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 struct dst_ops xfrm4_dst_ops_template = {
 128         .family =               AF_INET,
 129         .update_pmtu =          xfrm4_update_pmtu,
 130         .redirect =             xfrm4_redirect,
 131         .cow_metrics =          dst_cow_metrics_generic,
 132         .destroy =              xfrm4_dst_destroy,
 133         .ifdown =               xfrm_dst_ifdown,
 134         .local_out =            __ip_local_out,
 135         .gc_thresh =            32768,
 136 };
 137
 138 static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
 139         .dst_ops =              &xfrm4_dst_ops_template,
 140         .dst_lookup =           xfrm4_dst_lookup,
 141         .get_saddr =            xfrm4_get_saddr,
 142         .fill_dst =             xfrm4_fill_dst,
 143         .blackhole_route =      ipv4_blackhole_route,
 144 };
 145
 146 #ifdef CONFIG_SYSCTL
 147 static struct ctl_table xfrm4_policy_table[] = {
 148         {
 149                 .procname       = "xfrm4_gc_thresh",
 150                 .data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
 151                 .maxlen         = sizeof(int),
 152                 .mode           = 0644,
 153                 .proc_handler   = proc_dointvec,
 154         },
 155         { }
 156 };
 157
 158 static __net_init int xfrm4_net_sysctl_init(struct net *net)
 159 {
 160         struct ctl_table *table;
 161         struct ctl_table_header *hdr;
 162
 163         table = xfrm4_policy_table;
 164         if (!net_eq(net, &init_net)) {
 165                 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
 166                 if (!table)
 167                         goto err_alloc;
 168
 169                 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
 170         }
 171
 172         hdr = register_net_sysctl_sz(net, "net/ipv4", table,
 173                                      ARRAY_SIZE(xfrm4_policy_table));
 174         if (!hdr)
 175                 goto err_reg;
 176
 177         net->ipv4.xfrm4_hdr = hdr;
 178         return 0;
 179
 180 err_reg:
 181         if (!net_eq(net, &init_net))
 182                 kfree(table);
 183 err_alloc:
 184         return -ENOMEM;
 185 }
 186
 187 static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
 188 {
 189         struct ctl_table *table;
 190
 191         if (!net->ipv4.xfrm4_hdr)
 192                 return;
 193
 194         table = net->ipv4.xfrm4_hdr->ctl_table_arg;
 195         unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
 196         if (!net_eq(net, &init_net))
 197                 kfree(table);
 198 }
 199 #else /* CONFIG_SYSCTL */
 200 static inline int xfrm4_net_sysctl_init(struct net *net)
 201 {
 202         return 0;
 203 }
 204
 205 static inline void xfrm4_net_sysctl_exit(struct net *net)
 206 {
 207 }
 208 #endif
 209
 210 static int __net_init xfrm4_net_init(struct net *net)
 211 {
 212         int ret;
 213
 214         memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
 215                sizeof(xfrm4_dst_ops_template));
 216         ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
 217         if (ret)
 218                 return ret;
 219
 220         ret = xfrm4_net_sysctl_init(net);
 221         if (ret)
 222                 dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 223
 224         return ret;
 225 }
 226
 227 static void __net_exit xfrm4_net_exit(struct net *net)
 228 {
 229         xfrm4_net_sysctl_exit(net);
 230         dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
 231 }
 232
 233 static struct pernet_operations __net_initdata xfrm4_net_ops = {
 234         .init   = xfrm4_net_init,
 235         .exit   = xfrm4_net_exit,
 236 };
 237
 238 static void __init xfrm4_policy_init(void)
 239 {
 240         xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
 241 }
 242
 243 void __init xfrm4_init(void)
 244 {
 245         xfrm4_state_init();
 246         xfrm4_policy_init();
 247         xfrm4_protocol_init();
 248         register_pernet_subsys(&xfrm4_net_ops);
 249 }