Release 4.11 net/ipv6/sit.c

/*
 *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 *
 *      Changes:
 * Roger Venning <r.venning@telstra.com>:       6to4 support
 * Nate Thompson <nate@thebog.net>:             6to4 support
 * Fred Templin <fred.l.templin@boeing.com>:    isatap support
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/icmp.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/init.h>
#include <linux/netfilter_ipv4.h>
#include <linux/if_ether.h>

#include <net/sock.h>
#include <net/snmp.h>

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/icmp.h>
#include <net/ip_tunnels.h>
#include <net/inet_ecn.h>
#include <net/xfrm.h>
#include <net/dsfield.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

/*
   This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c

   For comments look at net/ipv4/ip_gre.c --ANK
 */


#define IP6_SIT_HASH_SIZE  16

#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)


static bool log_ecn_error = true;
module_param(log_ecn_error, bool, 0644);
MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");

static int ipip6_tunnel_init(struct net_device *dev);
static void ipip6_tunnel_setup(struct net_device *dev);
static void ipip6_dev_free(struct net_device *dev);
static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
		      __be32 *v4dst);

static struct rtnl_link_ops sit_link_ops __read_mostly;


static unsigned int sit_net_id __read_mostly;

struct sit_net {
	
struct ip_tunnel __rcu *tunnels_r_l[IP6_SIT_HASH_SIZE];
	
struct ip_tunnel __rcu *tunnels_r[IP6_SIT_HASH_SIZE];
	
struct ip_tunnel __rcu *tunnels_l[IP6_SIT_HASH_SIZE];
	
struct ip_tunnel __rcu *tunnels_wc[1];
	
struct ip_tunnel __rcu **tunnels[4];

	
struct net_device *fb_tunnel_dev;
};

/*
 * Must be invoked with rcu_read_lock
 */


static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
		struct net_device *dev, __be32 remote, __be32 local)
{
	unsigned int h0 = HASH(remote);
	unsigned int h1 = HASH(local);
	struct ip_tunnel *t;
	struct sit_net *sitn = net_generic(net, sit_net_id);

	for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
		if (local == t->parms.iph.saddr &&
		    remote == t->parms.iph.daddr &&
		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
		    (t->dev->flags & IFF_UP))
			return t;
	}
	for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
		if (remote == t->parms.iph.daddr &&
		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
		    (t->dev->flags & IFF_UP))
			return t;
	}
	for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
		if (local == t->parms.iph.saddr &&
		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
		    (t->dev->flags & IFF_UP))
			return t;
	}
	t = rcu_dereference(sitn->tunnels_wc[0]);
	if (t && (t->dev->flags & IFF_UP))
		return t;
	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
147
55.26%
2
20.00%
Sascha Hlusiak
72
27.07%
1
10.00%
Pavel Emelyanov
19
7.14%
2
20.00%
Eric Dumazet
17
6.39%
2
20.00%
Américo Wang
6
2.26%
1
10.00%
Shmulik Ladkani
3
1.13%
1
10.00%
Al Viro
2
0.75%
1
10.00%
Total
266
100.00%
10
100.00%



static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
		struct ip_tunnel_parm *parms)
{
	__be32 remote = parms->iph.daddr;
	__be32 local = parms->iph.saddr;
	unsigned int h = 0;
	int prio = 0;

	if (remote) {
		prio |= 2;
		h ^= HASH(remote);
	}
	if (local) {
		prio |= 1;
		h ^= HASH(local);
	}
	return &sitn->tunnels[prio][h];
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
79
83.16%
1
16.67%
Pavel Emelyanov
7
7.37%
2
33.33%
Hideaki Yoshifuji / 吉藤英明
5
5.26%
1
16.67%
Al Viro
2
2.11%
1
16.67%
Eric Dumazet
2
2.11%
1
16.67%
Total
95
100.00%
6
100.00%



static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
		struct ip_tunnel *t)
{
	return __ipip6_bucket(sitn, &t->parms);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Hideaki Yoshifuji / 吉藤英明
24
75.00%
1
33.33%
Pavel Emelyanov
7
21.88%
1
33.33%
Eric Dumazet
1
3.12%
1
33.33%
Total
32
100.00%
3
100.00%



static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
{
	struct ip_tunnel __rcu **tp;
	struct ip_tunnel *iter;

	for (tp = ipip6_bucket(sitn, t);
	     (iter = rtnl_dereference(*tp)) != NULL;
	     tp = &iter->next) {
		if (t == iter) {
			rcu_assign_pointer(*tp, t->next);
			break;
		}
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
53
67.09%
2
40.00%
Eric Dumazet
19
24.05%
2
40.00%
Pavel Emelyanov
7
8.86%
1
20.00%
Total
79
100.00%
5
100.00%



static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
{
	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);

	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
	rcu_assign_pointer(*tp, t);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
33
64.71%
2
33.33%
Eric Dumazet
11
21.57%
3
50.00%
Pavel Emelyanov
7
13.73%
1
16.67%
Total
51
100.00%
6
100.00%



static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
{
#ifdef CONFIG_IPV6_SIT_6RD
	struct ip_tunnel *t = netdev_priv(dev);

	if (t->dev == sitn->fb_tunnel_dev) {
		ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
		t->ip6rd.relay_prefix = 0;
		t->ip6rd.prefixlen = 16;
		t->ip6rd.relay_prefixlen = 0;
	} else {
		struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
		memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
	}
#endif
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Hideaki Yoshifuji / 吉藤英明
123
100.00%
2
100.00%
Total
123
100.00%
2
100.00%



static int ipip6_tunnel_create(struct net_device *dev)
{
	struct ip_tunnel *t = netdev_priv(dev);
	struct net *net = dev_net(dev);
	struct sit_net *sitn = net_generic(net, sit_net_id);
	int err;

	memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
	memcpy(dev->broadcast, &t->parms.iph.daddr, 4);

	if ((__force u16)t->parms.i_flags & SIT_ISATAP)
		dev->priv_flags |= IFF_ISATAP;

	dev->rtnl_link_ops = &sit_link_ops;

	err = register_netdevice(dev);
	if (err < 0)
		goto out;

	ipip6_tunnel_clone_6rd(dev, sitn);

	dev_hold(dev);

	ipip6_tunnel_link(sitn, t);
	return 0;

out:
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Nicolas Dichtel
115
75.66%
2
50.00%
Steffen Klassert
30
19.74%
1
25.00%
Thadeu Lima de Souza Cascardo
7
4.61%
1
25.00%
Total
152
100.00%
4
100.00%



static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
		struct ip_tunnel_parm *parms, int create)
{
	__be32 remote = parms->iph.daddr;
	__be32 local = parms->iph.saddr;
	struct ip_tunnel *t, *nt;
	struct ip_tunnel __rcu **tp;
	struct net_device *dev;
	char name[IFNAMSIZ];
	struct sit_net *sitn = net_generic(net, sit_net_id);

	for (tp = __ipip6_bucket(sitn, parms);
	    (t = rtnl_dereference(*tp)) != NULL;
	     tp = &t->next) {
		if (local == t->parms.iph.saddr &&
		    remote == t->parms.iph.daddr &&
		    parms->link == t->parms.link) {
			if (create)
				return NULL;
			else
				return t;
		}
	}
	if (!create)
		goto failed;

	if (parms->name[0])
		strlcpy(name, parms->name, IFNAMSIZ);
	else
		strcpy(name, "sit%d");

	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
			   ipip6_tunnel_setup);
	if (!dev)
		return NULL;

	dev_net_set(dev, net);

	nt = netdev_priv(dev);

	nt->parms = *parms;
	if (ipip6_tunnel_create(dev) < 0)
		goto failed_free;

	return nt;

failed_free:
	ipip6_dev_free(dev);
failed:
	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
135
51.33%
4
19.05%
Stephen Hemminger
41
15.59%
1
4.76%
Pavel Emelyanov
33
12.55%
3
14.29%
Sascha Hlusiak
20
7.60%
2
9.52%
Eric Dumazet
14
5.32%
2
9.52%
Linus Torvalds
4
1.52%
1
4.76%
Hideaki Yoshifuji / 吉藤英明
4
1.52%
1
4.76%
Patrick McHardy
3
1.14%
1
4.76%
Al Viro
2
0.76%
1
4.76%
Tom Gundersen
2
0.76%
1
4.76%
David S. Miller
2
0.76%
1
4.76%
Stephen Rothwell
1
0.38%
1
4.76%
Ian Morris
1
0.38%
1
4.76%
Nicolas Dichtel
1
0.38%
1
4.76%
Total
263
100.00%
21
100.00%


#define for_each_prl_rcu(start)			\
	for (prl = rcu_dereference(start);      \
             prl;                               \
             prl = rcu_dereference(prl->next))


static struct ip_tunnel_prl_entry *

__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
{
	struct ip_tunnel_prl_entry *prl;

	for_each_prl_rcu(t->prl)
		if (prl->addr == addr)
			break;
	return prl;

}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Fred L. Templin
18
48.65%
1
20.00%
Linus Torvalds (pre-git)
11
29.73%
2
40.00%
Eric Dumazet
7
18.92%
1
20.00%
Hideaki Yoshifuji / 吉藤英明
1
2.70%
1
20.00%
Total
37
100.00%
5
100.00%



static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
				struct ip_tunnel_prl __user *a)
{
	struct ip_tunnel_prl kprl, *kp;
	struct ip_tunnel_prl_entry *prl;
	unsigned int cmax, c = 0, ca, len;
	int ret = 0;

	if (copy_from_user(&kprl, a, sizeof(kprl)))
		return -EFAULT;
	cmax = kprl.datalen / sizeof(kprl);
	if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
		cmax = 1;

	/* For simple GET or for root users,
         * we try harder to allocate.
         */
	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
		kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
		NULL;

	rcu_read_lock();

	ca = t->prl_count < cmax ? t->prl_count : cmax;

	if (!kp) {
		/* We don't try hard to allocate much memory for
                 * non-root users.
                 * For root users, retry allocating enough memory for
                 * the answer.
                 */
		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
		if (!kp) {
			ret = -ENOMEM;
			goto out;
		}
	}

	c = 0;
	for_each_prl_rcu(t->prl) {
		if (c >= cmax)
			break;
		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
			continue;
		kp[c].addr = prl->addr;
		kp[c].flags = prl->flags;
		c++;
		if (kprl.addr != htonl(INADDR_ANY))
			break;
	}
out:
	rcu_read_unlock();

	len = sizeof(*kp) * c;
	ret = 0;
	if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
		ret = -EFAULT;

	kfree(kp);

	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Hideaki Yoshifuji / 吉藤英明
303
97.12%
2
50.00%
Eric Dumazet
8
2.56%
1
25.00%
Sascha Hlusiak
1
0.32%
1
25.00%
Total
312
100.00%
4
100.00%


static int

ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
{
	struct ip_tunnel_prl_entry *p;
	int err = 0;

	if (a->addr == htonl(INADDR_ANY))
		return -EINVAL;

	ASSERT_RTNL();

	for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
		if (p->addr == a->addr) {
			if (chg) {
				p->flags = a->flags;
				goto out;
			}
			err = -EEXIST;
			goto out;
		}
	}

	if (chg) {
		err = -ENXIO;
		goto out;
	}

	p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
	if (!p) {
		err = -ENOBUFS;
		goto out;
	}

	p->next = t->prl;
	p->addr = a->addr;
	p->flags = a->flags;
	t->prl_count++;
	rcu_assign_pointer(t->prl, p);
out:
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Hideaki Yoshifuji / 吉藤英明
65
33.68%
3
23.08%
Fred L. Templin
61
31.61%
1
7.69%
Eric Dumazet
36
18.65%
4
30.77%
Linus Torvalds (pre-git)
28
14.51%
3
23.08%
Kazunori Miyazawa
2
1.04%
1
7.69%
Stephen Rothwell
1
0.52%
1
7.69%
Total
193
100.00%
13
100.00%



static void prl_list_destroy_rcu(struct rcu_head *head)
{
	struct ip_tunnel_prl_entry *p, *n;

	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
	do {
		n = rcu_dereference_protected(p->next, 1);
		kfree(p);
		p = n;
	} while (p);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric Dumazet
59
100.00%
2
100.00%
Total
59
100.00%
2
100.00%


static int

ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
{
	struct ip_tunnel_prl_entry *x;
	struct ip_tunnel_prl_entry __rcu **p;
	int err = 0;

	ASSERT_RTNL();

	if (a && a->addr != htonl(INADDR_ANY)) {
		for (p = &t->prl;
		     (x = rtnl_dereference(*p)) != NULL;
		     p = &x->next) {
			if (x->addr == a->addr) {
				*p = x->next;
				kfree_rcu(x, rcu_head);
				t->prl_count--;
				goto out;
			}
		}
		err = -ENXIO;
	} else {
		x = rtnl_dereference(t->prl);
		if (x) {
			t->prl_count = 0;
			call_rcu(&x->rcu_head, prl_list_destroy_rcu);
			t->prl = NULL;
		}
	}
out:
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Fred L. Templin
79
47.88%
1
10.00%
Eric Dumazet
39
23.64%
3
30.00%
Hideaki Yoshifuji / 吉藤英明
31
18.79%
3
30.00%
Linus Torvalds (pre-git)
13
7.88%
1
10.00%
Paul E. McKenney
2
1.21%
1
10.00%
Sascha Hlusiak
1
0.61%
1
10.00%
Total
165
100.00%
10
100.00%


static int

isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
{
	struct ip_tunnel_prl_entry *p;
	int ok = 1;

	rcu_read_lock();
	p = __ipip6_tunnel_locate_prl(t, iph->saddr);
	if (p) {
		if (p->flags & PRL_DEFAULT)
			skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
		else
			skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
	} else {
		const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;

		if (ipv6_addr_is_isatap(addr6) &&
		    (addr6->s6_addr32[3] == iph->saddr) &&
		    ipv6_chk_prefix(addr6, t->dev))
			skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
		else
			ok = 0;
	}
	rcu_read_unlock();
	return ok;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Fred L. Templin
113
83.09%
1
16.67%
Hideaki Yoshifuji / 吉藤英明
12
8.82%
2
33.33%
Eric Dumazet
6
4.41%
2
33.33%
Linus Torvalds (pre-git)
5
3.68%
1
16.67%
Total
136
100.00%
6
100.00%



static void ipip6_tunnel_uninit(struct net_device *dev)
{
	struct ip_tunnel *tunnel = netdev_priv(dev);
	struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);

	if (dev == sitn->fb_tunnel_dev) {
		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
	} else {
		ipip6_tunnel_unlink(sitn, tunnel);
		ipip6_tunnel_del_prl(tunnel, NULL);
	}
	dst_cache_reset(&tunnel->dst_cache);
	dev_put(dev);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Fred L. Templin
41
47.13%
1
9.09%
Pavel Emelyanov
26
29.89%
3
27.27%
Nicolas Dichtel
11
12.64%
2
18.18%
Paolo Abeni
4
4.60%
1
9.09%
Eric Dumazet
2
2.30%
1
9.09%
Stephen Hemminger
1
1.15%
1
9.09%
Linus Torvalds (pre-git)
1
1.15%
1
9.09%
Hideaki Yoshifuji / 吉藤英明
1
1.15%
1
9.09%
Total
87
100.00%
11
100.00%



static int ipip6_err(struct sk_buff *skb, u32 info)
{
	const struct iphdr *iph = (const struct iphdr *)skb->data;
	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	unsigned int data_len = 0;
	struct ip_tunnel *t;
	int err;

	switch (type) {
	default:
	case ICMP_PARAMETERPROB:
		return 0;

	case ICMP_DEST_UNREACH:
		switch (code) {
		case ICMP_SR_FAILED:
			/* Impossible event. */
			return 0;
		default:
			/* All others are translated to HOST_UNREACH.
                           rfc2003 contains "deep thoughts" about NET_UNREACH,
                           I believe they are just ether pollution. --ANK
                         */
			break;
		}
		break;
	case ICMP_TIME_EXCEEDED:
		if (code != ICMP_EXC_TTL)
			return 0;
		data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
		break;
	case ICMP_REDIRECT:
		break;
	}

	err = -ENOENT;

	t = ipip6_tunnel_lookup(dev_net(skb->dev),
				skb->dev,
				iph->daddr,
				iph->saddr);
	if (!t)
		goto out;

	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
				 t->parms.link, 0, iph->protocol, 0);
		err = 0;
		goto out;
	}
	if (type == ICMP_REDIRECT) {
		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
			      iph->protocol, 0);
		err = 0;
		goto out;
	}

	err = 0;
	if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
		goto out;

	if (t->parms.iph.daddr == 0)
		goto out;

	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
		goto out;

	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
		t->err_count++;
	else
		t->err_count = 1;
	t->err_time = jiffies;
out:
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
92
26.06%
1
5.56%
David S. Miller
84
23.80%
2
11.11%
Fred L. Templin
74
20.96%
1
5.56%
Eric Dumazet
51
14.45%
4
22.22%
Oussama Ghorbel
10
2.83%
1
5.56%
Arnaldo Carvalho de Melo
8
2.27%
1
5.56%
Pavel Emelyanov
7
1.98%
2
11.11%
Dmitry Popov
6
1.70%
1
5.56%
Simon Horman
6
1.70%
1
5.56%
Kazunori Miyazawa
5
1.42%
1
5.56%
Wei Yongjun
5
1.42%
1
5.56%
Sascha Hlusiak
4
1.13%
1
5.56%
Ian Morris
1
0.28%
1
5.56%
Total
353
100.00%
18
100.00%



static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
				  const struct in6_addr *v6addr)
{
	__be32 v4embed = 0;
	if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
		return true;
	return false;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Hannes Frederic Sowa
49
100.00%
1
100.00%
Total
49
100.00%
1
100.00%

/* Checks if an address matches an address on the tunnel interface.
 * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 * Long story:
 * This function is called after we considered the packet as spoofed
 * in is_spoofed_6rd.
 * We may have a router that is doing NAT for proto 41 packets
 * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 * function will return true, dropping the packet.
 * But, we can still check if is spoofed against the IP
 * addresses associated with the interface.
 */


static bool only_dnatted(const struct ip_tunnel *tunnel,
	const struct in6_addr *v6dst)
{
	int prefix_len;

#ifdef CONFIG_IPV6_SIT_6RD
	prefix_len = tunnel->ip6rd.prefixlen + 32
		- tunnel->ip6rd.relay_prefixlen;
#else
	prefix_len = 48;
#endif
	return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Catalin(ux aka Dino) M. Boie
60
100.00%
1
100.00%
Total
60
100.00%
1
100.00%

/* Returns true if a packet is spoofed */


static bool packet_is_spoofed(struct sk_buff *skb,
			      const struct iphdr *iph,
			      struct ip_tunnel *tunnel)
{
	const struct ipv6hdr *ipv6h;

	if (tunnel->dev->priv_flags & IFF_ISATAP) {
		if (!isatap_chksrc(skb, iph, tunnel))
			return true;

		return false;
	}

	if (tunnel->dev->flags & IFF_POINTOPOINT)
		return false;

	ipv6h = ipv6_hdr(skb);

	if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
		net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
				     &iph->saddr, &ipv6h->saddr,
				     &iph->daddr, &ipv6h->daddr);
		return true;
	}

	if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
		return false;

	if (only_dnatted(tunnel, &ipv6h->daddr))
		return false;

	net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
			     &iph->saddr, &ipv6h->saddr,
			     &iph->daddr, &ipv6h->daddr);
	return true;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Catalin(ux aka Dino) M. Boie
193
100.00%
1
100.00%
Total
193
100.00%
1
100.00%



static int ipip6_rcv(struct sk_buff *sk