net/ipv4/ip_tunnel_core.c

   1 /*
   2  * Copyright (c) 2013 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301, USA
  17  */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/skbuff.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/in.h>
  26 #include <linux/if_arp.h>
  27 #include <linux/init.h>
  28 #include <linux/in6.h>
  29 #include <linux/inetdevice.h>
  30 #include <linux/netfilter_ipv4.h>
  31 #include <linux/etherdevice.h>
  32 #include <linux/if_ether.h>
  33 #include <linux/if_vlan.h>
  34 #include <linux/static_key.h>
  35
  36 #include <net/ip.h>
  37 #include <net/icmp.h>
  38 #include <net/protocol.h>
  39 #include <net/ip_tunnels.h>
  40 #include <net/ip6_tunnel.h>
  41 #include <net/arp.h>
  42 #include <net/checksum.h>
  43 #include <net/dsfield.h>
  44 #include <net/inet_ecn.h>
  45 #include <net/xfrm.h>
  46 #include <net/net_namespace.h>
  47 #include <net/netns/generic.h>
  48 #include <net/rtnetlink.h>
  49 #include <net/dst_metadata.h>
  50
  51 const struct ip_tunnel_encap_ops __rcu *
  52                 iptun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
  53 EXPORT_SYMBOL(iptun_encaps);
  54
  55 const struct ip6_tnl_encap_ops __rcu *
  56                 ip6tun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
  57 EXPORT_SYMBOL(ip6tun_encaps);
  58
  59 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
  60                    __be32 src, __be32 dst, __u8 proto,
  61                    __u8 tos, __u8 ttl, __be16 df, bool xnet)
  62 {
  63         int pkt_len = skb->len - skb_inner_network_offset(skb);
  64         struct net *net = dev_net(rt->dst.dev);
  65         struct net_device *dev = skb->dev;
  66         struct iphdr *iph;
  67         int err;
  68
  69         skb_scrub_packet(skb, xnet);
  70
  71         skb_clear_hash_if_not_l4(skb);
  72         skb_dst_set(skb, &rt->dst);
  73         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
  74
  75         /* Push down and install the IP header. */
  76         skb_push(skb, sizeof(struct iphdr));
  77         skb_reset_network_header(skb);
  78
  79         iph = ip_hdr(skb);
  80
  81         iph->version    =       4;
  82         iph->ihl        =       sizeof(struct iphdr) >> 2;
  83         iph->frag_off   =       ip_mtu_locked(&rt->dst) ? 0 : df;
  84         iph->protocol   =       proto;
  85         iph->tos        =       tos;
  86         iph->daddr      =       dst;
  87         iph->saddr      =       src;
  88         iph->ttl        =       ttl;
  89         __ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
  90
  91         err = ip_local_out(net, sk, skb);
  92
  93         if (dev) {
  94                 if (unlikely(net_xmit_eval(err)))
  95                         pkt_len = 0;
  96                 iptunnel_xmit_stats(dev, pkt_len);
  97         }
  98 }
  99 EXPORT_SYMBOL_GPL(iptunnel_xmit);
 100
 101 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
 102                            __be16 inner_proto, bool raw_proto, bool xnet)
 103 {
 104         if (unlikely(!pskb_may_pull(skb, hdr_len)))
 105                 return -ENOMEM;
 106
 107         skb_pull_rcsum(skb, hdr_len);
 108
 109         if (!raw_proto && inner_proto == htons(ETH_P_TEB)) {
 110                 struct ethhdr *eh;
 111
 112                 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
 113                         return -ENOMEM;
 114
 115                 eh = (struct ethhdr *)skb->data;
 116                 if (likely(eth_proto_is_802_3(eh->h_proto)))
 117                         skb->protocol = eh->h_proto;
 118                 else
 119                         skb->protocol = htons(ETH_P_802_2);
 120
 121         } else {
 122                 skb->protocol = inner_proto;
 123         }
 124
 125         skb_clear_hash_if_not_l4(skb);
 126         skb->vlan_tci = 0;
 127         skb_set_queue_mapping(skb, 0);
 128         skb_scrub_packet(skb, xnet);
 129
 130         return iptunnel_pull_offloads(skb);
 131 }
 132 EXPORT_SYMBOL_GPL(__iptunnel_pull_header);
 133
 134 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 135                                              gfp_t flags)
 136 {
 137         struct metadata_dst *res;
 138         struct ip_tunnel_info *dst, *src;
 139
 140         if (!md || md->type != METADATA_IP_TUNNEL ||
 141             md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
 142
 143                 return NULL;
 144
 145         res = metadata_dst_alloc(0, METADATA_IP_TUNNEL, flags);
 146         if (!res)
 147                 return NULL;
 148
 149         dst = &res->u.tun_info;
 150         src = &md->u.tun_info;
 151         dst->key.tun_id = src->key.tun_id;
 152         if (src->mode & IP_TUNNEL_INFO_IPV6)
 153                 memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
 154                        sizeof(struct in6_addr));
 155         else
 156                 dst->key.u.ipv4.dst = src->key.u.ipv4.src;
 157         dst->mode = src->mode | IP_TUNNEL_INFO_TX;
 158
 159         return res;
 160 }
 161 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
 162
 163 int iptunnel_handle_offloads(struct sk_buff *skb,
 164                              int gso_type_mask)
 165 {
 166         int err;
 167
 168         if (likely(!skb->encapsulation)) {
 169                 skb_reset_inner_headers(skb);
 170                 skb->encapsulation = 1;
 171         }
 172
 173         if (skb_is_gso(skb)) {
 174                 err = skb_header_unclone(skb, GFP_ATOMIC);
 175                 if (unlikely(err))
 176                         return err;
 177                 skb_shinfo(skb)->gso_type |= gso_type_mask;
 178                 return 0;
 179         }
 180
 181         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 182                 skb->ip_summed = CHECKSUM_NONE;
 183                 /* We clear encapsulation here to prevent badly-written
 184                  * drivers potentially deciding to offload an inner checksum
 185                  * if we set CHECKSUM_PARTIAL on the outer header.
 186                  * This should go away when the drivers are all fixed.
 187                  */
 188                 skb->encapsulation = 0;
 189         }
 190
 191         return 0;
 192 }
 193 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
 194
 195 /* Often modified stats are per cpu, other are shared (netdev->stats) */
 196 void ip_tunnel_get_stats64(struct net_device *dev,
 197                            struct rtnl_link_stats64 *tot)
 198 {
 199         int i;
 200
 201         netdev_stats_to_stats64(tot, &dev->stats);
 202
 203         for_each_possible_cpu(i) {
 204                 const struct pcpu_sw_netstats *tstats =
 205                                                    per_cpu_ptr(dev->tstats, i);
 206                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 207                 unsigned int start;
 208
 209                 do {
 210                         start = u64_stats_fetch_begin_irq(&tstats->syncp);
 211                         rx_packets = tstats->rx_packets;
 212                         tx_packets = tstats->tx_packets;
 213                         rx_bytes = tstats->rx_bytes;
 214                         tx_bytes = tstats->tx_bytes;
 215                 } while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
 216
 217                 tot->rx_packets += rx_packets;
 218                 tot->tx_packets += tx_packets;
 219                 tot->rx_bytes   += rx_bytes;
 220                 tot->tx_bytes   += tx_bytes;
 221         }
 222 }
 223 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
 224
 225 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 226         [LWTUNNEL_IP_ID]        = { .type = NLA_U64 },
 227         [LWTUNNEL_IP_DST]       = { .type = NLA_U32 },
 228         [LWTUNNEL_IP_SRC]       = { .type = NLA_U32 },
 229         [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
 230         [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
 231         [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
 232 };
 233
 234 static int ip_tun_build_state(struct nlattr *attr,
 235                               unsigned int family, const void *cfg,
 236                               struct lwtunnel_state **ts,
 237                               struct netlink_ext_ack *extack)
 238 {
 239         struct ip_tunnel_info *tun_info;
 240         struct lwtunnel_state *new_state;
 241         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
 242         int err;
 243
 244         err = nla_parse_nested(tb, LWTUNNEL_IP_MAX, attr, ip_tun_policy,
 245                                extack);
 246         if (err < 0)
 247                 return err;
 248
 249         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 250         if (!new_state)
 251                 return -ENOMEM;
 252
 253         new_state->type = LWTUNNEL_ENCAP_IP;
 254
 255         tun_info = lwt_tun_info(new_state);
 256
 257         if (tb[LWTUNNEL_IP_ID])
 258                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
 259
 260         if (tb[LWTUNNEL_IP_DST])
 261                 tun_info->key.u.ipv4.dst = nla_get_in_addr(tb[LWTUNNEL_IP_DST]);
 262
 263         if (tb[LWTUNNEL_IP_SRC])
 264                 tun_info->key.u.ipv4.src = nla_get_in_addr(tb[LWTUNNEL_IP_SRC]);
 265
 266         if (tb[LWTUNNEL_IP_TTL])
 267                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
 268
 269         if (tb[LWTUNNEL_IP_TOS])
 270                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 271
 272         if (tb[LWTUNNEL_IP_FLAGS])
 273                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP_FLAGS]);
 274
 275         tun_info->mode = IP_TUNNEL_INFO_TX;
 276         tun_info->options_len = 0;
 277
 278         *ts = new_state;
 279
 280         return 0;
 281 }
 282
 283 static int ip_tun_fill_encap_info(struct sk_buff *skb,
 284                                   struct lwtunnel_state *lwtstate)
 285 {
 286         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 287
 288         if (nla_put_be64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id,
 289                          LWTUNNEL_IP_PAD) ||
 290             nla_put_in_addr(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
 291             nla_put_in_addr(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
 292             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
 293             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 294             nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
 295                 return -ENOMEM;
 296
 297         return 0;
 298 }
 299
 300 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 301 {
 302         return nla_total_size_64bit(8)  /* LWTUNNEL_IP_ID */
 303                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
 304                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
 305                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
 306                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
 307                 + nla_total_size(2);    /* LWTUNNEL_IP_FLAGS */
 308 }
 309
 310 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 311 {
 312         return memcmp(lwt_tun_info(a), lwt_tun_info(b),
 313                       sizeof(struct ip_tunnel_info));
 314 }
 315
 316 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
 317         .build_state = ip_tun_build_state,
 318         .fill_encap = ip_tun_fill_encap_info,
 319         .get_encap_size = ip_tun_encap_nlsize,
 320         .cmp_encap = ip_tun_cmp_encap,
 321         .owner = THIS_MODULE,
 322 };
 323
 324 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 325         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
 326         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
 327         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
 328         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
 329         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
 330         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
 331 };
 332
 333 static int ip6_tun_build_state(struct nlattr *attr,
 334                                unsigned int family, const void *cfg,
 335                                struct lwtunnel_state **ts,
 336                                struct netlink_ext_ack *extack)
 337 {
 338         struct ip_tunnel_info *tun_info;
 339         struct lwtunnel_state *new_state;
 340         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 341         int err;
 342
 343         err = nla_parse_nested(tb, LWTUNNEL_IP6_MAX, attr, ip6_tun_policy,
 344                                extack);
 345         if (err < 0)
 346                 return err;
 347
 348         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 349         if (!new_state)
 350                 return -ENOMEM;
 351
 352         new_state->type = LWTUNNEL_ENCAP_IP6;
 353
 354         tun_info = lwt_tun_info(new_state);
 355
 356         if (tb[LWTUNNEL_IP6_ID])
 357                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP6_ID]);
 358
 359         if (tb[LWTUNNEL_IP6_DST])
 360                 tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
 361
 362         if (tb[LWTUNNEL_IP6_SRC])
 363                 tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
 364
 365         if (tb[LWTUNNEL_IP6_HOPLIMIT])
 366                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
 367
 368         if (tb[LWTUNNEL_IP6_TC])
 369                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
 370
 371         if (tb[LWTUNNEL_IP6_FLAGS])
 372                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP6_FLAGS]);
 373
 374         tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
 375         tun_info->options_len = 0;
 376
 377         *ts = new_state;
 378
 379         return 0;
 380 }
 381
 382 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
 383                                    struct lwtunnel_state *lwtstate)
 384 {
 385         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 386
 387         if (nla_put_be64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id,
 388                          LWTUNNEL_IP6_PAD) ||
 389             nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
 390             nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
 391             nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.tos) ||
 392             nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.ttl) ||
 393             nla_put_be16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags))
 394                 return -ENOMEM;
 395
 396         return 0;
 397 }
 398
 399 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 400 {
 401         return nla_total_size_64bit(8)  /* LWTUNNEL_IP6_ID */
 402                 + nla_total_size(16)    /* LWTUNNEL_IP6_DST */
 403                 + nla_total_size(16)    /* LWTUNNEL_IP6_SRC */
 404                 + nla_total_size(1)     /* LWTUNNEL_IP6_HOPLIMIT */
 405                 + nla_total_size(1)     /* LWTUNNEL_IP6_TC */
 406                 + nla_total_size(2);    /* LWTUNNEL_IP6_FLAGS */
 407 }
 408
 409 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
 410         .build_state = ip6_tun_build_state,
 411         .fill_encap = ip6_tun_fill_encap_info,
 412         .get_encap_size = ip6_tun_encap_nlsize,
 413         .cmp_encap = ip_tun_cmp_encap,
 414         .owner = THIS_MODULE,
 415 };
 416
 417 void __init ip_tunnel_core_init(void)
 418 {
 419         /* If you land here, make sure whether increasing ip_tunnel_info's
 420          * options_len is a reasonable choice with its usage in front ends
 421          * (f.e., it's part of flow keys, etc).
 422          */
 423         BUILD_BUG_ON(IP_TUNNEL_OPTS_MAX != 255);
 424
 425         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
 426         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
 427 }
 428
 429 DEFINE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
 430 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
 431
 432 void ip_tunnel_need_metadata(void)
 433 {
 434         static_branch_inc(&ip_tunnel_metadata_cnt);
 435 }
 436 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
 437
 438 void ip_tunnel_unneed_metadata(void)
 439 {
 440         static_branch_dec(&ip_tunnel_metadata_cnt);
 441 }
 442 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);