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         if (unlikely(net_xmit_eval(err)))
  80                 pkt_len = 0;
  81         iptunnel_xmit_stats(dev, pkt_len);
  82 }
  83 EXPORT_SYMBOL_GPL(iptunnel_xmit);
  84
  85 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
  86                            __be16 inner_proto, bool raw_proto, bool xnet)
  87 {
  88         if (unlikely(!pskb_may_pull(skb, hdr_len)))
  89                 return -ENOMEM;
  90
  91         skb_pull_rcsum(skb, hdr_len);
  92
  93         if (!raw_proto && inner_proto == htons(ETH_P_TEB)) {
  94                 struct ethhdr *eh;
  95
  96                 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
  97                         return -ENOMEM;
  98
  99                 eh = (struct ethhdr *)skb->data;
 100                 if (likely(eth_proto_is_802_3(eh->h_proto)))
 101                         skb->protocol = eh->h_proto;
 102                 else
 103                         skb->protocol = htons(ETH_P_802_2);
 104
 105         } else {
 106                 skb->protocol = inner_proto;
 107         }
 108
 109         skb_clear_hash_if_not_l4(skb);
 110         __vlan_hwaccel_clear_tag(skb);
 111         skb_set_queue_mapping(skb, 0);
 112         skb_scrub_packet(skb, xnet);
 113
 114         return iptunnel_pull_offloads(skb);
 115 }
 116 EXPORT_SYMBOL_GPL(__iptunnel_pull_header);
 117
 118 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 119                                              gfp_t flags)
 120 {
 121         struct metadata_dst *res;
 122         struct ip_tunnel_info *dst, *src;
 123
 124         if (!md || md->type != METADATA_IP_TUNNEL ||
 125             md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
 126
 127                 return NULL;
 128
 129         res = metadata_dst_alloc(0, METADATA_IP_TUNNEL, flags);
 130         if (!res)
 131                 return NULL;
 132
 133         dst = &res->u.tun_info;
 134         src = &md->u.tun_info;
 135         dst->key.tun_id = src->key.tun_id;
 136         if (src->mode & IP_TUNNEL_INFO_IPV6)
 137                 memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
 138                        sizeof(struct in6_addr));
 139         else
 140                 dst->key.u.ipv4.dst = src->key.u.ipv4.src;
 141         dst->key.tun_flags = src->key.tun_flags;
 142         dst->mode = src->mode | IP_TUNNEL_INFO_TX;
 143
 144         return res;
 145 }
 146 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
 147
 148 int iptunnel_handle_offloads(struct sk_buff *skb,
 149                              int gso_type_mask)
 150 {
 151         int err;
 152
 153         if (likely(!skb->encapsulation)) {
 154                 skb_reset_inner_headers(skb);
 155                 skb->encapsulation = 1;
 156         }
 157
 158         if (skb_is_gso(skb)) {
 159                 err = skb_header_unclone(skb, GFP_ATOMIC);
 160                 if (unlikely(err))
 161                         return err;
 162                 skb_shinfo(skb)->gso_type |= gso_type_mask;
 163                 return 0;
 164         }
 165
 166         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 167                 skb->ip_summed = CHECKSUM_NONE;
 168                 /* We clear encapsulation here to prevent badly-written
 169                  * drivers potentially deciding to offload an inner checksum
 170                  * if we set CHECKSUM_PARTIAL on the outer header.
 171                  * This should go away when the drivers are all fixed.
 172                  */
 173                 skb->encapsulation = 0;
 174         }
 175
 176         return 0;
 177 }
 178 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
 179
 180 /* Often modified stats are per cpu, other are shared (netdev->stats) */
 181 void ip_tunnel_get_stats64(struct net_device *dev,
 182                            struct rtnl_link_stats64 *tot)
 183 {
 184         int i;
 185
 186         netdev_stats_to_stats64(tot, &dev->stats);
 187
 188         for_each_possible_cpu(i) {
 189                 const struct pcpu_sw_netstats *tstats =
 190                                                    per_cpu_ptr(dev->tstats, i);
 191                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 192                 unsigned int start;
 193
 194                 do {
 195                         start = u64_stats_fetch_begin_irq(&tstats->syncp);
 196                         rx_packets = tstats->rx_packets;
 197                         tx_packets = tstats->tx_packets;
 198                         rx_bytes = tstats->rx_bytes;
 199                         tx_bytes = tstats->tx_bytes;
 200                 } while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
 201
 202                 tot->rx_packets += rx_packets;
 203                 tot->tx_packets += tx_packets;
 204                 tot->rx_bytes   += rx_bytes;
 205                 tot->tx_bytes   += tx_bytes;
 206         }
 207 }
 208 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
 209
 210 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 211         [LWTUNNEL_IP_ID]        = { .type = NLA_U64 },
 212         [LWTUNNEL_IP_DST]       = { .type = NLA_U32 },
 213         [LWTUNNEL_IP_SRC]       = { .type = NLA_U32 },
 214         [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
 215         [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
 216         [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
 217 };
 218
 219 static int ip_tun_build_state(struct nlattr *attr,
 220                               unsigned int family, const void *cfg,
 221                               struct lwtunnel_state **ts,
 222                               struct netlink_ext_ack *extack)
 223 {
 224         struct ip_tunnel_info *tun_info;
 225         struct lwtunnel_state *new_state;
 226         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
 227         int err;
 228
 229         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP_MAX, attr,
 230                                           ip_tun_policy, extack);
 231         if (err < 0)
 232                 return err;
 233
 234         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 235         if (!new_state)
 236                 return -ENOMEM;
 237
 238         new_state->type = LWTUNNEL_ENCAP_IP;
 239
 240         tun_info = lwt_tun_info(new_state);
 241
 242 #ifdef CONFIG_DST_CACHE
 243         err = dst_cache_init(&tun_info->dst_cache, GFP_KERNEL);
 244         if (err) {
 245                 lwtstate_free(new_state);
 246                 return err;
 247         }
 248 #endif
 249
 250         if (tb[LWTUNNEL_IP_ID])
 251                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
 252
 253         if (tb[LWTUNNEL_IP_DST])
 254                 tun_info->key.u.ipv4.dst = nla_get_in_addr(tb[LWTUNNEL_IP_DST]);
 255
 256         if (tb[LWTUNNEL_IP_SRC])
 257                 tun_info->key.u.ipv4.src = nla_get_in_addr(tb[LWTUNNEL_IP_SRC]);
 258
 259         if (tb[LWTUNNEL_IP_TTL])
 260                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
 261
 262         if (tb[LWTUNNEL_IP_TOS])
 263                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 264
 265         if (tb[LWTUNNEL_IP_FLAGS])
 266                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP_FLAGS]);
 267
 268         tun_info->mode = IP_TUNNEL_INFO_TX;
 269         tun_info->options_len = 0;
 270
 271         *ts = new_state;
 272
 273         return 0;
 274 }
 275
 276 static void ip_tun_destroy_state(struct lwtunnel_state *lwtstate)
 277 {
 278 #ifdef CONFIG_DST_CACHE
 279         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 280
 281         dst_cache_destroy(&tun_info->dst_cache);
 282 #endif
 283 }
 284
 285 static int ip_tun_fill_encap_info(struct sk_buff *skb,
 286                                   struct lwtunnel_state *lwtstate)
 287 {
 288         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 289
 290         if (nla_put_be64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id,
 291                          LWTUNNEL_IP_PAD) ||
 292             nla_put_in_addr(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
 293             nla_put_in_addr(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
 294             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
 295             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 296             nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
 297                 return -ENOMEM;
 298
 299         return 0;
 300 }
 301
 302 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 303 {
 304         return nla_total_size_64bit(8)  /* LWTUNNEL_IP_ID */
 305                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
 306                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
 307                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
 308                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
 309                 + nla_total_size(2);    /* LWTUNNEL_IP_FLAGS */
 310 }
 311
 312 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 313 {
 314         return memcmp(lwt_tun_info(a), lwt_tun_info(b),
 315                       sizeof(struct ip_tunnel_info));
 316 }
 317
 318 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
 319         .build_state = ip_tun_build_state,
 320         .destroy_state = ip_tun_destroy_state,
 321         .fill_encap = ip_tun_fill_encap_info,
 322         .get_encap_size = ip_tun_encap_nlsize,
 323         .cmp_encap = ip_tun_cmp_encap,
 324         .owner = THIS_MODULE,
 325 };
 326
 327 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 328         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
 329         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
 330         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
 331         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
 332         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
 333         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
 334 };
 335
 336 static int ip6_tun_build_state(struct nlattr *attr,
 337                                unsigned int family, const void *cfg,
 338                                struct lwtunnel_state **ts,
 339                                struct netlink_ext_ack *extack)
 340 {
 341         struct ip_tunnel_info *tun_info;
 342         struct lwtunnel_state *new_state;
 343         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 344         int err;
 345
 346         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP6_MAX, attr,
 347                                           ip6_tun_policy, extack);
 348         if (err < 0)
 349                 return err;
 350
 351         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 352         if (!new_state)
 353                 return -ENOMEM;
 354
 355         new_state->type = LWTUNNEL_ENCAP_IP6;
 356
 357         tun_info = lwt_tun_info(new_state);
 358
 359         if (tb[LWTUNNEL_IP6_ID])
 360                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP6_ID]);
 361
 362         if (tb[LWTUNNEL_IP6_DST])
 363                 tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
 364
 365         if (tb[LWTUNNEL_IP6_SRC])
 366                 tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
 367
 368         if (tb[LWTUNNEL_IP6_HOPLIMIT])
 369                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
 370
 371         if (tb[LWTUNNEL_IP6_TC])
 372                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
 373
 374         if (tb[LWTUNNEL_IP6_FLAGS])
 375                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP6_FLAGS]);
 376
 377         tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
 378         tun_info->options_len = 0;
 379
 380         *ts = new_state;
 381
 382         return 0;
 383 }
 384
 385 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
 386                                    struct lwtunnel_state *lwtstate)
 387 {
 388         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 389
 390         if (nla_put_be64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id,
 391                          LWTUNNEL_IP6_PAD) ||
 392             nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
 393             nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
 394             nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.tos) ||
 395             nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.ttl) ||
 396             nla_put_be16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags))
 397                 return -ENOMEM;
 398
 399         return 0;
 400 }
 401
 402 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 403 {
 404         return nla_total_size_64bit(8)  /* LWTUNNEL_IP6_ID */
 405                 + nla_total_size(16)    /* LWTUNNEL_IP6_DST */
 406                 + nla_total_size(16)    /* LWTUNNEL_IP6_SRC */
 407                 + nla_total_size(1)     /* LWTUNNEL_IP6_HOPLIMIT */
 408                 + nla_total_size(1)     /* LWTUNNEL_IP6_TC */
 409                 + nla_total_size(2);    /* LWTUNNEL_IP6_FLAGS */
 410 }
 411
 412 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
 413         .build_state = ip6_tun_build_state,
 414         .fill_encap = ip6_tun_fill_encap_info,
 415         .get_encap_size = ip6_tun_encap_nlsize,
 416         .cmp_encap = ip_tun_cmp_encap,
 417         .owner = THIS_MODULE,
 418 };
 419
 420 void __init ip_tunnel_core_init(void)
 421 {
 422         /* If you land here, make sure whether increasing ip_tunnel_info's
 423          * options_len is a reasonable choice with its usage in front ends
 424          * (f.e., it's part of flow keys, etc).
 425          */
 426         BUILD_BUG_ON(IP_TUNNEL_OPTS_MAX != 255);
 427
 428         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
 429         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
 430 }
 431
 432 DEFINE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
 433 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
 434
 435 void ip_tunnel_need_metadata(void)
 436 {
 437         static_branch_inc(&ip_tunnel_metadata_cnt);
 438 }
 439 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
 440
 441 void ip_tunnel_unneed_metadata(void)
 442 {
 443         static_branch_dec(&ip_tunnel_metadata_cnt);
 444 }
 445 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);