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/mroute.h>
  28 #include <linux/init.h>
  29 #include <linux/in6.h>
  30 #include <linux/inetdevice.h>
  31 #include <linux/netfilter_ipv4.h>
  32 #include <linux/etherdevice.h>
  33 #include <linux/if_ether.h>
  34 #include <linux/if_vlan.h>
  35 #include <linux/static_key.h>
  36
  37 #include <net/ip.h>
  38 #include <net/icmp.h>
  39 #include <net/protocol.h>
  40 #include <net/ip_tunnels.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 int iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
  52                   __be32 src, __be32 dst, __u8 proto,
  53                   __u8 tos, __u8 ttl, __be16 df, bool xnet)
  54 {
  55         int pkt_len = skb->len - skb_inner_network_offset(skb);
  56         struct net *net = dev_net(rt->dst.dev);
  57         struct iphdr *iph;
  58         int err;
  59
  60         skb_scrub_packet(skb, xnet);
  61
  62         skb_clear_hash(skb);
  63         skb_dst_set(skb, &rt->dst);
  64         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
  65
  66         /* Push down and install the IP header. */
  67         skb_push(skb, sizeof(struct iphdr));
  68         skb_reset_network_header(skb);
  69
  70         iph = ip_hdr(skb);
  71
  72         iph->version    =       4;
  73         iph->ihl        =       sizeof(struct iphdr) >> 2;
  74         iph->frag_off   =       df;
  75         iph->protocol   =       proto;
  76         iph->tos        =       tos;
  77         iph->daddr      =       dst;
  78         iph->saddr      =       src;
  79         iph->ttl        =       ttl;
  80         __ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
  81
  82         err = ip_local_out(net, sk, skb);
  83         if (unlikely(net_xmit_eval(err)))
  84                 pkt_len = 0;
  85         return pkt_len;
  86 }
  87 EXPORT_SYMBOL_GPL(iptunnel_xmit);
  88
  89 int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
  90 {
  91         if (unlikely(!pskb_may_pull(skb, hdr_len)))
  92                 return -ENOMEM;
  93
  94         skb_pull_rcsum(skb, hdr_len);
  95
  96         if (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         nf_reset(skb);
 113         secpath_reset(skb);
 114         skb_clear_hash_if_not_l4(skb);
 115         skb_dst_drop(skb);
 116         skb->vlan_tci = 0;
 117         skb_set_queue_mapping(skb, 0);
 118         skb->pkt_type = PACKET_HOST;
 119
 120         return iptunnel_pull_offloads(skb);
 121 }
 122 EXPORT_SYMBOL_GPL(iptunnel_pull_header);
 123
 124 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 125                                              gfp_t flags)
 126 {
 127         struct metadata_dst *res;
 128         struct ip_tunnel_info *dst, *src;
 129
 130         if (!md || md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
 131                 return NULL;
 132
 133         res = metadata_dst_alloc(0, flags);
 134         if (!res)
 135                 return NULL;
 136
 137         dst = &res->u.tun_info;
 138         src = &md->u.tun_info;
 139         dst->key.tun_id = src->key.tun_id;
 140         if (src->mode & IP_TUNNEL_INFO_IPV6)
 141                 memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
 142                        sizeof(struct in6_addr));
 143         else
 144                 dst->key.u.ipv4.dst = src->key.u.ipv4.src;
 145         dst->mode = src->mode | IP_TUNNEL_INFO_TX;
 146
 147         return res;
 148 }
 149 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
 150
 151 struct sk_buff *iptunnel_handle_offloads(struct sk_buff *skb,
 152                                          bool csum_help,
 153                                          int gso_type_mask)
 154 {
 155         int err;
 156
 157         if (likely(!skb->encapsulation)) {
 158                 skb_reset_inner_headers(skb);
 159                 skb->encapsulation = 1;
 160         }
 161
 162         if (skb_is_gso(skb)) {
 163                 err = skb_unclone(skb, GFP_ATOMIC);
 164                 if (unlikely(err))
 165                         goto error;
 166                 skb_shinfo(skb)->gso_type |= gso_type_mask;
 167                 return skb;
 168         }
 169
 170         /* If packet is not gso and we are resolving any partial checksum,
 171          * clear encapsulation flag. This allows setting CHECKSUM_PARTIAL
 172          * on the outer header without confusing devices that implement
 173          * NETIF_F_IP_CSUM with encapsulation.
 174          */
 175         if (csum_help)
 176                 skb->encapsulation = 0;
 177
 178         if (skb->ip_summed == CHECKSUM_PARTIAL && csum_help) {
 179                 err = skb_checksum_help(skb);
 180                 if (unlikely(err))
 181                         goto error;
 182         } else if (skb->ip_summed != CHECKSUM_PARTIAL)
 183                 skb->ip_summed = CHECKSUM_NONE;
 184
 185         return skb;
 186 error:
 187         kfree_skb(skb);
 188         return ERR_PTR(err);
 189 }
 190 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
 191
 192 /* Often modified stats are per cpu, other are shared (netdev->stats) */
 193 struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
 194                                                 struct rtnl_link_stats64 *tot)
 195 {
 196         int i;
 197
 198         netdev_stats_to_stats64(tot, &dev->stats);
 199
 200         for_each_possible_cpu(i) {
 201                 const struct pcpu_sw_netstats *tstats =
 202                                                    per_cpu_ptr(dev->tstats, i);
 203                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 204                 unsigned int start;
 205
 206                 do {
 207                         start = u64_stats_fetch_begin_irq(&tstats->syncp);
 208                         rx_packets = tstats->rx_packets;
 209                         tx_packets = tstats->tx_packets;
 210                         rx_bytes = tstats->rx_bytes;
 211                         tx_bytes = tstats->tx_bytes;
 212                 } while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
 213
 214                 tot->rx_packets += rx_packets;
 215                 tot->tx_packets += tx_packets;
 216                 tot->rx_bytes   += rx_bytes;
 217                 tot->tx_bytes   += tx_bytes;
 218         }
 219
 220         return tot;
 221 }
 222 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
 223
 224 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 225         [LWTUNNEL_IP_ID]        = { .type = NLA_U64 },
 226         [LWTUNNEL_IP_DST]       = { .type = NLA_U32 },
 227         [LWTUNNEL_IP_SRC]       = { .type = NLA_U32 },
 228         [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
 229         [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
 230         [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
 231 };
 232
 233 static int ip_tun_build_state(struct net_device *dev, struct nlattr *attr,
 234                               unsigned int family, const void *cfg,
 235                               struct lwtunnel_state **ts)
 236 {
 237         struct ip_tunnel_info *tun_info;
 238         struct lwtunnel_state *new_state;
 239         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
 240         int err;
 241
 242         err = nla_parse_nested(tb, LWTUNNEL_IP_MAX, attr, ip_tun_policy);
 243         if (err < 0)
 244                 return err;
 245
 246         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 247         if (!new_state)
 248                 return -ENOMEM;
 249
 250         new_state->type = LWTUNNEL_ENCAP_IP;
 251
 252         tun_info = lwt_tun_info(new_state);
 253
 254         if (tb[LWTUNNEL_IP_ID])
 255                 tun_info->key.tun_id = nla_get_u64(tb[LWTUNNEL_IP_ID]);
 256
 257         if (tb[LWTUNNEL_IP_DST])
 258                 tun_info->key.u.ipv4.dst = nla_get_be32(tb[LWTUNNEL_IP_DST]);
 259
 260         if (tb[LWTUNNEL_IP_SRC])
 261                 tun_info->key.u.ipv4.src = nla_get_be32(tb[LWTUNNEL_IP_SRC]);
 262
 263         if (tb[LWTUNNEL_IP_TTL])
 264                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
 265
 266         if (tb[LWTUNNEL_IP_TOS])
 267                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 268
 269         if (tb[LWTUNNEL_IP_FLAGS])
 270                 tun_info->key.tun_flags = nla_get_u16(tb[LWTUNNEL_IP_FLAGS]);
 271
 272         tun_info->mode = IP_TUNNEL_INFO_TX;
 273         tun_info->options_len = 0;
 274
 275         *ts = new_state;
 276
 277         return 0;
 278 }
 279
 280 static int ip_tun_fill_encap_info(struct sk_buff *skb,
 281                                   struct lwtunnel_state *lwtstate)
 282 {
 283         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 284
 285         if (nla_put_u64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id) ||
 286             nla_put_be32(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
 287             nla_put_be32(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
 288             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
 289             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 290             nla_put_u16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
 291                 return -ENOMEM;
 292
 293         return 0;
 294 }
 295
 296 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 297 {
 298         return nla_total_size(8)        /* LWTUNNEL_IP_ID */
 299                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
 300                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
 301                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
 302                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
 303                 + nla_total_size(2);    /* LWTUNNEL_IP_FLAGS */
 304 }
 305
 306 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 307 {
 308         return memcmp(lwt_tun_info(a), lwt_tun_info(b),
 309                       sizeof(struct ip_tunnel_info));
 310 }
 311
 312 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
 313         .build_state = ip_tun_build_state,
 314         .fill_encap = ip_tun_fill_encap_info,
 315         .get_encap_size = ip_tun_encap_nlsize,
 316         .cmp_encap = ip_tun_cmp_encap,
 317 };
 318
 319 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 320         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
 321         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
 322         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
 323         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
 324         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
 325         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
 326 };
 327
 328 static int ip6_tun_build_state(struct net_device *dev, struct nlattr *attr,
 329                                unsigned int family, const void *cfg,
 330                                struct lwtunnel_state **ts)
 331 {
 332         struct ip_tunnel_info *tun_info;
 333         struct lwtunnel_state *new_state;
 334         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 335         int err;
 336
 337         err = nla_parse_nested(tb, LWTUNNEL_IP6_MAX, attr, ip6_tun_policy);
 338         if (err < 0)
 339                 return err;
 340
 341         new_state = lwtunnel_state_alloc(sizeof(*tun_info));
 342         if (!new_state)
 343                 return -ENOMEM;
 344
 345         new_state->type = LWTUNNEL_ENCAP_IP6;
 346
 347         tun_info = lwt_tun_info(new_state);
 348
 349         if (tb[LWTUNNEL_IP6_ID])
 350                 tun_info->key.tun_id = nla_get_u64(tb[LWTUNNEL_IP6_ID]);
 351
 352         if (tb[LWTUNNEL_IP6_DST])
 353                 tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
 354
 355         if (tb[LWTUNNEL_IP6_SRC])
 356                 tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
 357
 358         if (tb[LWTUNNEL_IP6_HOPLIMIT])
 359                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
 360
 361         if (tb[LWTUNNEL_IP6_TC])
 362                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
 363
 364         if (tb[LWTUNNEL_IP6_FLAGS])
 365                 tun_info->key.tun_flags = nla_get_u16(tb[LWTUNNEL_IP6_FLAGS]);
 366
 367         tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
 368         tun_info->options_len = 0;
 369
 370         *ts = new_state;
 371
 372         return 0;
 373 }
 374
 375 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
 376                                    struct lwtunnel_state *lwtstate)
 377 {
 378         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 379
 380         if (nla_put_u64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id) ||
 381             nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
 382             nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
 383             nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.tos) ||
 384             nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.ttl) ||
 385             nla_put_u16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags))
 386                 return -ENOMEM;
 387
 388         return 0;
 389 }
 390
 391 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 392 {
 393         return nla_total_size(8)        /* LWTUNNEL_IP6_ID */
 394                 + nla_total_size(16)    /* LWTUNNEL_IP6_DST */
 395                 + nla_total_size(16)    /* LWTUNNEL_IP6_SRC */
 396                 + nla_total_size(1)     /* LWTUNNEL_IP6_HOPLIMIT */
 397                 + nla_total_size(1)     /* LWTUNNEL_IP6_TC */
 398                 + nla_total_size(2);    /* LWTUNNEL_IP6_FLAGS */
 399 }
 400
 401 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
 402         .build_state = ip6_tun_build_state,
 403         .fill_encap = ip6_tun_fill_encap_info,
 404         .get_encap_size = ip6_tun_encap_nlsize,
 405         .cmp_encap = ip_tun_cmp_encap,
 406 };
 407
 408 void __init ip_tunnel_core_init(void)
 409 {
 410         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
 411         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
 412 }
 413
 414 struct static_key ip_tunnel_metadata_cnt = STATIC_KEY_INIT_FALSE;
 415 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
 416
 417 void ip_tunnel_need_metadata(void)
 418 {
 419         static_key_slow_inc(&ip_tunnel_metadata_cnt);
 420 }
 421 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
 422
 423 void ip_tunnel_unneed_metadata(void)
 424 {
 425         static_key_slow_dec(&ip_tunnel_metadata_cnt);
 426 }
 427 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);