net/ipv6/ila/ila_lwt.c

   1 #include <linux/errno.h>
   2 #include <linux/ip.h>
   3 #include <linux/kernel.h>
   4 #include <linux/module.h>
   5 #include <linux/skbuff.h>
   6 #include <linux/socket.h>
   7 #include <linux/types.h>
   8 #include <net/checksum.h>
   9 #include <net/ip.h>
  10 #include <net/ip6_fib.h>
  11 #include <net/lwtunnel.h>
  12 #include <net/protocol.h>
  13 #include <uapi/linux/ila.h>
  14 #include "ila.h"
  15
  16 static inline struct ila_params *ila_params_lwtunnel(
  17         struct lwtunnel_state *lwstate)
  18 {
  19         return (struct ila_params *)lwstate->data;
  20 }
  21
  22 static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
  23 {
  24         struct dst_entry *dst = skb_dst(skb);
  25
  26         if (skb->protocol != htons(ETH_P_IPV6))
  27                 goto drop;
  28
  29         update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
  30
  31         return dst->lwtstate->orig_output(net, sk, skb);
  32
  33 drop:
  34         kfree_skb(skb);
  35         return -EINVAL;
  36 }
  37
  38 static int ila_input(struct sk_buff *skb)
  39 {
  40         struct dst_entry *dst = skb_dst(skb);
  41
  42         if (skb->protocol != htons(ETH_P_IPV6))
  43                 goto drop;
  44
  45         update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
  46
  47         return dst->lwtstate->orig_input(skb);
  48
  49 drop:
  50         kfree_skb(skb);
  51         return -EINVAL;
  52 }
  53
  54 static struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
  55         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
  56 };
  57
  58 static int ila_build_state(struct net_device *dev, struct nlattr *nla,
  59                            unsigned int family, const void *cfg,
  60                            struct lwtunnel_state **ts)
  61 {
  62         struct ila_params *p;
  63         struct nlattr *tb[ILA_ATTR_MAX + 1];
  64         size_t encap_len = sizeof(*p);
  65         struct lwtunnel_state *newts;
  66         const struct fib6_config *cfg6 = cfg;
  67         int ret;
  68
  69         if (family != AF_INET6)
  70                 return -EINVAL;
  71
  72         ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla,
  73                                ila_nl_policy);
  74         if (ret < 0)
  75                 return ret;
  76
  77         if (!tb[ILA_ATTR_LOCATOR])
  78                 return -EINVAL;
  79
  80         newts = lwtunnel_state_alloc(encap_len);
  81         if (!newts)
  82                 return -ENOMEM;
  83
  84         newts->len = encap_len;
  85         p = ila_params_lwtunnel(newts);
  86
  87         p->locator = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
  88
  89         if (cfg6->fc_dst_len > sizeof(__be64)) {
  90                 /* Precompute checksum difference for translation since we
  91                  * know both the old locator and the new one.
  92                  */
  93                 p->locator_match = *(__be64 *)&cfg6->fc_dst;
  94                 p->csum_diff = compute_csum_diff8(
  95                         (__be32 *)&p->locator_match, (__be32 *)&p->locator);
  96         }
  97
  98         newts->type = LWTUNNEL_ENCAP_ILA;
  99         newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
 100                         LWTUNNEL_STATE_INPUT_REDIRECT;
 101
 102         *ts = newts;
 103
 104         return 0;
 105 }
 106
 107 static int ila_fill_encap_info(struct sk_buff *skb,
 108                                struct lwtunnel_state *lwtstate)
 109 {
 110         struct ila_params *p = ila_params_lwtunnel(lwtstate);
 111
 112         if (nla_put_u64(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator))
 113                 goto nla_put_failure;
 114
 115         return 0;
 116
 117 nla_put_failure:
 118         return -EMSGSIZE;
 119 }
 120
 121 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
 122 {
 123         /* No encapsulation overhead */
 124         return 0;
 125 }
 126
 127 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 128 {
 129         struct ila_params *a_p = ila_params_lwtunnel(a);
 130         struct ila_params *b_p = ila_params_lwtunnel(b);
 131
 132         return (a_p->locator != b_p->locator);
 133 }
 134
 135 static const struct lwtunnel_encap_ops ila_encap_ops = {
 136         .build_state = ila_build_state,
 137         .output = ila_output,
 138         .input = ila_input,
 139         .fill_encap = ila_fill_encap_info,
 140         .get_encap_size = ila_encap_nlsize,
 141         .cmp_encap = ila_encap_cmp,
 142 };
 143
 144 int ila_lwt_init(void)
 145 {
 146         return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 147 }
 148
 149 void ila_lwt_fini(void)
 150 {
 151         lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 152 }