net/ipv6/xfrm6_policy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * xfrm6_policy.c: based on xfrm4_policy.c
   4  *
   5  * Authors:
   6  *      Mitsuru KANDA @USAGI
   7  *      Kazunori MIYAZAWA @USAGI
   8  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
   9  *              IPv6 support
  10  *      YOSHIFUJI Hideaki
  11  *              Split up af-specific portion
  12  *
  13  */
  14
  15 #include <linux/err.h>
  16 #include <linux/kernel.h>
  17 #include <linux/netdevice.h>
  18 #include <net/addrconf.h>
  19 #include <net/dst.h>
  20 #include <net/xfrm.h>
  21 #include <net/ip.h>
  22 #include <net/ipv6.h>
  23 #include <net/ip6_route.h>
  24 #include <net/l3mdev.h>
  25
  26 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif,
  27                                           const xfrm_address_t *saddr,
  28                                           const xfrm_address_t *daddr,
  29                                           u32 mark)
  30 {
  31         struct flowi6 fl6;
  32         struct dst_entry *dst;
  33         int err;
  34
  35         memset(&fl6, 0, sizeof(fl6));
  36         fl6.flowi6_oif = l3mdev_master_ifindex_by_index(net, oif);
  37         fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
  38         fl6.flowi6_mark = mark;
  39         memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
  40         if (saddr)
  41                 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
  42
  43         dst = ip6_route_output(net, NULL, &fl6);
  44
  45         err = dst->error;
  46         if (dst->error) {
  47                 dst_release(dst);
  48                 dst = ERR_PTR(err);
  49         }
  50
  51         return dst;
  52 }
  53
  54 static int xfrm6_get_saddr(struct net *net, int oif,
  55                            xfrm_address_t *saddr, xfrm_address_t *daddr,
  56                            u32 mark)
  57 {
  58         struct dst_entry *dst;
  59         struct net_device *dev;
  60
  61         dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark);
  62         if (IS_ERR(dst))
  63                 return -EHOSTUNREACH;
  64
  65         dev = ip6_dst_idev(dst)->dev;
  66         ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
  67         dst_release(dst);
  68         return 0;
  69 }
  70
  71 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  72                           const struct flowi *fl)
  73 {
  74         struct rt6_info *rt = (struct rt6_info *)xdst->route;
  75
  76         xdst->u.dst.dev = dev;
  77         dev_hold(dev);
  78
  79         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
  80         if (!xdst->u.rt6.rt6i_idev) {
  81                 dev_put(dev);
  82                 return -ENODEV;
  83         }
  84
  85         /* Sheit... I remember I did this right. Apparently,
  86          * it was magically lost, so this code needs audit */
  87         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
  88                                                    RTF_LOCAL);
  89         xdst->route_cookie = rt6_get_cookie(rt);
  90         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
  91         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
  92         xdst->u.rt6.rt6i_src = rt->rt6i_src;
  93         INIT_LIST_HEAD(&xdst->u.rt6.rt6i_uncached);
  94         rt6_uncached_list_add(&xdst->u.rt6);
  95         atomic_inc(&dev_net(dev)->ipv6.rt6_stats->fib_rt_uncache);
  96
  97         return 0;
  98 }
  99
 100 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
 101                               struct sk_buff *skb, u32 mtu)
 102 {
 103         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 104         struct dst_entry *path = xdst->route;
 105
 106         path->ops->update_pmtu(path, sk, skb, mtu);
 107 }
 108
 109 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
 110                            struct sk_buff *skb)
 111 {
 112         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 113         struct dst_entry *path = xdst->route;
 114
 115         path->ops->redirect(path, sk, skb);
 116 }
 117
 118 static void xfrm6_dst_destroy(struct dst_entry *dst)
 119 {
 120         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 121
 122         if (likely(xdst->u.rt6.rt6i_idev))
 123                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 124         dst_destroy_metrics_generic(dst);
 125         if (xdst->u.rt6.rt6i_uncached_list)
 126                 rt6_uncached_list_del(&xdst->u.rt6);
 127         xfrm_dst_destroy(xdst);
 128 }
 129
 130 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 131                              int unregister)
 132 {
 133         struct xfrm_dst *xdst;
 134
 135         if (!unregister)
 136                 return;
 137
 138         xdst = (struct xfrm_dst *)dst;
 139         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 140                 struct inet6_dev *loopback_idev =
 141                         in6_dev_get(dev_net(dev)->loopback_dev);
 142
 143                 do {
 144                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 145                         xdst->u.rt6.rt6i_idev = loopback_idev;
 146                         in6_dev_hold(loopback_idev);
 147                         xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst);
 148                 } while (xdst->u.dst.xfrm);
 149
 150                 __in6_dev_put(loopback_idev);
 151         }
 152
 153         xfrm_dst_ifdown(dst, dev);
 154 }
 155
 156 static struct dst_ops xfrm6_dst_ops_template = {
 157         .family =               AF_INET6,
 158         .update_pmtu =          xfrm6_update_pmtu,
 159         .redirect =             xfrm6_redirect,
 160         .cow_metrics =          dst_cow_metrics_generic,
 161         .destroy =              xfrm6_dst_destroy,
 162         .ifdown =               xfrm6_dst_ifdown,
 163         .local_out =            __ip6_local_out,
 164         .gc_thresh =            32768,
 165 };
 166
 167 static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 168         .dst_ops =              &xfrm6_dst_ops_template,
 169         .dst_lookup =           xfrm6_dst_lookup,
 170         .get_saddr =            xfrm6_get_saddr,
 171         .fill_dst =             xfrm6_fill_dst,
 172         .blackhole_route =      ip6_blackhole_route,
 173 };
 174
 175 static int __init xfrm6_policy_init(void)
 176 {
 177         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
 178 }
 179
 180 static void xfrm6_policy_fini(void)
 181 {
 182         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 183 }
 184
 185 #ifdef CONFIG_SYSCTL
 186 static struct ctl_table xfrm6_policy_table[] = {
 187         {
 188                 .procname       = "xfrm6_gc_thresh",
 189                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 190                 .maxlen         = sizeof(int),
 191                 .mode           = 0644,
 192                 .proc_handler   = proc_dointvec,
 193         },
 194         { }
 195 };
 196
 197 static int __net_init xfrm6_net_sysctl_init(struct net *net)
 198 {
 199         struct ctl_table *table;
 200         struct ctl_table_header *hdr;
 201
 202         table = xfrm6_policy_table;
 203         if (!net_eq(net, &init_net)) {
 204                 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
 205                 if (!table)
 206                         goto err_alloc;
 207
 208                 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
 209         }
 210
 211         hdr = register_net_sysctl(net, "net/ipv6", table);
 212         if (!hdr)
 213                 goto err_reg;
 214
 215         net->ipv6.sysctl.xfrm6_hdr = hdr;
 216         return 0;
 217
 218 err_reg:
 219         if (!net_eq(net, &init_net))
 220                 kfree(table);
 221 err_alloc:
 222         return -ENOMEM;
 223 }
 224
 225 static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
 226 {
 227         struct ctl_table *table;
 228
 229         if (!net->ipv6.sysctl.xfrm6_hdr)
 230                 return;
 231
 232         table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
 233         unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
 234         if (!net_eq(net, &init_net))
 235                 kfree(table);
 236 }
 237 #else /* CONFIG_SYSCTL */
 238 static inline int xfrm6_net_sysctl_init(struct net *net)
 239 {
 240         return 0;
 241 }
 242
 243 static inline void xfrm6_net_sysctl_exit(struct net *net)
 244 {
 245 }
 246 #endif
 247
 248 static int __net_init xfrm6_net_init(struct net *net)
 249 {
 250         int ret;
 251
 252         memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
 253                sizeof(xfrm6_dst_ops_template));
 254         ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
 255         if (ret)
 256                 return ret;
 257
 258         ret = xfrm6_net_sysctl_init(net);
 259         if (ret)
 260                 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 261
 262         return ret;
 263 }
 264
 265 static void __net_exit xfrm6_net_exit(struct net *net)
 266 {
 267         xfrm6_net_sysctl_exit(net);
 268         dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 269 }
 270
 271 static struct pernet_operations xfrm6_net_ops = {
 272         .init   = xfrm6_net_init,
 273         .exit   = xfrm6_net_exit,
 274 };
 275
 276 int __init xfrm6_init(void)
 277 {
 278         int ret;
 279
 280         ret = xfrm6_policy_init();
 281         if (ret)
 282                 goto out;
 283         ret = xfrm6_state_init();
 284         if (ret)
 285                 goto out_policy;
 286
 287         ret = xfrm6_protocol_init();
 288         if (ret)
 289                 goto out_state;
 290
 291         register_pernet_subsys(&xfrm6_net_ops);
 292 out:
 293         return ret;
 294 out_state:
 295         xfrm6_state_fini();
 296 out_policy:
 297         xfrm6_policy_fini();
 298         goto out;
 299 }
 300
 301 void xfrm6_fini(void)
 302 {
 303         unregister_pernet_subsys(&xfrm6_net_ops);
 304         xfrm6_protocol_fini();
 305         xfrm6_policy_fini();
 306         xfrm6_state_fini();
 307 }