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 {
 105         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 106         struct dst_entry *path = xdst->route;
 107
 108         path->ops->update_pmtu(path, sk, skb, mtu);
 109 }
 110
 111 static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
 112                            struct sk_buff *skb)
 113 {
 114         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 115         struct dst_entry *path = xdst->route;
 116
 117         path->ops->redirect(path, sk, skb);
 118 }
 119
 120 static void xfrm4_dst_destroy(struct dst_entry *dst)
 121 {
 122         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 123
 124         dst_destroy_metrics_generic(dst);
 125         if (xdst->u.rt.rt_uncached_list)
 126                 rt_del_uncached_list(&xdst->u.rt);
 127         xfrm_dst_destroy(xdst);
 128 }
 129
 130 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 131                              int unregister)
 132 {
 133         if (!unregister)
 134                 return;
 135
 136         xfrm_dst_ifdown(dst, dev);
 137 }
 138
 139 static struct dst_ops xfrm4_dst_ops_template = {
 140         .family =               AF_INET,
 141         .update_pmtu =          xfrm4_update_pmtu,
 142         .redirect =             xfrm4_redirect,
 143         .cow_metrics =          dst_cow_metrics_generic,
 144         .destroy =              xfrm4_dst_destroy,
 145         .ifdown =               xfrm4_dst_ifdown,
 146         .local_out =            __ip_local_out,
 147         .gc_thresh =            32768,
 148 };
 149
 150 static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
 151         .dst_ops =              &xfrm4_dst_ops_template,
 152         .dst_lookup =           xfrm4_dst_lookup,
 153         .get_saddr =            xfrm4_get_saddr,
 154         .fill_dst =             xfrm4_fill_dst,
 155         .blackhole_route =      ipv4_blackhole_route,
 156 };
 157
 158 #ifdef CONFIG_SYSCTL
 159 static struct ctl_table xfrm4_policy_table[] = {
 160         {
 161                 .procname       = "xfrm4_gc_thresh",
 162                 .data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
 163                 .maxlen         = sizeof(int),
 164                 .mode           = 0644,
 165                 .proc_handler   = proc_dointvec,
 166         },
 167         { }
 168 };
 169
 170 static __net_init int xfrm4_net_sysctl_init(struct net *net)
 171 {
 172         struct ctl_table *table;
 173         struct ctl_table_header *hdr;
 174
 175         table = xfrm4_policy_table;
 176         if (!net_eq(net, &init_net)) {
 177                 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
 178                 if (!table)
 179                         goto err_alloc;
 180
 181                 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
 182         }
 183
 184         hdr = register_net_sysctl(net, "net/ipv4", table);
 185         if (!hdr)
 186                 goto err_reg;
 187
 188         net->ipv4.xfrm4_hdr = hdr;
 189         return 0;
 190
 191 err_reg:
 192         if (!net_eq(net, &init_net))
 193                 kfree(table);
 194 err_alloc:
 195         return -ENOMEM;
 196 }
 197
 198 static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
 199 {
 200         struct ctl_table *table;
 201
 202         if (!net->ipv4.xfrm4_hdr)
 203                 return;
 204
 205         table = net->ipv4.xfrm4_hdr->ctl_table_arg;
 206         unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
 207         if (!net_eq(net, &init_net))
 208                 kfree(table);
 209 }
 210 #else /* CONFIG_SYSCTL */
 211 static inline int xfrm4_net_sysctl_init(struct net *net)
 212 {
 213         return 0;
 214 }
 215
 216 static inline void xfrm4_net_sysctl_exit(struct net *net)
 217 {
 218 }
 219 #endif
 220
 221 static int __net_init xfrm4_net_init(struct net *net)
 222 {
 223         int ret;
 224
 225         memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
 226                sizeof(xfrm4_dst_ops_template));
 227         ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
 228         if (ret)
 229                 return ret;
 230
 231         ret = xfrm4_net_sysctl_init(net);
 232         if (ret)
 233                 dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 234
 235         return ret;
 236 }
 237
 238 static void __net_exit xfrm4_net_exit(struct net *net)
 239 {
 240         xfrm4_net_sysctl_exit(net);
 241         dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 242 }
 243
 244 static struct pernet_operations __net_initdata xfrm4_net_ops = {
 245         .init   = xfrm4_net_init,
 246         .exit   = xfrm4_net_exit,
 247 };
 248
 249 static void __init xfrm4_policy_init(void)
 250 {
 251         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
 252 }
 253
 254 void __init xfrm4_init(void)
 255 {
 256         xfrm4_state_init();
 257         xfrm4_policy_init();
 258         xfrm4_protocol_init();
 259         register_pernet_subsys(&xfrm4_net_ops);
 260 }