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Release 4.11 net/ipv6/ip6_vti.c

Directory: net/ipv6
/*
 *      IPv6 virtual tunneling interface
 *
 *      Copyright (C) 2013 secunet Security Networks AG
 *
 *      Author:
 *      Steffen Klassert <steffen.klassert@secunet.com>
 *
 *      Based on:
 *      net/ipv6/ip6_tunnel.c
 *
 *      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.
 */

#include <linux/module.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/sockios.h>
#include <linux/icmp.h>
#include <linux/if.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/icmpv6.h>
#include <linux/init.h>
#include <linux/route.h>
#include <linux/rtnetlink.h>
#include <linux/netfilter_ipv6.h>
#include <linux/slab.h>
#include <linux/hash.h>

#include <linux/uaccess.h>
#include <linux/atomic.h>

#include <net/icmp.h>
#include <net/ip.h>
#include <net/ip_tunnels.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/ip6_tunnel.h>
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/etherdevice.h>


#define IP6_VTI_HASH_SIZE_SHIFT  5

#define IP6_VTI_HASH_SIZE (1 << IP6_VTI_HASH_SIZE_SHIFT)




static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
{
	u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);

	return hash_32(hash, IP6_VTI_HASH_SIZE_SHIFT);
}


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Steffen Klassert3897.44%150.00%


Jiri Kosina12.56%150.00%


Total39100.00%2100.00%



static int vti6_dev_init(struct net_device *dev);
static void vti6_dev_setup(struct net_device *dev);

static struct rtnl_link_ops vti6_link_ops __read_mostly;


static unsigned int vti6_net_id __read_mostly;

struct vti6_net {
	/* the vti6 tunnel fallback device */
	
struct net_device *fb_tnl_dev;
	/* lists for storing tunnels in use */
	
struct ip6_tnl __rcu *tnls_r_l[IP6_VTI_HASH_SIZE];
	
struct ip6_tnl __rcu *tnls_wc[1];
	
struct ip6_tnl __rcu **tnls[2];
};


#define for_each_vti6_tunnel_rcu(start) \
	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))

/**
 * vti6_tnl_lookup - fetch tunnel matching the end-point addresses
 *   @net: network namespace
 *   @remote: the address of the tunnel exit-point
 *   @local: the address of the tunnel entry-point
 *
 * Return:
 *   tunnel matching given end-points if found,
 *   else fallback tunnel if its device is up,
 *   else %NULL
 **/


static struct ip6_tnl *

vti6_tnl_lookup(struct net *net, const struct in6_addr *remote,
		const struct in6_addr *local)
{
	unsigned int hash = HASH(remote, local);
	struct ip6_tnl *t;
	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
	struct in6_addr any;

	for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
		if (ipv6_addr_equal(local, &t->parms.laddr) &&
		    ipv6_addr_equal(remote, &t->parms.raddr) &&
		    (t->dev->flags & IFF_UP))
			return t;
	}

	memset(&any, 0, sizeof(any));
	hash = HASH(&any, local);
	for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
		if (ipv6_addr_equal(local, &t->parms.laddr) &&
		    (t->dev->flags & IFF_UP))
			return t;
	}

	hash = HASH(remote, &any);
	for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
		if (ipv6_addr_equal(remote, &t->parms.raddr) &&
		    (t->dev->flags & IFF_UP))
			return t;
	}

	t = rcu_dereference(ip6n->tnls_wc[0]);
	if (t && (t->dev->flags & IFF_UP))
		return t;

	return NULL;
}


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/**
 * vti6_tnl_bucket - get head of list matching given tunnel parameters
 *   @p: parameters containing tunnel end-points
 *
 * Description:
 *   vti6_tnl_bucket() returns the head of the list matching the
 *   &struct in6_addr entries laddr and raddr in @p.
 *
 * Return: head of IPv6 tunnel list
 **/


static struct ip6_tnl __rcu **

vti6_tnl_bucket(struct vti6_net *ip6n, const struct __ip6_tnl_parm *p)
{
	const struct in6_addr *remote = &p->raddr;
	const struct in6_addr *local = &p->laddr;
	unsigned int h = 0;
	int prio = 0;

	if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
		prio = 1;
		h = HASH(remote, local);
	}
	return &ip6n->tnls[prio][h];
}


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Total95100.00%1100.00%





static void

vti6_tnl_link(struct vti6_net *ip6n, struct ip6_tnl *t)
{
	struct ip6_tnl __rcu **tp = vti6_tnl_bucket(ip6n, &t->parms);

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


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Total54100.00%1100.00%





static void

vti6_tnl_unlink(struct vti6_net *ip6n, struct ip6_tnl *t)
{
	struct ip6_tnl __rcu **tp;
	struct ip6_tnl *iter;

	for (tp = vti6_tnl_bucket(ip6n, &t->parms);
	     (iter = rtnl_dereference(*tp)) != NULL;
	     tp = &iter->next) {
		if (t == iter) {
			rcu_assign_pointer(*tp, t->next);
			break;
		}
	}
}


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Total82100.00%1100.00%






static void vti6_dev_free(struct net_device *dev)
{
	free_percpu(dev->tstats);
	free_netdev(dev);
}


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static int vti6_tnl_create2(struct net_device *dev)
{
	struct ip6_tnl *t = netdev_priv(dev);
	struct net *net = dev_net(dev);
	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
	int err;

	dev->rtnl_link_ops = &vti6_link_ops;
	err = register_netdevice(dev);
	if (err < 0)
		goto out;

	strcpy(t->parms.name, dev->name);

	dev_hold(dev);
	vti6_tnl_link(ip6n, t);

	return 0;

out:
	return err;
}


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David Forster76.86%150.00%


Total102100.00%2100.00%






static struct ip6_tnl *vti6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
{
	struct net_device *dev;
	struct ip6_tnl *t;
	char name[IFNAMSIZ];
	int err;

	if (p->name[0])
		strlcpy(name, p->name, IFNAMSIZ);
	else
		sprintf(name, "ip6_vti%%d");

	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, vti6_dev_setup);
	if (!dev)
		goto failed;

	dev_net_set(dev, net);

	t = netdev_priv(dev);
	t->parms = *p;
	t->net = dev_net(dev);

	err = vti6_tnl_create2(dev);
	if (err < 0)
		goto failed_free;

	return t;

failed_free:
	vti6_dev_free(dev);
failed:
	return NULL;
}


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Tom Gundersen21.32%133.33%


Ian Morris10.66%133.33%


Total151100.00%3100.00%



/**
 * vti6_locate - find or create tunnel matching given parameters
 *   @net: network namespace
 *   @p: tunnel parameters
 *   @create: != 0 if allowed to create new tunnel if no match found
 *
 * Description:
 *   vti6_locate() first tries to locate an existing tunnel
 *   based on @parms. If this is unsuccessful, but @create is set a new
 *   tunnel device is created and registered for use.
 *
 * Return:
 *   matching tunnel or NULL
 **/



static struct ip6_tnl *vti6_locate(struct net *net, struct __ip6_tnl_parm *p,
				   int create)
{
	const struct in6_addr *remote = &p->raddr;
	const struct in6_addr *local = &p->laddr;
	struct ip6_tnl __rcu **tp;
	struct ip6_tnl *t;
	struct vti6_net *ip6n = net_generic(net, vti6_net_id);

	for (tp = vti6_tnl_bucket(ip6n, p);
	     (t = rtnl_dereference(*tp)) != NULL;
	     tp = &t->next) {
		if (ipv6_addr_equal(local, &t->parms.laddr) &&
		    ipv6_addr_equal(remote, &t->parms.raddr)) {
			if (create)
				return NULL;

			return t;
		}
	}
	if (!create)
		return NULL;
	return vti6_tnl_create(net, p);
}


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Total153100.00%2100.00%



/**
 * vti6_dev_uninit - tunnel device uninitializer
 *   @dev: the device to be destroyed
 *
 * Description:
 *   vti6_dev_uninit() removes tunnel from its list
 **/



static void vti6_dev_uninit(struct net_device *dev)
{
	struct ip6_tnl *t = netdev_priv(dev);
	struct vti6_net *ip6n = net_generic(t->net, vti6_net_id);

	if (dev == ip6n->fb_tnl_dev)
		RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
	else
		vti6_tnl_unlink(ip6n, t);
	dev_put(dev);
}


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Yao Xiwei22.94%150.00%


Total68100.00%2100.00%






static int vti6_rcv(struct sk_buff *skb)
{
	struct ip6_tnl *t;
	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);

	rcu_read_lock();
	t = vti6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
	if (t) {
		if (t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) {
			rcu_read_unlock();
			goto discard;
		}

		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
			rcu_read_unlock();
			return 0;
		}

		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
			t->dev->stats.rx_dropped++;
			rcu_read_unlock();
			goto discard;
		}

		rcu_read_unlock();

		return xfrm6_rcv_tnl(skb, t);
	}
	rcu_read_unlock();
	return -EINVAL;
discard:
	kfree_skb(skb);
	return 0;
}


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Steffen Klassert16095.81%250.00%


Ian Morris42.40%125.00%


Nicolas Dichtel31.80%125.00%


Total167100.00%4100.00%






static int vti6_rcv_cb(struct sk_buff *skb, int err)
{
	unsigned short family;
	struct net_device *dev;
	struct pcpu_sw_netstats *tstats;
	struct xfrm_state *x;
	struct xfrm_mode *inner_mode;
	struct ip6_tnl *t = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6;
	u32 orig_mark = skb->mark;
	int ret;

	if (!t)
		return 1;

	dev = t->dev;

	if (err) {
		dev->stats.rx_errors++;
		dev->stats.rx_dropped++;

		return 0;
	}

	x = xfrm_input_state(skb);

	inner_mode = x->inner_mode;

	if (x->sel.family == AF_UNSPEC) {
		inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
		if (inner_mode == NULL) {
			XFRM_INC_STATS(dev_net(skb->dev),
				       LINUX_MIB_XFRMINSTATEMODEERROR);
			return -EINVAL;
		}
	}

	family = inner_mode->afinfo->family;

	skb->mark = be32_to_cpu(t->parms.i_key);
	ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
	skb->mark = orig_mark;

	if (!ret)
		return -EPERM;

	skb_scrub_packet(skb, !net_eq(t->net, dev_net(skb->dev)));
	skb->dev = dev;

	tstats = this_cpu_ptr(dev->tstats);
	u64_stats_update_begin(&tstats->syncp);
	tstats->rx_packets++;
	tstats->rx_bytes += skb->len;
	u64_stats_update_end(&tstats->syncp);

	return 0;
}


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Steffen Klassert16860.43%240.00%


thomas.zeitlhofer+lkml@ze-it.at5820.86%120.00%


Alexander Duyck3612.95%120.00%


Li RongQing165.76%120.00%


Total278100.00%5100.00%



/**
 * vti6_addr_conflict - compare packet addresses to tunnel's own
 *   @t: the outgoing tunnel device
 *   @hdr: IPv6 header from the incoming packet
 *
 * Description:
 *   Avoid trivial tunneling loop by checking that tunnel exit-point
 *   doesn't match source of incoming packet.
 *
 * Return:
 *   1 if conflict,
 *   0 else
 **/


static inline bool

vti6_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
{
	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
}


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static bool vti6_state_check(const struct xfrm_state *x,
			     const struct in6_addr *dst,
			     const struct in6_addr *src)
{
	xfrm_address_t *daddr = (xfrm_address_t *)dst;
	xfrm_address_t *saddr = (xfrm_address_t *)src;

	/* if there is no transform then this tunnel is not functional.
         * Or if the xfrm is not mode tunnel.
         */
	if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
	    x->props.family != AF_INET6)
		return false;

	if (ipv6_addr_any(dst))
		return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET6);

	if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET6))
		return false;

	return true;
}


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/**
 * vti6_xmit - send a packet
 *   @skb: the outgoing socket buffer
 *   @dev: the outgoing tunnel device
 *   @fl: the flow informations for the xfrm_lookup
 **/


static int

vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
{
	struct ip6_tnl *t = netdev_priv(dev);
	struct net_device_stats *stats = &t->dev->stats;
	struct dst_entry *dst = skb_dst(skb);
	struct net_device *tdev;
	struct xfrm_state *x;
	int err = -1;
	int mtu;

	if (!dst)
		goto tx_err_link_failure;

	dst_hold(dst);
	dst = xfrm_lookup(t->net, dst, fl, NULL, 0);
	if (IS_ERR(dst)) {
		err = PTR_ERR(dst);
		dst = NULL;
		goto tx_err_link_failure;
	}

	x = dst->xfrm;
	if (!vti6_state_check(x, &t->parms.raddr, &t->parms.laddr))
		goto tx_err_link_failure;

	if (!ip6_tnl_xmit_ctl(t, (const struct in6_addr *)&x->props.saddr,
			      (const struct in6_addr *)&x->id.daddr))
		goto tx_err_link_failure;

	tdev = dst->dev;

	if (tdev == dev) {
		stats->collisions++;
		net_warn_ratelimited("%s: Local routing loop detected!\n",
				     t->parms.name);
		goto tx_err_dst_release;
	}

	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
	skb_dst_set(skb, dst);
	skb->dev = skb_dst(skb)->dev;

	mtu = dst_mtu(dst);
	if (!skb->ignore_df && skb->len > mtu) {
		skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu);

		if (skb->protocol == htons(ETH_P_IPV6)) {
			if (mtu < IPV6_MIN_MTU)
				mtu = IPV6_MIN_MTU;

			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
		} else {
			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
				  htonl(mtu));
		}

		return -EMSGSIZE;
	}

	err = dst_output(t->net, skb->sk, skb);
	if (net_xmit_eval(err) == 0) {
		struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats);

		u64_stats_update_begin(&tstats->syncp);
		tstats->tx_bytes += skb->len;
		tstats->tx_packets++;
		u64_stats_update_end(&tstats->syncp);
	} else {
		stats->tx_errors++;
		stats->tx_aborted_errors++;
	}

	return 0;
tx_err_link_failure:
	stats->tx_carrier_errors++;
	dst_link_failure(skb);
tx_err_dst_release:
	dst_release(dst);
	return err;
}


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Eric W. Biedermann81.73%222.22%


Total462100.00%9100.00%





static netdev_tx_t

vti6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct ip6_tnl *t = netdev_priv(dev);
	struct net_device_stats *stats = &t->dev->stats;
	struct ipv6hdr *ipv6h;
	struct flowi fl;
	int ret;

	memset(&fl, 0, sizeof(fl));

	switch (skb->protocol) {
	case htons(ETH_P_IPV6):
		ipv6h = ipv6_hdr(skb);

		if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
		    vti6_addr_conflict(t, ipv6h))
			goto tx_err;

		xfrm_decode_session(skb, &fl, AF_INET6);
		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
		break;
	case htons(ETH_P_IP):
		xfrm_decode_session(skb, &fl, AF_INET);
		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
		break;
	default:
		goto tx_err;
	}

	/* override mark with tunnel output key */
	fl.flowi_mark = be32_to_cpu(t->parms.o_key);

	ret = vti6_xmit(skb, dev, &fl);
	if (ret < 0)
		goto tx_err;

	return NETDEV_TX_OK;

tx_err:
	stats->tx_errors++;
	stats->tx_dropped++;
	kfree_skb(skb);
	return NETDEV_TX_OK;
}


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Alexander Duyck145.79%125.00%


Total242100.00%4100.00%






static int vti6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
		    u8 type, u8 code, int offset, __be32 info)
{
	__be32 spi;
	__u32 mark;
	struct xfrm_state *x;
	struct ip6_tnl *t;
	struct ip_esp_hdr *esph;
	struct ip_auth_hdr *ah;
	struct ip_comp_hdr *ipch;
	struct net *net = dev_net(skb->dev);
	const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
	int protocol = iph->nexthdr;

	t = vti6_tnl_lookup(dev_net(skb->dev), &iph->daddr, &iph->saddr);
	if (!t)
		return -1;

	mark = be32_to_cpu(t->parms.o_key);

	switch (protocol) {
	case IPPROTO_ESP:
		esph = (struct ip_esp_hdr *)(skb->data + offset);
		spi = esph->spi;
		break;
	case IPPROTO_AH:
		ah = (struct ip_auth_hdr *)(skb->data + offset);
		spi = ah->spi;
		break;
	case IPPROTO_COMP:
		ipch = (struct ip_comp_hdr *)(skb->data + offset);
		spi = htonl(ntohs(ipch->cpi));
		break;
	default:
		return 0;
	}

	if (type != ICMPV6_PKT_TOOBIG &&
	    type != NDISC_REDIRECT)
		return 0;

	x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
			      spi, protocol, AF_INET6);
	if (!x)
		return 0;

	if (type == NDISC_REDIRECT)
		ip6_redirect(skb, net, skb->dev->ifindex, 0,
			     sock_net_uid(net, NULL));
	else
		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
	xfrm_state_put(x);

	return 0;
}


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Steffen Klassert31695.76%375.00%


Lorenzo Colitti144.24%125.00%


Total330100.00%4100.00%






static void vti6_link_config(struct ip6_tnl *t)
{
	struct net_device *dev = t->dev;
	struct __ip6_tnl_parm *p = &t->parms;

	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));

	p->flags &= ~(IP6_TNL_F_CAP_XMIT | IP6_TNL_F_CAP_RCV |
		      IP6_TNL_F_CAP_PER_PACKET);
	p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);

	if (p->flags & IP6_TNL_F_CAP_XMIT && p->flags & IP6_TNL_F_CAP_RCV)
		dev->flags |= IFF_POINTOPOINT;
	else
		dev->flags &= ~IFF_POINTOPOINT;
}


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