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/rculist.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/hash.h>
  30 #include <linux/ethtool.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 #define PORT_HASH_BITS 8
  54 #define PORT_HASH_SIZE (1<<PORT_HASH_BITS)
  55
  56 /* per-network namespace private data for this module */
  57 struct geneve_net {
  58         struct hlist_head       sock_list[PORT_HASH_SIZE];
  59         spinlock_t              sock_lock;   /* Protects sock_list */
  60 };
  61
  62 static int geneve_net_id;
  63
  64 static struct workqueue_struct *geneve_wq;
  65
  66 static inline struct genevehdr *geneve_hdr(const struct sk_buff *skb)
  67 {
  68         return (struct genevehdr *)(udp_hdr(skb) + 1);
  69 }
  70
  71 static struct hlist_head *gs_head(struct net *net, __be16 port)
  72 {
  73         struct geneve_net *gn = net_generic(net, geneve_net_id);
  74
  75         return &gn->sock_list[hash_32(ntohs(port), PORT_HASH_BITS)];
  76 }
  77
  78 /* Find geneve socket based on network namespace and UDP port */
  79 static struct geneve_sock *geneve_find_sock(struct net *net, __be16 port)
  80 {
  81         struct geneve_sock *gs;
  82
  83         hlist_for_each_entry_rcu(gs, gs_head(net, port), hlist) {
  84                 if (inet_sk(gs->sock->sk)->inet_sport == port)
  85                         return gs;
  86         }
  87
  88         return NULL;
  89 }
  90
  91 static void geneve_build_header(struct genevehdr *geneveh,
  92                                 __be16 tun_flags, u8 vni[3],
  93                                 u8 options_len, u8 *options)
  94 {
  95         geneveh->ver = GENEVE_VER;
  96         geneveh->opt_len = options_len / 4;
  97         geneveh->oam = !!(tun_flags & TUNNEL_OAM);
  98         geneveh->critical = !!(tun_flags & TUNNEL_CRIT_OPT);
  99         geneveh->rsvd1 = 0;
 100         memcpy(geneveh->vni, vni, 3);
 101         geneveh->proto_type = htons(ETH_P_TEB);
 102         geneveh->rsvd2 = 0;
 103
 104         memcpy(geneveh->options, options, options_len);
 105 }
 106
 107 /* Transmit a fully formated Geneve frame.
 108  *
 109  * When calling this function. The skb->data should point
 110  * to the geneve header which is fully formed.
 111  *
 112  * This function will add other UDP tunnel headers.
 113  */
 114 int geneve_xmit_skb(struct geneve_sock *gs, struct rtable *rt,
 115                     struct sk_buff *skb, __be32 src, __be32 dst, __u8 tos,
 116                     __u8 ttl, __be16 df, __be16 src_port, __be16 dst_port,
 117                     __be16 tun_flags, u8 vni[3], u8 opt_len, u8 *opt,
 118                     bool xnet)
 119 {
 120         struct genevehdr *gnvh;
 121         int min_headroom;
 122         int err;
 123
 124         skb = udp_tunnel_handle_offloads(skb, !gs->sock->sk->sk_no_check_tx);
 125
 126         min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
 127                         + GENEVE_BASE_HLEN + opt_len + sizeof(struct iphdr)
 128                         + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);
 129
 130         err = skb_cow_head(skb, min_headroom);
 131         if (unlikely(err))
 132                 return err;
 133
 134         if (vlan_tx_tag_present(skb)) {
 135                 if (unlikely(!__vlan_put_tag(skb,
 136                                              skb->vlan_proto,
 137                                              vlan_tx_tag_get(skb)))) {
 138                         err = -ENOMEM;
 139                         return err;
 140                 }
 141                 skb->vlan_tci = 0;
 142         }
 143
 144         gnvh = (struct genevehdr *)__skb_push(skb, sizeof(*gnvh) + opt_len);
 145         geneve_build_header(gnvh, tun_flags, vni, opt_len, opt);
 146
 147         return udp_tunnel_xmit_skb(gs->sock, rt, skb, src, dst,
 148                                    tos, ttl, df, src_port, dst_port, xnet);
 149 }
 150 EXPORT_SYMBOL_GPL(geneve_xmit_skb);
 151
 152 static void geneve_notify_add_rx_port(struct geneve_sock *gs)
 153 {
 154         struct sock *sk = gs->sock->sk;
 155         sa_family_t sa_family = sk->sk_family;
 156         int err;
 157
 158         if (sa_family == AF_INET) {
 159                 err = udp_add_offload(&gs->udp_offloads);
 160                 if (err)
 161                         pr_warn("geneve: udp_add_offload failed with status %d\n",
 162                                 err);
 163         }
 164 }
 165
 166 /* Callback from net/ipv4/udp.c to receive packets */
 167 static int geneve_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 168 {
 169         struct genevehdr *geneveh;
 170         struct geneve_sock *gs;
 171         int opts_len;
 172
 173         /* Need Geneve and inner Ethernet header to be present */
 174         if (unlikely(!pskb_may_pull(skb, GENEVE_BASE_HLEN)))
 175                 goto error;
 176
 177         /* Return packets with reserved bits set */
 178         geneveh = geneve_hdr(skb);
 179
 180         if (unlikely(geneveh->ver != GENEVE_VER))
 181                 goto error;
 182
 183         if (unlikely(geneveh->proto_type != htons(ETH_P_TEB)))
 184                 goto error;
 185
 186         opts_len = geneveh->opt_len * 4;
 187         if (iptunnel_pull_header(skb, GENEVE_BASE_HLEN + opts_len,
 188                                  htons(ETH_P_TEB)))
 189                 goto drop;
 190
 191         gs = rcu_dereference_sk_user_data(sk);
 192         if (!gs)
 193                 goto drop;
 194
 195         gs->rcv(gs, skb);
 196         return 0;
 197
 198 drop:
 199         /* Consume bad packet */
 200         kfree_skb(skb);
 201         return 0;
 202
 203 error:
 204         /* Let the UDP layer deal with the skb */
 205         return 1;
 206 }
 207
 208 static void geneve_del_work(struct work_struct *work)
 209 {
 210         struct geneve_sock *gs = container_of(work, struct geneve_sock,
 211                                               del_work);
 212
 213         udp_tunnel_sock_release(gs->sock);
 214         kfree_rcu(gs, rcu);
 215 }
 216
 217 static struct socket *geneve_create_sock(struct net *net, bool ipv6,
 218                                          __be16 port)
 219 {
 220         struct socket *sock;
 221         struct udp_port_cfg udp_conf;
 222         int err;
 223
 224         memset(&udp_conf, 0, sizeof(udp_conf));
 225
 226         if (ipv6) {
 227                 udp_conf.family = AF_INET6;
 228         } else {
 229                 udp_conf.family = AF_INET;
 230                 udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
 231         }
 232
 233         udp_conf.local_udp_port = port;
 234
 235         /* Open UDP socket */
 236         err = udp_sock_create(net, &udp_conf, &sock);
 237         if (err < 0)
 238                 return ERR_PTR(err);
 239
 240         return sock;
 241 }
 242
 243 /* Create new listen socket if needed */
 244 static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port,
 245                                                 geneve_rcv_t *rcv, void *data,
 246                                                 bool ipv6)
 247 {
 248         struct geneve_net *gn = net_generic(net, geneve_net_id);
 249         struct geneve_sock *gs;
 250         struct socket *sock;
 251         struct udp_tunnel_sock_cfg tunnel_cfg;
 252
 253         gs = kzalloc(sizeof(*gs), GFP_KERNEL);
 254         if (!gs)
 255                 return ERR_PTR(-ENOMEM);
 256
 257         INIT_WORK(&gs->del_work, geneve_del_work);
 258
 259         sock = geneve_create_sock(net, ipv6, port);
 260         if (IS_ERR(sock)) {
 261                 kfree(gs);
 262                 return ERR_CAST(sock);
 263         }
 264
 265         gs->sock = sock;
 266         atomic_set(&gs->refcnt, 1);
 267         gs->rcv = rcv;
 268         gs->rcv_data = data;
 269
 270         /* Initialize the geneve udp offloads structure */
 271         gs->udp_offloads.port = port;
 272         gs->udp_offloads.callbacks.gro_receive = NULL;
 273         gs->udp_offloads.callbacks.gro_complete = NULL;
 274
 275         spin_lock(&gn->sock_lock);
 276         hlist_add_head_rcu(&gs->hlist, gs_head(net, port));
 277         geneve_notify_add_rx_port(gs);
 278         spin_unlock(&gn->sock_lock);
 279
 280         /* Mark socket as an encapsulation socket */
 281         tunnel_cfg.sk_user_data = gs;
 282         tunnel_cfg.encap_type = 1;
 283         tunnel_cfg.encap_rcv = geneve_udp_encap_recv;
 284         tunnel_cfg.encap_destroy = NULL;
 285         setup_udp_tunnel_sock(net, sock, &tunnel_cfg);
 286
 287         return gs;
 288 }
 289
 290 struct geneve_sock *geneve_sock_add(struct net *net, __be16 port,
 291                                     geneve_rcv_t *rcv, void *data,
 292                                     bool no_share, bool ipv6)
 293 {
 294         struct geneve_sock *gs;
 295
 296         gs = geneve_socket_create(net, port, rcv, data, ipv6);
 297         if (!IS_ERR(gs))
 298                 return gs;
 299
 300         if (no_share)   /* Return error if sharing is not allowed. */
 301                 return ERR_PTR(-EINVAL);
 302
 303         gs = geneve_find_sock(net, port);
 304         if (gs) {
 305                 if (gs->rcv == rcv)
 306                         atomic_inc(&gs->refcnt);
 307                 else
 308                         gs = ERR_PTR(-EBUSY);
 309         } else {
 310                 gs = ERR_PTR(-EINVAL);
 311         }
 312
 313         return gs;
 314 }
 315 EXPORT_SYMBOL_GPL(geneve_sock_add);
 316
 317 void geneve_sock_release(struct geneve_sock *gs)
 318 {
 319         if (!atomic_dec_and_test(&gs->refcnt))
 320                 return;
 321
 322         queue_work(geneve_wq, &gs->del_work);
 323 }
 324 EXPORT_SYMBOL_GPL(geneve_sock_release);
 325
 326 static __net_init int geneve_init_net(struct net *net)
 327 {
 328         struct geneve_net *gn = net_generic(net, geneve_net_id);
 329         unsigned int h;
 330
 331         spin_lock_init(&gn->sock_lock);
 332
 333         for (h = 0; h < PORT_HASH_SIZE; ++h)
 334                 INIT_HLIST_HEAD(&gn->sock_list[h]);
 335
 336         return 0;
 337 }
 338
 339 static struct pernet_operations geneve_net_ops = {
 340         .init = geneve_init_net,
 341         .exit = NULL,
 342         .id   = &geneve_net_id,
 343         .size = sizeof(struct geneve_net),
 344 };
 345
 346 static int __init geneve_init_module(void)
 347 {
 348         int rc;
 349
 350         geneve_wq = alloc_workqueue("geneve", 0, 0);
 351         if (!geneve_wq)
 352                 return -ENOMEM;
 353
 354         rc = register_pernet_subsys(&geneve_net_ops);
 355         if (rc)
 356                 return rc;
 357
 358         pr_info("Geneve driver\n");
 359
 360         return 0;
 361 }
 362 late_initcall(geneve_init_module);
 363
 364 static void __exit geneve_cleanup_module(void)
 365 {
 366         destroy_workqueue(geneve_wq);
 367 }
 368 module_exit(geneve_cleanup_module);
 369
 370 MODULE_LICENSE("GPL");
 371 MODULE_AUTHOR("Jesse Gross <jesse@nicira.com>");
 372 MODULE_DESCRIPTION("Driver for GENEVE encapsulated traffic");
 373 MODULE_ALIAS_RTNL_LINK("geneve");