net/ipv6/ila/ila_lwt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/errno.h>
   3 #include <linux/ip.h>
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/skbuff.h>
   7 #include <linux/socket.h>
   8 #include <linux/types.h>
   9 #include <net/checksum.h>
  10 #include <net/dst_cache.h>
  11 #include <net/ip.h>
  12 #include <net/ip6_fib.h>
  13 #include <net/ip6_route.h>
  14 #include <net/lwtunnel.h>
  15 #include <net/protocol.h>
  16 #include <uapi/linux/ila.h>
  17 #include "ila.h"
  18
  19 struct ila_lwt {
  20         struct ila_params p;
  21         struct dst_cache dst_cache;
  22         u32 connected : 1;
  23 };
  24
  25 static inline struct ila_lwt *ila_lwt_lwtunnel(
  26         struct lwtunnel_state *lwt)
  27 {
  28         return (struct ila_lwt *)lwt->data;
  29 }
  30
  31 static inline struct ila_params *ila_params_lwtunnel(
  32         struct lwtunnel_state *lwt)
  33 {
  34         return &ila_lwt_lwtunnel(lwt)->p;
  35 }
  36
  37 static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
  38 {
  39         struct dst_entry *orig_dst = skb_dst(skb);
  40         struct rt6_info *rt = (struct rt6_info *)orig_dst;
  41         struct ila_lwt *ilwt = ila_lwt_lwtunnel(orig_dst->lwtstate);
  42         struct dst_entry *dst;
  43         int err = -EINVAL;
  44
  45         if (skb->protocol != htons(ETH_P_IPV6))
  46                 goto drop;
  47
  48         ila_update_ipv6_locator(skb, ila_params_lwtunnel(orig_dst->lwtstate),
  49                                 true);
  50
  51         if (rt->rt6i_flags & (RTF_GATEWAY | RTF_CACHE)) {
  52                 /* Already have a next hop address in route, no need for
  53                  * dest cache route.
  54                  */
  55                 return orig_dst->lwtstate->orig_output(net, sk, skb);
  56         }
  57
  58         dst = dst_cache_get(&ilwt->dst_cache);
  59         if (unlikely(!dst)) {
  60                 struct ipv6hdr *ip6h = ipv6_hdr(skb);
  61                 struct flowi6 fl6;
  62
  63                 /* Lookup a route for the new destination. Take into
  64                  * account that the base route may already have a gateway.
  65                  */
  66
  67                 memset(&fl6, 0, sizeof(fl6));
  68                 fl6.flowi6_oif = orig_dst->dev->ifindex;
  69                 fl6.flowi6_iif = LOOPBACK_IFINDEX;
  70                 fl6.daddr = *rt6_nexthop((struct rt6_info *)orig_dst,
  71                                          &ip6h->daddr);
  72
  73                 dst = ip6_route_output(net, NULL, &fl6);
  74                 if (dst->error) {
  75                         err = -EHOSTUNREACH;
  76                         dst_release(dst);
  77                         goto drop;
  78                 }
  79
  80                 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
  81                 if (IS_ERR(dst)) {
  82                         err = PTR_ERR(dst);
  83                         goto drop;
  84                 }
  85
  86                 if (ilwt->connected)
  87                         dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
  88         }
  89
  90         skb_dst_set(skb, dst);
  91         return dst_output(net, sk, skb);
  92
  93 drop:
  94         kfree_skb(skb);
  95         return err;
  96 }
  97
  98 static int ila_input(struct sk_buff *skb)
  99 {
 100         struct dst_entry *dst = skb_dst(skb);
 101
 102         if (skb->protocol != htons(ETH_P_IPV6))
 103                 goto drop;
 104
 105         ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate), false);
 106
 107         return dst->lwtstate->orig_input(skb);
 108
 109 drop:
 110         kfree_skb(skb);
 111         return -EINVAL;
 112 }
 113
 114 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 115         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 116         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
 117 };
 118
 119 static int ila_build_state(struct nlattr *nla,
 120                            unsigned int family, const void *cfg,
 121                            struct lwtunnel_state **ts,
 122                            struct netlink_ext_ack *extack)
 123 {
 124         struct ila_lwt *ilwt;
 125         struct ila_params *p;
 126         struct nlattr *tb[ILA_ATTR_MAX + 1];
 127         struct lwtunnel_state *newts;
 128         const struct fib6_config *cfg6 = cfg;
 129         struct ila_addr *iaddr;
 130         int ret;
 131
 132         if (family != AF_INET6)
 133                 return -EINVAL;
 134
 135         if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
 136                 /* Need to have full locator and at least type field
 137                  * included in destination
 138                  */
 139                 return -EINVAL;
 140         }
 141
 142         iaddr = (struct ila_addr *)&cfg6->fc_dst;
 143
 144         if (!ila_addr_is_ila(iaddr) || ila_csum_neutral_set(iaddr->ident)) {
 145                 /* Don't allow translation for a non-ILA address or checksum
 146                  * neutral flag to be set.
 147                  */
 148                 return -EINVAL;
 149         }
 150
 151         ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla, ila_nl_policy, extack);
 152         if (ret < 0)
 153                 return ret;
 154
 155         if (!tb[ILA_ATTR_LOCATOR])
 156                 return -EINVAL;
 157
 158         newts = lwtunnel_state_alloc(sizeof(*ilwt));
 159         if (!newts)
 160                 return -ENOMEM;
 161
 162         ilwt = ila_lwt_lwtunnel(newts);
 163         ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
 164         if (ret) {
 165                 kfree(newts);
 166                 return ret;
 167         }
 168
 169         p = ila_params_lwtunnel(newts);
 170
 171         p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
 172
 173         /* Precompute checksum difference for translation since we
 174          * know both the old locator and the new one.
 175          */
 176         p->locator_match = iaddr->loc;
 177         p->csum_diff = compute_csum_diff8(
 178                 (__be32 *)&p->locator_match, (__be32 *)&p->locator);
 179
 180         if (tb[ILA_ATTR_CSUM_MODE])
 181                 p->csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
 182
 183         ila_init_saved_csum(p);
 184
 185         newts->type = LWTUNNEL_ENCAP_ILA;
 186         newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
 187                         LWTUNNEL_STATE_INPUT_REDIRECT;
 188
 189         if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
 190                 ilwt->connected = 1;
 191
 192         *ts = newts;
 193
 194         return 0;
 195 }
 196
 197 static void ila_destroy_state(struct lwtunnel_state *lwt)
 198 {
 199         dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
 200 }
 201
 202 static int ila_fill_encap_info(struct sk_buff *skb,
 203                                struct lwtunnel_state *lwtstate)
 204 {
 205         struct ila_params *p = ila_params_lwtunnel(lwtstate);
 206
 207         if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
 208                               ILA_ATTR_PAD))
 209                 goto nla_put_failure;
 210         if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
 211                 goto nla_put_failure;
 212
 213         return 0;
 214
 215 nla_put_failure:
 216         return -EMSGSIZE;
 217 }
 218
 219 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
 220 {
 221         return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
 222                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
 223                0;
 224 }
 225
 226 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 227 {
 228         struct ila_params *a_p = ila_params_lwtunnel(a);
 229         struct ila_params *b_p = ila_params_lwtunnel(b);
 230
 231         return (a_p->locator.v64 != b_p->locator.v64);
 232 }
 233
 234 static const struct lwtunnel_encap_ops ila_encap_ops = {
 235         .build_state = ila_build_state,
 236         .destroy_state = ila_destroy_state,
 237         .output = ila_output,
 238         .input = ila_input,
 239         .fill_encap = ila_fill_encap_info,
 240         .get_encap_size = ila_encap_nlsize,
 241         .cmp_encap = ila_encap_cmp,
 242         .owner = THIS_MODULE,
 243 };
 244
 245 int ila_lwt_init(void)
 246 {
 247         return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 248 }
 249
 250 void ila_lwt_fini(void)
 251 {
 252         lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 253 }