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/config.h> 13 #include <linux/inetdevice.h> 14 #include <net/xfrm.h> 15 #include <net/ip.h> 16 17 static struct dst_ops xfrm4_dst_ops; 18 static struct xfrm_policy_afinfo xfrm4_policy_afinfo; 19 20 static struct xfrm_type_map xfrm4_type_map = { .lock = RW_LOCK_UNLOCKED }; 21 22 static int xfrm4_dst_lookup(struct xfrm_dst **dst, struct flowi *fl) 23 { 24 return __ip_route_output_key((struct rtable**)dst, fl); 25 } 26 27 static struct dst_entry * 28 __xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy) 29 { 30 struct dst_entry *dst; 31 32 read_lock_bh(&policy->lock); 33 for (dst = policy->bundles; dst; dst = dst->next) { 34 struct xfrm_dst *xdst = (struct xfrm_dst*)dst; 35 if (xdst->u.rt.fl.oif == fl->oif && /*XXX*/ 36 xdst->u.rt.fl.fl4_dst == fl->fl4_dst && 37 xdst->u.rt.fl.fl4_src == fl->fl4_src && 38 xdst->u.rt.fl.fl4_tos == fl->fl4_tos && 39 xfrm_bundle_ok(xdst, fl, AF_INET)) { 40 dst_clone(dst); 41 break; 42 } 43 } 44 read_unlock_bh(&policy->lock); 45 return dst; 46 } 47 48 /* Allocate chain of dst_entry's, attach known xfrm's, calculate 49 * all the metrics... Shortly, bundle a bundle. 50 */ 51 52 static int 53 __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx, 54 struct flowi *fl, struct dst_entry **dst_p) 55 { 56 struct dst_entry *dst, *dst_prev; 57 struct rtable *rt0 = (struct rtable*)(*dst_p); 58 struct rtable *rt = rt0; 59 u32 remote = fl->fl4_dst; 60 u32 local = fl->fl4_src; 61 struct flowi fl_tunnel = { 62 .nl_u = { 63 .ip4_u = { 64 .saddr = local, 65 .daddr = remote, 66 .tos = fl->fl4_tos 67 } 68 } 69 }; 70 int i; 71 int err; 72 int header_len = 0; 73 int trailer_len = 0; 74 75 dst = dst_prev = NULL; 76 dst_hold(&rt->u.dst); 77 78 for (i = 0; i < nx; i++) { 79 struct dst_entry *dst1 = dst_alloc(&xfrm4_dst_ops); 80 struct xfrm_dst *xdst; 81 int tunnel = 0; 82 83 if (unlikely(dst1 == NULL)) { 84 err = -ENOBUFS; 85 dst_release(&rt->u.dst); 86 goto error; 87 } 88 89 if (!dst) 90 dst = dst1; 91 else { 92 dst_prev->child = dst1; 93 dst1->flags |= DST_NOHASH; 94 dst_clone(dst1); 95 } 96 97 xdst = (struct xfrm_dst *)dst1; 98 xdst->route = &rt->u.dst; 99 100 dst1->next = dst_prev; 101 dst_prev = dst1; 102 if (xfrm[i]->props.mode) { 103 remote = xfrm[i]->id.daddr.a4; 104 local = xfrm[i]->props.saddr.a4; 105 tunnel = 1; 106 } 107 header_len += xfrm[i]->props.header_len; 108 trailer_len += xfrm[i]->props.trailer_len; 109 110 if (tunnel) { 111 fl_tunnel.fl4_src = local; 112 fl_tunnel.fl4_dst = remote; 113 err = xfrm_dst_lookup((struct xfrm_dst **)&rt, 114 &fl_tunnel, AF_INET); 115 if (err) 116 goto error; 117 } else 118 dst_hold(&rt->u.dst); 119 } 120 121 dst_prev->child = &rt->u.dst; 122 dst->path = &rt->u.dst; 123 124 *dst_p = dst; 125 dst = dst_prev; 126 127 dst_prev = *dst_p; 128 i = 0; 129 for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) { 130 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev; 131 x->u.rt.fl = *fl; 132 133 dst_prev->xfrm = xfrm[i++]; 134 dst_prev->dev = rt->u.dst.dev; 135 if (rt->u.dst.dev) 136 dev_hold(rt->u.dst.dev); 137 dst_prev->obsolete = -1; 138 dst_prev->flags |= DST_HOST; 139 dst_prev->lastuse = jiffies; 140 dst_prev->header_len = header_len; 141 dst_prev->trailer_len = trailer_len; 142 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics)); 143 144 /* Copy neighbout for reachability confirmation */ 145 dst_prev->neighbour = neigh_clone(rt->u.dst.neighbour); 146 dst_prev->input = rt->u.dst.input; 147 dst_prev->output = xfrm4_output; 148 if (rt->peer) 149 atomic_inc(&rt->peer->refcnt); 150 x->u.rt.peer = rt->peer; 151 /* Sheit... I remember I did this right. Apparently, 152 * it was magically lost, so this code needs audit */ 153 x->u.rt.rt_flags = rt0->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL); 154 x->u.rt.rt_type = rt->rt_type; 155 x->u.rt.rt_src = rt0->rt_src; 156 x->u.rt.rt_dst = rt0->rt_dst; 157 x->u.rt.rt_gateway = rt->rt_gateway; 158 x->u.rt.rt_spec_dst = rt0->rt_spec_dst; 159 x->u.rt.idev = rt0->idev; 160 in_dev_hold(rt0->idev); 161 header_len -= x->u.dst.xfrm->props.header_len; 162 trailer_len -= x->u.dst.xfrm->props.trailer_len; 163 } 164 165 xfrm_init_pmtu(dst); 166 return 0; 167 168 error: 169 if (dst) 170 dst_free(dst); 171 return err; 172 } 173 174 static void 175 _decode_session4(struct sk_buff *skb, struct flowi *fl) 176 { 177 struct iphdr *iph = skb->nh.iph; 178 u8 *xprth = skb->nh.raw + iph->ihl*4; 179 180 memset(fl, 0, sizeof(struct flowi)); 181 if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) { 182 switch (iph->protocol) { 183 case IPPROTO_UDP: 184 case IPPROTO_TCP: 185 case IPPROTO_SCTP: 186 case IPPROTO_DCCP: 187 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 188 u16 *ports = (u16 *)xprth; 189 190 fl->fl_ip_sport = ports[0]; 191 fl->fl_ip_dport = ports[1]; 192 } 193 break; 194 195 case IPPROTO_ICMP: 196 if (pskb_may_pull(skb, xprth + 2 - skb->data)) { 197 u8 *icmp = xprth; 198 199 fl->fl_icmp_type = icmp[0]; 200 fl->fl_icmp_code = icmp[1]; 201 } 202 break; 203 204 case IPPROTO_ESP: 205 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 206 u32 *ehdr = (u32 *)xprth; 207 208 fl->fl_ipsec_spi = ehdr[0]; 209 } 210 break; 211 212 case IPPROTO_AH: 213 if (pskb_may_pull(skb, xprth + 8 - skb->data)) { 214 u32 *ah_hdr = (u32*)xprth; 215 216 fl->fl_ipsec_spi = ah_hdr[1]; 217 } 218 break; 219 220 case IPPROTO_COMP: 221 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 222 u16 *ipcomp_hdr = (u16 *)xprth; 223 224 fl->fl_ipsec_spi = ntohl(ntohs(ipcomp_hdr[1])); 225 } 226 break; 227 default: 228 fl->fl_ipsec_spi = 0; 229 break; 230 }; 231 } 232 fl->proto = iph->protocol; 233 fl->fl4_dst = iph->daddr; 234 fl->fl4_src = iph->saddr; 235 fl->fl4_tos = iph->tos; 236 } 237 238 static inline int xfrm4_garbage_collect(void) 239 { 240 read_lock(&xfrm4_policy_afinfo.lock); 241 xfrm4_policy_afinfo.garbage_collect(); 242 read_unlock(&xfrm4_policy_afinfo.lock); 243 return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2); 244 } 245 246 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu) 247 { 248 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 249 struct dst_entry *path = xdst->route; 250 251 path->ops->update_pmtu(path, mtu); 252 } 253 254 static void xfrm4_dst_destroy(struct dst_entry *dst) 255 { 256 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 257 258 if (likely(xdst->u.rt.idev)) 259 in_dev_put(xdst->u.rt.idev); 260 xfrm_dst_destroy(xdst); 261 } 262 263 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 264 int unregister) 265 { 266 struct xfrm_dst *xdst; 267 268 if (!unregister) 269 return; 270 271 xdst = (struct xfrm_dst *)dst; 272 if (xdst->u.rt.idev->dev == dev) { 273 struct in_device *loopback_idev = in_dev_get(&loopback_dev); 274 BUG_ON(!loopback_idev); 275 276 do { 277 in_dev_put(xdst->u.rt.idev); 278 xdst->u.rt.idev = loopback_idev; 279 in_dev_hold(loopback_idev); 280 xdst = (struct xfrm_dst *)xdst->u.dst.child; 281 } while (xdst->u.dst.xfrm); 282 283 __in_dev_put(loopback_idev); 284 } 285 286 xfrm_dst_ifdown(dst, dev); 287 } 288 289 static struct dst_ops xfrm4_dst_ops = { 290 .family = AF_INET, 291 .protocol = __constant_htons(ETH_P_IP), 292 .gc = xfrm4_garbage_collect, 293 .update_pmtu = xfrm4_update_pmtu, 294 .destroy = xfrm4_dst_destroy, 295 .ifdown = xfrm4_dst_ifdown, 296 .gc_thresh = 1024, 297 .entry_size = sizeof(struct xfrm_dst), 298 }; 299 300 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 301 .family = AF_INET, 302 .lock = RW_LOCK_UNLOCKED, 303 .type_map = &xfrm4_type_map, 304 .dst_ops = &xfrm4_dst_ops, 305 .dst_lookup = xfrm4_dst_lookup, 306 .find_bundle = __xfrm4_find_bundle, 307 .bundle_create = __xfrm4_bundle_create, 308 .decode_session = _decode_session4, 309 }; 310 311 static void __init xfrm4_policy_init(void) 312 { 313 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); 314 } 315 316 static void __exit xfrm4_policy_fini(void) 317 { 318 xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); 319 } 320 321 void __init xfrm4_init(void) 322 { 323 xfrm4_state_init(); 324 xfrm4_policy_init(); 325 } 326 327