net/ipv4/geneve.c

   1 /*
   2  * Geneve: Generic Network Virtualization Encapsulation
   3  *
   4  * Copyright (c) 2014 Nicira, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/kernel.h>
  15 #include <linux/types.h>
  16 #include <linux/module.h>
  17 #include <linux/errno.h>
  18 #include <linux/slab.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/list.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/in.h>
  23 #include <linux/ip.h>
  24 #include <linux/udp.h>
  25 #include <linux/igmp.h>
  26 #include <linux/etherdevice.h>
  27 #include <linux/if_ether.h>
  28 #include <linux/if_vlan.h>
  29 #include <linux/ethtool.h>
  30 #include <linux/mutex.h>
  31 #include <net/arp.h>
  32 #include <net/ndisc.h>
  33 #include <net/ip.h>
  34 #include <net/ip_tunnels.h>
  35 #include <net/icmp.h>
  36 #include <net/udp.h>
  37 #include <net/rtnetlink.h>
  38 #include <net/route.h>
  39 #include <net/dsfield.h>
  40 #include <net/inet_ecn.h>
  41 #include <net/net_namespace.h>
  42 #include <net/netns/generic.h>
  43 #include <net/geneve.h>
  44 #include <net/protocol.h>
  45 #include <net/udp_tunnel.h>
  46 #if IS_ENABLED(CONFIG_IPV6)
  47 #include <net/ipv6.h>
  48 #include <net/addrconf.h>
  49 #include <net/ip6_tunnel.h>
  50 #include <net/ip6_checksum.h>
  51 #endif
  52
  53 /* Protects sock_list and refcounts. */
  54 static DEFINE_MUTEX(geneve_mutex);
  55
  56 /* per-network namespace private data for this module */
  57 struct geneve_net {
  58         struct list_head        sock_list;
  59 };
  60
  61 static int geneve_net_id;
  62
  63 static inline struct genevehdr *geneve_hdr(const struct sk_buff *skb)
  64 {
  65         return (struct genevehdr *)(udp_hdr(skb) + 1);
  66 }
  67
  68 static struct geneve_sock *geneve_find_sock(struct net *net,
  69                                             sa_family_t family, __be16 port)
  70 {
  71         struct geneve_net *gn = net_generic(net, geneve_net_id);
  72         struct geneve_sock *gs;
  73
  74         list_for_each_entry(gs, &gn->sock_list, list) {
  75                 if (inet_sk(gs->sock->sk)->inet_sport == port &&
  76                     inet_sk(gs->sock->sk)->sk.sk_family == family)
  77                         return gs;
  78         }
  79
  80         return NULL;
  81 }
  82
  83 static void geneve_build_header(struct genevehdr *geneveh,
  84                                 __be16 tun_flags, u8 vni[3],
  85                                 u8 options_len, u8 *options)
  86 {
  87         geneveh->ver = GENEVE_VER;
  88         geneveh->opt_len = options_len / 4;
  89         geneveh->oam = !!(tun_flags & TUNNEL_OAM);
  90         geneveh->critical = !!(tun_flags & TUNNEL_CRIT_OPT);
  91         geneveh->rsvd1 = 0;
  92         memcpy(geneveh->vni, vni, 3);
  93         geneveh->proto_type = htons(ETH_P_TEB);
  94         geneveh->rsvd2 = 0;
  95
  96         memcpy(geneveh->options, options, options_len);
  97 }
  98
  99 /* Transmit a fully formatted Geneve frame.
 100  *
 101  * When calling this function. The skb->data should point
 102  * to the geneve header which is fully formed.
 103  *
 104  * This function will add other UDP tunnel headers.
 105  */
 106 int geneve_xmit_skb(struct geneve_sock *gs, struct rtable *rt,
 107                     struct sk_buff *skb, __be32 src, __be32 dst, __u8 tos,
 108                     __u8 ttl, __be16 df, __be16 src_port, __be16 dst_port,
 109                     __be16 tun_flags, u8 vni[3], u8 opt_len, u8 *opt,
 110                     bool csum, bool xnet)
 111 {
 112         struct genevehdr *gnvh;
 113         int min_headroom;
 114         int err;
 115
 116         skb = udp_tunnel_handle_offloads(skb, csum);
 117         if (IS_ERR(skb))
 118                 return PTR_ERR(skb);
 119
 120         min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
 121                         + GENEVE_BASE_HLEN + opt_len + sizeof(struct iphdr)
 122                         + (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);
 123
 124         err = skb_cow_head(skb, min_headroom);
 125         if (unlikely(err)) {
 126                 kfree_skb(skb);
 127                 return err;
 128         }
 129
 130         skb = vlan_hwaccel_push_inside(skb);
 131         if (unlikely(!skb))
 132                 return -ENOMEM;
 133
 134         gnvh = (struct genevehdr *)__skb_push(skb, sizeof(*gnvh) + opt_len);
 135         geneve_build_header(gnvh, tun_flags, vni, opt_len, opt);
 136
 137         skb_set_inner_protocol(skb, htons(ETH_P_TEB));
 138
 139         return udp_tunnel_xmit_skb(rt, skb, src, dst,
 140                                    tos, ttl, df, src_port, dst_port, xnet,
 141                                    !csum);
 142 }
 143 EXPORT_SYMBOL_GPL(geneve_xmit_skb);
 144
 145 static int geneve_hlen(struct genevehdr *gh)
 146 {
 147         return sizeof(*gh) + gh->opt_len * 4;
 148 }
 149
 150 static struct sk_buff **geneve_gro_receive(struct sk_buff **head,
 151                                            struct sk_buff *skb,
 152                                            struct udp_offload *uoff)
 153 {
 154         struct sk_buff *p, **pp = NULL;
 155         struct genevehdr *gh, *gh2;
 156         unsigned int hlen, gh_len, off_gnv;
 157         const struct packet_offload *ptype;
 158         __be16 type;
 159         int flush = 1;
 160
 161         off_gnv = skb_gro_offset(skb);
 162         hlen = off_gnv + sizeof(*gh);
 163         gh = skb_gro_header_fast(skb, off_gnv);
 164         if (skb_gro_header_hard(skb, hlen)) {
 165                 gh = skb_gro_header_slow(skb, hlen, off_gnv);
 166                 if (unlikely(!gh))
 167                         goto out;
 168         }
 169
 170         if (gh->ver != GENEVE_VER || gh->oam)
 171                 goto out;
 172         gh_len = geneve_hlen(gh);
 173
 174         hlen = off_gnv + gh_len;
 175         if (skb_gro_header_hard(skb, hlen)) {
 176                 gh = skb_gro_header_slow(skb, hlen, off_gnv);
 177                 if (unlikely(!gh))
 178                         goto out;
 179         }
 180
 181         flush = 0;
 182
 183         for (p = *head; p; p = p->next) {
 184                 if (!NAPI_GRO_CB(p)->same_flow)
 185                         continue;
 186
 187                 gh2 = (struct genevehdr *)(p->data + off_gnv);
 188                 if (gh->opt_len != gh2->opt_len ||
 189                     memcmp(gh, gh2, gh_len)) {
 190                         NAPI_GRO_CB(p)->same_flow = 0;
 191                         continue;
 192                 }
 193         }
 194
 195         type = gh->proto_type;
 196
 197         rcu_read_lock();
 198         ptype = gro_find_receive_by_type(type);
 199         if (ptype == NULL) {
 200                 flush = 1;
 201                 goto out_unlock;
 202         }
 203
 204         skb_gro_pull(skb, gh_len);
 205         skb_gro_postpull_rcsum(skb, gh, gh_len);
 206         pp = ptype->callbacks.gro_receive(head, skb);
 207
 208 out_unlock:
 209         rcu_read_unlock();
 210 out:
 211         NAPI_GRO_CB(skb)->flush |= flush;
 212
 213         return pp;
 214 }
 215
 216 static int geneve_gro_complete(struct sk_buff *skb, int nhoff,
 217                                struct udp_offload *uoff)
 218 {
 219         struct genevehdr *gh;
 220         struct packet_offload *ptype;
 221         __be16 type;
 222         int gh_len;
 223         int err = -ENOSYS;
 224
 225         udp_tunnel_gro_complete(skb, nhoff);
 226
 227         gh = (struct genevehdr *)(skb->data + nhoff);
 228         gh_len = geneve_hlen(gh);
 229         type = gh->proto_type;
 230
 231         rcu_read_lock();
 232         ptype = gro_find_complete_by_type(type);
 233         if (ptype != NULL)
 234                 err = ptype->callbacks.gro_complete(skb, nhoff + gh_len);
 235
 236         rcu_read_unlock();
 237         return err;
 238 }
 239
 240 static void geneve_notify_add_rx_port(struct geneve_sock *gs)
 241 {
 242         struct sock *sk = gs->sock->sk;
 243         sa_family_t sa_family = sk->sk_family;
 244         int err;
 245
 246         if (sa_family == AF_INET) {
 247                 err = udp_add_offload(&gs->udp_offloads);
 248                 if (err)
 249                         pr_warn("geneve: udp_add_offload failed with status %d\n",
 250                                 err);
 251         }
 252 }
 253
 254 static void geneve_notify_del_rx_port(struct geneve_sock *gs)
 255 {
 256         struct sock *sk = gs->sock->sk;
 257         sa_family_t sa_family = sk->sk_family;
 258
 259         if (sa_family == AF_INET)
 260                 udp_del_offload(&gs->udp_offloads);
 261 }
 262
 263 /* Callback from net/ipv4/udp.c to receive packets */
 264 static int geneve_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 265 {
 266         struct genevehdr *geneveh;
 267         struct geneve_sock *gs;
 268         int opts_len;
 269
 270         /* Need Geneve and inner Ethernet header to be present */
 271         if (unlikely(!pskb_may_pull(skb, GENEVE_BASE_HLEN)))
 272                 goto error;
 273
 274         /* Return packets with reserved bits set */
 275         geneveh = geneve_hdr(skb);
 276
 277         if (unlikely(geneveh->ver != GENEVE_VER))
 278                 goto error;
 279
 280         if (unlikely(geneveh->proto_type != htons(ETH_P_TEB)))
 281                 goto error;
 282
 283         opts_len = geneveh->opt_len * 4;
 284         if (iptunnel_pull_header(skb, GENEVE_BASE_HLEN + opts_len,
 285                                  htons(ETH_P_TEB)))
 286                 goto drop;
 287
 288         gs = rcu_dereference_sk_user_data(sk);
 289         if (!gs)
 290                 goto drop;
 291
 292         gs->rcv(gs, skb);
 293         return 0;
 294
 295 drop:
 296         /* Consume bad packet */
 297         kfree_skb(skb);
 298         return 0;
 299
 300 error:
 301         /* Let the UDP layer deal with the skb */
 302         return 1;
 303 }
 304
 305 static struct socket *geneve_create_sock(struct net *net, bool ipv6,
 306                                          __be16 port)
 307 {
 308         struct socket *sock;
 309         struct udp_port_cfg udp_conf;
 310         int err;
 311
 312         memset(&udp_conf, 0, sizeof(udp_conf));
 313
 314         if (ipv6) {
 315                 udp_conf.family = AF_INET6;
 316         } else {
 317                 udp_conf.family = AF_INET;
 318                 udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
 319         }
 320
 321         udp_conf.local_udp_port = port;
 322
 323         /* Open UDP socket */
 324         err = udp_sock_create(net, &udp_conf, &sock);
 325         if (err < 0)
 326                 return ERR_PTR(err);
 327
 328         return sock;
 329 }
 330
 331 /* Create new listen socket if needed */
 332 static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port,
 333                                                 geneve_rcv_t *rcv, void *data,
 334                                                 bool ipv6)
 335 {
 336         struct geneve_net *gn = net_generic(net, geneve_net_id);
 337         struct geneve_sock *gs;
 338         struct socket *sock;
 339         struct udp_tunnel_sock_cfg tunnel_cfg;
 340
 341         gs = kzalloc(sizeof(*gs), GFP_KERNEL);
 342         if (!gs)
 343                 return ERR_PTR(-ENOMEM);
 344
 345         sock = geneve_create_sock(net, ipv6, port);
 346         if (IS_ERR(sock)) {
 347                 kfree(gs);
 348                 return ERR_CAST(sock);
 349         }
 350
 351         gs->sock = sock;
 352         gs->refcnt = 1;
 353         gs->rcv = rcv;
 354         gs->rcv_data = data;
 355
 356         /* Initialize the geneve udp offloads structure */
 357         gs->udp_offloads.port = port;
 358         gs->udp_offloads.callbacks.gro_receive  = geneve_gro_receive;
 359         gs->udp_offloads.callbacks.gro_complete = geneve_gro_complete;
 360         geneve_notify_add_rx_port(gs);
 361
 362         /* Mark socket as an encapsulation socket */
 363         tunnel_cfg.sk_user_data = gs;
 364         tunnel_cfg.encap_type = 1;
 365         tunnel_cfg.encap_rcv = geneve_udp_encap_recv;
 366         tunnel_cfg.encap_destroy = NULL;
 367         setup_udp_tunnel_sock(net, sock, &tunnel_cfg);
 368
 369         list_add(&gs->list, &gn->sock_list);
 370
 371         return gs;
 372 }
 373
 374 struct geneve_sock *geneve_sock_add(struct net *net, __be16 port,
 375                                     geneve_rcv_t *rcv, void *data,
 376                                     bool no_share, bool ipv6)
 377 {
 378         struct geneve_sock *gs;
 379
 380         mutex_lock(&geneve_mutex);
 381
 382         gs = geneve_find_sock(net, ipv6 ? AF_INET6 : AF_INET, port);
 383         if (gs) {
 384                 if (!no_share && gs->rcv == rcv)
 385                         gs->refcnt++;
 386                 else
 387                         gs = ERR_PTR(-EBUSY);
 388         } else {
 389                 gs = geneve_socket_create(net, port, rcv, data, ipv6);
 390         }
 391
 392         mutex_unlock(&geneve_mutex);
 393
 394         return gs;
 395 }
 396 EXPORT_SYMBOL_GPL(geneve_sock_add);
 397
 398 void geneve_sock_release(struct geneve_sock *gs)
 399 {
 400         mutex_lock(&geneve_mutex);
 401
 402         if (--gs->refcnt)
 403                 goto unlock;
 404
 405         list_del(&gs->list);
 406         geneve_notify_del_rx_port(gs);
 407         udp_tunnel_sock_release(gs->sock);
 408         kfree_rcu(gs, rcu);
 409
 410 unlock:
 411         mutex_unlock(&geneve_mutex);
 412 }
 413 EXPORT_SYMBOL_GPL(geneve_sock_release);
 414
 415 static __net_init int geneve_init_net(struct net *net)
 416 {
 417         struct geneve_net *gn = net_generic(net, geneve_net_id);
 418
 419         INIT_LIST_HEAD(&gn->sock_list);
 420
 421         return 0;
 422 }
 423
 424 static struct pernet_operations geneve_net_ops = {
 425         .init = geneve_init_net,
 426         .id   = &geneve_net_id,
 427         .size = sizeof(struct geneve_net),
 428 };
 429
 430 static int __init geneve_init_module(void)
 431 {
 432         int rc;
 433
 434         rc = register_pernet_subsys(&geneve_net_ops);
 435         if (rc)
 436                 return rc;
 437
 438         pr_info("Geneve driver\n");
 439
 440         return 0;
 441 }
 442 module_init(geneve_init_module);
 443
 444 static void __exit geneve_cleanup_module(void)
 445 {
 446         unregister_pernet_subsys(&geneve_net_ops);
 447 }
 448 module_exit(geneve_cleanup_module);
 449
 450 MODULE_LICENSE("GPL");
 451 MODULE_AUTHOR("Jesse Gross <jesse@nicira.com>");
 452 MODULE_DESCRIPTION("Driver for GENEVE encapsulated traffic");
 453 MODULE_ALIAS_RTNL_LINK("geneve");