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_l3mdev = l3mdev_master_ifindex_by_index(net, oif);
  37         fl6.flowi6_mark = mark;
  38         memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
  39         if (saddr)
  40                 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
  41
  42         dst = ip6_route_output(net, NULL, &fl6);
  43
  44         err = dst->error;
  45         if (dst->error) {
  46                 dst_release(dst);
  47                 dst = ERR_PTR(err);
  48         }
  49
  50         return dst;
  51 }
  52
  53 static int xfrm6_get_saddr(struct net *net, int oif,
  54                            xfrm_address_t *saddr, xfrm_address_t *daddr,
  55                            u32 mark)
  56 {
  57         struct dst_entry *dst;
  58         struct net_device *dev;
  59
  60         dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark);
  61         if (IS_ERR(dst))
  62                 return -EHOSTUNREACH;
  63
  64         dev = ip6_dst_idev(dst)->dev;
  65         ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
  66         dst_release(dst);
  67         return 0;
  68 }
  69
  70 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  71                           const struct flowi *fl)
  72 {
  73         struct rt6_info *rt = (struct rt6_info *)xdst->route;
  74
  75         xdst->u.dst.dev = dev;
  76         netdev_hold(dev, &xdst->u.dst.dev_tracker, GFP_ATOMIC);
  77
  78         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
  79         if (!xdst->u.rt6.rt6i_idev) {
  80                 netdev_put(dev, &xdst->u.dst.dev_tracker);
  81                 return -ENODEV;
  82         }
  83
  84         /* Sheit... I remember I did this right. Apparently,
  85          * it was magically lost, so this code needs audit */
  86         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
  87                                                    RTF_LOCAL);
  88         xdst->route_cookie = rt6_get_cookie(rt);
  89         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
  90         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
  91         xdst->u.rt6.rt6i_src = rt->rt6i_src;
  92         rt6_uncached_list_add(&xdst->u.rt6);
  93
  94         return 0;
  95 }
  96
  97 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
  98                               struct sk_buff *skb, u32 mtu,
  99                               bool confirm_neigh)
 100 {
 101         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 102         struct dst_entry *path = xdst->route;
 103
 104         path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
 105 }
 106
 107 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
 108                            struct sk_buff *skb)
 109 {
 110         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 111         struct dst_entry *path = xdst->route;
 112
 113         path->ops->redirect(path, sk, skb);
 114 }
 115
 116 static void xfrm6_dst_destroy(struct dst_entry *dst)
 117 {
 118         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 119
 120         if (likely(xdst->u.rt6.rt6i_idev))
 121                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 122         dst_destroy_metrics_generic(dst);
 123         rt6_uncached_list_del(&xdst->u.rt6);
 124         xfrm_dst_destroy(xdst);
 125 }
 126
 127 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 128                              int unregister)
 129 {
 130         struct xfrm_dst *xdst;
 131
 132         if (!unregister)
 133                 return;
 134
 135         xdst = (struct xfrm_dst *)dst;
 136         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 137                 struct inet6_dev *loopback_idev =
 138                         in6_dev_get(dev_net(dev)->loopback_dev);
 139
 140                 do {
 141                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 142                         xdst->u.rt6.rt6i_idev = loopback_idev;
 143                         in6_dev_hold(loopback_idev);
 144                         xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst);
 145                 } while (xdst->u.dst.xfrm);
 146
 147                 __in6_dev_put(loopback_idev);
 148         }
 149
 150         xfrm_dst_ifdown(dst, dev);
 151 }
 152
 153 static struct dst_ops xfrm6_dst_ops_template = {
 154         .family =               AF_INET6,
 155         .update_pmtu =          xfrm6_update_pmtu,
 156         .redirect =             xfrm6_redirect,
 157         .cow_metrics =          dst_cow_metrics_generic,
 158         .destroy =              xfrm6_dst_destroy,
 159         .ifdown =               xfrm6_dst_ifdown,
 160         .local_out =            __ip6_local_out,
 161         .gc_thresh =            32768,
 162 };
 163
 164 static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 165         .dst_ops =              &xfrm6_dst_ops_template,
 166         .dst_lookup =           xfrm6_dst_lookup,
 167         .get_saddr =            xfrm6_get_saddr,
 168         .fill_dst =             xfrm6_fill_dst,
 169         .blackhole_route =      ip6_blackhole_route,
 170 };
 171
 172 static int __init xfrm6_policy_init(void)
 173 {
 174         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
 175 }
 176
 177 static void xfrm6_policy_fini(void)
 178 {
 179         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 180 }
 181
 182 #ifdef CONFIG_SYSCTL
 183 static struct ctl_table xfrm6_policy_table[] = {
 184         {
 185                 .procname       = "xfrm6_gc_thresh",
 186                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 187                 .maxlen         = sizeof(int),
 188                 .mode           = 0644,
 189                 .proc_handler   = proc_dointvec,
 190         },
 191         { }
 192 };
 193
 194 static int __net_init xfrm6_net_sysctl_init(struct net *net)
 195 {
 196         struct ctl_table *table;
 197         struct ctl_table_header *hdr;
 198
 199         table = xfrm6_policy_table;
 200         if (!net_eq(net, &init_net)) {
 201                 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
 202                 if (!table)
 203                         goto err_alloc;
 204
 205                 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
 206         }
 207
 208         hdr = register_net_sysctl(net, "net/ipv6", table);
 209         if (!hdr)
 210                 goto err_reg;
 211
 212         net->ipv6.sysctl.xfrm6_hdr = hdr;
 213         return 0;
 214
 215 err_reg:
 216         if (!net_eq(net, &init_net))
 217                 kfree(table);
 218 err_alloc:
 219         return -ENOMEM;
 220 }
 221
 222 static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
 223 {
 224         struct ctl_table *table;
 225
 226         if (!net->ipv6.sysctl.xfrm6_hdr)
 227                 return;
 228
 229         table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
 230         unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
 231         if (!net_eq(net, &init_net))
 232                 kfree(table);
 233 }
 234 #else /* CONFIG_SYSCTL */
 235 static inline int xfrm6_net_sysctl_init(struct net *net)
 236 {
 237         return 0;
 238 }
 239
 240 static inline void xfrm6_net_sysctl_exit(struct net *net)
 241 {
 242 }
 243 #endif
 244
 245 static int __net_init xfrm6_net_init(struct net *net)
 246 {
 247         int ret;
 248
 249         memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
 250                sizeof(xfrm6_dst_ops_template));
 251         ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
 252         if (ret)
 253                 return ret;
 254
 255         ret = xfrm6_net_sysctl_init(net);
 256         if (ret)
 257                 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 258
 259         return ret;
 260 }
 261
 262 static void __net_exit xfrm6_net_exit(struct net *net)
 263 {
 264         xfrm6_net_sysctl_exit(net);
 265         dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 266 }
 267
 268 static struct pernet_operations xfrm6_net_ops = {
 269         .init   = xfrm6_net_init,
 270         .exit   = xfrm6_net_exit,
 271 };
 272
 273 int __init xfrm6_init(void)
 274 {
 275         int ret;
 276
 277         ret = xfrm6_policy_init();
 278         if (ret)
 279                 goto out;
 280         ret = xfrm6_state_init();
 281         if (ret)
 282                 goto out_policy;
 283
 284         ret = xfrm6_protocol_init();
 285         if (ret)
 286                 goto out_state;
 287
 288         ret = register_pernet_subsys(&xfrm6_net_ops);
 289         if (ret)
 290                 goto out_protocol;
 291 out:
 292         return ret;
 293 out_protocol:
 294         xfrm6_protocol_fini();
 295 out_state:
 296         xfrm6_state_fini();
 297 out_policy:
 298         xfrm6_policy_fini();
 299         goto out;
 300 }
 301
 302 void xfrm6_fini(void)
 303 {
 304         unregister_pernet_subsys(&xfrm6_net_ops);
 305         xfrm6_protocol_fini();
 306         xfrm6_policy_fini();
 307         xfrm6_state_fini();
 308 }