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   1 /*
   2  * xfrm6_policy.c: based on xfrm4_policy.c
   3  *
   4  * Authors:
   5  *      Mitsuru KANDA @USAGI
   6  *      Kazunori MIYAZAWA @USAGI
   7  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
   8  *              IPv6 support
   9  *      YOSHIFUJI Hideaki
  10  *              Split up af-specific portion
  11  *
  12  */
  13
  14 #include <linux/compiler.h>
  15 #include <linux/netdevice.h>
  16 #include <net/addrconf.h>
  17 #include <net/xfrm.h>
  18 #include <net/ip.h>
  19 #include <net/ipv6.h>
  20 #include <net/ip6_route.h>
  21
  22 static struct dst_ops xfrm6_dst_ops;
  23 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  24
  25 static int xfrm6_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
  26 {
  27         int err = 0;
  28         *dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
  29         if (!*dst)
  30                 err = -ENETUNREACH;
  31         return err;
  32 }
  33
  34 static struct dst_entry *
  35 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  36 {
  37         struct dst_entry *dst;
  38
  39         /* Still not clear if we should set fl->fl6_{src,dst}... */
  40         read_lock_bh(&policy->lock);
  41         for (dst = policy->bundles; dst; dst = dst->next) {
  42                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  43                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  44
  45                 ipv6_addr_prefix(&fl_dst_prefix,
  46                                  &fl->fl6_dst,
  47                                  xdst->u.rt6.rt6i_dst.plen);
  48                 ipv6_addr_prefix(&fl_src_prefix,
  49                                  &fl->fl6_src,
  50                                  xdst->u.rt6.rt6i_src.plen);
  51                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  52                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  53                     xfrm_bundle_ok(xdst, fl, AF_INET6)) {
  54                         dst_clone(dst);
  55                         break;
  56                 }
  57         }
  58         read_unlock_bh(&policy->lock);
  59         return dst;
  60 }
  61
  62 static inline struct in6_addr*
  63 __xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
  64 {
  65         return (x->type->remote_addr) ?
  66                 (struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
  67                 (struct in6_addr*)&x->id.daddr;
  68 }
  69
  70 static inline struct in6_addr*
  71 __xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
  72 {
  73         return (x->type->local_addr) ?
  74                 (struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
  75                 (struct in6_addr*)&x->props.saddr;
  76 }
  77
  78 static inline void
  79 __xfrm6_bundle_len_inc(int *len, int *nflen, struct xfrm_state *x)
  80 {
  81         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
  82                 *nflen += x->props.header_len;
  83         else
  84                 *len += x->props.header_len;
  85 }
  86
  87 static inline void
  88 __xfrm6_bundle_len_dec(int *len, int *nflen, struct xfrm_state *x)
  89 {
  90         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
  91                 *nflen -= x->props.header_len;
  92         else
  93                 *len -= x->props.header_len;
  94 }
  95
  96 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  97  * all the metrics... Shortly, bundle a bundle.
  98  */
  99
 100 static int
 101 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 102                       struct flowi *fl, struct dst_entry **dst_p)
 103 {
 104         struct dst_entry *dst, *dst_prev;
 105         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
 106         struct rt6_info *rt  = rt0;
 107         struct in6_addr *remote = &fl->fl6_dst;
 108         struct in6_addr *local  = &fl->fl6_src;
 109         struct flowi fl_tunnel = {
 110                 .nl_u = {
 111                         .ip6_u = {
 112                                 .saddr = *local,
 113                                 .daddr = *remote
 114                         }
 115                 }
 116         };
 117         int i;
 118         int err = 0;
 119         int header_len = 0;
 120         int nfheader_len = 0;
 121         int trailer_len = 0;
 122
 123         dst = dst_prev = NULL;
 124         dst_hold(&rt->u.dst);
 125
 126         for (i = 0; i < nx; i++) {
 127                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 128                 struct xfrm_dst *xdst;
 129                 int tunnel = 0;
 130
 131                 if (unlikely(dst1 == NULL)) {
 132                         err = -ENOBUFS;
 133                         dst_release(&rt->u.dst);
 134                         goto error;
 135                 }
 136
 137                 if (!dst)
 138                         dst = dst1;
 139                 else {
 140                         dst_prev->child = dst1;
 141                         dst1->flags |= DST_NOHASH;
 142                         dst_clone(dst1);
 143                 }
 144
 145                 xdst = (struct xfrm_dst *)dst1;
 146                 xdst->route = &rt->u.dst;
 147                 if (rt->rt6i_node)
 148                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 149
 150                 dst1->next = dst_prev;
 151                 dst_prev = dst1;
 152                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 153                         remote = __xfrm6_bundle_addr_remote(xfrm[i], remote);
 154                         local  = __xfrm6_bundle_addr_local(xfrm[i], local);
 155                         tunnel = 1;
 156                 }
 157                 __xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
 158                 trailer_len += xfrm[i]->props.trailer_len;
 159
 160                 if (tunnel) {
 161                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 162                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 163                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 164                                               &fl_tunnel, AF_INET6);
 165                         if (err)
 166                                 goto error;
 167                 } else
 168                         dst_hold(&rt->u.dst);
 169         }
 170
 171         dst_prev->child = &rt->u.dst;
 172         dst->path = &rt->u.dst;
 173         if (rt->rt6i_node)
 174                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 175
 176         *dst_p = dst;
 177         dst = dst_prev;
 178
 179         dst_prev = *dst_p;
 180         i = 0;
 181         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 182                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 183
 184                 dst_prev->xfrm = xfrm[i++];
 185                 dst_prev->dev = rt->u.dst.dev;
 186                 if (rt->u.dst.dev)
 187                         dev_hold(rt->u.dst.dev);
 188                 dst_prev->obsolete      = -1;
 189                 dst_prev->flags        |= DST_HOST;
 190                 dst_prev->lastuse       = jiffies;
 191                 dst_prev->header_len    = header_len;
 192                 dst_prev->nfheader_len  = nfheader_len;
 193                 dst_prev->trailer_len   = trailer_len;
 194                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 195
 196                 /* Copy neighbour for reachability confirmation */
 197                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 198                 dst_prev->input         = rt->u.dst.input;
 199                 dst_prev->output        = xfrm6_output;
 200                 /* Sheit... I remember I did this right. Apparently,
 201                  * it was magically lost, so this code needs audit */
 202                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 203                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 204                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 205                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 206                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 207                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 208                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 209                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 210                 in6_dev_hold(rt0->rt6i_idev);
 211                 __xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
 212                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 213         }
 214
 215         xfrm_init_pmtu(dst);
 216         return 0;
 217
 218 error:
 219         if (dst)
 220                 dst_free(dst);
 221         return err;
 222 }
 223
 224 static inline void
 225 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 226 {
 227         u16 offset = skb->h.raw - skb->nh.raw;
 228         struct ipv6hdr *hdr = skb->nh.ipv6h;
 229         struct ipv6_opt_hdr *exthdr;
 230         u8 nexthdr = skb->nh.raw[IP6CB(skb)->nhoff];
 231
 232         memset(fl, 0, sizeof(struct flowi));
 233         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 234         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 235
 236         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 237                 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 238
 239                 switch (nexthdr) {
 240                 case NEXTHDR_ROUTING:
 241                 case NEXTHDR_HOP:
 242                 case NEXTHDR_DEST:
 243                         offset += ipv6_optlen(exthdr);
 244                         nexthdr = exthdr->nexthdr;
 245                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 246                         break;
 247
 248                 case IPPROTO_UDP:
 249                 case IPPROTO_TCP:
 250                 case IPPROTO_SCTP:
 251                 case IPPROTO_DCCP:
 252                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 253                                 u16 *ports = (u16 *)exthdr;
 254
 255                                 fl->fl_ip_sport = ports[0];
 256                                 fl->fl_ip_dport = ports[1];
 257                         }
 258                         fl->proto = nexthdr;
 259                         return;
 260
 261                 case IPPROTO_ICMPV6:
 262                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 263                                 u8 *icmp = (u8 *)exthdr;
 264
 265                                 fl->fl_icmp_type = icmp[0];
 266                                 fl->fl_icmp_code = icmp[1];
 267                         }
 268                         fl->proto = nexthdr;
 269                         return;
 270
 271                 /* XXX Why are there these headers? */
 272                 case IPPROTO_AH:
 273                 case IPPROTO_ESP:
 274                 case IPPROTO_COMP:
 275                 default:
 276                         fl->fl_ipsec_spi = 0;
 277                         fl->proto = nexthdr;
 278                         return;
 279                 };
 280         }
 281 }
 282
 283 static inline int xfrm6_garbage_collect(void)
 284 {
 285         xfrm6_policy_afinfo.garbage_collect();
 286         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 287 }
 288
 289 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 290 {
 291         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 292         struct dst_entry *path = xdst->route;
 293
 294         path->ops->update_pmtu(path, mtu);
 295 }
 296
 297 static void xfrm6_dst_destroy(struct dst_entry *dst)
 298 {
 299         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 300
 301         if (likely(xdst->u.rt6.rt6i_idev))
 302                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 303         xfrm_dst_destroy(xdst);
 304 }
 305
 306 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 307                              int unregister)
 308 {
 309         struct xfrm_dst *xdst;
 310
 311         if (!unregister)
 312                 return;
 313
 314         xdst = (struct xfrm_dst *)dst;
 315         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 316                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 317                 BUG_ON(!loopback_idev);
 318
 319                 do {
 320                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 321                         xdst->u.rt6.rt6i_idev = loopback_idev;
 322                         in6_dev_hold(loopback_idev);
 323                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 324                 } while (xdst->u.dst.xfrm);
 325
 326                 __in6_dev_put(loopback_idev);
 327         }
 328
 329         xfrm_dst_ifdown(dst, dev);
 330 }
 331
 332 static struct dst_ops xfrm6_dst_ops = {
 333         .family =               AF_INET6,
 334         .protocol =             __constant_htons(ETH_P_IPV6),
 335         .gc =                   xfrm6_garbage_collect,
 336         .update_pmtu =          xfrm6_update_pmtu,
 337         .destroy =              xfrm6_dst_destroy,
 338         .ifdown =               xfrm6_dst_ifdown,
 339         .gc_thresh =            1024,
 340         .entry_size =           sizeof(struct xfrm_dst),
 341 };
 342
 343 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 344         .family =               AF_INET6,
 345         .dst_ops =              &xfrm6_dst_ops,
 346         .dst_lookup =           xfrm6_dst_lookup,
 347         .find_bundle =          __xfrm6_find_bundle,
 348         .bundle_create =        __xfrm6_bundle_create,
 349         .decode_session =       _decode_session6,
 350 };
 351
 352 static void __init xfrm6_policy_init(void)
 353 {
 354         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 355 }
 356
 357 static void xfrm6_policy_fini(void)
 358 {
 359         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 360 }
 361
 362 void __init xfrm6_init(void)
 363 {
 364         xfrm6_policy_init();
 365         xfrm6_state_init();
 366 }
 367
 368 void xfrm6_fini(void)
 369 {
 370         //xfrm6_input_fini();
 371         xfrm6_policy_fini();
 372         xfrm6_state_fini();
 373 }