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         ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate), true);
  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         ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate), false);
  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         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
  57 };
  58
  59 static int ila_build_state(struct net_device *dev, struct nlattr *nla,
  60                            unsigned int family, const void *cfg,
  61                            struct lwtunnel_state **ts)
  62 {
  63         struct ila_params *p;
  64         struct nlattr *tb[ILA_ATTR_MAX + 1];
  65         size_t encap_len = sizeof(*p);
  66         struct lwtunnel_state *newts;
  67         const struct fib6_config *cfg6 = cfg;
  68         struct ila_addr *iaddr;
  69         int ret;
  70
  71         if (family != AF_INET6)
  72                 return -EINVAL;
  73
  74         if (cfg6->fc_dst_len < sizeof(struct ila_locator) + 1) {
  75                 /* Need to have full locator and at least type field
  76                  * included in destination
  77                  */
  78                 return -EINVAL;
  79         }
  80
  81         iaddr = (struct ila_addr *)&cfg6->fc_dst;
  82
  83         if (!ila_addr_is_ila(iaddr) || ila_csum_neutral_set(iaddr->ident)) {
  84                 /* Don't allow translation for a non-ILA address or checksum
  85                  * neutral flag to be set.
  86                  */
  87                 return -EINVAL;
  88         }
  89
  90         ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla,
  91                                ila_nl_policy);
  92         if (ret < 0)
  93                 return ret;
  94
  95         if (!tb[ILA_ATTR_LOCATOR])
  96                 return -EINVAL;
  97
  98         newts = lwtunnel_state_alloc(encap_len);
  99         if (!newts)
 100                 return -ENOMEM;
 101
 102         newts->len = encap_len;
 103         p = ila_params_lwtunnel(newts);
 104
 105         p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
 106
 107         /* Precompute checksum difference for translation since we
 108          * know both the old locator and the new one.
 109          */
 110         p->locator_match = iaddr->loc;
 111         p->csum_diff = compute_csum_diff8(
 112                 (__be32 *)&p->locator_match, (__be32 *)&p->locator);
 113
 114         if (tb[ILA_ATTR_CSUM_MODE])
 115                 p->csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
 116
 117         ila_init_saved_csum(p);
 118
 119         newts->type = LWTUNNEL_ENCAP_ILA;
 120         newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
 121                         LWTUNNEL_STATE_INPUT_REDIRECT;
 122
 123         *ts = newts;
 124
 125         return 0;
 126 }
 127
 128 static int ila_fill_encap_info(struct sk_buff *skb,
 129                                struct lwtunnel_state *lwtstate)
 130 {
 131         struct ila_params *p = ila_params_lwtunnel(lwtstate);
 132
 133         if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
 134                               ILA_ATTR_PAD))
 135                 goto nla_put_failure;
 136         if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
 137                 goto nla_put_failure;
 138
 139         return 0;
 140
 141 nla_put_failure:
 142         return -EMSGSIZE;
 143 }
 144
 145 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
 146 {
 147         return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
 148                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
 149                0;
 150 }
 151
 152 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 153 {
 154         struct ila_params *a_p = ila_params_lwtunnel(a);
 155         struct ila_params *b_p = ila_params_lwtunnel(b);
 156
 157         return (a_p->locator.v64 != b_p->locator.v64);
 158 }
 159
 160 static const struct lwtunnel_encap_ops ila_encap_ops = {
 161         .build_state = ila_build_state,
 162         .output = ila_output,
 163         .input = ila_input,
 164         .fill_encap = ila_fill_encap_info,
 165         .get_encap_size = ila_encap_nlsize,
 166         .cmp_encap = ila_encap_cmp,
 167 };
 168
 169 int ila_lwt_init(void)
 170 {
 171         return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 172 }
 173
 174 void ila_lwt_fini(void)
 175 {
 176         lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 177 }