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/dst_cache.h>
  10 #include <net/ip.h>
  11 #include <net/ip6_fib.h>
  12 #include <net/ip6_route.h>
  13 #include <net/lwtunnel.h>
  14 #include <net/protocol.h>
  15 #include <uapi/linux/ila.h>
  16 #include "ila.h"
  17
  18 struct ila_lwt {
  19         struct ila_params p;
  20         struct dst_cache dst_cache;
  21         u32 connected : 1;
  22 };
  23
  24 static inline struct ila_lwt *ila_lwt_lwtunnel(
  25         struct lwtunnel_state *lwt)
  26 {
  27         return (struct ila_lwt *)lwt->data;
  28 }
  29
  30 static inline struct ila_params *ila_params_lwtunnel(
  31         struct lwtunnel_state *lwt)
  32 {
  33         return &ila_lwt_lwtunnel(lwt)->p;
  34 }
  35
  36 static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
  37 {
  38         struct dst_entry *orig_dst = skb_dst(skb);
  39         struct rt6_info *rt = (struct rt6_info *)orig_dst;
  40         struct ila_lwt *ilwt = ila_lwt_lwtunnel(orig_dst->lwtstate);
  41         struct dst_entry *dst;
  42         int err = -EINVAL;
  43
  44         if (skb->protocol != htons(ETH_P_IPV6))
  45                 goto drop;
  46
  47         ila_update_ipv6_locator(skb, ila_params_lwtunnel(orig_dst->lwtstate),
  48                                 true);
  49
  50         if (rt->rt6i_flags & (RTF_GATEWAY | RTF_CACHE)) {
  51                 /* Already have a next hop address in route, no need for
  52                  * dest cache route.
  53                  */
  54                 return orig_dst->lwtstate->orig_output(net, sk, skb);
  55         }
  56
  57         dst = dst_cache_get(&ilwt->dst_cache);
  58         if (unlikely(!dst)) {
  59                 struct ipv6hdr *ip6h = ipv6_hdr(skb);
  60                 struct flowi6 fl6;
  61
  62                 /* Lookup a route for the new destination. Take into
  63                  * account that the base route may already have a gateway.
  64                  */
  65
  66                 memset(&fl6, 0, sizeof(fl6));
  67                 fl6.flowi6_oif = orig_dst->dev->ifindex;
  68                 fl6.flowi6_iif = LOOPBACK_IFINDEX;
  69                 fl6.daddr = *rt6_nexthop((struct rt6_info *)orig_dst,
  70                                          &ip6h->daddr);
  71
  72                 dst = ip6_route_output(net, NULL, &fl6);
  73                 if (dst->error) {
  74                         err = -EHOSTUNREACH;
  75                         dst_release(dst);
  76                         goto drop;
  77                 }
  78
  79                 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
  80                 if (IS_ERR(dst)) {
  81                         err = PTR_ERR(dst);
  82                         goto drop;
  83                 }
  84
  85                 if (ilwt->connected)
  86                         dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
  87         }
  88
  89         skb_dst_set(skb, dst);
  90         return dst_output(net, sk, skb);
  91
  92 drop:
  93         kfree_skb(skb);
  94         return -EINVAL;
  95 }
  96
  97 static int ila_input(struct sk_buff *skb)
  98 {
  99         struct dst_entry *dst = skb_dst(skb);
 100
 101         if (skb->protocol != htons(ETH_P_IPV6))
 102                 goto drop;
 103
 104         ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate), false);
 105
 106         return dst->lwtstate->orig_input(skb);
 107
 108 drop:
 109         kfree_skb(skb);
 110         return -EINVAL;
 111 }
 112
 113 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 114         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 115         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
 116 };
 117
 118 static int ila_build_state(struct nlattr *nla,
 119                            unsigned int family, const void *cfg,
 120                            struct lwtunnel_state **ts)
 121 {
 122         struct ila_lwt *ilwt;
 123         struct ila_params *p;
 124         struct nlattr *tb[ILA_ATTR_MAX + 1];
 125         struct lwtunnel_state *newts;
 126         const struct fib6_config *cfg6 = cfg;
 127         struct ila_addr *iaddr;
 128         int ret;
 129
 130         if (family != AF_INET6)
 131                 return -EINVAL;
 132
 133         if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
 134                 /* Need to have full locator and at least type field
 135                  * included in destination
 136                  */
 137                 return -EINVAL;
 138         }
 139
 140         iaddr = (struct ila_addr *)&cfg6->fc_dst;
 141
 142         if (!ila_addr_is_ila(iaddr) || ila_csum_neutral_set(iaddr->ident)) {
 143                 /* Don't allow translation for a non-ILA address or checksum
 144                  * neutral flag to be set.
 145                  */
 146                 return -EINVAL;
 147         }
 148
 149         ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla,
 150                                ila_nl_policy);
 151         if (ret < 0)
 152                 return ret;
 153
 154         if (!tb[ILA_ATTR_LOCATOR])
 155                 return -EINVAL;
 156
 157         newts = lwtunnel_state_alloc(sizeof(*ilwt));
 158         if (!newts)
 159                 return -ENOMEM;
 160
 161         ilwt = ila_lwt_lwtunnel(newts);
 162         ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
 163         if (ret) {
 164                 kfree(newts);
 165                 return ret;
 166         }
 167
 168         p = ila_params_lwtunnel(newts);
 169
 170         p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
 171
 172         /* Precompute checksum difference for translation since we
 173          * know both the old locator and the new one.
 174          */
 175         p->locator_match = iaddr->loc;
 176         p->csum_diff = compute_csum_diff8(
 177                 (__be32 *)&p->locator_match, (__be32 *)&p->locator);
 178
 179         if (tb[ILA_ATTR_CSUM_MODE])
 180                 p->csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
 181
 182         ila_init_saved_csum(p);
 183
 184         newts->type = LWTUNNEL_ENCAP_ILA;
 185         newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
 186                         LWTUNNEL_STATE_INPUT_REDIRECT;
 187
 188         if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
 189                 ilwt->connected = 1;
 190
 191         *ts = newts;
 192
 193         return 0;
 194 }
 195
 196 static void ila_destroy_state(struct lwtunnel_state *lwt)
 197 {
 198         dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
 199 }
 200
 201 static int ila_fill_encap_info(struct sk_buff *skb,
 202                                struct lwtunnel_state *lwtstate)
 203 {
 204         struct ila_params *p = ila_params_lwtunnel(lwtstate);
 205
 206         if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
 207                               ILA_ATTR_PAD))
 208                 goto nla_put_failure;
 209         if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
 210                 goto nla_put_failure;
 211
 212         return 0;
 213
 214 nla_put_failure:
 215         return -EMSGSIZE;
 216 }
 217
 218 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
 219 {
 220         return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
 221                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
 222                0;
 223 }
 224
 225 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 226 {
 227         struct ila_params *a_p = ila_params_lwtunnel(a);
 228         struct ila_params *b_p = ila_params_lwtunnel(b);
 229
 230         return (a_p->locator.v64 != b_p->locator.v64);
 231 }
 232
 233 static const struct lwtunnel_encap_ops ila_encap_ops = {
 234         .build_state = ila_build_state,
 235         .destroy_state = ila_destroy_state,
 236         .output = ila_output,
 237         .input = ila_input,
 238         .fill_encap = ila_fill_encap_info,
 239         .get_encap_size = ila_encap_nlsize,
 240         .cmp_encap = ila_encap_cmp,
 241         .owner = THIS_MODULE,
 242 };
 243
 244 int ila_lwt_init(void)
 245 {
 246         return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 247 }
 248
 249 void ila_lwt_fini(void)
 250 {
 251         lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 252 }