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 <asm/bug.h> 12 #include <linux/compiler.h> 13 #include <linux/config.h> 14 #include <linux/inetdevice.h> 15 #include <net/xfrm.h> 16 #include <net/ip.h> 17 18 static struct dst_ops xfrm4_dst_ops; 19 static struct xfrm_policy_afinfo xfrm4_policy_afinfo; 20 21 static struct xfrm_type_map xfrm4_type_map = { .lock = RW_LOCK_UNLOCKED }; 22 23 static int xfrm4_dst_lookup(struct xfrm_dst **dst, struct flowi *fl) 24 { 25 return __ip_route_output_key((struct rtable**)dst, fl); 26 } 27 28 static struct dst_entry * 29 __xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy) 30 { 31 struct dst_entry *dst; 32 33 read_lock_bh(&policy->lock); 34 for (dst = policy->bundles; dst; dst = dst->next) { 35 struct xfrm_dst *xdst = (struct xfrm_dst*)dst; 36 if (xdst->u.rt.fl.oif == fl->oif && /*XXX*/ 37 xdst->u.rt.fl.fl4_dst == fl->fl4_dst && 38 xdst->u.rt.fl.fl4_src == fl->fl4_src && 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 } 67 } 68 }; 69 int i; 70 int err; 71 int header_len = 0; 72 int trailer_len = 0; 73 74 dst = dst_prev = NULL; 75 dst_hold(&rt->u.dst); 76 77 for (i = 0; i < nx; i++) { 78 struct dst_entry *dst1 = dst_alloc(&xfrm4_dst_ops); 79 struct xfrm_dst *xdst; 80 int tunnel = 0; 81 82 if (unlikely(dst1 == NULL)) { 83 err = -ENOBUFS; 84 dst_release(&rt->u.dst); 85 goto error; 86 } 87 88 if (!dst) 89 dst = dst1; 90 else { 91 dst_prev->child = dst1; 92 dst1->flags |= DST_NOHASH; 93 dst_clone(dst1); 94 } 95 96 xdst = (struct xfrm_dst *)dst1; 97 xdst->route = &rt->u.dst; 98 99 dst1->next = dst_prev; 100 dst_prev = dst1; 101 if (xfrm[i]->props.mode) { 102 remote = xfrm[i]->id.daddr.a4; 103 local = xfrm[i]->props.saddr.a4; 104 tunnel = 1; 105 } 106 header_len += xfrm[i]->props.header_len; 107 trailer_len += xfrm[i]->props.trailer_len; 108 109 if (tunnel) { 110 fl_tunnel.fl4_src = local; 111 fl_tunnel.fl4_dst = remote; 112 err = xfrm_dst_lookup((struct xfrm_dst **)&rt, 113 &fl_tunnel, AF_INET); 114 if (err) 115 goto error; 116 } else 117 dst_hold(&rt->u.dst); 118 } 119 120 dst_prev->child = &rt->u.dst; 121 dst->path = &rt->u.dst; 122 123 *dst_p = dst; 124 dst = dst_prev; 125 126 dst_prev = *dst_p; 127 i = 0; 128 for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) { 129 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev; 130 x->u.rt.fl = *fl; 131 132 dst_prev->xfrm = xfrm[i++]; 133 dst_prev->dev = rt->u.dst.dev; 134 if (rt->u.dst.dev) 135 dev_hold(rt->u.dst.dev); 136 dst_prev->obsolete = -1; 137 dst_prev->flags |= DST_HOST; 138 dst_prev->lastuse = jiffies; 139 dst_prev->header_len = header_len; 140 dst_prev->trailer_len = trailer_len; 141 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics)); 142 143 /* Copy neighbout for reachability confirmation */ 144 dst_prev->neighbour = neigh_clone(rt->u.dst.neighbour); 145 dst_prev->input = rt->u.dst.input; 146 dst_prev->output = xfrm4_output; 147 if (rt->peer) 148 atomic_inc(&rt->peer->refcnt); 149 x->u.rt.peer = rt->peer; 150 /* Sheit... I remember I did this right. Apparently, 151 * it was magically lost, so this code needs audit */ 152 x->u.rt.rt_flags = rt0->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL); 153 x->u.rt.rt_type = rt->rt_type; 154 x->u.rt.rt_src = rt0->rt_src; 155 x->u.rt.rt_dst = rt0->rt_dst; 156 x->u.rt.rt_gateway = rt->rt_gateway; 157 x->u.rt.rt_spec_dst = rt0->rt_spec_dst; 158 x->u.rt.idev = rt0->idev; 159 in_dev_hold(rt0->idev); 160 header_len -= x->u.dst.xfrm->props.header_len; 161 trailer_len -= x->u.dst.xfrm->props.trailer_len; 162 } 163 164 xfrm_init_pmtu(dst); 165 return 0; 166 167 error: 168 if (dst) 169 dst_free(dst); 170 return err; 171 } 172 173 static void 174 _decode_session4(struct sk_buff *skb, struct flowi *fl) 175 { 176 struct iphdr *iph = skb->nh.iph; 177 u8 *xprth = skb->nh.raw + iph->ihl*4; 178 179 memset(fl, 0, sizeof(struct flowi)); 180 if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) { 181 switch (iph->protocol) { 182 case IPPROTO_UDP: 183 case IPPROTO_TCP: 184 case IPPROTO_SCTP: 185 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 186 u16 *ports = (u16 *)xprth; 187 188 fl->fl_ip_sport = ports[0]; 189 fl->fl_ip_dport = ports[1]; 190 } 191 break; 192 193 case IPPROTO_ICMP: 194 if (pskb_may_pull(skb, xprth + 2 - skb->data)) { 195 u8 *icmp = xprth; 196 197 fl->fl_icmp_type = icmp[0]; 198 fl->fl_icmp_code = icmp[1]; 199 } 200 break; 201 202 case IPPROTO_ESP: 203 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 204 u32 *ehdr = (u32 *)xprth; 205 206 fl->fl_ipsec_spi = ehdr[0]; 207 } 208 break; 209 210 case IPPROTO_AH: 211 if (pskb_may_pull(skb, xprth + 8 - skb->data)) { 212 u32 *ah_hdr = (u32*)xprth; 213 214 fl->fl_ipsec_spi = ah_hdr[1]; 215 } 216 break; 217 218 case IPPROTO_COMP: 219 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 220 u16 *ipcomp_hdr = (u16 *)xprth; 221 222 fl->fl_ipsec_spi = ntohl(ntohs(ipcomp_hdr[1])); 223 } 224 break; 225 default: 226 fl->fl_ipsec_spi = 0; 227 break; 228 }; 229 } 230 fl->proto = iph->protocol; 231 fl->fl4_dst = iph->daddr; 232 fl->fl4_src = iph->saddr; 233 } 234 235 static inline int xfrm4_garbage_collect(void) 236 { 237 read_lock(&xfrm4_policy_afinfo.lock); 238 xfrm4_policy_afinfo.garbage_collect(); 239 read_unlock(&xfrm4_policy_afinfo.lock); 240 return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2); 241 } 242 243 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu) 244 { 245 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 246 struct dst_entry *path = xdst->route; 247 248 path->ops->update_pmtu(path, mtu); 249 } 250 251 static void xfrm4_dst_destroy(struct dst_entry *dst) 252 { 253 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 254 255 if (likely(xdst->u.rt.idev)) 256 in_dev_put(xdst->u.rt.idev); 257 xfrm_dst_destroy(xdst); 258 } 259 260 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 261 int unregister) 262 { 263 struct xfrm_dst *xdst; 264 265 if (!unregister) 266 return; 267 268 xdst = (struct xfrm_dst *)dst; 269 if (xdst->u.rt.idev->dev == dev) { 270 struct in_device *loopback_idev = in_dev_get(&loopback_dev); 271 BUG_ON(!loopback_idev); 272 273 do { 274 in_dev_put(xdst->u.rt.idev); 275 xdst->u.rt.idev = loopback_idev; 276 in_dev_hold(loopback_idev); 277 xdst = (struct xfrm_dst *)xdst->u.dst.child; 278 } while (xdst->u.dst.xfrm); 279 280 __in_dev_put(loopback_idev); 281 } 282 283 xfrm_dst_ifdown(dst, dev); 284 } 285 286 static struct dst_ops xfrm4_dst_ops = { 287 .family = AF_INET, 288 .protocol = __constant_htons(ETH_P_IP), 289 .gc = xfrm4_garbage_collect, 290 .update_pmtu = xfrm4_update_pmtu, 291 .destroy = xfrm4_dst_destroy, 292 .ifdown = xfrm4_dst_ifdown, 293 .gc_thresh = 1024, 294 .entry_size = sizeof(struct xfrm_dst), 295 }; 296 297 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 298 .family = AF_INET, 299 .lock = RW_LOCK_UNLOCKED, 300 .type_map = &xfrm4_type_map, 301 .dst_ops = &xfrm4_dst_ops, 302 .dst_lookup = xfrm4_dst_lookup, 303 .find_bundle = __xfrm4_find_bundle, 304 .bundle_create = __xfrm4_bundle_create, 305 .decode_session = _decode_session4, 306 }; 307 308 static void __init xfrm4_policy_init(void) 309 { 310 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); 311 } 312 313 static void __exit xfrm4_policy_fini(void) 314 { 315 xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); 316 } 317 318 void __init xfrm4_init(void) 319 { 320 xfrm4_state_init(); 321 xfrm4_policy_init(); 322 } 323 324