net/core/lwtunnel.c

   1 /*
   2  * lwtunnel     Infrastructure for light weight tunnels like mpls
   3  *
   4  * Authors:     Roopa Prabhu, <roopa@cumulusnetworks.com>
   5  *
   6  *              This program is free software; you can redistribute it and/or
   7  *              modify it under the terms of the GNU General Public License
   8  *              as published by the Free Software Foundation; either version
   9  *              2 of the License, or (at your option) any later version.
  10  *
  11  */
  12
  13 #include <linux/capability.h>
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/slab.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/lwtunnel.h>
  22 #include <linux/in.h>
  23 #include <linux/init.h>
  24 #include <linux/err.h>
  25
  26 #include <net/lwtunnel.h>
  27 #include <net/rtnetlink.h>
  28 #include <net/ip6_fib.h>
  29
  30 struct lwtunnel_state *lwtunnel_state_alloc(int encap_len)
  31 {
  32         struct lwtunnel_state *lws;
  33
  34         lws = kzalloc(sizeof(*lws) + encap_len, GFP_ATOMIC);
  35
  36         return lws;
  37 }
  38 EXPORT_SYMBOL(lwtunnel_state_alloc);
  39
  40 static const struct lwtunnel_encap_ops __rcu *
  41                 lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly;
  42
  43 int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops,
  44                            unsigned int num)
  45 {
  46         if (num > LWTUNNEL_ENCAP_MAX)
  47                 return -ERANGE;
  48
  49         return !cmpxchg((const struct lwtunnel_encap_ops **)
  50                         &lwtun_encaps[num],
  51                         NULL, ops) ? 0 : -1;
  52 }
  53 EXPORT_SYMBOL(lwtunnel_encap_add_ops);
  54
  55 int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *ops,
  56                            unsigned int encap_type)
  57 {
  58         int ret;
  59
  60         if (encap_type == LWTUNNEL_ENCAP_NONE ||
  61             encap_type > LWTUNNEL_ENCAP_MAX)
  62                 return -ERANGE;
  63
  64         ret = (cmpxchg((const struct lwtunnel_encap_ops **)
  65                        &lwtun_encaps[encap_type],
  66                        ops, NULL) == ops) ? 0 : -1;
  67
  68         synchronize_net();
  69
  70         return ret;
  71 }
  72 EXPORT_SYMBOL(lwtunnel_encap_del_ops);
  73
  74 int lwtunnel_build_state(struct net_device *dev, u16 encap_type,
  75                          struct nlattr *encap, unsigned int family,
  76                          const void *cfg, struct lwtunnel_state **lws)
  77 {
  78         const struct lwtunnel_encap_ops *ops;
  79         int ret = -EINVAL;
  80
  81         if (encap_type == LWTUNNEL_ENCAP_NONE ||
  82             encap_type > LWTUNNEL_ENCAP_MAX)
  83                 return ret;
  84
  85         ret = -EOPNOTSUPP;
  86         rcu_read_lock();
  87         ops = rcu_dereference(lwtun_encaps[encap_type]);
  88         if (likely(ops && ops->build_state))
  89                 ret = ops->build_state(dev, encap, family, cfg, lws);
  90         rcu_read_unlock();
  91
  92         return ret;
  93 }
  94 EXPORT_SYMBOL(lwtunnel_build_state);
  95
  96 int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate)
  97 {
  98         const struct lwtunnel_encap_ops *ops;
  99         struct nlattr *nest;
 100         int ret = -EINVAL;
 101
 102         if (!lwtstate)
 103                 return 0;
 104
 105         if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
 106             lwtstate->type > LWTUNNEL_ENCAP_MAX)
 107                 return 0;
 108
 109         ret = -EOPNOTSUPP;
 110         nest = nla_nest_start(skb, RTA_ENCAP);
 111         rcu_read_lock();
 112         ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
 113         if (likely(ops && ops->fill_encap))
 114                 ret = ops->fill_encap(skb, lwtstate);
 115         rcu_read_unlock();
 116
 117         if (ret)
 118                 goto nla_put_failure;
 119         nla_nest_end(skb, nest);
 120         ret = nla_put_u16(skb, RTA_ENCAP_TYPE, lwtstate->type);
 121         if (ret)
 122                 goto nla_put_failure;
 123
 124         return 0;
 125
 126 nla_put_failure:
 127         nla_nest_cancel(skb, nest);
 128
 129         return (ret == -EOPNOTSUPP ? 0 : ret);
 130 }
 131 EXPORT_SYMBOL(lwtunnel_fill_encap);
 132
 133 int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
 134 {
 135         const struct lwtunnel_encap_ops *ops;
 136         int ret = 0;
 137
 138         if (!lwtstate)
 139                 return 0;
 140
 141         if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
 142             lwtstate->type > LWTUNNEL_ENCAP_MAX)
 143                 return 0;
 144
 145         rcu_read_lock();
 146         ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
 147         if (likely(ops && ops->get_encap_size))
 148                 ret = nla_total_size(ops->get_encap_size(lwtstate));
 149         rcu_read_unlock();
 150
 151         return ret;
 152 }
 153 EXPORT_SYMBOL(lwtunnel_get_encap_size);
 154
 155 int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 156 {
 157         const struct lwtunnel_encap_ops *ops;
 158         int ret = 0;
 159
 160         if (!a && !b)
 161                 return 0;
 162
 163         if (!a || !b)
 164                 return 1;
 165
 166         if (a->type != b->type)
 167                 return 1;
 168
 169         if (a->type == LWTUNNEL_ENCAP_NONE ||
 170             a->type > LWTUNNEL_ENCAP_MAX)
 171                 return 0;
 172
 173         rcu_read_lock();
 174         ops = rcu_dereference(lwtun_encaps[a->type]);
 175         if (likely(ops && ops->cmp_encap))
 176                 ret = ops->cmp_encap(a, b);
 177         rcu_read_unlock();
 178
 179         return ret;
 180 }
 181 EXPORT_SYMBOL(lwtunnel_cmp_encap);
 182
 183 int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 184 {
 185         struct dst_entry *dst = skb_dst(skb);
 186         const struct lwtunnel_encap_ops *ops;
 187         struct lwtunnel_state *lwtstate;
 188         int ret = -EINVAL;
 189
 190         if (!dst)
 191                 goto drop;
 192         lwtstate = dst->lwtstate;
 193
 194         if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
 195             lwtstate->type > LWTUNNEL_ENCAP_MAX)
 196                 return 0;
 197
 198         ret = -EOPNOTSUPP;
 199         rcu_read_lock();
 200         ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
 201         if (likely(ops && ops->output))
 202                 ret = ops->output(net, sk, skb);
 203         rcu_read_unlock();
 204
 205         if (ret == -EOPNOTSUPP)
 206                 goto drop;
 207
 208         return ret;
 209
 210 drop:
 211         kfree_skb(skb);
 212
 213         return ret;
 214 }
 215 EXPORT_SYMBOL(lwtunnel_output);
 216
 217 int lwtunnel_input(struct sk_buff *skb)
 218 {
 219         struct dst_entry *dst = skb_dst(skb);
 220         const struct lwtunnel_encap_ops *ops;
 221         struct lwtunnel_state *lwtstate;
 222         int ret = -EINVAL;
 223
 224         if (!dst)
 225                 goto drop;
 226         lwtstate = dst->lwtstate;
 227
 228         if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
 229             lwtstate->type > LWTUNNEL_ENCAP_MAX)
 230                 return 0;
 231
 232         ret = -EOPNOTSUPP;
 233         rcu_read_lock();
 234         ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
 235         if (likely(ops && ops->input))
 236                 ret = ops->input(skb);
 237         rcu_read_unlock();
 238
 239         if (ret == -EOPNOTSUPP)
 240                 goto drop;
 241
 242         return ret;
 243
 244 drop:
 245         kfree_skb(skb);
 246
 247         return ret;
 248 }
 249 EXPORT_SYMBOL(lwtunnel_input);