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 = (struct 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         dst = dst_cache_get(&ilwt->dst_cache);
  62         if (unlikely(!dst)) {
  63                 struct ipv6hdr *ip6h = ipv6_hdr(skb);
  64                 struct flowi6 fl6;
  65
  66                 /* Lookup a route for the new destination. Take into
  67                  * account that the base route may already have a gateway.
  68                  */
  69
  70                 memset(&fl6, 0, sizeof(fl6));
  71                 fl6.flowi6_oif = orig_dst->dev->ifindex;
  72                 fl6.flowi6_iif = LOOPBACK_IFINDEX;
  73                 fl6.daddr = *rt6_nexthop((struct rt6_info *)orig_dst,
  74                                          &ip6h->daddr);
  75
  76                 dst = ip6_route_output(net, NULL, &fl6);
  77                 if (dst->error) {
  78                         err = -EHOSTUNREACH;
  79                         dst_release(dst);
  80                         goto drop;
  81                 }
  82
  83                 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
  84                 if (IS_ERR(dst)) {
  85                         err = PTR_ERR(dst);
  86                         goto drop;
  87                 }
  88
  89                 if (ilwt->connected)
  90                         dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
  91         }
  92
  93         skb_dst_set(skb, dst);
  94         return dst_output(net, sk, skb);
  95
  96 drop:
  97         kfree_skb(skb);
  98         return err;
  99 }
 100
 101 static int ila_input(struct sk_buff *skb)
 102 {
 103         struct dst_entry *dst = skb_dst(skb);
 104         struct ila_lwt *ilwt = ila_lwt_lwtunnel(dst->lwtstate);
 105
 106         if (skb->protocol != htons(ETH_P_IPV6))
 107                 goto drop;
 108
 109         if (!ilwt->lwt_output)
 110                 ila_update_ipv6_locator(skb,
 111                                         ila_params_lwtunnel(dst->lwtstate),
 112                                         false);
 113
 114         return dst->lwtstate->orig_input(skb);
 115
 116 drop:
 117         kfree_skb(skb);
 118         return -EINVAL;
 119 }
 120
 121 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 122         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 123         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
 124         [ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
 125         [ILA_ATTR_HOOK_TYPE] = { .type = NLA_U8, },
 126 };
 127
 128 static int ila_build_state(struct nlattr *nla,
 129                            unsigned int family, const void *cfg,
 130                            struct lwtunnel_state **ts,
 131                            struct netlink_ext_ack *extack)
 132 {
 133         struct ila_lwt *ilwt;
 134         struct ila_params *p;
 135         struct nlattr *tb[ILA_ATTR_MAX + 1];
 136         struct lwtunnel_state *newts;
 137         const struct fib6_config *cfg6 = cfg;
 138         struct ila_addr *iaddr;
 139         u8 ident_type = ILA_ATYPE_USE_FORMAT;
 140         u8 hook_type = ILA_HOOK_ROUTE_OUTPUT;
 141         u8 csum_mode = ILA_CSUM_NO_ACTION;
 142         bool lwt_output = true;
 143         u8 eff_ident_type;
 144         int ret;
 145
 146         if (family != AF_INET6)
 147                 return -EINVAL;
 148
 149         ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla, ila_nl_policy, extack);
 150         if (ret < 0)
 151                 return ret;
 152
 153         if (!tb[ILA_ATTR_LOCATOR])
 154                 return -EINVAL;
 155
 156         iaddr = (struct ila_addr *)&cfg6->fc_dst;
 157
 158         if (tb[ILA_ATTR_IDENT_TYPE])
 159                 ident_type = nla_get_u8(tb[ILA_ATTR_IDENT_TYPE]);
 160
 161         if (ident_type == ILA_ATYPE_USE_FORMAT) {
 162                 /* Infer identifier type from type field in formatted
 163                  * identifier.
 164                  */
 165
 166                 if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
 167                         /* Need to have full locator and at least type field
 168                          * included in destination
 169                          */
 170                         return -EINVAL;
 171                 }
 172
 173                 eff_ident_type = iaddr->ident.type;
 174         } else {
 175                 eff_ident_type = ident_type;
 176         }
 177
 178         switch (eff_ident_type) {
 179         case ILA_ATYPE_IID:
 180                 /* Don't allow ILA for IID type */
 181                 return -EINVAL;
 182         case ILA_ATYPE_LUID:
 183                 break;
 184         case ILA_ATYPE_VIRT_V4:
 185         case ILA_ATYPE_VIRT_UNI_V6:
 186         case ILA_ATYPE_VIRT_MULTI_V6:
 187         case ILA_ATYPE_NONLOCAL_ADDR:
 188                 /* These ILA formats are not supported yet. */
 189         default:
 190                 return -EINVAL;
 191         }
 192
 193         if (tb[ILA_ATTR_HOOK_TYPE])
 194                 hook_type = nla_get_u8(tb[ILA_ATTR_HOOK_TYPE]);
 195
 196         switch (hook_type) {
 197         case ILA_HOOK_ROUTE_OUTPUT:
 198                 lwt_output = true;
 199                 break;
 200         case ILA_HOOK_ROUTE_INPUT:
 201                 lwt_output = false;
 202                 break;
 203         default:
 204                 return -EINVAL;
 205         }
 206
 207         if (tb[ILA_ATTR_CSUM_MODE])
 208                 csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
 209
 210         if (csum_mode == ILA_CSUM_NEUTRAL_MAP &&
 211             ila_csum_neutral_set(iaddr->ident)) {
 212                 /* Don't allow translation if checksum neutral bit is
 213                  * configured and it's set in the SIR address.
 214                  */
 215                 return -EINVAL;
 216         }
 217
 218         newts = lwtunnel_state_alloc(sizeof(*ilwt));
 219         if (!newts)
 220                 return -ENOMEM;
 221
 222         ilwt = ila_lwt_lwtunnel(newts);
 223         ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
 224         if (ret) {
 225                 kfree(newts);
 226                 return ret;
 227         }
 228
 229         ilwt->lwt_output = !!lwt_output;
 230
 231         p = ila_params_lwtunnel(newts);
 232
 233         p->csum_mode = csum_mode;
 234         p->ident_type = ident_type;
 235         p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
 236
 237         /* Precompute checksum difference for translation since we
 238          * know both the old locator and the new one.
 239          */
 240         p->locator_match = iaddr->loc;
 241
 242         ila_init_saved_csum(p);
 243
 244         newts->type = LWTUNNEL_ENCAP_ILA;
 245         newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
 246                         LWTUNNEL_STATE_INPUT_REDIRECT;
 247
 248         if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
 249                 ilwt->connected = 1;
 250
 251         *ts = newts;
 252
 253         return 0;
 254 }
 255
 256 static void ila_destroy_state(struct lwtunnel_state *lwt)
 257 {
 258         dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
 259 }
 260
 261 static int ila_fill_encap_info(struct sk_buff *skb,
 262                                struct lwtunnel_state *lwtstate)
 263 {
 264         struct ila_params *p = ila_params_lwtunnel(lwtstate);
 265         struct ila_lwt *ilwt = ila_lwt_lwtunnel(lwtstate);
 266
 267         if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
 268                               ILA_ATTR_PAD))
 269                 goto nla_put_failure;
 270
 271         if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
 272                 goto nla_put_failure;
 273
 274         if (nla_put_u8(skb, ILA_ATTR_IDENT_TYPE, (__force u8)p->ident_type))
 275                 goto nla_put_failure;
 276
 277         if (nla_put_u8(skb, ILA_ATTR_HOOK_TYPE,
 278                        ilwt->lwt_output ? ILA_HOOK_ROUTE_OUTPUT :
 279                                           ILA_HOOK_ROUTE_INPUT))
 280                 goto nla_put_failure;
 281
 282         return 0;
 283
 284 nla_put_failure:
 285         return -EMSGSIZE;
 286 }
 287
 288 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
 289 {
 290         return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
 291                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
 292                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_IDENT_TYPE */
 293                nla_total_size(sizeof(u8)) +        /* ILA_ATTR_HOOK_TYPE */
 294                0;
 295 }
 296
 297 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 298 {
 299         struct ila_params *a_p = ila_params_lwtunnel(a);
 300         struct ila_params *b_p = ila_params_lwtunnel(b);
 301
 302         return (a_p->locator.v64 != b_p->locator.v64);
 303 }
 304
 305 static const struct lwtunnel_encap_ops ila_encap_ops = {
 306         .build_state = ila_build_state,
 307         .destroy_state = ila_destroy_state,
 308         .output = ila_output,
 309         .input = ila_input,
 310         .fill_encap = ila_fill_encap_info,
 311         .get_encap_size = ila_encap_nlsize,
 312         .cmp_encap = ila_encap_cmp,
 313         .owner = THIS_MODULE,
 314 };
 315
 316 int ila_lwt_init(void)
 317 {
 318         return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 319 }
 320
 321 void ila_lwt_fini(void)
 322 {
 323         lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
 324 }