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 <[email protected]>
   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         INIT_LIST_HEAD(&xdst->u.rt6.rt6i_uncached);
  93         rt6_uncached_list_add(&xdst->u.rt6);
  94
  95         return 0;
  96 }
  97
  98 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
  99                               struct sk_buff *skb, u32 mtu,
 100                               bool confirm_neigh)
 101 {
 102         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 103         struct dst_entry *path = xdst->route;
 104
 105         path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
 106 }
 107
 108 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
 109                            struct sk_buff *skb)
 110 {
 111         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 112         struct dst_entry *path = xdst->route;
 113
 114         path->ops->redirect(path, sk, skb);
 115 }
 116
 117 static void xfrm6_dst_destroy(struct dst_entry *dst)
 118 {
 119         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 120
 121         if (likely(xdst->u.rt6.rt6i_idev))
 122                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 123         dst_destroy_metrics_generic(dst);
 124         if (xdst->u.rt6.rt6i_uncached_list)
 125                 rt6_uncached_list_del(&xdst->u.rt6);
 126         xfrm_dst_destroy(xdst);
 127 }
 128
 129 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 130                              int unregister)
 131 {
 132         struct xfrm_dst *xdst;
 133
 134         if (!unregister)
 135                 return;
 136
 137         xdst = (struct xfrm_dst *)dst;
 138         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 139                 struct inet6_dev *loopback_idev =
 140                         in6_dev_get(dev_net(dev)->loopback_dev);
 141
 142                 do {
 143                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 144                         xdst->u.rt6.rt6i_idev = loopback_idev;
 145                         in6_dev_hold(loopback_idev);
 146                         xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst);
 147                 } while (xdst->u.dst.xfrm);
 148
 149                 __in6_dev_put(loopback_idev);
 150         }
 151
 152         xfrm_dst_ifdown(dst, dev);
 153 }
 154
 155 static struct dst_ops xfrm6_dst_ops_template = {
 156         .family =               AF_INET6,
 157         .update_pmtu =          xfrm6_update_pmtu,
 158         .redirect =             xfrm6_redirect,
 159         .cow_metrics =          dst_cow_metrics_generic,
 160         .destroy =              xfrm6_dst_destroy,
 161         .ifdown =               xfrm6_dst_ifdown,
 162         .local_out =            __ip6_local_out,
 163         .gc_thresh =            32768,
 164 };
 165
 166 static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 167         .dst_ops =              &xfrm6_dst_ops_template,
 168         .dst_lookup =           xfrm6_dst_lookup,
 169         .get_saddr =            xfrm6_get_saddr,
 170         .fill_dst =             xfrm6_fill_dst,
 171         .blackhole_route =      ip6_blackhole_route,
 172 };
 173
 174 static int __init xfrm6_policy_init(void)
 175 {
 176         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
 177 }
 178
 179 static void xfrm6_policy_fini(void)
 180 {
 181         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 182 }
 183
 184 #ifdef CONFIG_SYSCTL
 185 static struct ctl_table xfrm6_policy_table[] = {
 186         {
 187                 .procname       = "xfrm6_gc_thresh",
 188                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 189                 .maxlen         = sizeof(int),
 190                 .mode           = 0644,
 191                 .proc_handler   = proc_dointvec,
 192         },
 193         { }
 194 };
 195
 196 static int __net_init xfrm6_net_sysctl_init(struct net *net)
 197 {
 198         struct ctl_table *table;
 199         struct ctl_table_header *hdr;
 200
 201         table = xfrm6_policy_table;
 202         if (!net_eq(net, &init_net)) {
 203                 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
 204                 if (!table)
 205                         goto err_alloc;
 206
 207                 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
 208         }
 209
 210         hdr = register_net_sysctl(net, "net/ipv6", table);
 211         if (!hdr)
 212                 goto err_reg;
 213
 214         net->ipv6.sysctl.xfrm6_hdr = hdr;
 215         return 0;
 216
 217 err_reg:
 218         if (!net_eq(net, &init_net))
 219                 kfree(table);
 220 err_alloc:
 221         return -ENOMEM;
 222 }
 223
 224 static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
 225 {
 226         struct ctl_table *table;
 227
 228         if (!net->ipv6.sysctl.xfrm6_hdr)
 229                 return;
 230
 231         table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
 232         unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
 233         if (!net_eq(net, &init_net))
 234                 kfree(table);
 235 }
 236 #else /* CONFIG_SYSCTL */
 237 static inline int xfrm6_net_sysctl_init(struct net *net)
 238 {
 239         return 0;
 240 }
 241
 242 static inline void xfrm6_net_sysctl_exit(struct net *net)
 243 {
 244 }
 245 #endif
 246
 247 static int __net_init xfrm6_net_init(struct net *net)
 248 {
 249         int ret;
 250
 251         memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
 252                sizeof(xfrm6_dst_ops_template));
 253         ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
 254         if (ret)
 255                 return ret;
 256
 257         ret = xfrm6_net_sysctl_init(net);
 258         if (ret)
 259                 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 260
 261         return ret;
 262 }
 263
 264 static void __net_exit xfrm6_net_exit(struct net *net)
 265 {
 266         xfrm6_net_sysctl_exit(net);
 267         dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 268 }
 269
 270 static struct pernet_operations xfrm6_net_ops = {
 271         .init   = xfrm6_net_init,
 272         .exit   = xfrm6_net_exit,
 273 };
 274
 275 int __init xfrm6_init(void)
 276 {
 277         int ret;
 278
 279         ret = xfrm6_policy_init();
 280         if (ret)
 281                 goto out;
 282         ret = xfrm6_state_init();
 283         if (ret)
 284                 goto out_policy;
 285
 286         ret = xfrm6_protocol_init();
 287         if (ret)
 288                 goto out_state;
 289
 290         ret = register_pernet_subsys(&xfrm6_net_ops);
 291         if (ret)
 292                 goto out_protocol;
 293 out:
 294         return ret;
 295 out_protocol:
 296         xfrm6_protocol_fini();
 297 out_state:
 298         xfrm6_state_fini();
 299 out_policy:
 300         xfrm6_policy_fini();
 301         goto out;
 302 }
 303
 304 void xfrm6_fini(void)
 305 {
 306         unregister_pernet_subsys(&xfrm6_net_ops);
 307         xfrm6_protocol_fini();
 308         xfrm6_policy_fini();
 309         xfrm6_state_fini();
 310 }