net/ipv6/xfrm6_policy.c

   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/config.h>
  15 #include <net/xfrm.h>
  16 #include <net/ip.h>
  17 #include <net/ipv6.h>
  18 #include <net/ip6_route.h>
  19
  20 extern struct dst_ops xfrm6_dst_ops;
  21 extern struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  22
  23 static struct xfrm_type_map xfrm6_type_map = { .lock = RW_LOCK_UNLOCKED };
  24
  25 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 /* Check that the bundle accepts the flow and its components are
  35  * still valid.
  36  */
  37
  38 static int __xfrm6_bundle_ok(struct xfrm_dst *xdst, struct flowi *fl)
  39 {
  40         do {
  41                 if (xdst->u.dst.ops != &xfrm6_dst_ops)
  42                         return 1;
  43
  44                 if (!xfrm_selector_match(&xdst->u.dst.xfrm->sel, fl, AF_INET6))
  45                         return 0;
  46                 if (xdst->u.dst.xfrm->km.state != XFRM_STATE_VALID ||
  47                     xdst->u.dst.path->obsolete > 0)
  48                         return 0;
  49                 xdst = (struct xfrm_dst*)xdst->u.dst.child;
  50         } while (xdst);
  51         return 0;
  52 }
  53
  54 static struct dst_entry *
  55 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  56 {
  57         struct dst_entry *dst;
  58
  59         /* Still not clear if we should set fl->fl6_{src,dst}... */
  60         read_lock_bh(&policy->lock);
  61         for (dst = policy->bundles; dst; dst = dst->next) {
  62                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  63                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  64
  65                 ipv6_addr_prefix(&fl_dst_prefix,
  66                                  &fl->fl6_dst,
  67                                  xdst->u.rt6.rt6i_dst.plen);
  68                 ipv6_addr_prefix(&fl_src_prefix,
  69                                  &fl->fl6_src,
  70                                  xdst->u.rt6.rt6i_src.plen);
  71                 if (!ipv6_addr_cmp(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  72                     !ipv6_addr_cmp(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  73                     __xfrm6_bundle_ok(xdst, fl)) {
  74                         dst_clone(dst);
  75                         break;
  76                 }
  77         }
  78         read_unlock_bh(&policy->lock);
  79         return dst;
  80 }
  81
  82 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  83  * all the metrics... Shortly, bundle a bundle.
  84  */
  85
  86 static int
  87 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
  88                       struct flowi *fl, struct dst_entry **dst_p)
  89 {
  90         struct dst_entry *dst, *dst_prev;
  91         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
  92         struct rt6_info *rt  = rt0;
  93         struct in6_addr *remote = &fl->fl6_dst;
  94         struct in6_addr *local  = &fl->fl6_src;
  95         int i;
  96         int err = 0;
  97         int header_len = 0;
  98         int trailer_len = 0;
  99
 100         dst = dst_prev = NULL;
 101
 102         for (i = 0; i < nx; i++) {
 103                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 104
 105                 if (unlikely(dst1 == NULL)) {
 106                         err = -ENOBUFS;
 107                         goto error;
 108                 }
 109
 110                 dst1->xfrm = xfrm[i];
 111                 if (!dst)
 112                         dst = dst1;
 113                 else {
 114                         dst_prev->child = dst1;
 115                         dst1->flags |= DST_NOHASH;
 116                         dst_clone(dst1);
 117                 }
 118                 dst_prev = dst1;
 119                 if (xfrm[i]->props.mode) {
 120                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
 121                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
 122                 }
 123                 header_len += xfrm[i]->props.header_len;
 124                 trailer_len += xfrm[i]->props.trailer_len;
 125         }
 126
 127         if (ipv6_addr_cmp(remote, &fl->fl6_dst)) {
 128                 struct flowi fl_tunnel;
 129
 130                 memset(&fl_tunnel, 0, sizeof(fl_tunnel));
 131                 ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 132                 ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 133
 134                 err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 135                                       &fl_tunnel, AF_INET6);
 136                 if (err)
 137                         goto error;
 138         } else {
 139                 dst_hold(&rt->u.dst);
 140         }
 141         dst_prev->child = &rt->u.dst;
 142         for (dst_prev = dst; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 143                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 144
 145                 dst_prev->dev = rt->u.dst.dev;
 146                 if (rt->u.dst.dev)
 147                         dev_hold(rt->u.dst.dev);
 148                 dst_prev->obsolete      = -1;
 149                 dst_prev->flags        |= DST_HOST;
 150                 dst_prev->lastuse       = jiffies;
 151                 dst_prev->header_len    = header_len;
 152                 dst_prev->trailer_len   = trailer_len;
 153                 memcpy(&dst_prev->metrics, &rt->u.dst.metrics, sizeof(dst_prev->metrics));
 154                 dst_prev->path          = &rt->u.dst;
 155
 156                 /* Copy neighbour for reachability confirmation */
 157                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 158                 dst_prev->input         = rt->u.dst.input;
 159                 dst_prev->output        = dst_prev->xfrm->type->output;
 160                 /* Sheit... I remember I did this right. Apparently,
 161                  * it was magically lost, so this code needs audit */
 162                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 163                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 164                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 165                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 166                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 167                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 168                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 169                 header_len -= x->u.dst.xfrm->props.header_len;
 170                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 171         }
 172         *dst_p = dst;
 173         return 0;
 174
 175 error:
 176         if (dst)
 177                 dst_free(dst);
 178         return err;
 179 }
 180
 181 static inline void
 182 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 183 {
 184         u16 offset = sizeof(struct ipv6hdr);
 185         struct ipv6hdr *hdr = skb->nh.ipv6h;
 186         struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 187         u8 nexthdr = skb->nh.ipv6h->nexthdr;
 188
 189         memset(fl, 0, sizeof(struct flowi));
 190         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 191         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 192
 193         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 194                 switch (nexthdr) {
 195                 case NEXTHDR_ROUTING:
 196                 case NEXTHDR_HOP:
 197                 case NEXTHDR_DEST:
 198                         offset += ipv6_optlen(exthdr);
 199                         nexthdr = exthdr->nexthdr;
 200                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 201                         break;
 202
 203                 case IPPROTO_UDP:
 204                 case IPPROTO_TCP:
 205                 case IPPROTO_SCTP:
 206                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 207                                 u16 *ports = (u16 *)exthdr;
 208
 209                                 fl->fl_ip_sport = ports[0];
 210                                 fl->fl_ip_dport = ports[1];
 211                         }
 212                         fl->proto = nexthdr;
 213                         return;
 214
 215                 /* XXX Why are there these headers? */
 216                 case IPPROTO_AH:
 217                 case IPPROTO_ESP:
 218                 case IPPROTO_COMP:
 219                 default:
 220                         fl->fl_ipsec_spi = 0;
 221                         fl->proto = nexthdr;
 222                         return;
 223                 };
 224         }
 225 }
 226
 227 static inline int xfrm6_garbage_collect(void)
 228 {
 229         read_lock(&xfrm6_policy_afinfo.lock);
 230         xfrm6_policy_afinfo.garbage_collect();
 231         read_unlock(&xfrm6_policy_afinfo.lock);
 232         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 233 }
 234
 235 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 236 {
 237         struct dst_entry *path = dst->path;
 238
 239         if (mtu >= 1280 && mtu < dst_pmtu(dst))
 240                 return;
 241
 242         path->ops->update_pmtu(path, mtu);
 243 }
 244
 245 struct dst_ops xfrm6_dst_ops = {
 246         .family =               AF_INET6,
 247         .protocol =             __constant_htons(ETH_P_IPV6),
 248         .gc =                   xfrm6_garbage_collect,
 249         .update_pmtu =          xfrm6_update_pmtu,
 250         .gc_thresh =            1024,
 251         .entry_size =           sizeof(struct xfrm_dst),
 252 };
 253
 254 struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 255         .family =               AF_INET6,
 256         .lock =                 RW_LOCK_UNLOCKED,
 257         .type_map =             &xfrm6_type_map,
 258         .dst_ops =              &xfrm6_dst_ops,
 259         .dst_lookup =           xfrm6_dst_lookup,
 260         .find_bundle =          __xfrm6_find_bundle,
 261         .bundle_create =        __xfrm6_bundle_create,
 262         .decode_session =       _decode_session6,
 263 };
 264
 265 void __init xfrm6_policy_init(void)
 266 {
 267         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 268 }
 269
 270 void __exit xfrm6_policy_fini(void)
 271 {
 272         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 273 }
 274
 275 void __init xfrm6_init(void)
 276 {
 277         xfrm6_policy_init();
 278         xfrm6_state_init();
 279 }
 280
 281 void __exit xfrm6_fini(void)
 282 {
 283         //xfrm6_input_fini();
 284         xfrm6_policy_fini();
 285         xfrm6_state_fini();
 286 }