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_l3mdev = l3mdev_master_ifindex_by_index(net, oif);
  32         fl4->flowi4_mark = mark;
  33         if (saddr)
  34                 fl4->saddr = saddr->a4;
  35
  36         rt = __ip_route_output_key(net, fl4);
  37         if (!IS_ERR(rt))
  38                 return &rt->dst;
  39
  40         return ERR_CAST(rt);
  41 }
  42
  43 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
  44                                           const xfrm_address_t *saddr,
  45                                           const xfrm_address_t *daddr,
  46                                           u32 mark)
  47 {
  48         struct flowi4 fl4;
  49
  50         return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
  51 }
  52
  53 static int xfrm4_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 flowi4 fl4;
  59
  60         dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
  61         if (IS_ERR(dst))
  62                 return -EHOSTUNREACH;
  63
  64         saddr->a4 = fl4.saddr;
  65         dst_release(dst);
  66         return 0;
  67 }
  68
  69 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  70                           const struct flowi *fl)
  71 {
  72         struct rtable *rt = (struct rtable *)xdst->route;
  73         const struct flowi4 *fl4 = &fl->u.ip4;
  74
  75         xdst->u.rt.rt_iif = fl4->flowi4_iif;
  76
  77         xdst->u.dst.dev = dev;
  78         netdev_hold(dev, &xdst->u.dst.dev_tracker, GFP_ATOMIC);
  79
  80         /* Sheit... I remember I did this right. Apparently,
  81          * it was magically lost, so this code needs audit */
  82         xdst->u.rt.rt_is_input = rt->rt_is_input;
  83         xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
  84                                               RTCF_LOCAL);
  85         xdst->u.rt.rt_type = rt->rt_type;
  86         xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
  87         xdst->u.rt.rt_gw_family = rt->rt_gw_family;
  88         if (rt->rt_gw_family == AF_INET)
  89                 xdst->u.rt.rt_gw4 = rt->rt_gw4;
  90         else if (rt->rt_gw_family == AF_INET6)
  91                 xdst->u.rt.rt_gw6 = rt->rt_gw6;
  92         xdst->u.rt.rt_pmtu = rt->rt_pmtu;
  93         xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
  94         rt_add_uncached_list(&xdst->u.rt);
  95
  96         return 0;
  97 }
  98
  99 static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
 100                               struct sk_buff *skb, u32 mtu,
 101                               bool confirm_neigh)
 102 {
 103         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 104         struct dst_entry *path = xdst->route;
 105
 106         path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
 107 }
 108
 109 static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
 110                            struct sk_buff *skb)
 111 {
 112         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 113         struct dst_entry *path = xdst->route;
 114
 115         path->ops->redirect(path, sk, skb);
 116 }
 117
 118 static void xfrm4_dst_destroy(struct dst_entry *dst)
 119 {
 120         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 121
 122         dst_destroy_metrics_generic(dst);
 123         rt_del_uncached_list(&xdst->u.rt);
 124         xfrm_dst_destroy(xdst);
 125 }
 126
 127 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 128                              int unregister)
 129 {
 130         if (!unregister)
 131                 return;
 132
 133         xfrm_dst_ifdown(dst, dev);
 134 }
 135
 136 static struct dst_ops xfrm4_dst_ops_template = {
 137         .family =               AF_INET,
 138         .update_pmtu =          xfrm4_update_pmtu,
 139         .redirect =             xfrm4_redirect,
 140         .cow_metrics =          dst_cow_metrics_generic,
 141         .destroy =              xfrm4_dst_destroy,
 142         .ifdown =               xfrm4_dst_ifdown,
 143         .local_out =            __ip_local_out,
 144         .gc_thresh =            32768,
 145 };
 146
 147 static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
 148         .dst_ops =              &xfrm4_dst_ops_template,
 149         .dst_lookup =           xfrm4_dst_lookup,
 150         .get_saddr =            xfrm4_get_saddr,
 151         .fill_dst =             xfrm4_fill_dst,
 152         .blackhole_route =      ipv4_blackhole_route,
 153 };
 154
 155 #ifdef CONFIG_SYSCTL
 156 static struct ctl_table xfrm4_policy_table[] = {
 157         {
 158                 .procname       = "xfrm4_gc_thresh",
 159                 .data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
 160                 .maxlen         = sizeof(int),
 161                 .mode           = 0644,
 162                 .proc_handler   = proc_dointvec,
 163         },
 164         { }
 165 };
 166
 167 static __net_init int xfrm4_net_sysctl_init(struct net *net)
 168 {
 169         struct ctl_table *table;
 170         struct ctl_table_header *hdr;
 171
 172         table = xfrm4_policy_table;
 173         if (!net_eq(net, &init_net)) {
 174                 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
 175                 if (!table)
 176                         goto err_alloc;
 177
 178                 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
 179         }
 180
 181         hdr = register_net_sysctl(net, "net/ipv4", table);
 182         if (!hdr)
 183                 goto err_reg;
 184
 185         net->ipv4.xfrm4_hdr = hdr;
 186         return 0;
 187
 188 err_reg:
 189         if (!net_eq(net, &init_net))
 190                 kfree(table);
 191 err_alloc:
 192         return -ENOMEM;
 193 }
 194
 195 static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
 196 {
 197         struct ctl_table *table;
 198
 199         if (!net->ipv4.xfrm4_hdr)
 200                 return;
 201
 202         table = net->ipv4.xfrm4_hdr->ctl_table_arg;
 203         unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
 204         if (!net_eq(net, &init_net))
 205                 kfree(table);
 206 }
 207 #else /* CONFIG_SYSCTL */
 208 static inline int xfrm4_net_sysctl_init(struct net *net)
 209 {
 210         return 0;
 211 }
 212
 213 static inline void xfrm4_net_sysctl_exit(struct net *net)
 214 {
 215 }
 216 #endif
 217
 218 static int __net_init xfrm4_net_init(struct net *net)
 219 {
 220         int ret;
 221
 222         memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
 223                sizeof(xfrm4_dst_ops_template));
 224         ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
 225         if (ret)
 226                 return ret;
 227
 228         ret = xfrm4_net_sysctl_init(net);
 229         if (ret)
 230                 dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 231
 232         return ret;
 233 }
 234
 235 static void __net_exit xfrm4_net_exit(struct net *net)
 236 {
 237         xfrm4_net_sysctl_exit(net);
 238         dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 239 }
 240
 241 static struct pernet_operations __net_initdata xfrm4_net_ops = {
 242         .init   = xfrm4_net_init,
 243         .exit   = xfrm4_net_exit,
 244 };
 245
 246 static void __init xfrm4_policy_init(void)
 247 {
 248         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
 249 }
 250
 251 void __init xfrm4_init(void)
 252 {
 253         xfrm4_state_init();
 254         xfrm4_policy_init();
 255         xfrm4_protocol_init();
 256         register_pernet_subsys(&xfrm4_net_ops);
 257 }