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 static struct dst_ops xfrm6_dst_ops;
  21 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  22
  23 static struct xfrm_type_map xfrm6_type_map = { .lock = RW_LOCK_UNLOCKED };
  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 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  63  * all the metrics... Shortly, bundle a bundle.
  64  */
  65
  66 static int
  67 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
  68                       struct flowi *fl, struct dst_entry **dst_p)
  69 {
  70         struct dst_entry *dst, *dst_prev;
  71         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
  72         struct rt6_info *rt  = rt0;
  73         struct in6_addr *remote = &fl->fl6_dst;
  74         struct in6_addr *local  = &fl->fl6_src;
  75         struct flowi fl_tunnel = {
  76                 .nl_u = {
  77                         .ip6_u = {
  78                                 .saddr = *local,
  79                                 .daddr = *remote
  80                         }
  81                 }
  82         };
  83         int i;
  84         int err = 0;
  85         int header_len = 0;
  86         int trailer_len = 0;
  87
  88         dst = dst_prev = NULL;
  89         dst_hold(&rt->u.dst);
  90
  91         for (i = 0; i < nx; i++) {
  92                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
  93                 struct xfrm_dst *xdst;
  94                 int tunnel = 0;
  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
 113                 dst1->next = dst_prev;
 114                 dst_prev = dst1;
 115                 if (xfrm[i]->props.mode) {
 116                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
 117                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
 118                         tunnel = 1;
 119                 }
 120                 header_len += xfrm[i]->props.header_len;
 121                 trailer_len += xfrm[i]->props.trailer_len;
 122
 123                 if (tunnel) {
 124                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 125                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 126                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 127                                               &fl_tunnel, AF_INET6);
 128                         if (err)
 129                                 goto error;
 130                 } else
 131                         dst_hold(&rt->u.dst);
 132         }
 133
 134         dst_prev->child = &rt->u.dst;
 135         dst->path = &rt->u.dst;
 136
 137         *dst_p = dst;
 138         dst = dst_prev;
 139
 140         dst_prev = *dst_p;
 141         i = 0;
 142         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 143                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 144
 145                 dst_prev->xfrm = xfrm[i++];
 146                 dst_prev->dev = rt->u.dst.dev;
 147                 if (rt->u.dst.dev)
 148                         dev_hold(rt->u.dst.dev);
 149                 dst_prev->obsolete      = -1;
 150                 dst_prev->flags        |= DST_HOST;
 151                 dst_prev->lastuse       = jiffies;
 152                 dst_prev->header_len    = header_len;
 153                 dst_prev->trailer_len   = trailer_len;
 154                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 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        = xfrm6_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
 173         xfrm_init_pmtu(dst);
 174         return 0;
 175
 176 error:
 177         if (dst)
 178                 dst_free(dst);
 179         return err;
 180 }
 181
 182 static inline void
 183 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 184 {
 185         u16 offset = sizeof(struct ipv6hdr);
 186         struct ipv6hdr *hdr = skb->nh.ipv6h;
 187         struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 188         u8 nexthdr = skb->nh.ipv6h->nexthdr;
 189
 190         memset(fl, 0, sizeof(struct flowi));
 191         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 192         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 193
 194         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 195                 switch (nexthdr) {
 196                 case NEXTHDR_ROUTING:
 197                 case NEXTHDR_HOP:
 198                 case NEXTHDR_DEST:
 199                         offset += ipv6_optlen(exthdr);
 200                         nexthdr = exthdr->nexthdr;
 201                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 202                         break;
 203
 204                 case IPPROTO_UDP:
 205                 case IPPROTO_TCP:
 206                 case IPPROTO_SCTP:
 207                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 208                                 u16 *ports = (u16 *)exthdr;
 209
 210                                 fl->fl_ip_sport = ports[0];
 211                                 fl->fl_ip_dport = ports[1];
 212                         }
 213                         fl->proto = nexthdr;
 214                         return;
 215
 216                 case IPPROTO_ICMPV6:
 217                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 218                                 u8 *icmp = (u8 *)exthdr;
 219
 220                                 fl->fl_icmp_type = icmp[0];
 221                                 fl->fl_icmp_code = icmp[1];
 222                         }
 223                         fl->proto = nexthdr;
 224                         return;
 225
 226                 /* XXX Why are there these headers? */
 227                 case IPPROTO_AH:
 228                 case IPPROTO_ESP:
 229                 case IPPROTO_COMP:
 230                 default:
 231                         fl->fl_ipsec_spi = 0;
 232                         fl->proto = nexthdr;
 233                         return;
 234                 };
 235         }
 236 }
 237
 238 static inline int xfrm6_garbage_collect(void)
 239 {
 240         read_lock(&xfrm6_policy_afinfo.lock);
 241         xfrm6_policy_afinfo.garbage_collect();
 242         read_unlock(&xfrm6_policy_afinfo.lock);
 243         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 244 }
 245
 246 static void xfrm6_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 struct dst_ops xfrm6_dst_ops = {
 255         .family =               AF_INET6,
 256         .protocol =             __constant_htons(ETH_P_IPV6),
 257         .gc =                   xfrm6_garbage_collect,
 258         .update_pmtu =          xfrm6_update_pmtu,
 259         .gc_thresh =            1024,
 260         .entry_size =           sizeof(struct xfrm_dst),
 261 };
 262
 263 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 264         .family =               AF_INET6,
 265         .lock =                 RW_LOCK_UNLOCKED,
 266         .type_map =             &xfrm6_type_map,
 267         .dst_ops =              &xfrm6_dst_ops,
 268         .dst_lookup =           xfrm6_dst_lookup,
 269         .find_bundle =          __xfrm6_find_bundle,
 270         .bundle_create =        __xfrm6_bundle_create,
 271         .decode_session =       _decode_session6,
 272 };
 273
 274 static void __init xfrm6_policy_init(void)
 275 {
 276         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 277 }
 278
 279 static void xfrm6_policy_fini(void)
 280 {
 281         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 282 }
 283
 284 void __init xfrm6_init(void)
 285 {
 286         xfrm6_policy_init();
 287         xfrm6_state_init();
 288 }
 289
 290 void xfrm6_fini(void)
 291 {
 292         //xfrm6_input_fini();
 293         xfrm6_policy_fini();
 294         xfrm6_state_fini();
 295 }