm4_policy_init(void) 344{ 345 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); 346} 347 348static void __exit xfrm4_policy_fini(void) 349{ 350 xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); 351} 352 353void __init xfrm4_init(void) 354{ 355 xfrm4_state_init(); 356 xfrm4_policy_init(); 357} 358