1/*
   2 *	IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
   3 *	Linux INET6 implementation
   4 *
   5 *	Authors:
   6 *	Pedro Roque		<roque@di.fc.ul.pt>
   7 *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
   8 *
   9 *	This program is free software; you can redistribute it and/or
  10 *      modify it under the terms of the GNU General Public License
  11 *      as published by the Free Software Foundation; either version
  12 *      2 of the License, or (at your option) any later version.
  13 *
  14 *	Changes:
  15 * Roger Venning <r.venning@telstra.com>:	6to4 support
  16 * Nate Thompson <nate@thebog.net>:		6to4 support
  17 * Fred Templin <fred.l.templin@boeing.com>:	isatap support
  18 */
  19
  20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22#include <linux/module.h>
  23#include <linux/capability.h>
  24#include <linux/errno.h>
  25#include <linux/types.h>
  26#include <linux/socket.h>
  27#include <linux/sockios.h>
  28#include <linux/net.h>
  29#include <linux/in6.h>
  30#include <linux/netdevice.h>
  31#include <linux/if_arp.h>
  32#include <linux/icmp.h>
  33#include <linux/slab.h>
  34#include <asm/uaccess.h>
  35#include <linux/init.h>
  36#include <linux/netfilter_ipv4.h>
  37#include <linux/if_ether.h>
  38
  39#include <net/sock.h>
  40#include <net/snmp.h>
  41
  42#include <net/ipv6.h>
  43#include <net/protocol.h>
  44#include <net/transp_v6.h>
  45#include <net/ip6_fib.h>
  46#include <net/ip6_route.h>
  47#include <net/ndisc.h>
  48#include <net/addrconf.h>
  49#include <net/ip.h>
  50#include <net/udp.h>
  51#include <net/icmp.h>
  52#include <net/ip_tunnels.h>
  53#include <net/inet_ecn.h>
  54#include <net/xfrm.h>
  55#include <net/dsfield.h>
  56#include <net/net_namespace.h>
  57#include <net/netns/generic.h>
  58
  59/*
  60   This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  61
  62   For comments look at net/ipv4/ip_gre.c --ANK
  63 */
  64
  65#define HASH_SIZE  16
  66#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  67
  68static bool log_ecn_error = true;
  69module_param(log_ecn_error, bool, 0644);
  70MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
  71
  72static int ipip6_tunnel_init(struct net_device *dev);
  73static void ipip6_tunnel_setup(struct net_device *dev);
  74static void ipip6_dev_free(struct net_device *dev);
  75static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
  76		      __be32 *v4dst);
  77static struct rtnl_link_ops sit_link_ops __read_mostly;
  78
  79static int sit_net_id __read_mostly;
  80struct sit_net {
  81	struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  82	struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  83	struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  84	struct ip_tunnel __rcu *tunnels_wc[1];
  85	struct ip_tunnel __rcu **tunnels[4];
  86
  87	struct net_device *fb_tunnel_dev;
  88};
  89
  90/*
  91 * Must be invoked with rcu_read_lock
  92 */
  93static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
  94		struct net_device *dev, __be32 remote, __be32 local)
  95{
  96	unsigned int h0 = HASH(remote);
  97	unsigned int h1 = HASH(local);
  98	struct ip_tunnel *t;
  99	struct sit_net *sitn = net_generic(net, sit_net_id);
 100
 101	for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 102		if (local == t->parms.iph.saddr &&
 103		    remote == t->parms.iph.daddr &&
 104		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 105		    (t->dev->flags & IFF_UP))
 106			return t;
 107	}
 108	for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 109		if (remote == t->parms.iph.daddr &&
 110		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 111		    (t->dev->flags & IFF_UP))
 112			return t;
 113	}
 114	for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 115		if (local == t->parms.iph.saddr &&
 116		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 117		    (t->dev->flags & IFF_UP))
 118			return t;
 119	}
 120	t = rcu_dereference(sitn->tunnels_wc[0]);
 121	if (t && (t->dev->flags & IFF_UP))
 122		return t;
 123	return NULL;
 124}
 125
 126static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 127		struct ip_tunnel_parm *parms)
 128{
 129	__be32 remote = parms->iph.daddr;
 130	__be32 local = parms->iph.saddr;
 131	unsigned int h = 0;
 132	int prio = 0;
 133
 134	if (remote) {
 135		prio |= 2;
 136		h ^= HASH(remote);
 137	}
 138	if (local) {
 139		prio |= 1;
 140		h ^= HASH(local);
 141	}
 142	return &sitn->tunnels[prio][h];
 143}
 144
 145static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 146		struct ip_tunnel *t)
 147{
 148	return __ipip6_bucket(sitn, &t->parms);
 149}
 150
 151static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 152{
 153	struct ip_tunnel __rcu **tp;
 154	struct ip_tunnel *iter;
 155
 156	for (tp = ipip6_bucket(sitn, t);
 157	     (iter = rtnl_dereference(*tp)) != NULL;
 158	     tp = &iter->next) {
 159		if (t == iter) {
 160			rcu_assign_pointer(*tp, t->next);
 161			break;
 162		}
 163	}
 164}
 165
 166static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 167{
 168	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 169
 170	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 171	rcu_assign_pointer(*tp, t);
 172}
 173
 174static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 175{
 176#ifdef CONFIG_IPV6_SIT_6RD
 177	struct ip_tunnel *t = netdev_priv(dev);
 178
 179	if (t->dev == sitn->fb_tunnel_dev) {
 180		ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 181		t->ip6rd.relay_prefix = 0;
 182		t->ip6rd.prefixlen = 16;
 183		t->ip6rd.relay_prefixlen = 0;
 184	} else {
 185		struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 186		memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 187	}
 188#endif
 189}
 190
 191static int ipip6_tunnel_create(struct net_device *dev)
 192{
 193	struct ip_tunnel *t = netdev_priv(dev);
 194	struct net *net = dev_net(dev);
 195	struct sit_net *sitn = net_generic(net, sit_net_id);
 196	int err;
 197
 198	memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
 199	memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
 200
 201	if ((__force u16)t->parms.i_flags & SIT_ISATAP)
 202		dev->priv_flags |= IFF_ISATAP;
 203
 204	dev->rtnl_link_ops = &sit_link_ops;
 205
 206	err = register_netdevice(dev);
 207	if (err < 0)
 208		goto out;
 209
 210	ipip6_tunnel_clone_6rd(dev, sitn);
 211
 212	dev_hold(dev);
 213
 214	ipip6_tunnel_link(sitn, t);
 215	return 0;
 216
 217out:
 218	return err;
 219}
 220
 221static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 222		struct ip_tunnel_parm *parms, int create)
 223{
 224	__be32 remote = parms->iph.daddr;
 225	__be32 local = parms->iph.saddr;
 226	struct ip_tunnel *t, *nt;
 227	struct ip_tunnel __rcu **tp;
 228	struct net_device *dev;
 229	char name[IFNAMSIZ];
 230	struct sit_net *sitn = net_generic(net, sit_net_id);
 231
 232	for (tp = __ipip6_bucket(sitn, parms);
 233	    (t = rtnl_dereference(*tp)) != NULL;
 234	     tp = &t->next) {
 235		if (local == t->parms.iph.saddr &&
 236		    remote == t->parms.iph.daddr &&
 237		    parms->link == t->parms.link) {
 238			if (create)
 239				return NULL;
 240			else
 241				return t;
 242		}
 243	}
 244	if (!create)
 245		goto failed;
 246
 247	if (parms->name[0])
 248		strlcpy(name, parms->name, IFNAMSIZ);
 249	else
 250		strcpy(name, "sit%d");
 251
 252	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
 253			   ipip6_tunnel_setup);
 254	if (!dev)
 255		return NULL;
 256
 257	dev_net_set(dev, net);
 258
 259	nt = netdev_priv(dev);
 260
 261	nt->parms = *parms;
 262	if (ipip6_tunnel_create(dev) < 0)
 263		goto failed_free;
 264
 265	return nt;
 266
 267failed_free:
 268	ipip6_dev_free(dev);
 269failed:
 270	return NULL;
 271}
 272
 273#define for_each_prl_rcu(start)			\
 274	for (prl = rcu_dereference(start);	\
 275	     prl;				\
 276	     prl = rcu_dereference(prl->next))
 277
 278static struct ip_tunnel_prl_entry *
 279__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 280{
 281	struct ip_tunnel_prl_entry *prl;
 282
 283	for_each_prl_rcu(t->prl)
 284		if (prl->addr == addr)
 285			break;
 286	return prl;
 287
 288}
 289
 290static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 291				struct ip_tunnel_prl __user *a)
 292{
 293	struct ip_tunnel_prl kprl, *kp;
 294	struct ip_tunnel_prl_entry *prl;
 295	unsigned int cmax, c = 0, ca, len;
 296	int ret = 0;
 297
 298	if (copy_from_user(&kprl, a, sizeof(kprl)))
 299		return -EFAULT;
 300	cmax = kprl.datalen / sizeof(kprl);
 301	if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 302		cmax = 1;
 303
 304	/* For simple GET or for root users,
 305	 * we try harder to allocate.
 306	 */
 307	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 308		kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 309		NULL;
 310
 311	rcu_read_lock();
 312
 313	ca = t->prl_count < cmax ? t->prl_count : cmax;
 314
 315	if (!kp) {
 316		/* We don't try hard to allocate much memory for
 317		 * non-root users.
 318		 * For root users, retry allocating enough memory for
 319		 * the answer.
 320		 */
 321		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 322		if (!kp) {
 323			ret = -ENOMEM;
 324			goto out;
 325		}
 326	}
 327
 328	c = 0;
 329	for_each_prl_rcu(t->prl) {
 330		if (c >= cmax)
 331			break;
 332		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 333			continue;
 334		kp[c].addr = prl->addr;
 335		kp[c].flags = prl->flags;
 336		c++;
 337		if (kprl.addr != htonl(INADDR_ANY))
 338			break;
 339	}
 340out:
 341	rcu_read_unlock();
 342
 343	len = sizeof(*kp) * c;
 344	ret = 0;
 345	if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 346		ret = -EFAULT;
 347
 348	kfree(kp);
 349
 350	return ret;
 351}
 352
 353static int
 354ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 355{
 356	struct ip_tunnel_prl_entry *p;
 357	int err = 0;
 358
 359	if (a->addr == htonl(INADDR_ANY))
 360		return -EINVAL;
 361
 362	ASSERT_RTNL();
 363
 364	for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 365		if (p->addr == a->addr) {
 366			if (chg) {
 367				p->flags = a->flags;
 368				goto out;
 369			}
 370			err = -EEXIST;
 371			goto out;
 372		}
 373	}
 374
 375	if (chg) {
 376		err = -ENXIO;
 377		goto out;
 378	}
 379
 380	p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 381	if (!p) {
 382		err = -ENOBUFS;
 383		goto out;
 384	}
 385
 386	p->next = t->prl;
 387	p->addr = a->addr;
 388	p->flags = a->flags;
 389	t->prl_count++;
 390	rcu_assign_pointer(t->prl, p);
 391out:
 392	return err;
 393}
 394
 395static void prl_list_destroy_rcu(struct rcu_head *head)
 396{
 397	struct ip_tunnel_prl_entry *p, *n;
 398
 399	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 400	do {
 401		n = rcu_dereference_protected(p->next, 1);
 402		kfree(p);
 403		p = n;
 404	} while (p);
 405}
 406
 407static int
 408ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 409{
 410	struct ip_tunnel_prl_entry *x;
 411	struct ip_tunnel_prl_entry __rcu **p;
 412	int err = 0;
 413
 414	ASSERT_RTNL();
 415
 416	if (a && a->addr != htonl(INADDR_ANY)) {
 417		for (p = &t->prl;
 418		     (x = rtnl_dereference(*p)) != NULL;
 419		     p = &x->next) {
 420			if (x->addr == a->addr) {
 421				*p = x->next;
 422				kfree_rcu(x, rcu_head);
 423				t->prl_count--;
 424				goto out;
 425			}
 426		}
 427		err = -ENXIO;
 428	} else {
 429		x = rtnl_dereference(t->prl);
 430		if (x) {
 431			t->prl_count = 0;
 432			call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 433			t->prl = NULL;
 434		}
 435	}
 436out:
 437	return err;
 438}
 439
 440static int
 441isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 442{
 443	struct ip_tunnel_prl_entry *p;
 444	int ok = 1;
 445
 446	rcu_read_lock();
 447	p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 448	if (p) {
 449		if (p->flags & PRL_DEFAULT)
 450			skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 451		else
 452			skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 453	} else {
 454		const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 455
 456		if (ipv6_addr_is_isatap(addr6) &&
 457		    (addr6->s6_addr32[3] == iph->saddr) &&
 458		    ipv6_chk_prefix(addr6, t->dev))
 459			skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 460		else
 461			ok = 0;
 462	}
 463	rcu_read_unlock();
 464	return ok;
 465}
 466
 467static void ipip6_tunnel_uninit(struct net_device *dev)
 468{
 469	struct ip_tunnel *tunnel = netdev_priv(dev);
 470	struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 471
 472	if (dev == sitn->fb_tunnel_dev) {
 473		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 474	} else {
 475		ipip6_tunnel_unlink(sitn, tunnel);
 476		ipip6_tunnel_del_prl(tunnel, NULL);
 477	}
 478	dst_cache_reset(&tunnel->dst_cache);
 479	dev_put(dev);
 480}
 481
 482/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
 483 * if sufficient data bytes are available
 484 */
 485static int ipip6_err_gen_icmpv6_unreach(struct sk_buff *skb)
 486{
 487	int ihl = ((const struct iphdr *)skb->data)->ihl*4;
 488	struct rt6_info *rt;
 489	struct sk_buff *skb2;
 490
 491	if (!pskb_may_pull(skb, ihl + sizeof(struct ipv6hdr) + 8))
 492		return 1;
 493
 494	skb2 = skb_clone(skb, GFP_ATOMIC);
 495
 496	if (!skb2)
 497		return 1;
 498
 499	skb_dst_drop(skb2);
 500	skb_pull(skb2, ihl);
 501	skb_reset_network_header(skb2);
 502
 503	rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 0);
 504
 505	if (rt && rt->dst.dev)
 506		skb2->dev = rt->dst.dev;
 507
 508	icmpv6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
 509
 510	if (rt)
 511		ip6_rt_put(rt);
 512
 513	kfree_skb(skb2);
 514
 515	return 0;
 516}
 517
 518static int ipip6_err(struct sk_buff *skb, u32 info)
 519{
 520	const struct iphdr *iph = (const struct iphdr *)skb->data;
 521	const int type = icmp_hdr(skb)->type;
 522	const int code = icmp_hdr(skb)->code;
 
 523	struct ip_tunnel *t;
 524	int err;
 525
 526	switch (type) {
 527	default:
 528	case ICMP_PARAMETERPROB:
 529		return 0;
 530
 531	case ICMP_DEST_UNREACH:
 532		switch (code) {
 533		case ICMP_SR_FAILED:
 534			/* Impossible event. */
 535			return 0;
 536		default:
 537			/* All others are translated to HOST_UNREACH.
 538			   rfc2003 contains "deep thoughts" about NET_UNREACH,
 539			   I believe they are just ether pollution. --ANK
 540			 */
 541			break;
 542		}
 543		break;
 544	case ICMP_TIME_EXCEEDED:
 545		if (code != ICMP_EXC_TTL)
 546			return 0;
 
 547		break;
 548	case ICMP_REDIRECT:
 549		break;
 550	}
 551
 552	err = -ENOENT;
 553
 554	t = ipip6_tunnel_lookup(dev_net(skb->dev),
 555				skb->dev,
 556				iph->daddr,
 557				iph->saddr);
 558	if (!t)
 559		goto out;
 560
 561	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 562		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 563				 t->parms.link, 0, IPPROTO_IPV6, 0);
 564		err = 0;
 565		goto out;
 566	}
 567	if (type == ICMP_REDIRECT) {
 568		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
 569			      IPPROTO_IPV6, 0);
 570		err = 0;
 571		goto out;
 572	}
 573
 574	if (t->parms.iph.daddr == 0)
 
 575		goto out;
 576
 577	err = 0;
 578	if (!ipip6_err_gen_icmpv6_unreach(skb))
 579		goto out;
 580
 581	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 582		goto out;
 583
 584	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 585		t->err_count++;
 586	else
 587		t->err_count = 1;
 588	t->err_time = jiffies;
 589out:
 590	return err;
 591}
 592
 593static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 594				  const struct in6_addr *v6addr)
 595{
 596	__be32 v4embed = 0;
 597	if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 598		return true;
 599	return false;
 600}
 601
 602/* Checks if an address matches an address on the tunnel interface.
 603 * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 604 * Long story:
 605 * This function is called after we considered the packet as spoofed
 606 * in is_spoofed_6rd.
 607 * We may have a router that is doing NAT for proto 41 packets
 608 * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 609 * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 610 * function will return true, dropping the packet.
 611 * But, we can still check if is spoofed against the IP
 612 * addresses associated with the interface.
 613 */
 614static bool only_dnatted(const struct ip_tunnel *tunnel,
 615	const struct in6_addr *v6dst)
 616{
 617	int prefix_len;
 618
 619#ifdef CONFIG_IPV6_SIT_6RD
 620	prefix_len = tunnel->ip6rd.prefixlen + 32
 621		- tunnel->ip6rd.relay_prefixlen;
 622#else
 623	prefix_len = 48;
 624#endif
 625	return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 626}
 627
 628/* Returns true if a packet is spoofed */
 629static bool packet_is_spoofed(struct sk_buff *skb,
 630			      const struct iphdr *iph,
 631			      struct ip_tunnel *tunnel)
 632{
 633	const struct ipv6hdr *ipv6h;
 634
 635	if (tunnel->dev->priv_flags & IFF_ISATAP) {
 636		if (!isatap_chksrc(skb, iph, tunnel))
 637			return true;
 638
 639		return false;
 640	}
 641
 642	if (tunnel->dev->flags & IFF_POINTOPOINT)
 643		return false;
 644
 645	ipv6h = ipv6_hdr(skb);
 646
 647	if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 648		net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 649				     &iph->saddr, &ipv6h->saddr,
 650				     &iph->daddr, &ipv6h->daddr);
 651		return true;
 652	}
 653
 654	if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 655		return false;
 656
 657	if (only_dnatted(tunnel, &ipv6h->daddr))
 658		return false;
 659
 660	net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 661			     &iph->saddr, &ipv6h->saddr,
 662			     &iph->daddr, &ipv6h->daddr);
 663	return true;
 664}
 665
 666static int ipip6_rcv(struct sk_buff *skb)
 667{
 668	const struct iphdr *iph = ip_hdr(skb);
 669	struct ip_tunnel *tunnel;
 670	int err;
 671
 672	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 673				     iph->saddr, iph->daddr);
 674	if (tunnel) {
 675		struct pcpu_sw_netstats *tstats;
 676
 677		if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 678		    tunnel->parms.iph.protocol != 0)
 679			goto out;
 680
 681		skb->mac_header = skb->network_header;
 682		skb_reset_network_header(skb);
 683		IPCB(skb)->flags = 0;
 684		skb->dev = tunnel->dev;
 685
 686		if (packet_is_spoofed(skb, iph, tunnel)) {
 687			tunnel->dev->stats.rx_errors++;
 688			goto out;
 689		}
 690
 691		if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 692		    !net_eq(tunnel->net, dev_net(tunnel->dev))))
 693			goto out;
 694
 695		err = IP_ECN_decapsulate(iph, skb);
 696		if (unlikely(err)) {
 697			if (log_ecn_error)
 698				net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 699						     &iph->saddr, iph->tos);
 700			if (err > 1) {
 701				++tunnel->dev->stats.rx_frame_errors;
 702				++tunnel->dev->stats.rx_errors;
 703				goto out;
 704			}
 705		}
 706
 707		tstats = this_cpu_ptr(tunnel->dev->tstats);
 708		u64_stats_update_begin(&tstats->syncp);
 709		tstats->rx_packets++;
 710		tstats->rx_bytes += skb->len;
 711		u64_stats_update_end(&tstats->syncp);
 712
 713		netif_rx(skb);
 714
 715		return 0;
 716	}
 717
 718	/* no tunnel matched,  let upstream know, ipsec may handle it */
 719	return 1;
 720out:
 721	kfree_skb(skb);
 722	return 0;
 723}
 724
 725static const struct tnl_ptk_info tpi = {
 726	/* no tunnel info required for ipip. */
 727	.proto = htons(ETH_P_IP),
 728};
 729
 730static int ipip_rcv(struct sk_buff *skb)
 
 
 
 
 
 
 
 731{
 732	const struct iphdr *iph;
 733	struct ip_tunnel *tunnel;
 734
 735	iph = ip_hdr(skb);
 736	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 737				     iph->saddr, iph->daddr);
 738	if (tunnel) {
 739		if (tunnel->parms.iph.protocol != IPPROTO_IPIP &&
 
 
 740		    tunnel->parms.iph.protocol != 0)
 741			goto drop;
 742
 743		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 744			goto drop;
 745		if (iptunnel_pull_header(skb, 0, tpi.proto, false))
 
 
 
 
 
 
 746			goto drop;
 747		return ip_tunnel_rcv(tunnel, skb, &tpi, NULL, log_ecn_error);
 748	}
 749
 750	return 1;
 751
 752drop:
 753	kfree_skb(skb);
 754	return 0;
 755}
 756
 
 
 
 
 
 
 
 
 
 
 
 
 757/*
 758 * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 759 * stores the embedded IPv4 address in v4dst and returns true.
 760 */
 761static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 762		      __be32 *v4dst)
 763{
 764#ifdef CONFIG_IPV6_SIT_6RD
 765	if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 766			      tunnel->ip6rd.prefixlen)) {
 767		unsigned int pbw0, pbi0;
 768		int pbi1;
 769		u32 d;
 770
 771		pbw0 = tunnel->ip6rd.prefixlen >> 5;
 772		pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 773
 774		d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 775		    tunnel->ip6rd.relay_prefixlen;
 776
 777		pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 778		if (pbi1 > 0)
 779			d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 780			     (32 - pbi1);
 781
 782		*v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 783		return true;
 784	}
 785#else
 786	if (v6dst->s6_addr16[0] == htons(0x2002)) {
 787		/* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 788		memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 789		return true;
 790	}
 791#endif
 792	return false;
 793}
 794
 795static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 796			     const struct in6_addr *v6dst)
 797{
 798	__be32 dst = 0;
 799	check_6rd(tunnel, v6dst, &dst);
 800	return dst;
 801}
 802
 803/*
 804 *	This function assumes it is being called from dev_queue_xmit()
 805 *	and that skb is filled properly by that function.
 806 */
 807
 808static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 809				     struct net_device *dev)
 810{
 811	struct ip_tunnel *tunnel = netdev_priv(dev);
 812	const struct iphdr  *tiph = &tunnel->parms.iph;
 813	const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 814	u8     tos = tunnel->parms.iph.tos;
 815	__be16 df = tiph->frag_off;
 816	struct rtable *rt;		/* Route to the other host */
 817	struct net_device *tdev;	/* Device to other host */
 818	unsigned int max_headroom;	/* The extra header space needed */
 819	__be32 dst = tiph->daddr;
 820	struct flowi4 fl4;
 821	int    mtu;
 822	const struct in6_addr *addr6;
 823	int addr_type;
 824	u8 ttl;
 825	u8 protocol = IPPROTO_IPV6;
 826	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 827
 828	if (skb->protocol != htons(ETH_P_IPV6))
 829		goto tx_error;
 830
 831	if (tos == 1)
 832		tos = ipv6_get_dsfield(iph6);
 833
 834	/* ISATAP (RFC4214) - must come before 6to4 */
 835	if (dev->priv_flags & IFF_ISATAP) {
 836		struct neighbour *neigh = NULL;
 837		bool do_tx_error = false;
 838
 839		if (skb_dst(skb))
 840			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 841
 842		if (!neigh) {
 843			net_dbg_ratelimited("nexthop == NULL\n");
 844			goto tx_error;
 845		}
 846
 847		addr6 = (const struct in6_addr *)&neigh->primary_key;
 848		addr_type = ipv6_addr_type(addr6);
 849
 850		if ((addr_type & IPV6_ADDR_UNICAST) &&
 851		     ipv6_addr_is_isatap(addr6))
 852			dst = addr6->s6_addr32[3];
 853		else
 854			do_tx_error = true;
 855
 856		neigh_release(neigh);
 857		if (do_tx_error)
 858			goto tx_error;
 859	}
 860
 861	if (!dst)
 862		dst = try_6rd(tunnel, &iph6->daddr);
 863
 864	if (!dst) {
 865		struct neighbour *neigh = NULL;
 866		bool do_tx_error = false;
 867
 868		if (skb_dst(skb))
 869			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 870
 871		if (!neigh) {
 872			net_dbg_ratelimited("nexthop == NULL\n");
 873			goto tx_error;
 874		}
 875
 876		addr6 = (const struct in6_addr *)&neigh->primary_key;
 877		addr_type = ipv6_addr_type(addr6);
 878
 879		if (addr_type == IPV6_ADDR_ANY) {
 880			addr6 = &ipv6_hdr(skb)->daddr;
 881			addr_type = ipv6_addr_type(addr6);
 882		}
 883
 884		if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 885			dst = addr6->s6_addr32[3];
 886		else
 887			do_tx_error = true;
 888
 889		neigh_release(neigh);
 890		if (do_tx_error)
 891			goto tx_error;
 892	}
 893
 894	rt = ip_route_output_ports(tunnel->net, &fl4, NULL,
 895				   dst, tiph->saddr,
 896				   0, 0,
 897				   IPPROTO_IPV6, RT_TOS(tos),
 898				   tunnel->parms.link);
 899	if (IS_ERR(rt)) {
 900		dev->stats.tx_carrier_errors++;
 901		goto tx_error_icmp;
 902	}
 903	if (rt->rt_type != RTN_UNICAST) {
 904		ip_rt_put(rt);
 905		dev->stats.tx_carrier_errors++;
 906		goto tx_error_icmp;
 907	}
 908	tdev = rt->dst.dev;
 909
 910	if (tdev == dev) {
 911		ip_rt_put(rt);
 912		dev->stats.collisions++;
 913		goto tx_error;
 914	}
 915
 916	skb = iptunnel_handle_offloads(skb, SKB_GSO_SIT);
 917	if (IS_ERR(skb)) {
 918		ip_rt_put(rt);
 919		goto out;
 920	}
 921
 922	if (df) {
 923		mtu = dst_mtu(&rt->dst) - t_hlen;
 924
 925		if (mtu < 68) {
 926			dev->stats.collisions++;
 927			ip_rt_put(rt);
 928			goto tx_error;
 929		}
 930
 931		if (mtu < IPV6_MIN_MTU) {
 932			mtu = IPV6_MIN_MTU;
 933			df = 0;
 934		}
 935
 936		if (tunnel->parms.iph.daddr && skb_dst(skb))
 937			skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 938
 939		if (skb->len > mtu && !skb_is_gso(skb)) {
 940			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 941			ip_rt_put(rt);
 942			goto tx_error;
 943		}
 944	}
 945
 946	if (tunnel->err_count > 0) {
 947		if (time_before(jiffies,
 948				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 949			tunnel->err_count--;
 950			dst_link_failure(skb);
 951		} else
 952			tunnel->err_count = 0;
 953	}
 954
 955	/*
 956	 * Okay, now see if we can stuff it in the buffer as-is.
 957	 */
 958	max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
 959
 960	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 961	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 962		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 963		if (!new_skb) {
 964			ip_rt_put(rt);
 965			dev->stats.tx_dropped++;
 966			kfree_skb(skb);
 967			return NETDEV_TX_OK;
 968		}
 969		if (skb->sk)
 970			skb_set_owner_w(new_skb, skb->sk);
 971		dev_kfree_skb(skb);
 972		skb = new_skb;
 973		iph6 = ipv6_hdr(skb);
 974	}
 975	ttl = tiph->ttl;
 976	if (ttl == 0)
 977		ttl = iph6->hop_limit;
 978	tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 979
 980	if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
 981		ip_rt_put(rt);
 982		goto tx_error;
 983	}
 984
 985	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
 986
 987	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
 988		      df, !net_eq(tunnel->net, dev_net(dev)));
 989	return NETDEV_TX_OK;
 990
 991tx_error_icmp:
 992	dst_link_failure(skb);
 993tx_error:
 994	kfree_skb(skb);
 995out:
 996	dev->stats.tx_errors++;
 997	return NETDEV_TX_OK;
 998}
 999
1000static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 
1001{
1002	struct ip_tunnel *tunnel = netdev_priv(dev);
1003	const struct iphdr  *tiph = &tunnel->parms.iph;
1004
1005	skb = iptunnel_handle_offloads(skb, SKB_GSO_IPIP);
1006	if (IS_ERR(skb))
1007		goto out;
1008
1009	skb_set_inner_ipproto(skb, IPPROTO_IPIP);
1010
1011	ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
1012	return NETDEV_TX_OK;
1013out:
 
1014	dev->stats.tx_errors++;
1015	return NETDEV_TX_OK;
1016}
1017
1018static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1019				   struct net_device *dev)
1020{
1021	switch (skb->protocol) {
1022	case htons(ETH_P_IP):
1023		ipip_tunnel_xmit(skb, dev);
1024		break;
1025	case htons(ETH_P_IPV6):
1026		ipip6_tunnel_xmit(skb, dev);
1027		break;
 
 
 
 
 
1028	default:
1029		goto tx_err;
1030	}
1031
1032	return NETDEV_TX_OK;
1033
1034tx_err:
1035	dev->stats.tx_errors++;
1036	kfree_skb(skb);
1037	return NETDEV_TX_OK;
1038
1039}
1040
1041static void ipip6_tunnel_bind_dev(struct net_device *dev)
1042{
1043	struct net_device *tdev = NULL;
1044	struct ip_tunnel *tunnel;
1045	const struct iphdr *iph;
1046	struct flowi4 fl4;
1047
1048	tunnel = netdev_priv(dev);
1049	iph = &tunnel->parms.iph;
1050
1051	if (iph->daddr) {
1052		struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1053							  NULL,
1054							  iph->daddr, iph->saddr,
1055							  0, 0,
1056							  IPPROTO_IPV6,
1057							  RT_TOS(iph->tos),
1058							  tunnel->parms.link);
1059
1060		if (!IS_ERR(rt)) {
1061			tdev = rt->dst.dev;
1062			ip_rt_put(rt);
1063		}
1064		dev->flags |= IFF_POINTOPOINT;
1065	}
1066
1067	if (!tdev && tunnel->parms.link)
1068		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1069
1070	if (tdev) {
1071		int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1072
1073		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1074		dev->mtu = tdev->mtu - t_hlen;
1075		if (dev->mtu < IPV6_MIN_MTU)
1076			dev->mtu = IPV6_MIN_MTU;
1077	}
1078}
1079
1080static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
1081{
1082	struct net *net = t->net;
1083	struct sit_net *sitn = net_generic(net, sit_net_id);
1084
1085	ipip6_tunnel_unlink(sitn, t);
1086	synchronize_net();
1087	t->parms.iph.saddr = p->iph.saddr;
1088	t->parms.iph.daddr = p->iph.daddr;
1089	memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1090	memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1091	ipip6_tunnel_link(sitn, t);
1092	t->parms.iph.ttl = p->iph.ttl;
1093	t->parms.iph.tos = p->iph.tos;
1094	if (t->parms.link != p->link) {
1095		t->parms.link = p->link;
1096		ipip6_tunnel_bind_dev(t->dev);
1097	}
1098	dst_cache_reset(&t->dst_cache);
1099	netdev_state_change(t->dev);
1100}
1101
1102#ifdef CONFIG_IPV6_SIT_6RD
1103static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1104				   struct ip_tunnel_6rd *ip6rd)
1105{
1106	struct in6_addr prefix;
1107	__be32 relay_prefix;
1108
1109	if (ip6rd->relay_prefixlen > 32 ||
1110	    ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1111		return -EINVAL;
1112
1113	ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1114	if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1115		return -EINVAL;
1116	if (ip6rd->relay_prefixlen)
1117		relay_prefix = ip6rd->relay_prefix &
1118			       htonl(0xffffffffUL <<
1119				     (32 - ip6rd->relay_prefixlen));
1120	else
1121		relay_prefix = 0;
1122	if (relay_prefix != ip6rd->relay_prefix)
1123		return -EINVAL;
1124
1125	t->ip6rd.prefix = prefix;
1126	t->ip6rd.relay_prefix = relay_prefix;
1127	t->ip6rd.prefixlen = ip6rd->prefixlen;
1128	t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1129	dst_cache_reset(&t->dst_cache);
1130	netdev_state_change(t->dev);
1131	return 0;
1132}
1133#endif
1134
 
 
 
 
 
 
 
 
 
 
1135static int
1136ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1137{
1138	int err = 0;
1139	struct ip_tunnel_parm p;
1140	struct ip_tunnel_prl prl;
1141	struct ip_tunnel *t = netdev_priv(dev);
1142	struct net *net = t->net;
1143	struct sit_net *sitn = net_generic(net, sit_net_id);
1144#ifdef CONFIG_IPV6_SIT_6RD
1145	struct ip_tunnel_6rd ip6rd;
1146#endif
1147
1148	switch (cmd) {
1149	case SIOCGETTUNNEL:
1150#ifdef CONFIG_IPV6_SIT_6RD
1151	case SIOCGET6RD:
1152#endif
1153		if (dev == sitn->fb_tunnel_dev) {
1154			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1155				err = -EFAULT;
1156				break;
1157			}
1158			t = ipip6_tunnel_locate(net, &p, 0);
1159			if (!t)
1160				t = netdev_priv(dev);
1161		}
1162
1163		err = -EFAULT;
1164		if (cmd == SIOCGETTUNNEL) {
1165			memcpy(&p, &t->parms, sizeof(p));
1166			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1167					 sizeof(p)))
1168				goto done;
1169#ifdef CONFIG_IPV6_SIT_6RD
1170		} else {
1171			ip6rd.prefix = t->ip6rd.prefix;
1172			ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1173			ip6rd.prefixlen = t->ip6rd.prefixlen;
1174			ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1175			if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1176					 sizeof(ip6rd)))
1177				goto done;
1178#endif
1179		}
1180		err = 0;
1181		break;
1182
1183	case SIOCADDTUNNEL:
1184	case SIOCCHGTUNNEL:
1185		err = -EPERM;
1186		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1187			goto done;
1188
1189		err = -EFAULT;
1190		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1191			goto done;
1192
1193		err = -EINVAL;
1194		if (p.iph.protocol != IPPROTO_IPV6 &&
1195		    p.iph.protocol != IPPROTO_IPIP &&
1196		    p.iph.protocol != 0)
1197			goto done;
1198		if (p.iph.version != 4 ||
1199		    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1200			goto done;
1201		if (p.iph.ttl)
1202			p.iph.frag_off |= htons(IP_DF);
1203
1204		t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1205
1206		if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1207			if (t) {
1208				if (t->dev != dev) {
1209					err = -EEXIST;
1210					break;
1211				}
1212			} else {
1213				if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1214				    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1215					err = -EINVAL;
1216					break;
1217				}
1218				t = netdev_priv(dev);
1219			}
1220
1221			ipip6_tunnel_update(t, &p);
1222		}
1223
1224		if (t) {
1225			err = 0;
1226			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1227				err = -EFAULT;
1228		} else
1229			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1230		break;
1231
1232	case SIOCDELTUNNEL:
1233		err = -EPERM;
1234		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1235			goto done;
1236
1237		if (dev == sitn->fb_tunnel_dev) {
1238			err = -EFAULT;
1239			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1240				goto done;
1241			err = -ENOENT;
1242			t = ipip6_tunnel_locate(net, &p, 0);
1243			if (!t)
1244				goto done;
1245			err = -EPERM;
1246			if (t == netdev_priv(sitn->fb_tunnel_dev))
1247				goto done;
1248			dev = t->dev;
1249		}
1250		unregister_netdevice(dev);
1251		err = 0;
1252		break;
1253
1254	case SIOCGETPRL:
1255		err = -EINVAL;
1256		if (dev == sitn->fb_tunnel_dev)
1257			goto done;
1258		err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1259		break;
1260
1261	case SIOCADDPRL:
1262	case SIOCDELPRL:
1263	case SIOCCHGPRL:
1264		err = -EPERM;
1265		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1266			goto done;
1267		err = -EINVAL;
1268		if (dev == sitn->fb_tunnel_dev)
1269			goto done;
1270		err = -EFAULT;
1271		if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1272			goto done;
1273
1274		switch (cmd) {
1275		case SIOCDELPRL:
1276			err = ipip6_tunnel_del_prl(t, &prl);
1277			break;
1278		case SIOCADDPRL:
1279		case SIOCCHGPRL:
1280			err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1281			break;
1282		}
1283		dst_cache_reset(&t->dst_cache);
1284		netdev_state_change(dev);
1285		break;
1286
1287#ifdef CONFIG_IPV6_SIT_6RD
1288	case SIOCADD6RD:
1289	case SIOCCHG6RD:
1290	case SIOCDEL6RD:
1291		err = -EPERM;
1292		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1293			goto done;
1294
1295		err = -EFAULT;
1296		if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1297				   sizeof(ip6rd)))
1298			goto done;
1299
1300		if (cmd != SIOCDEL6RD) {
1301			err = ipip6_tunnel_update_6rd(t, &ip6rd);
1302			if (err < 0)
1303				goto done;
1304		} else
1305			ipip6_tunnel_clone_6rd(dev, sitn);
1306
1307		err = 0;
1308		break;
1309#endif
1310
1311	default:
1312		err = -EINVAL;
1313	}
1314
1315done:
1316	return err;
1317}
1318
1319static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1320{
1321	struct ip_tunnel *tunnel = netdev_priv(dev);
1322	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1323
1324	if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - t_hlen)
1325		return -EINVAL;
1326	dev->mtu = new_mtu;
1327	return 0;
1328}
1329
1330static const struct net_device_ops ipip6_netdev_ops = {
1331	.ndo_init	= ipip6_tunnel_init,
1332	.ndo_uninit	= ipip6_tunnel_uninit,
1333	.ndo_start_xmit	= sit_tunnel_xmit,
1334	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
1335	.ndo_change_mtu	= ipip6_tunnel_change_mtu,
1336	.ndo_get_stats64 = ip_tunnel_get_stats64,
1337	.ndo_get_iflink = ip_tunnel_get_iflink,
1338};
1339
1340static void ipip6_dev_free(struct net_device *dev)
1341{
1342	struct ip_tunnel *tunnel = netdev_priv(dev);
1343
1344	dst_cache_destroy(&tunnel->dst_cache);
1345	free_percpu(dev->tstats);
1346	free_netdev(dev);
1347}
1348
1349#define SIT_FEATURES (NETIF_F_SG	   | \
1350		      NETIF_F_FRAGLIST	   | \
1351		      NETIF_F_HIGHDMA	   | \
1352		      NETIF_F_GSO_SOFTWARE | \
1353		      NETIF_F_HW_CSUM)
1354
1355static void ipip6_tunnel_setup(struct net_device *dev)
1356{
1357	struct ip_tunnel *tunnel = netdev_priv(dev);
1358	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1359
1360	dev->netdev_ops		= &ipip6_netdev_ops;
1361	dev->destructor		= ipip6_dev_free;
1362
1363	dev->type		= ARPHRD_SIT;
1364	dev->hard_header_len	= LL_MAX_HEADER + t_hlen;
1365	dev->mtu		= ETH_DATA_LEN - t_hlen;
 
 
1366	dev->flags		= IFF_NOARP;
1367	netif_keep_dst(dev);
1368	dev->addr_len		= 4;
1369	dev->features		|= NETIF_F_LLTX;
1370	dev->features		|= SIT_FEATURES;
1371	dev->hw_features	|= SIT_FEATURES;
1372}
1373
1374static int ipip6_tunnel_init(struct net_device *dev)
1375{
1376	struct ip_tunnel *tunnel = netdev_priv(dev);
1377	int err;
1378
1379	tunnel->dev = dev;
1380	tunnel->net = dev_net(dev);
1381	strcpy(tunnel->parms.name, dev->name);
1382
1383	ipip6_tunnel_bind_dev(dev);
1384	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1385	if (!dev->tstats)
1386		return -ENOMEM;
1387
1388	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1389	if (err) {
1390		free_percpu(dev->tstats);
 
1391		return err;
1392	}
1393
1394	return 0;
1395}
1396
1397static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1398{
1399	struct ip_tunnel *tunnel = netdev_priv(dev);
1400	struct iphdr *iph = &tunnel->parms.iph;
1401	struct net *net = dev_net(dev);
1402	struct sit_net *sitn = net_generic(net, sit_net_id);
1403
1404	iph->version		= 4;
1405	iph->protocol		= IPPROTO_IPV6;
1406	iph->ihl		= 5;
1407	iph->ttl		= 64;
1408
1409	dev_hold(dev);
1410	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1411}
1412
1413static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1414{
1415	u8 proto;
1416
1417	if (!data || !data[IFLA_IPTUN_PROTO])
1418		return 0;
1419
1420	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1421	if (proto != IPPROTO_IPV6 &&
1422	    proto != IPPROTO_IPIP &&
1423	    proto != 0)
1424		return -EINVAL;
1425
1426	return 0;
1427}
1428
1429static void ipip6_netlink_parms(struct nlattr *data[],
1430				struct ip_tunnel_parm *parms)
1431{
1432	memset(parms, 0, sizeof(*parms));
1433
1434	parms->iph.version = 4;
1435	parms->iph.protocol = IPPROTO_IPV6;
1436	parms->iph.ihl = 5;
1437	parms->iph.ttl = 64;
1438
1439	if (!data)
1440		return;
1441
1442	if (data[IFLA_IPTUN_LINK])
1443		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1444
1445	if (data[IFLA_IPTUN_LOCAL])
1446		parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1447
1448	if (data[IFLA_IPTUN_REMOTE])
1449		parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1450
1451	if (data[IFLA_IPTUN_TTL]) {
1452		parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1453		if (parms->iph.ttl)
1454			parms->iph.frag_off = htons(IP_DF);
1455	}
1456
1457	if (data[IFLA_IPTUN_TOS])
1458		parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1459
1460	if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1461		parms->iph.frag_off = htons(IP_DF);
1462
1463	if (data[IFLA_IPTUN_FLAGS])
1464		parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1465
1466	if (data[IFLA_IPTUN_PROTO])
1467		parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1468
1469}
1470
1471/* This function returns true when ENCAP attributes are present in the nl msg */
1472static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1473				      struct ip_tunnel_encap *ipencap)
1474{
1475	bool ret = false;
1476
1477	memset(ipencap, 0, sizeof(*ipencap));
1478
1479	if (!data)
1480		return ret;
1481
1482	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1483		ret = true;
1484		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1485	}
1486
1487	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1488		ret = true;
1489		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1490	}
1491
1492	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1493		ret = true;
1494		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1495	}
1496
1497	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1498		ret = true;
1499		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1500	}
1501
1502	return ret;
1503}
1504
1505#ifdef CONFIG_IPV6_SIT_6RD
1506/* This function returns true when 6RD attributes are present in the nl msg */
1507static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1508				    struct ip_tunnel_6rd *ip6rd)
1509{
1510	bool ret = false;
1511	memset(ip6rd, 0, sizeof(*ip6rd));
1512
1513	if (!data)
1514		return ret;
1515
1516	if (data[IFLA_IPTUN_6RD_PREFIX]) {
1517		ret = true;
1518		ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1519	}
1520
1521	if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1522		ret = true;
1523		ip6rd->relay_prefix =
1524			nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1525	}
1526
1527	if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1528		ret = true;
1529		ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1530	}
1531
1532	if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1533		ret = true;
1534		ip6rd->relay_prefixlen =
1535			nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1536	}
1537
1538	return ret;
1539}
1540#endif
1541
1542static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1543			 struct nlattr *tb[], struct nlattr *data[])
1544{
1545	struct net *net = dev_net(dev);
1546	struct ip_tunnel *nt;
1547	struct ip_tunnel_encap ipencap;
1548#ifdef CONFIG_IPV6_SIT_6RD
1549	struct ip_tunnel_6rd ip6rd;
1550#endif
1551	int err;
1552
1553	nt = netdev_priv(dev);
1554
1555	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1556		err = ip_tunnel_encap_setup(nt, &ipencap);
1557		if (err < 0)
1558			return err;
1559	}
1560
1561	ipip6_netlink_parms(data, &nt->parms);
1562
1563	if (ipip6_tunnel_locate(net, &nt->parms, 0))
1564		return -EEXIST;
1565
1566	err = ipip6_tunnel_create(dev);
1567	if (err < 0)
1568		return err;
1569
1570#ifdef CONFIG_IPV6_SIT_6RD
1571	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1572		err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1573#endif
1574
1575	return err;
1576}
1577
1578static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1579			  struct nlattr *data[])
1580{
1581	struct ip_tunnel *t = netdev_priv(dev);
1582	struct ip_tunnel_parm p;
1583	struct ip_tunnel_encap ipencap;
1584	struct net *net = t->net;
1585	struct sit_net *sitn = net_generic(net, sit_net_id);
1586#ifdef CONFIG_IPV6_SIT_6RD
1587	struct ip_tunnel_6rd ip6rd;
1588#endif
1589	int err;
1590
1591	if (dev == sitn->fb_tunnel_dev)
1592		return -EINVAL;
1593
1594	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1595		err = ip_tunnel_encap_setup(t, &ipencap);
1596		if (err < 0)
1597			return err;
1598	}
1599
1600	ipip6_netlink_parms(data, &p);
1601
1602	if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1603	    (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1604		return -EINVAL;
1605
1606	t = ipip6_tunnel_locate(net, &p, 0);
1607
1608	if (t) {
1609		if (t->dev != dev)
1610			return -EEXIST;
1611	} else
1612		t = netdev_priv(dev);
1613
1614	ipip6_tunnel_update(t, &p);
1615
1616#ifdef CONFIG_IPV6_SIT_6RD
1617	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1618		return ipip6_tunnel_update_6rd(t, &ip6rd);
1619#endif
1620
1621	return 0;
1622}
1623
1624static size_t ipip6_get_size(const struct net_device *dev)
1625{
1626	return
1627		/* IFLA_IPTUN_LINK */
1628		nla_total_size(4) +
1629		/* IFLA_IPTUN_LOCAL */
1630		nla_total_size(4) +
1631		/* IFLA_IPTUN_REMOTE */
1632		nla_total_size(4) +
1633		/* IFLA_IPTUN_TTL */
1634		nla_total_size(1) +
1635		/* IFLA_IPTUN_TOS */
1636		nla_total_size(1) +
1637		/* IFLA_IPTUN_PMTUDISC */
1638		nla_total_size(1) +
1639		/* IFLA_IPTUN_FLAGS */
1640		nla_total_size(2) +
1641		/* IFLA_IPTUN_PROTO */
1642		nla_total_size(1) +
1643#ifdef CONFIG_IPV6_SIT_6RD
1644		/* IFLA_IPTUN_6RD_PREFIX */
1645		nla_total_size(sizeof(struct in6_addr)) +
1646		/* IFLA_IPTUN_6RD_RELAY_PREFIX */
1647		nla_total_size(4) +
1648		/* IFLA_IPTUN_6RD_PREFIXLEN */
1649		nla_total_size(2) +
1650		/* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1651		nla_total_size(2) +
1652#endif
1653		/* IFLA_IPTUN_ENCAP_TYPE */
1654		nla_total_size(2) +
1655		/* IFLA_IPTUN_ENCAP_FLAGS */
1656		nla_total_size(2) +
1657		/* IFLA_IPTUN_ENCAP_SPORT */
1658		nla_total_size(2) +
1659		/* IFLA_IPTUN_ENCAP_DPORT */
1660		nla_total_size(2) +
1661		0;
1662}
1663
1664static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1665{
1666	struct ip_tunnel *tunnel = netdev_priv(dev);
1667	struct ip_tunnel_parm *parm = &tunnel->parms;
1668
1669	if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1670	    nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1671	    nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1672	    nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1673	    nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1674	    nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1675		       !!(parm->iph.frag_off & htons(IP_DF))) ||
1676	    nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1677	    nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1678		goto nla_put_failure;
1679
1680#ifdef CONFIG_IPV6_SIT_6RD
1681	if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1682			     &tunnel->ip6rd.prefix) ||
1683	    nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1684			    tunnel->ip6rd.relay_prefix) ||
1685	    nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1686			tunnel->ip6rd.prefixlen) ||
1687	    nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1688			tunnel->ip6rd.relay_prefixlen))
1689		goto nla_put_failure;
1690#endif
1691
1692	if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1693			tunnel->encap.type) ||
1694	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1695			tunnel->encap.sport) ||
1696	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1697			tunnel->encap.dport) ||
1698	    nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1699			tunnel->encap.flags))
1700		goto nla_put_failure;
1701
1702	return 0;
1703
1704nla_put_failure:
1705	return -EMSGSIZE;
1706}
1707
1708static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1709	[IFLA_IPTUN_LINK]		= { .type = NLA_U32 },
1710	[IFLA_IPTUN_LOCAL]		= { .type = NLA_U32 },
1711	[IFLA_IPTUN_REMOTE]		= { .type = NLA_U32 },
1712	[IFLA_IPTUN_TTL]		= { .type = NLA_U8 },
1713	[IFLA_IPTUN_TOS]		= { .type = NLA_U8 },
1714	[IFLA_IPTUN_PMTUDISC]		= { .type = NLA_U8 },
1715	[IFLA_IPTUN_FLAGS]		= { .type = NLA_U16 },
1716	[IFLA_IPTUN_PROTO]		= { .type = NLA_U8 },
1717#ifdef CONFIG_IPV6_SIT_6RD
1718	[IFLA_IPTUN_6RD_PREFIX]		= { .len = sizeof(struct in6_addr) },
1719	[IFLA_IPTUN_6RD_RELAY_PREFIX]	= { .type = NLA_U32 },
1720	[IFLA_IPTUN_6RD_PREFIXLEN]	= { .type = NLA_U16 },
1721	[IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1722#endif
1723	[IFLA_IPTUN_ENCAP_TYPE]		= { .type = NLA_U16 },
1724	[IFLA_IPTUN_ENCAP_FLAGS]	= { .type = NLA_U16 },
1725	[IFLA_IPTUN_ENCAP_SPORT]	= { .type = NLA_U16 },
1726	[IFLA_IPTUN_ENCAP_DPORT]	= { .type = NLA_U16 },
1727};
1728
1729static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1730{
1731	struct net *net = dev_net(dev);
1732	struct sit_net *sitn = net_generic(net, sit_net_id);
1733
1734	if (dev != sitn->fb_tunnel_dev)
1735		unregister_netdevice_queue(dev, head);
1736}
1737
1738static struct rtnl_link_ops sit_link_ops __read_mostly = {
1739	.kind		= "sit",
1740	.maxtype	= IFLA_IPTUN_MAX,
1741	.policy		= ipip6_policy,
1742	.priv_size	= sizeof(struct ip_tunnel),
1743	.setup		= ipip6_tunnel_setup,
1744	.validate	= ipip6_validate,
1745	.newlink	= ipip6_newlink,
1746	.changelink	= ipip6_changelink,
1747	.get_size	= ipip6_get_size,
1748	.fill_info	= ipip6_fill_info,
1749	.dellink	= ipip6_dellink,
1750	.get_link_net	= ip_tunnel_get_link_net,
1751};
1752
1753static struct xfrm_tunnel sit_handler __read_mostly = {
1754	.handler	=	ipip6_rcv,
1755	.err_handler	=	ipip6_err,
1756	.priority	=	1,
1757};
1758
1759static struct xfrm_tunnel ipip_handler __read_mostly = {
1760	.handler	=	ipip_rcv,
1761	.err_handler	=	ipip6_err,
1762	.priority	=	2,
1763};
1764
 
 
 
 
 
 
 
 
1765static void __net_exit sit_destroy_tunnels(struct net *net,
1766					   struct list_head *head)
1767{
1768	struct sit_net *sitn = net_generic(net, sit_net_id);
1769	struct net_device *dev, *aux;
1770	int prio;
1771
1772	for_each_netdev_safe(net, dev, aux)
1773		if (dev->rtnl_link_ops == &sit_link_ops)
1774			unregister_netdevice_queue(dev, head);
1775
1776	for (prio = 1; prio < 4; prio++) {
1777		int h;
1778		for (h = 0; h < HASH_SIZE; h++) {
1779			struct ip_tunnel *t;
1780
1781			t = rtnl_dereference(sitn->tunnels[prio][h]);
1782			while (t) {
1783				/* If dev is in the same netns, it has already
1784				 * been added to the list by the previous loop.
1785				 */
1786				if (!net_eq(dev_net(t->dev), net))
1787					unregister_netdevice_queue(t->dev,
1788								   head);
1789				t = rtnl_dereference(t->next);
1790			}
1791		}
1792	}
1793}
1794
1795static int __net_init sit_init_net(struct net *net)
1796{
1797	struct sit_net *sitn = net_generic(net, sit_net_id);
1798	struct ip_tunnel *t;
1799	int err;
1800
1801	sitn->tunnels[0] = sitn->tunnels_wc;
1802	sitn->tunnels[1] = sitn->tunnels_l;
1803	sitn->tunnels[2] = sitn->tunnels_r;
1804	sitn->tunnels[3] = sitn->tunnels_r_l;
1805
1806	sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1807					   NET_NAME_UNKNOWN,
1808					   ipip6_tunnel_setup);
1809	if (!sitn->fb_tunnel_dev) {
1810		err = -ENOMEM;
1811		goto err_alloc_dev;
1812	}
1813	dev_net_set(sitn->fb_tunnel_dev, net);
1814	sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1815	/* FB netdevice is special: we have one, and only one per netns.
1816	 * Allowing to move it to another netns is clearly unsafe.
1817	 */
1818	sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1819
1820	err = register_netdev(sitn->fb_tunnel_dev);
1821	if (err)
1822		goto err_reg_dev;
1823
1824	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1825	ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1826
1827	t = netdev_priv(sitn->fb_tunnel_dev);
1828
1829	strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1830	return 0;
1831
1832err_reg_dev:
1833	ipip6_dev_free(sitn->fb_tunnel_dev);
1834err_alloc_dev:
1835	return err;
1836}
1837
1838static void __net_exit sit_exit_net(struct net *net)
1839{
1840	LIST_HEAD(list);
1841
1842	rtnl_lock();
1843	sit_destroy_tunnels(net, &list);
1844	unregister_netdevice_many(&list);
1845	rtnl_unlock();
1846}
1847
1848static struct pernet_operations sit_net_ops = {
1849	.init = sit_init_net,
1850	.exit = sit_exit_net,
1851	.id   = &sit_net_id,
1852	.size = sizeof(struct sit_net),
1853};
1854
1855static void __exit sit_cleanup(void)
1856{
1857	rtnl_link_unregister(&sit_link_ops);
1858	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1859	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
 
 
 
1860
1861	unregister_pernet_device(&sit_net_ops);
1862	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1863}
1864
1865static int __init sit_init(void)
1866{
1867	int err;
1868
1869	pr_info("IPv6 over IPv4 tunneling driver\n");
1870
1871	err = register_pernet_device(&sit_net_ops);
1872	if (err < 0)
1873		return err;
1874	err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1875	if (err < 0) {
1876		pr_info("%s: can't register ip6ip4\n", __func__);
1877		goto xfrm_tunnel_failed;
1878	}
1879	err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1880	if (err < 0) {
1881		pr_info("%s: can't register ip4ip4\n", __func__);
1882		goto xfrm_tunnel4_failed;
1883	}
 
 
 
 
 
 
 
1884	err = rtnl_link_register(&sit_link_ops);
1885	if (err < 0)
1886		goto rtnl_link_failed;
1887
1888out:
1889	return err;
1890
1891rtnl_link_failed:
 
 
 
 
1892	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1893xfrm_tunnel4_failed:
1894	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1895xfrm_tunnel_failed:
1896	unregister_pernet_device(&sit_net_ops);
1897	goto out;
1898}
1899
1900module_init(sit_init);
1901module_exit(sit_cleanup);
1902MODULE_LICENSE("GPL");
1903MODULE_ALIAS_RTNL_LINK("sit");
1904MODULE_ALIAS_NETDEV("sit0");