net/ipv4/ip_tunnel_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2013 Nicira, Inc.
   4  */
   5
   6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7
   8 #include <linux/types.h>
   9 #include <linux/kernel.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/netdevice.h>
  12 #include <linux/in.h>
  13 #include <linux/if_arp.h>
  14 #include <linux/init.h>
  15 #include <linux/in6.h>
  16 #include <linux/inetdevice.h>
  17 #include <linux/netfilter_ipv4.h>
  18 #include <linux/etherdevice.h>
  19 #include <linux/if_ether.h>
  20 #include <linux/if_vlan.h>
  21 #include <linux/static_key.h>
  22
  23 #include <net/ip.h>
  24 #include <net/icmp.h>
  25 #include <net/protocol.h>
  26 #include <net/ip_tunnels.h>
  27 #include <net/ip6_tunnel.h>
  28 #include <net/arp.h>
  29 #include <net/checksum.h>
  30 #include <net/dsfield.h>
  31 #include <net/inet_ecn.h>
  32 #include <net/xfrm.h>
  33 #include <net/net_namespace.h>
  34 #include <net/netns/generic.h>
  35 #include <net/rtnetlink.h>
  36 #include <net/dst_metadata.h>
  37
  38 const struct ip_tunnel_encap_ops __rcu *
  39                 iptun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
  40 EXPORT_SYMBOL(iptun_encaps);
  41
  42 const struct ip6_tnl_encap_ops __rcu *
  43                 ip6tun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
  44 EXPORT_SYMBOL(ip6tun_encaps);
  45
  46 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
  47                    __be32 src, __be32 dst, __u8 proto,
  48                    __u8 tos, __u8 ttl, __be16 df, bool xnet)
  49 {
  50         int pkt_len = skb->len - skb_inner_network_offset(skb);
  51         struct net *net = dev_net(rt->dst.dev);
  52         struct net_device *dev = skb->dev;
  53         struct iphdr *iph;
  54         int err;
  55
  56         skb_scrub_packet(skb, xnet);
  57
  58         skb_clear_hash_if_not_l4(skb);
  59         skb_dst_set(skb, &rt->dst);
  60         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
  61
  62         /* Push down and install the IP header. */
  63         skb_push(skb, sizeof(struct iphdr));
  64         skb_reset_network_header(skb);
  65
  66         iph = ip_hdr(skb);
  67
  68         iph->version    =       4;
  69         iph->ihl        =       sizeof(struct iphdr) >> 2;
  70         iph->frag_off   =       ip_mtu_locked(&rt->dst) ? 0 : df;
  71         iph->protocol   =       proto;
  72         iph->tos        =       tos;
  73         iph->daddr      =       dst;
  74         iph->saddr      =       src;
  75         iph->ttl        =       ttl;
  76         __ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
  77
  78         err = ip_local_out(net, sk, skb);
  79
  80         if (dev) {
  81                 if (unlikely(net_xmit_eval(err)))
  82                         pkt_len = 0;
  83                 iptunnel_xmit_stats(dev, pkt_len);
  84         }
  85 }
  86 EXPORT_SYMBOL_GPL(iptunnel_xmit);
  87
  88 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
  89                            __be16 inner_proto, bool raw_proto, bool xnet)
  90 {
  91         if (unlikely(!pskb_may_pull(skb, hdr_len)))
  92                 return -ENOMEM;
  93
  94         skb_pull_rcsum(skb, hdr_len);
  95
  96         if (!raw_proto && inner_proto == htons(ETH_P_TEB)) {
  97                 struct ethhdr *eh;
  98
  99                 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
 100                         return -ENOMEM;
 101
 102                 eh = (struct ethhdr *)skb->data;
 103                 if (likely(eth_proto_is_802_3(eh->h_proto)))
 104                         skb->protocol = eh->h_proto;
 105                 else
 106                         skb->protocol = htons(ETH_P_802_2);
 107
 108         } else {
 109                 skb->protocol = inner_proto;
 110         }
 111
 112         skb_clear_hash_if_not_l4(skb);
 113         __vlan_hwaccel_clear_tag(skb);
 114         skb_set_queue_mapping(skb, 0);
 115         skb_scrub_packet(skb, xnet);
 116
 117         return iptunnel_pull_offloads(skb);
 118 }
 119 EXPORT_SYMBOL_GPL(__iptunnel_pull_header);
 120
 121 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 122                                              gfp_t flags)
 123 {
 124         struct metadata_dst *res;
 125         struct ip_tunnel_info *dst, *src;
 126
 127         if (!md || md->type != METADATA_IP_TUNNEL ||
 128             md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
 129
 130                 return NULL;
 131
 132         res = metadata_dst_alloc(0, METADATA_IP_TUNNEL, flags);
 133         if (!res)
 134                 return NULL;
 135
 136         dst = &res->u.tun_info;
 137         src = &md->u.tun_info;
 138         dst->key.tun_id = src->key.tun_id;
 139         if (src->mode & IP_TUNNEL_INFO_IPV6)
 140                 memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
 141                        sizeof(struct in6_addr));
 142         else
 143                 dst->key.u.ipv4.dst = src->key.u.ipv4.src;
 144         dst->key.tun_flags = src->key.tun_flags;
 145         dst->mode = src->mode | IP_TUNNEL_INFO_TX;
 146
 147         return res;
 148 }
 149 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
 150
 151 int iptunnel_handle_offloads(struct sk_buff *skb,
 152                              int gso_type_mask)
 153 {
 154         int err;
 155
 156         if (likely(!skb->encapsulation)) {
 157                 skb_reset_inner_headers(skb);
 158                 skb->encapsulation = 1;
 159         }
 160
 161         if (skb_is_gso(skb)) {
 162                 err = skb_header_unclone(skb, GFP_ATOMIC);
 163                 if (unlikely(err))
 164                         return err;
 165                 skb_shinfo(skb)->gso_type |= gso_type_mask;
 166                 return 0;
 167         }
 168
 169         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 170                 skb->ip_summed = CHECKSUM_NONE;
 171                 /* We clear encapsulation here to prevent badly-written
 172                  * drivers potentially deciding to offload an inner checksum
 173                  * if we set CHECKSUM_PARTIAL on the outer header.
 174                  * This should go away when the drivers are all fixed.
 175                  */
 176                 skb->encapsulation = 0;
 177         }
 178
 179         return 0;
 180 }
 181 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
 182
 183 /* Often modified stats are per cpu, other are shared (netdev->stats) */
 184 void ip_tunnel_get_stats64(struct net_device *dev,
 185                            struct rtnl_link_stats64 *tot)
 186 {
 187         int i;
 188
 189         netdev_stats_to_stats64(tot, &dev->stats);
 190
 191         for_each_possible_cpu(i) {
 192                 const struct pcpu_sw_netstats *tstats =
 193                                                    per_cpu_ptr(dev->tstats, i);
 194                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 195                 unsigned int start;
 196
 197                 do {
 198                         start = u64_stats_fetch_begin_irq(&tstats->syncp);
 199                         rx_packets = tstats->rx_packets;
 200                         tx_packets = tstats->tx_packets;
 201                         rx_bytes = tstats->rx_bytes;
 202                         tx_bytes = tstats->tx_bytes;
 203                 } while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
 204
 205                 tot->rx_packets += rx_packets;
 206                 tot->tx_packets += tx_packets;
 207                 tot->rx_bytes   += rx_bytes;
 208                 tot->tx_bytes   += tx_bytes;
 209         }
 210 }
 211 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
 212
 213 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 214         [LWTUNNEL_IP_ID]        = { .type = NLA_U64 },
 215         [LWTUNNEL_IP_DST]       = { .type = NLA_U32 },
 216         [LWTUNNEL_IP_SRC]       = { .type = NLA_U32 },
 217         [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
 218         [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
 219         [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
 220 };
 221
 222 static int ip_tun_build_state(struct nlattr *attr,
 223                               unsigned int family, const void *cfg,
 224                               struct lwtunnel_state **ts,
 225                               struct netlink_ext_ack *extack)
 226 {
 227         struct ip_tunnel_info *tun_info;
 228         struct lwtunnel_state *new_state;
 229         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
 230         int err;
 231
 232         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP_MAX, attr,
 233                                           ip_tun_policy, extack);
 234         if (err < 0)
 235                 return err;
 236
 237         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 238         if (!new_state)
 239                 return -ENOMEM;
 240
 241         new_state->type = LWTUNNEL_ENCAP_IP;
 242
 243         tun_info = lwt_tun_info(new_state);
 244
 245 #ifdef CONFIG_DST_CACHE
 246         err = dst_cache_init(&tun_info->dst_cache, GFP_KERNEL);
 247         if (err) {
 248                 lwtstate_free(new_state);
 249                 return err;
 250         }
 251 #endif
 252
 253         if (tb[LWTUNNEL_IP_ID])
 254                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
 255
 256         if (tb[LWTUNNEL_IP_DST])
 257                 tun_info->key.u.ipv4.dst = nla_get_in_addr(tb[LWTUNNEL_IP_DST]);
 258
 259         if (tb[LWTUNNEL_IP_SRC])
 260                 tun_info->key.u.ipv4.src = nla_get_in_addr(tb[LWTUNNEL_IP_SRC]);
 261
 262         if (tb[LWTUNNEL_IP_TTL])
 263                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
 264
 265         if (tb[LWTUNNEL_IP_TOS])
 266                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 267
 268         if (tb[LWTUNNEL_IP_FLAGS])
 269                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP_FLAGS]);
 270
 271         tun_info->mode = IP_TUNNEL_INFO_TX;
 272         tun_info->options_len = 0;
 273
 274         *ts = new_state;
 275
 276         return 0;
 277 }
 278
 279 static void ip_tun_destroy_state(struct lwtunnel_state *lwtstate)
 280 {
 281 #ifdef CONFIG_DST_CACHE
 282         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 283
 284         dst_cache_destroy(&tun_info->dst_cache);
 285 #endif
 286 }
 287
 288 static int ip_tun_fill_encap_info(struct sk_buff *skb,
 289                                   struct lwtunnel_state *lwtstate)
 290 {
 291         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 292
 293         if (nla_put_be64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id,
 294                          LWTUNNEL_IP_PAD) ||
 295             nla_put_in_addr(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
 296             nla_put_in_addr(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
 297             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
 298             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 299             nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
 300                 return -ENOMEM;
 301
 302         return 0;
 303 }
 304
 305 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 306 {
 307         return nla_total_size_64bit(8)  /* LWTUNNEL_IP_ID */
 308                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
 309                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
 310                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
 311                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
 312                 + nla_total_size(2);    /* LWTUNNEL_IP_FLAGS */
 313 }
 314
 315 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 316 {
 317         return memcmp(lwt_tun_info(a), lwt_tun_info(b),
 318                       sizeof(struct ip_tunnel_info));
 319 }
 320
 321 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
 322         .build_state = ip_tun_build_state,
 323         .destroy_state = ip_tun_destroy_state,
 324         .fill_encap = ip_tun_fill_encap_info,
 325         .get_encap_size = ip_tun_encap_nlsize,
 326         .cmp_encap = ip_tun_cmp_encap,
 327         .owner = THIS_MODULE,
 328 };
 329
 330 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 331         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
 332         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
 333         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
 334         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
 335         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
 336         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
 337 };
 338
 339 static int ip6_tun_build_state(struct nlattr *attr,
 340                                unsigned int family, const void *cfg,
 341                                struct lwtunnel_state **ts,
 342                                struct netlink_ext_ack *extack)
 343 {
 344         struct ip_tunnel_info *tun_info;
 345         struct lwtunnel_state *new_state;
 346         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 347         int err;
 348
 349         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP6_MAX, attr,
 350                                           ip6_tun_policy, extack);
 351         if (err < 0)
 352                 return err;
 353
 354         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 355         if (!new_state)
 356                 return -ENOMEM;
 357
 358         new_state->type = LWTUNNEL_ENCAP_IP6;
 359
 360         tun_info = lwt_tun_info(new_state);
 361
 362         if (tb[LWTUNNEL_IP6_ID])
 363                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP6_ID]);
 364
 365         if (tb[LWTUNNEL_IP6_DST])
 366                 tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
 367
 368         if (tb[LWTUNNEL_IP6_SRC])
 369                 tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
 370
 371         if (tb[LWTUNNEL_IP6_HOPLIMIT])
 372                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
 373
 374         if (tb[LWTUNNEL_IP6_TC])
 375                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
 376
 377         if (tb[LWTUNNEL_IP6_FLAGS])
 378                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP6_FLAGS]);
 379
 380         tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
 381         tun_info->options_len = 0;
 382
 383         *ts = new_state;
 384
 385         return 0;
 386 }
 387
 388 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
 389                                    struct lwtunnel_state *lwtstate)
 390 {
 391         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 392
 393         if (nla_put_be64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id,
 394                          LWTUNNEL_IP6_PAD) ||
 395             nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
 396             nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
 397             nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.tos) ||
 398             nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.ttl) ||
 399             nla_put_be16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags))
 400                 return -ENOMEM;
 401
 402         return 0;
 403 }
 404
 405 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 406 {
 407         return nla_total_size_64bit(8)  /* LWTUNNEL_IP6_ID */
 408                 + nla_total_size(16)    /* LWTUNNEL_IP6_DST */
 409                 + nla_total_size(16)    /* LWTUNNEL_IP6_SRC */
 410                 + nla_total_size(1)     /* LWTUNNEL_IP6_HOPLIMIT */
 411                 + nla_total_size(1)     /* LWTUNNEL_IP6_TC */
 412                 + nla_total_size(2);    /* LWTUNNEL_IP6_FLAGS */
 413 }
 414
 415 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
 416         .build_state = ip6_tun_build_state,
 417         .fill_encap = ip6_tun_fill_encap_info,
 418         .get_encap_size = ip6_tun_encap_nlsize,
 419         .cmp_encap = ip_tun_cmp_encap,
 420         .owner = THIS_MODULE,
 421 };
 422
 423 void __init ip_tunnel_core_init(void)
 424 {
 425         /* If you land here, make sure whether increasing ip_tunnel_info's
 426          * options_len is a reasonable choice with its usage in front ends
 427          * (f.e., it's part of flow keys, etc).
 428          */
 429         BUILD_BUG_ON(IP_TUNNEL_OPTS_MAX != 255);
 430
 431         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
 432         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
 433 }
 434
 435 DEFINE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
 436 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
 437
 438 void ip_tunnel_need_metadata(void)
 439 {
 440         static_branch_inc(&ip_tunnel_metadata_cnt);
 441 }
 442 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
 443
 444 void ip_tunnel_unneed_metadata(void)
 445 {
 446         static_branch_dec(&ip_tunnel_metadata_cnt);
 447 }
 448 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);