net/ipv4/xfrm4_policy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * xfrm4_policy.c
   4  *
   5  * Changes:
   6  *      Kazunori MIYAZAWA @USAGI
   7  *      YOSHIFUJI Hideaki @USAGI
   8  *              Split up af-specific portion
   9  *
  10  */
  11
  12 #include <linux/err.h>
  13 #include <linux/kernel.h>
  14 #include <linux/inetdevice.h>
  15 #include <net/dst.h>
  16 #include <net/xfrm.h>
  17 #include <net/ip.h>
  18 #include <net/l3mdev.h>
  19
  20 static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
  21                                             int tos, int oif,
  22                                             const xfrm_address_t *saddr,
  23                                             const xfrm_address_t *daddr,
  24                                             u32 mark)
  25 {
  26         struct rtable *rt;
  27
  28         memset(fl4, 0, sizeof(*fl4));
  29         fl4->daddr = daddr->a4;
  30         fl4->flowi4_tos = tos;
  31         fl4->flowi4_oif = l3mdev_master_ifindex_by_index(net, oif);
  32         fl4->flowi4_mark = mark;
  33         if (saddr)
  34                 fl4->saddr = saddr->a4;
  35
  36         fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF;
  37
  38         rt = __ip_route_output_key(net, fl4);
  39         if (!IS_ERR(rt))
  40                 return &rt->dst;
  41
  42         return ERR_CAST(rt);
  43 }
  44
  45 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
  46                                           const xfrm_address_t *saddr,
  47                                           const xfrm_address_t *daddr,
  48                                           u32 mark)
  49 {
  50         struct flowi4 fl4;
  51
  52         return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
  53 }
  54
  55 static int xfrm4_get_saddr(struct net *net, int oif,
  56                            xfrm_address_t *saddr, xfrm_address_t *daddr,
  57                            u32 mark)
  58 {
  59         struct dst_entry *dst;
  60         struct flowi4 fl4;
  61
  62         dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
  63         if (IS_ERR(dst))
  64                 return -EHOSTUNREACH;
  65
  66         saddr->a4 = fl4.saddr;
  67         dst_release(dst);
  68         return 0;
  69 }
  70
  71 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  72                           const struct flowi *fl)
  73 {
  74         struct rtable *rt = (struct rtable *)xdst->route;
  75         const struct flowi4 *fl4 = &fl->u.ip4;
  76
  77         xdst->u.rt.rt_iif = fl4->flowi4_iif;
  78
  79         xdst->u.dst.dev = dev;
  80         dev_hold(dev);
  81
  82         /* Sheit... I remember I did this right. Apparently,
  83          * it was magically lost, so this code needs audit */
  84         xdst->u.rt.rt_is_input = rt->rt_is_input;
  85         xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
  86                                               RTCF_LOCAL);
  87         xdst->u.rt.rt_type = rt->rt_type;
  88         xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
  89         xdst->u.rt.rt_gw_family = rt->rt_gw_family;
  90         if (rt->rt_gw_family == AF_INET)
  91                 xdst->u.rt.rt_gw4 = rt->rt_gw4;
  92         else if (rt->rt_gw_family == AF_INET6)
  93                 xdst->u.rt.rt_gw6 = rt->rt_gw6;
  94         xdst->u.rt.rt_pmtu = rt->rt_pmtu;
  95         xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
  96         INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
  97         rt_add_uncached_list(&xdst->u.rt);
  98
  99         return 0;
 100 }
 101
 102 static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
 103                               struct sk_buff *skb, u32 mtu,
 104                               bool confirm_neigh)
 105 {
 106         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 107         struct dst_entry *path = xdst->route;
 108
 109         path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
 110 }
 111
 112 static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
 113                            struct sk_buff *skb)
 114 {
 115         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 116         struct dst_entry *path = xdst->route;
 117
 118         path->ops->redirect(path, sk, skb);
 119 }
 120
 121 static void xfrm4_dst_destroy(struct dst_entry *dst)
 122 {
 123         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 124
 125         dst_destroy_metrics_generic(dst);
 126         if (xdst->u.rt.rt_uncached_list)
 127                 rt_del_uncached_list(&xdst->u.rt);
 128         xfrm_dst_destroy(xdst);
 129 }
 130
 131 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 132                              int unregister)
 133 {
 134         if (!unregister)
 135                 return;
 136
 137         xfrm_dst_ifdown(dst, dev);
 138 }
 139
 140 static struct dst_ops xfrm4_dst_ops_template = {
 141         .family =               AF_INET,
 142         .update_pmtu =          xfrm4_update_pmtu,
 143         .redirect =             xfrm4_redirect,
 144         .cow_metrics =          dst_cow_metrics_generic,
 145         .destroy =              xfrm4_dst_destroy,
 146         .ifdown =               xfrm4_dst_ifdown,
 147         .local_out =            __ip_local_out,
 148         .gc_thresh =            32768,
 149 };
 150
 151 static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
 152         .dst_ops =              &xfrm4_dst_ops_template,
 153         .dst_lookup =           xfrm4_dst_lookup,
 154         .get_saddr =            xfrm4_get_saddr,
 155         .fill_dst =             xfrm4_fill_dst,
 156         .blackhole_route =      ipv4_blackhole_route,
 157 };
 158
 159 #ifdef CONFIG_SYSCTL
 160 static struct ctl_table xfrm4_policy_table[] = {
 161         {
 162                 .procname       = "xfrm4_gc_thresh",
 163                 .data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
 164                 .maxlen         = sizeof(int),
 165                 .mode           = 0644,
 166                 .proc_handler   = proc_dointvec,
 167         },
 168         { }
 169 };
 170
 171 static __net_init int xfrm4_net_sysctl_init(struct net *net)
 172 {
 173         struct ctl_table *table;
 174         struct ctl_table_header *hdr;
 175
 176         table = xfrm4_policy_table;
 177         if (!net_eq(net, &init_net)) {
 178                 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
 179                 if (!table)
 180                         goto err_alloc;
 181
 182                 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
 183         }
 184
 185         hdr = register_net_sysctl(net, "net/ipv4", table);
 186         if (!hdr)
 187                 goto err_reg;
 188
 189         net->ipv4.xfrm4_hdr = hdr;
 190         return 0;
 191
 192 err_reg:
 193         if (!net_eq(net, &init_net))
 194                 kfree(table);
 195 err_alloc:
 196         return -ENOMEM;
 197 }
 198
 199 static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
 200 {
 201         struct ctl_table *table;
 202
 203         if (!net->ipv4.xfrm4_hdr)
 204                 return;
 205
 206         table = net->ipv4.xfrm4_hdr->ctl_table_arg;
 207         unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
 208         if (!net_eq(net, &init_net))
 209                 kfree(table);
 210 }
 211 #else /* CONFIG_SYSCTL */
 212 static inline int xfrm4_net_sysctl_init(struct net *net)
 213 {
 214         return 0;
 215 }
 216
 217 static inline void xfrm4_net_sysctl_exit(struct net *net)
 218 {
 219 }
 220 #endif
 221
 222 static int __net_init xfrm4_net_init(struct net *net)
 223 {
 224         int ret;
 225
 226         memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
 227                sizeof(xfrm4_dst_ops_template));
 228         ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
 229         if (ret)
 230                 return ret;
 231
 232         ret = xfrm4_net_sysctl_init(net);
 233         if (ret)
 234                 dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 235
 236         return ret;
 237 }
 238
 239 static void __net_exit xfrm4_net_exit(struct net *net)
 240 {
 241         xfrm4_net_sysctl_exit(net);
 242         dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 243 }
 244
 245 static struct pernet_operations __net_initdata xfrm4_net_ops = {
 246         .init   = xfrm4_net_init,
 247         .exit   = xfrm4_net_exit,
 248 };
 249
 250 static void __init xfrm4_policy_init(void)
 251 {
 252         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
 253 }
 254
 255 void __init xfrm4_init(void)
 256 {
 257         xfrm4_state_init();
 258         xfrm4_policy_init();
 259         xfrm4_protocol_init();
 260         register_pernet_subsys(&xfrm4_net_ops);
 261 }