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         int skb_iif = skb->skb_iif;
  67         struct iphdr *iph;
  68         int err;
  69
  70         skb_scrub_packet(skb, xnet);
  71
  72         skb_clear_hash(skb);
  73         skb_dst_set(skb, &rt->dst);
  74         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
  75
  76         if (skb_iif && !(df & htons(IP_DF))) {
  77                 /* Arrived from an ingress interface, got encapsulated, with
  78                  * fragmentation of encapulating frames allowed.
  79                  * If skb is gso, the resulting encapsulated network segments
  80                  * may exceed dst mtu.
  81                  * Allow IP Fragmentation of segments.
  82                  */
  83                 IPCB(skb)->flags |= IPSKB_FRAG_SEGS;
  84         }
  85
  86         /* Push down and install the IP header. */
  87         skb_push(skb, sizeof(struct iphdr));
  88         skb_reset_network_header(skb);
  89
  90         iph = ip_hdr(skb);
  91
  92         iph->version    =       4;
  93         iph->ihl        =       sizeof(struct iphdr) >> 2;
  94         iph->frag_off   =       df;
  95         iph->protocol   =       proto;
  96         iph->tos        =       tos;
  97         iph->daddr      =       dst;
  98         iph->saddr      =       src;
  99         iph->ttl        =       ttl;
 100         __ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
 101
 102         err = ip_local_out(net, sk, skb);
 103         if (unlikely(net_xmit_eval(err)))
 104                 pkt_len = 0;
 105         iptunnel_xmit_stats(dev, pkt_len);
 106 }
 107 EXPORT_SYMBOL_GPL(iptunnel_xmit);
 108
 109 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
 110                            __be16 inner_proto, bool raw_proto, bool xnet)
 111 {
 112         if (unlikely(!pskb_may_pull(skb, hdr_len)))
 113                 return -ENOMEM;
 114
 115         skb_pull_rcsum(skb, hdr_len);
 116
 117         if (!raw_proto && inner_proto == htons(ETH_P_TEB)) {
 118                 struct ethhdr *eh;
 119
 120                 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
 121                         return -ENOMEM;
 122
 123                 eh = (struct ethhdr *)skb->data;
 124                 if (likely(eth_proto_is_802_3(eh->h_proto)))
 125                         skb->protocol = eh->h_proto;
 126                 else
 127                         skb->protocol = htons(ETH_P_802_2);
 128
 129         } else {
 130                 skb->protocol = inner_proto;
 131         }
 132
 133         skb_clear_hash_if_not_l4(skb);
 134         skb->vlan_tci = 0;
 135         skb_set_queue_mapping(skb, 0);
 136         skb_scrub_packet(skb, xnet);
 137
 138         return iptunnel_pull_offloads(skb);
 139 }
 140 EXPORT_SYMBOL_GPL(__iptunnel_pull_header);
 141
 142 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 143                                              gfp_t flags)
 144 {
 145         struct metadata_dst *res;
 146         struct ip_tunnel_info *dst, *src;
 147
 148         if (!md || md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
 149                 return NULL;
 150
 151         res = metadata_dst_alloc(0, flags);
 152         if (!res)
 153                 return NULL;
 154
 155         dst = &res->u.tun_info;
 156         src = &md->u.tun_info;
 157         dst->key.tun_id = src->key.tun_id;
 158         if (src->mode & IP_TUNNEL_INFO_IPV6)
 159                 memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
 160                        sizeof(struct in6_addr));
 161         else
 162                 dst->key.u.ipv4.dst = src->key.u.ipv4.src;
 163         dst->mode = src->mode | IP_TUNNEL_INFO_TX;
 164
 165         return res;
 166 }
 167 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
 168
 169 int iptunnel_handle_offloads(struct sk_buff *skb,
 170                              int gso_type_mask)
 171 {
 172         int err;
 173
 174         if (likely(!skb->encapsulation)) {
 175                 skb_reset_inner_headers(skb);
 176                 skb->encapsulation = 1;
 177         }
 178
 179         if (skb_is_gso(skb)) {
 180                 err = skb_header_unclone(skb, GFP_ATOMIC);
 181                 if (unlikely(err))
 182                         return err;
 183                 skb_shinfo(skb)->gso_type |= gso_type_mask;
 184                 return 0;
 185         }
 186
 187         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 188                 skb->ip_summed = CHECKSUM_NONE;
 189                 /* We clear encapsulation here to prevent badly-written
 190                  * drivers potentially deciding to offload an inner checksum
 191                  * if we set CHECKSUM_PARTIAL on the outer header.
 192                  * This should go away when the drivers are all fixed.
 193                  */
 194                 skb->encapsulation = 0;
 195         }
 196
 197         return 0;
 198 }
 199 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
 200
 201 /* Often modified stats are per cpu, other are shared (netdev->stats) */
 202 struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
 203                                                 struct rtnl_link_stats64 *tot)
 204 {
 205         int i;
 206
 207         netdev_stats_to_stats64(tot, &dev->stats);
 208
 209         for_each_possible_cpu(i) {
 210                 const struct pcpu_sw_netstats *tstats =
 211                                                    per_cpu_ptr(dev->tstats, i);
 212                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 213                 unsigned int start;
 214
 215                 do {
 216                         start = u64_stats_fetch_begin_irq(&tstats->syncp);
 217                         rx_packets = tstats->rx_packets;
 218                         tx_packets = tstats->tx_packets;
 219                         rx_bytes = tstats->rx_bytes;
 220                         tx_bytes = tstats->tx_bytes;
 221                 } while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
 222
 223                 tot->rx_packets += rx_packets;
 224                 tot->tx_packets += tx_packets;
 225                 tot->rx_bytes   += rx_bytes;
 226                 tot->tx_bytes   += tx_bytes;
 227         }
 228
 229         return tot;
 230 }
 231 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
 232
 233 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 234         [LWTUNNEL_IP_ID]        = { .type = NLA_U64 },
 235         [LWTUNNEL_IP_DST]       = { .type = NLA_U32 },
 236         [LWTUNNEL_IP_SRC]       = { .type = NLA_U32 },
 237         [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
 238         [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
 239         [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
 240 };
 241
 242 static int ip_tun_build_state(struct net_device *dev, struct nlattr *attr,
 243                               unsigned int family, const void *cfg,
 244                               struct lwtunnel_state **ts)
 245 {
 246         struct ip_tunnel_info *tun_info;
 247         struct lwtunnel_state *new_state;
 248         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
 249         int err;
 250
 251         err = nla_parse_nested(tb, LWTUNNEL_IP_MAX, attr, ip_tun_policy);
 252         if (err < 0)
 253                 return err;
 254
 255         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 256         if (!new_state)
 257                 return -ENOMEM;
 258
 259         new_state->type = LWTUNNEL_ENCAP_IP;
 260
 261         tun_info = lwt_tun_info(new_state);
 262
 263         if (tb[LWTUNNEL_IP_ID])
 264                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
 265
 266         if (tb[LWTUNNEL_IP_DST])
 267                 tun_info->key.u.ipv4.dst = nla_get_in_addr(tb[LWTUNNEL_IP_DST]);
 268
 269         if (tb[LWTUNNEL_IP_SRC])
 270                 tun_info->key.u.ipv4.src = nla_get_in_addr(tb[LWTUNNEL_IP_SRC]);
 271
 272         if (tb[LWTUNNEL_IP_TTL])
 273                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
 274
 275         if (tb[LWTUNNEL_IP_TOS])
 276                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 277
 278         if (tb[LWTUNNEL_IP_FLAGS])
 279                 tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP_FLAGS]);
 280
 281         tun_info->mode = IP_TUNNEL_INFO_TX;
 282         tun_info->options_len = 0;
 283
 284         *ts = new_state;
 285
 286         return 0;
 287 }
 288
 289 static int ip_tun_fill_encap_info(struct sk_buff *skb,
 290                                   struct lwtunnel_state *lwtstate)
 291 {
 292         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 293
 294         if (nla_put_be64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id,
 295                          LWTUNNEL_IP_PAD) ||
 296             nla_put_in_addr(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
 297             nla_put_in_addr(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
 298             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
 299             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 300             nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
 301                 return -ENOMEM;
 302
 303         return 0;
 304 }
 305
 306 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 307 {
 308         return nla_total_size_64bit(8)  /* LWTUNNEL_IP_ID */
 309                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
 310                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
 311                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
 312                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
 313                 + nla_total_size(2);    /* LWTUNNEL_IP_FLAGS */
 314 }
 315
 316 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 317 {
 318         return memcmp(lwt_tun_info(a), lwt_tun_info(b),
 319                       sizeof(struct ip_tunnel_info));
 320 }
 321
 322 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
 323         .build_state = ip_tun_build_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 };
 328
 329 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 330         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
 331         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
 332         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
 333         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
 334         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
 335         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
 336 };
 337
 338 static int ip6_tun_build_state(struct net_device *dev, struct nlattr *attr,
 339                                unsigned int family, const void *cfg,
 340                                struct lwtunnel_state **ts)
 341 {
 342         struct ip_tunnel_info *tun_info;
 343         struct lwtunnel_state *new_state;
 344         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 345         int err;
 346
 347         err = nla_parse_nested(tb, LWTUNNEL_IP6_MAX, attr, ip6_tun_policy);
 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 };
 418
 419 void __init ip_tunnel_core_init(void)
 420 {
 421         /* If you land here, make sure whether increasing ip_tunnel_info's
 422          * options_len is a reasonable choice with its usage in front ends
 423          * (f.e., it's part of flow keys, etc).
 424          */
 425         BUILD_BUG_ON(IP_TUNNEL_OPTS_MAX != 255);
 426
 427         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
 428         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
 429 }
 430
 431 struct static_key ip_tunnel_metadata_cnt = STATIC_KEY_INIT_FALSE;
 432 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
 433
 434 void ip_tunnel_need_metadata(void)
 435 {
 436         static_key_slow_inc(&ip_tunnel_metadata_cnt);
 437 }
 438 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
 439
 440 void ip_tunnel_unneed_metadata(void)
 441 {
 442         static_key_slow_dec(&ip_tunnel_metadata_cnt);
 443 }
 444 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);