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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/err.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <net/addrconf.h>
  18 #include <net/dst.h>
  19 #include <net/xfrm.h>
  20 #include <net/ip.h>
  21 #include <net/ipv6.h>
  22 #include <net/ip6_route.h>
  23 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
  24 #include <net/mip6.h>
  25 #endif
  26
  27 static struct dst_ops xfrm6_dst_ops;
  28 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  29
  30 static struct dst_entry *xfrm6_dst_lookup(int tos, xfrm_address_t *saddr,
  31                                           xfrm_address_t *daddr)
  32 {
  33         struct flowi fl = {};
  34         struct dst_entry *dst;
  35         int err;
  36
  37         memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
  38         if (saddr)
  39                 memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
  40
  41         dst = ip6_route_output(NULL, &fl);
  42
  43         err = dst->error;
  44         if (dst->error) {
  45                 dst_release(dst);
  46                 dst = ERR_PTR(err);
  47         }
  48
  49         return dst;
  50 }
  51
  52 static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
  53 {
  54         struct dst_entry *dst;
  55
  56         dst = xfrm6_dst_lookup(0, NULL, daddr);
  57         if (IS_ERR(dst))
  58                 return -EHOSTUNREACH;
  59
  60         ipv6_get_saddr(dst, (struct in6_addr *)&daddr->a6,
  61                        (struct in6_addr *)&saddr->a6);
  62         dst_release(dst);
  63         return 0;
  64 }
  65
  66 static struct dst_entry *
  67 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  68 {
  69         struct dst_entry *dst;
  70
  71         /* Still not clear if we should set fl->fl6_{src,dst}... */
  72         read_lock_bh(&policy->lock);
  73         for (dst = policy->bundles; dst; dst = dst->next) {
  74                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  75                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  76
  77                 ipv6_addr_prefix(&fl_dst_prefix,
  78                                  &fl->fl6_dst,
  79                                  xdst->u.rt6.rt6i_dst.plen);
  80                 ipv6_addr_prefix(&fl_src_prefix,
  81                                  &fl->fl6_src,
  82                                  xdst->u.rt6.rt6i_src.plen);
  83                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  84                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  85                     xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
  86                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  87                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  88                         dst_clone(dst);
  89                         break;
  90                 }
  91         }
  92         read_unlock_bh(&policy->lock);
  93         return dst;
  94 }
  95
  96 static int xfrm6_get_tos(struct flowi *fl)
  97 {
  98         return 0;
  99 }
 100
 101 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
 102 {
 103         struct rt6_info *rt = (struct rt6_info*)xdst->route;
 104
 105         xdst->u.dst.dev = dev;
 106         dev_hold(dev);
 107
 108         xdst->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
 109         if (!xdst->u.rt6.rt6i_idev)
 110                 return -ENODEV;
 111
 112         /* Sheit... I remember I did this right. Apparently,
 113          * it was magically lost, so this code needs audit */
 114         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 115                                                    RTF_LOCAL);
 116         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 117         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 118         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 119         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 120         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 121
 122         return 0;
 123 }
 124
 125 static inline void
 126 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 127 {
 128         u16 offset = skb_network_header_len(skb);
 129         struct ipv6hdr *hdr = ipv6_hdr(skb);
 130         struct ipv6_opt_hdr *exthdr;
 131         const unsigned char *nh = skb_network_header(skb);
 132         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 133
 134         memset(fl, 0, sizeof(struct flowi));
 135         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 136         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 137
 138         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 139                 nh = skb_network_header(skb);
 140                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 141
 142                 switch (nexthdr) {
 143                 case NEXTHDR_ROUTING:
 144                 case NEXTHDR_HOP:
 145                 case NEXTHDR_DEST:
 146                         offset += ipv6_optlen(exthdr);
 147                         nexthdr = exthdr->nexthdr;
 148                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 149                         break;
 150
 151                 case IPPROTO_UDP:
 152                 case IPPROTO_UDPLITE:
 153                 case IPPROTO_TCP:
 154                 case IPPROTO_SCTP:
 155                 case IPPROTO_DCCP:
 156                         if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
 157                                 __be16 *ports = (__be16 *)exthdr;
 158
 159                                 fl->fl_ip_sport = ports[0];
 160                                 fl->fl_ip_dport = ports[1];
 161                         }
 162                         fl->proto = nexthdr;
 163                         return;
 164
 165                 case IPPROTO_ICMPV6:
 166                         if (pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 167                                 u8 *icmp = (u8 *)exthdr;
 168
 169                                 fl->fl_icmp_type = icmp[0];
 170                                 fl->fl_icmp_code = icmp[1];
 171                         }
 172                         fl->proto = nexthdr;
 173                         return;
 174
 175 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 176                 case IPPROTO_MH:
 177                         if (pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 178                                 struct ip6_mh *mh;
 179                                 mh = (struct ip6_mh *)exthdr;
 180
 181                                 fl->fl_mh_type = mh->ip6mh_type;
 182                         }
 183                         fl->proto = nexthdr;
 184                         return;
 185 #endif
 186
 187                 /* XXX Why are there these headers? */
 188                 case IPPROTO_AH:
 189                 case IPPROTO_ESP:
 190                 case IPPROTO_COMP:
 191                 default:
 192                         fl->fl_ipsec_spi = 0;
 193                         fl->proto = nexthdr;
 194                         return;
 195                 }
 196         }
 197 }
 198
 199 static inline int xfrm6_garbage_collect(void)
 200 {
 201         xfrm6_policy_afinfo.garbage_collect();
 202         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 203 }
 204
 205 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 206 {
 207         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 208         struct dst_entry *path = xdst->route;
 209
 210         path->ops->update_pmtu(path, mtu);
 211 }
 212
 213 static void xfrm6_dst_destroy(struct dst_entry *dst)
 214 {
 215         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 216
 217         if (likely(xdst->u.rt6.rt6i_idev))
 218                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 219         xfrm_dst_destroy(xdst);
 220 }
 221
 222 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 223                              int unregister)
 224 {
 225         struct xfrm_dst *xdst;
 226
 227         if (!unregister)
 228                 return;
 229
 230         xdst = (struct xfrm_dst *)dst;
 231         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 232                 struct inet6_dev *loopback_idev = in6_dev_get(init_net.loopback_dev);
 233                 BUG_ON(!loopback_idev);
 234
 235                 do {
 236                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 237                         xdst->u.rt6.rt6i_idev = loopback_idev;
 238                         in6_dev_hold(loopback_idev);
 239                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 240                 } while (xdst->u.dst.xfrm);
 241
 242                 __in6_dev_put(loopback_idev);
 243         }
 244
 245         xfrm_dst_ifdown(dst, dev);
 246 }
 247
 248 static struct dst_ops xfrm6_dst_ops = {
 249         .family =               AF_INET6,
 250         .protocol =             __constant_htons(ETH_P_IPV6),
 251         .gc =                   xfrm6_garbage_collect,
 252         .update_pmtu =          xfrm6_update_pmtu,
 253         .destroy =              xfrm6_dst_destroy,
 254         .ifdown =               xfrm6_dst_ifdown,
 255         .local_out =            __ip6_local_out,
 256         .gc_thresh =            1024,
 257         .entry_size =           sizeof(struct xfrm_dst),
 258 };
 259
 260 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 261         .family =               AF_INET6,
 262         .dst_ops =              &xfrm6_dst_ops,
 263         .dst_lookup =           xfrm6_dst_lookup,
 264         .get_saddr =            xfrm6_get_saddr,
 265         .find_bundle =          __xfrm6_find_bundle,
 266         .decode_session =       _decode_session6,
 267         .get_tos =              xfrm6_get_tos,
 268         .fill_dst =             xfrm6_fill_dst,
 269 };
 270
 271 static void __init xfrm6_policy_init(void)
 272 {
 273         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 274 }
 275
 276 static void xfrm6_policy_fini(void)
 277 {
 278         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 279 }
 280
 281 void __init xfrm6_init(void)
 282 {
 283         xfrm6_policy_init();
 284         xfrm6_state_init();
 285 }
 286
 287 void xfrm6_fini(void)
 288 {
 289         //xfrm6_input_fini();
 290         xfrm6_policy_fini();
 291         xfrm6_state_fini();
 292 }