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         u32 lwt_output : 1;
  24 };
  25
  26 static inline struct ila_lwt *ila_lwt_lwtunnel(
  27         struct lwtunnel_state *lwt)
  28 {
  29         return (struct ila_lwt *)lwt->data;
  30 }
  31
  32 static inline struct ila_params *ila_params_lwtunnel(
  33         struct lwtunnel_state *lwt)
  34 {
  35         return &ila_lwt_lwtunnel(lwt)->p;
  36 }
  37
  38 static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
  39 {
  40         struct dst_entry *orig_dst = skb_dst(skb);
  41         struct rt6_info *rt = dst_rt6_info(orig_dst);
  42         struct ila_lwt *ilwt = ila_lwt_lwtunnel(orig_dst->lwtstate);
  43         struct dst_entry *dst;
  44         int err = -EINVAL;
  45
  46         if (skb->protocol != htons(ETH_P_IPV6))
  47                 goto drop;
  48
  49         if (ilwt->lwt_output)
  50                 ila_update_ipv6_locator(skb,
  51                                         ila_params_lwtunnel(orig_dst->lwtstate),
  52                                         true);
  53
  54         if (rt->rt6i_flags & (RTF_GATEWAY | RTF_CACHE)) {
  55                 /* Already have a next hop address in route, no need for
  56                  * dest cache route.
  57                  */
  58                 return orig_dst->lwtstate->orig_output(net, sk, skb);
  59         }
  60
  61         local_bh_disable();
  62         dst = dst_cache_get(&ilwt->dst_cache);
  63         local_bh_enable();
  64         if (unlikely(!dst)) {
  65                 struct ipv6hdr *ip6h = ipv6_hdr(skb);
  66                 struct flowi6 fl6;
  67
  68                 /* Lookup a route for the new destination. Take into
  69                  * account that the base route may already have a gateway.
  70                  */
  71
  72                 memset(&fl6, 0, sizeof(fl6));
  73                 fl6.flowi6_oif = orig_dst->dev->ifindex;
  74                 fl6.flowi6_iif = LOOPBACK_IFINDEX;
  75                 fl6.daddr = *rt6_nexthop(dst_rt6_info(orig_dst),
  76                                          &ip6h->daddr);
  77
  78                 dst = ip6_route_output(net, NULL, &fl6);
  79                 if (dst->error) {
  80                         err = -EHOSTUNREACH;
  81                         dst_release(dst);
  82                         goto drop;
  83                 }
  84
  85                 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
  86                 if (IS_ERR(dst)) {
  87                         err = PTR_ERR(dst);
  88                         goto drop;
  89                 }
  90
  91                 if (ilwt->connected) {
  92                         local_bh_disable();
  93                         dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
  94                         local_bh_enable();
  95                 }
  96         }
  97
  98         skb_dst_set(skb, dst);
  99         return dst_output(net, sk, skb);
 100
 101 drop:
 102         kfree_skb(skb);
 103         return err;
 104 }
 105
 106 static int ila_input(struct sk_buff *skb)
 107 {
 108         struct dst_entry *dst = skb_dst(skb);
 109         struct ila_lwt *ilwt = ila_lwt_lwtunnel(dst->lwtstate);
 110
 111         if (skb->protocol != htons(ETH_P_IPV6))
 112                 goto drop;
 113
 114         if (!ilwt->lwt_output)
 115                 ila_update_ipv6_locator(skb,
 116                                         ila_params_lwtunnel(dst->lwtstate),
 117                                         false);
 118
 119         return dst->lwtstate->orig_input(skb);
 120
 121 drop:
 122         kfree_skb(skb);
 123         return -EINVAL;
 124 }
 125
 126 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 127         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 128         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
 129         [ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
 130         [ILA_ATTR_HOOK_TYPE] = { .type = NLA_U8, },
 131 };
 132
 133 static int ila_build_state(struct net *net, struct nlattr *nla,
 134                            unsigned int family, const void *cfg,
 135                            struct lwtunnel_state **ts,
 136                            struct netlink_ext_ack *extack)
 137 {
 138         struct ila_lwt *ilwt;
 139         struct ila_params *p;
 140         struct nlattr *tb[ILA_ATTR_MAX + 1];
 141         struct lwtunnel_state *newts;
 142         const struct fib6_config *cfg6 = cfg;
 143         struct ila_addr *iaddr;
 144         u8 ident_type = ILA_ATYPE_USE_FORMAT;
 145         u8 hook_type = ILA_HOOK_ROUTE_OUTPUT;
 146         u8 csum_mode = ILA_CSUM_NO_ACTION;
 147         bool lwt_output = true;
 148         u8 eff_ident_type;
 149         int ret;
 150
 151         if (family != AF_INET6)
 152                 return -EINVAL;
 153
 154         ret = nla_parse_nested_deprecated(tb, ILA_ATTR_MAX, nla,
 155                                           ila_nl_policy, extack);
 156         if (ret < 0)
 157                 return ret;
 158
 159         if (!tb[ILA_ATTR_LOCATOR])
 160                 return -EINVAL;
 161
 162         iaddr = (struct ila_addr *)&cfg6->fc_dst;
 163
 164         if (tb[ILA_ATTR_IDENT_TYPE])
 165                 ident_type = nla_get_u8(tb[ILA_ATTR_IDENT_TYPE]);
 166
 167         if (ident_type == ILA_ATYPE_USE_FORMAT) {
 168                 /* Infer identifier type from type field in formatted
 169                  * identifier.
 170                  */
 171
 172                 if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
 173                         /* Need to have full locator and at least type field
 174                          * included in destination
 175                          */
 176                         return -EINVAL;
 177                 }
 178
 179                 eff_ident_type = iaddr->ident.type;
 180         } else {
 181                 eff_ident_type = ident_type;
 182         }
 183
 184         switch (eff_ident_type) {
 185         case ILA_ATYPE_IID:
 186                 /* Don't allow ILA for IID type */
 187                 return -EINVAL;
 188         case ILA_ATYPE_LUID:
 189                 break;
 190         case ILA_ATYPE_VIRT_V4:
 191         case ILA_ATYPE_VIRT_UNI_V6:
 192         case ILA_ATYPE_VIRT_MULTI_V6:
 193         case ILA_ATYPE_NONLOCAL_ADDR:
 194                 /* These ILA formats are not supported yet. */
 195         default:
 196                 return -EINVAL;
 197         }
 198
 199         if (tb[ILA_ATTR_HOOK_TYPE])
 200                 hook_type = nla_get_u8(tb[ILA_ATTR_HOOK_TYPE]);
 201
 202         switch (hook_type) {
 203         case ILA_HOOK_ROUTE_OUTPUT:
 204                 lwt_output = true;
 205                 break;
 206         case ILA_HOOK_ROUTE_INPUT:
 207                 lwt_output = false;
 208                 break;
 209         default:
 210                 return -EINVAL;
 211         }
 212
 213         if (tb[ILA_ATTR_CSUM_MODE])
 214                 csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
 215
 216         if (csum_mode == ILA_CSUM_NEUTRAL_MAP &&
 217             ila_csum_neutral_set(iaddr->ident)) {
 218                 /* Don't allow translation if checksum neutral bit is
 219                  * configured and it's set in the SIR address.
 220                  */
 221                 return -EINVAL;
 222         }
 223
 224         newts = lwtunnel_state_alloc(sizeof(*ilwt));
 225         if (!newts)
 226                 return -ENOMEM;
 227
 228         ilwt = ila_lwt_lwtunnel(newts);
 229         ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
 230         if (ret) {
 231                 kfree(newts);
 232                 return ret;
 233         }
 234
 235         ilwt->lwt_output = !!lwt_output;
 236
 237         p = ila_params_lwtunnel(newts);
 238
 239         p->csum_mode = csum_mode;
 240         p->ident_type = ident_type;
 241         p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
 242
 243         /* Precompute checksum difference for translation since we
 244          * know both the old locator and the new one.
 245          */
 246         p->locator_match = iaddr->loc;
 247
 248         ila_init_saved_csum(p);
 249
 250         newts->type = LWTUNNEL_ENCAP_ILA;
 251         newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
 252                         LWTUNNEL_STATE_INPUT_REDIRECT;
 253
 254         if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
 255                 ilwt->connected = 1;
 256
 257         *ts = newts;
 258
 259         return 0;
 260 }
 261
 262 static void ila_destroy_state(struct lwtunnel_state *lwt)
 263 {
 264         dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
 265 }
 266
 267 static int ila_fill_encap_info(struct sk_buff *skb,
 268                                struct lwtunnel_state *lwtstate)
 269 {
 270         struct ila_params *p = ila_params_lwtunnel(lwtstate);
 271         struct ila_lwt *ilwt = ila_lwt_lwtunnel(lwtstate);
 272
 273         if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
 274                               ILA_ATTR_PAD))
 275                 goto nla_put_failure;
 276
 277         if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
 278                 goto nla_put_failure;
 279
 280         if (nla_put_u8(skb, ILA_ATTR_IDENT_TYPE, (__force u8)p->ident_type))
 281                 goto nla_put_failure;
 282
 283         if (nla_put_u8(skb, ILA_ATTR_HOOK_TYPE,
 284                        ilwt->lwt_output ? ILA_HOOK_ROUTE_OUTPUT :
 285                                           ILA_HOOK_ROUTE_INPUT))
 286                 goto nla_put_failure;
 287
 288         return 0;
 289
 290 nla_put_failure:
 291         return -EMSGSIZE;
 292 }
 293
 294 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
 295 {
 296         return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
 297                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
 298                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_IDENT_TYPE */
 299                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_HOOK_TYPE */
 300                0;
 301 }
 302
 303 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 304 {
 305         struct ila_params *a_p = ila_params_lwtunnel(a);
 306         struct ila_params *b_p = ila_params_lwtunnel(b);
 307
 308         return (a_p->locator.v64 != b_p->locator.v64);
 309 }
 310
 311 static const struct lwtunnel_encap_ops ila_encap_ops = {
 312         .build_state = ila_build_state,
 313         .destroy_state = ila_destroy_state,
 314         .output = ila_output,
 315         .input = ila_input,
 316         .fill_encap = ila_fill_encap_info,
 317         .get_encap_size = ila_encap_nlsize,
 318         .cmp_encap = ila_encap_cmp,
 319         .owner = THIS_MODULE,
 320 };
 321
 322 int ila_lwt_init(void)
 323 {
 324         return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 325 }
 326
 327 void ila_lwt_fini(void)
 328 {
 329         lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 330 }