net/ipv6/xfrm6_policy.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * xfrm6_policy.c: based on xfrm4_policy.c
0004  *
0005  * Authors:
0006  *  Mitsuru KANDA @USAGI
0007  *  Kazunori MIYAZAWA @USAGI
0008  *  Kunihiro Ishiguro <kunihiro@ipinfusion.com>
0009  *      IPv6 support
0010  *  YOSHIFUJI Hideaki
0011  *      Split up af-specific portion
0012  *
0013  */
0014
0015 #include <linux/err.h>
0016 #include <linux/kernel.h>
0017 #include <linux/netdevice.h>
0018 #include <net/addrconf.h>
0019 #include <net/dst.h>
0020 #include <net/xfrm.h>
0021 #include <net/ip.h>
0022 #include <net/ipv6.h>
0023 #include <net/ip6_route.h>
0024 #include <net/l3mdev.h>
0025
0026 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif,
0027                       const xfrm_address_t *saddr,
0028                       const xfrm_address_t *daddr,
0029                       u32 mark)
0030 {
0031     struct flowi6 fl6;
0032     struct dst_entry *dst;
0033     int err;
0034
0035     memset(&fl6, 0, sizeof(fl6));
0036     fl6.flowi6_l3mdev = l3mdev_master_ifindex_by_index(net, oif);
0037     fl6.flowi6_mark = mark;
0038     memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
0039     if (saddr)
0040         memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
0041
0042     dst = ip6_route_output(net, NULL, &fl6);
0043
0044     err = dst->error;
0045     if (dst->error) {
0046         dst_release(dst);
0047         dst = ERR_PTR(err);
0048     }
0049
0050     return dst;
0051 }
0052
0053 static int xfrm6_get_saddr(struct net *net, int oif,
0054                xfrm_address_t *saddr, xfrm_address_t *daddr,
0055                u32 mark)
0056 {
0057     struct dst_entry *dst;
0058     struct net_device *dev;
0059
0060     dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark);
0061     if (IS_ERR(dst))
0062         return -EHOSTUNREACH;
0063
0064     dev = ip6_dst_idev(dst)->dev;
0065     ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
0066     dst_release(dst);
0067     return 0;
0068 }
0069
0070 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
0071               const struct flowi *fl)
0072 {
0073     struct rt6_info *rt = (struct rt6_info *)xdst->route;
0074
0075     xdst->u.dst.dev = dev;
0076     netdev_hold(dev, &xdst->u.dst.dev_tracker, GFP_ATOMIC);
0077
0078     xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
0079     if (!xdst->u.rt6.rt6i_idev) {
0080         netdev_put(dev, &xdst->u.dst.dev_tracker);
0081         return -ENODEV;
0082     }
0083
0084     /* Sheit... I remember I did this right. Apparently,
0085      * it was magically lost, so this code needs audit */
0086     xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
0087                            RTF_LOCAL);
0088     xdst->route_cookie = rt6_get_cookie(rt);
0089     xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
0090     xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
0091     xdst->u.rt6.rt6i_src = rt->rt6i_src;
0092     INIT_LIST_HEAD(&xdst->u.rt6.rt6i_uncached);
0093     rt6_uncached_list_add(&xdst->u.rt6);
0094
0095     return 0;
0096 }
0097
0098 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
0099                   struct sk_buff *skb, u32 mtu,
0100                   bool confirm_neigh)
0101 {
0102     struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
0103     struct dst_entry *path = xdst->route;
0104
0105     path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
0106 }
0107
0108 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
0109                struct sk_buff *skb)
0110 {
0111     struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
0112     struct dst_entry *path = xdst->route;
0113
0114     path->ops->redirect(path, sk, skb);
0115 }
0116
0117 static void xfrm6_dst_destroy(struct dst_entry *dst)
0118 {
0119     struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
0120
0121     if (likely(xdst->u.rt6.rt6i_idev))
0122         in6_dev_put(xdst->u.rt6.rt6i_idev);
0123     dst_destroy_metrics_generic(dst);
0124     if (xdst->u.rt6.rt6i_uncached_list)
0125         rt6_uncached_list_del(&xdst->u.rt6);
0126     xfrm_dst_destroy(xdst);
0127 }
0128
0129 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
0130                  int unregister)
0131 {
0132     struct xfrm_dst *xdst;
0133
0134     if (!unregister)
0135         return;
0136
0137     xdst = (struct xfrm_dst *)dst;
0138     if (xdst->u.rt6.rt6i_idev->dev == dev) {
0139         struct inet6_dev *loopback_idev =
0140             in6_dev_get(dev_net(dev)->loopback_dev);
0141
0142         do {
0143             in6_dev_put(xdst->u.rt6.rt6i_idev);
0144             xdst->u.rt6.rt6i_idev = loopback_idev;
0145             in6_dev_hold(loopback_idev);
0146             xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst);
0147         } while (xdst->u.dst.xfrm);
0148
0149         __in6_dev_put(loopback_idev);
0150     }
0151
0152     xfrm_dst_ifdown(dst, dev);
0153 }
0154
0155 static struct dst_ops xfrm6_dst_ops_template = {
0156     .family =       AF_INET6,
0157     .update_pmtu =      xfrm6_update_pmtu,
0158     .redirect =     xfrm6_redirect,
0159     .cow_metrics =      dst_cow_metrics_generic,
0160     .destroy =      xfrm6_dst_destroy,
0161     .ifdown =       xfrm6_dst_ifdown,
0162     .local_out =        __ip6_local_out,
0163     .gc_thresh =        32768,
0164 };
0165
0166 static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
0167     .dst_ops =      &xfrm6_dst_ops_template,
0168     .dst_lookup =       xfrm6_dst_lookup,
0169     .get_saddr =        xfrm6_get_saddr,
0170     .fill_dst =     xfrm6_fill_dst,
0171     .blackhole_route =  ip6_blackhole_route,
0172 };
0173
0174 static int __init xfrm6_policy_init(void)
0175 {
0176     return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
0177 }
0178
0179 static void xfrm6_policy_fini(void)
0180 {
0181     xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
0182 }
0183
0184 #ifdef CONFIG_SYSCTL
0185 static struct ctl_table xfrm6_policy_table[] = {
0186     {
0187         .procname       = "xfrm6_gc_thresh",
0188         .data       = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
0189         .maxlen     = sizeof(int),
0190         .mode       = 0644,
0191         .proc_handler   = proc_dointvec,
0192     },
0193     { }
0194 };
0195
0196 static int __net_init xfrm6_net_sysctl_init(struct net *net)
0197 {
0198     struct ctl_table *table;
0199     struct ctl_table_header *hdr;
0200
0201     table = xfrm6_policy_table;
0202     if (!net_eq(net, &init_net)) {
0203         table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
0204         if (!table)
0205             goto err_alloc;
0206
0207         table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
0208     }
0209
0210     hdr = register_net_sysctl(net, "net/ipv6", table);
0211     if (!hdr)
0212         goto err_reg;
0213
0214     net->ipv6.sysctl.xfrm6_hdr = hdr;
0215     return 0;
0216
0217 err_reg:
0218     if (!net_eq(net, &init_net))
0219         kfree(table);
0220 err_alloc:
0221     return -ENOMEM;
0222 }
0223
0224 static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
0225 {
0226     struct ctl_table *table;
0227
0228     if (!net->ipv6.sysctl.xfrm6_hdr)
0229         return;
0230
0231     table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
0232     unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
0233     if (!net_eq(net, &init_net))
0234         kfree(table);
0235 }
0236 #else /* CONFIG_SYSCTL */
0237 static inline int xfrm6_net_sysctl_init(struct net *net)
0238 {
0239     return 0;
0240 }
0241
0242 static inline void xfrm6_net_sysctl_exit(struct net *net)
0243 {
0244 }
0245 #endif
0246
0247 static int __net_init xfrm6_net_init(struct net *net)
0248 {
0249     int ret;
0250
0251     memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
0252            sizeof(xfrm6_dst_ops_template));
0253     ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
0254     if (ret)
0255         return ret;
0256
0257     ret = xfrm6_net_sysctl_init(net);
0258     if (ret)
0259         dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
0260
0261     return ret;
0262 }
0263
0264 static void __net_exit xfrm6_net_exit(struct net *net)
0265 {
0266     xfrm6_net_sysctl_exit(net);
0267     dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
0268 }
0269
0270 static struct pernet_operations xfrm6_net_ops = {
0271     .init   = xfrm6_net_init,
0272     .exit   = xfrm6_net_exit,
0273 };
0274
0275 int __init xfrm6_init(void)
0276 {
0277     int ret;
0278
0279     ret = xfrm6_policy_init();
0280     if (ret)
0281         goto out;
0282     ret = xfrm6_state_init();
0283     if (ret)
0284         goto out_policy;
0285
0286     ret = xfrm6_protocol_init();
0287     if (ret)
0288         goto out_state;
0289
0290     register_pernet_subsys(&xfrm6_net_ops);
0291 out:
0292     return ret;
0293 out_state:
0294     xfrm6_state_fini();
0295 out_policy:
0296     xfrm6_policy_fini();
0297     goto out;
0298 }
0299
0300 void xfrm6_fini(void)
0301 {
0302     unregister_pernet_subsys(&xfrm6_net_ops);
0303     xfrm6_protocol_fini();
0304     xfrm6_policy_fini();
0305     xfrm6_state_fini();
0306 }