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ip6_tunnel.c
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/*
* IPv6 tunneling device
* Linux INET6 implementation
*
* Authors:
* Ville Nuorvala <vnuorval@tcs.hut.fi>
* Yasuyuki Kozakai <kozakai@linux-ipv6.org>
*
* Based on:
* linux/net/ipv6/sit.c and linux/net/ipv4/ipip.c
*
* RFC 2473
*
* 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.
*
*/
#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/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/etherdevice.h>
#include <asm/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/dsfield.h>
#include <net/inet_ecn.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
MODULE_AUTHOR("Ville Nuorvala");
MODULE_DESCRIPTION("IPv6 tunneling device");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETDEV("ip6tnl0");
#ifdef IP6_TNL_DEBUG
#define IP6_TNL_TRACE(x...) pr_debug("%s:" x "\n", __func__)
#else
#define IP6_TNL_TRACE(x...) do {;} while(0)
#endif
#define HASH_SIZE_SHIFT 5
#define HASH_SIZE (1 << HASH_SIZE_SHIFT)
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 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, HASH_SIZE_SHIFT);
}
static int ip6_tnl_dev_init(struct net_device *dev);
static void ip6_tnl_dev_setup(struct net_device *dev);
static struct rtnl_link_ops ip6_link_ops __read_mostly;
static int ip6_tnl_net_id __read_mostly;
struct ip6_tnl_net {
/* the IPv6 tunnel fallback device */
struct net_device *fb_tnl_dev;
/* lists for storing tunnels in use */
struct ip6_tnl __rcu *tnls_r_l[HASH_SIZE];
struct ip6_tnl __rcu *tnls_wc[1];
struct ip6_tnl __rcu **tnls[2];
};
static struct net_device_stats *ip6_get_stats(struct net_device *dev)
{
struct pcpu_sw_netstats tmp, sum = { 0 };
int i;
for_each_possible_cpu(i) {
unsigned int start;
const struct pcpu_sw_netstats *tstats =
per_cpu_ptr(dev->tstats, i);
do {
start = u64_stats_fetch_begin_irq(&tstats->syncp);
tmp.rx_packets = tstats->rx_packets;
tmp.rx_bytes = tstats->rx_bytes;
tmp.tx_packets = tstats->tx_packets;
tmp.tx_bytes = tstats->tx_bytes;
} while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
sum.rx_packets += tmp.rx_packets;
sum.rx_bytes += tmp.rx_bytes;
sum.tx_packets += tmp.tx_packets;
sum.tx_bytes += tmp.tx_bytes;
}
dev->stats.rx_packets = sum.rx_packets;
dev->stats.rx_bytes = sum.rx_bytes;
dev->stats.tx_packets = sum.tx_packets;
dev->stats.tx_bytes = sum.tx_bytes;
return &dev->stats;
}
/*
* Locking : hash tables are protected by RCU and RTNL
*/
struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t)
{
struct dst_entry *dst = t->dst_cache;
if (dst && dst->obsolete &&
dst->ops->check(dst, t->dst_cookie) == NULL) {
t->dst_cache = NULL;
dst_release(dst);
return NULL;
}
return dst;
}
EXPORT_SYMBOL_GPL(ip6_tnl_dst_check);
void ip6_tnl_dst_reset(struct ip6_tnl *t)
{
dst_release(t->dst_cache);
t->dst_cache = NULL;
}
EXPORT_SYMBOL_GPL(ip6_tnl_dst_reset);
void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
{
struct rt6_info *rt = (struct rt6_info *) dst;
t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
dst_release(t->dst_cache);
t->dst_cache = dst;
}
EXPORT_SYMBOL_GPL(ip6_tnl_dst_store);
/**
* ip6_tnl_lookup - fetch tunnel matching the end-point addresses
* @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
**/
#define for_each_ip6_tunnel_rcu(start) \
for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
static struct ip6_tnl *
ip6_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 ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
for_each_ip6_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;
}
t = rcu_dereference(ip6n->tnls_wc[0]);
if (t && (t->dev->flags & IFF_UP))
return t;
return NULL;
}
/**
* ip6_tnl_bucket - get head of list matching given tunnel parameters
* @p: parameters containing tunnel end-points
*
* Description:
* ip6_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 **
ip6_tnl_bucket(struct ip6_tnl_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];
}
/**
* ip6_tnl_link - add tunnel to hash table
* @t: tunnel to be added
**/
static void
ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
{
struct ip6_tnl __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms);
rcu_assign_pointer(t->next , rtnl_dereference(*tp));
rcu_assign_pointer(*tp, t);
}
/**
* ip6_tnl_unlink - remove tunnel from hash table
* @t: tunnel to be removed
**/
static void
ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
{
struct ip6_tnl __rcu **tp;
struct ip6_tnl *iter;
for (tp = ip6_tnl_bucket(ip6n, &t->parms);
(iter = rtnl_dereference(*tp)) != NULL;
tp = &iter->next) {
if (t == iter) {
rcu_assign_pointer(*tp, t->next);
break;
}
}
}
static void ip6_dev_free(struct net_device *dev)
{
free_percpu(dev->tstats);
free_netdev(dev);
}
static int ip6_tnl_create2(struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
struct net *net = dev_net(dev);
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
int err;
t = netdev_priv(dev);
err = ip6_tnl_dev_init(dev);
if (err < 0)
goto out;
err = register_netdevice(dev);
if (err < 0)
goto out;
strcpy(t->parms.name, dev->name);
dev->rtnl_link_ops = &ip6_link_ops;
dev_hold(dev);
ip6_tnl_link(ip6n, t);
return 0;
out:
return err;
}
/**
* ip6_tnl_create - create a new tunnel
* @p: tunnel parameters
* @pt: pointer to new tunnel
*
* Description:
* Create tunnel matching given parameters.
*
* Return:
* created tunnel or NULL
**/
static struct ip6_tnl *ip6_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, "ip6tnl%%d");
dev = alloc_netdev(sizeof (*t), name, ip6_tnl_dev_setup);
if (dev == NULL)
goto failed;
dev_net_set(dev, net);
t = netdev_priv(dev);
t->parms = *p;
t->net = dev_net(dev);
err = ip6_tnl_create2(dev);
if (err < 0)
goto failed_free;
return t;
failed_free:
ip6_dev_free(dev);
failed:
return NULL;
}
/**
* ip6_tnl_locate - find or create tunnel matching given parameters
* @p: tunnel parameters
* @create: != 0 if allowed to create new tunnel if no match found
*
* Description:
* ip6_tnl_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 *ip6_tnl_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 ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
for (tp = ip6_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))
return t;
}
if (!create)
return NULL;
return ip6_tnl_create(net, p);
}
/**
* ip6_tnl_dev_uninit - tunnel device uninitializer
* @dev: the device to be destroyed
*
* Description:
* ip6_tnl_dev_uninit() removes tunnel from its list
**/
static void
ip6_tnl_dev_uninit(struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
struct net *net = t->net;
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
if (dev == ip6n->fb_tnl_dev)
RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
else
ip6_tnl_unlink(ip6n, t);
ip6_tnl_dst_reset(t);
dev_put(dev);
}
/**
* parse_tvl_tnl_enc_lim - handle encapsulation limit option
* @skb: received socket buffer
*
* Return:
* 0 if none was found,
* else index to encapsulation limit
**/
__u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
{
const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) raw;
__u8 nexthdr = ipv6h->nexthdr;
__u16 off = sizeof (*ipv6h);
while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
__u16 optlen = 0;
struct ipv6_opt_hdr *hdr;
if (raw + off + sizeof (*hdr) > skb->data &&
!pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
break;
hdr = (struct ipv6_opt_hdr *) (raw + off);
if (nexthdr == NEXTHDR_FRAGMENT) {
struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
if (frag_hdr->frag_off)
break;
optlen = 8;
} else if (nexthdr == NEXTHDR_AUTH) {
optlen = (hdr->hdrlen + 2) << 2;
} else {
optlen = ipv6_optlen(hdr);
}
if (nexthdr == NEXTHDR_DEST) {
__u16 i = off + 2;
while (1) {
struct ipv6_tlv_tnl_enc_lim *tel;
/* No more room for encapsulation limit */
if (i + sizeof (*tel) > off + optlen)
break;
tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
/* return index of option if found and valid */
if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
tel->length == 1)
return i;
/* else jump to next option */
if (tel->type)
i += tel->length + 2;
else
i++;
}
}
nexthdr = hdr->nexthdr;
off += optlen;
}
return 0;
}
EXPORT_SYMBOL(ip6_tnl_parse_tlv_enc_lim);
/**
* ip6_tnl_err - tunnel error handler
*
* Description:
* ip6_tnl_err() should handle errors in the tunnel according
* to the specifications in RFC 2473.
**/
static int
ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
u8 *type, u8 *code, int *msg, __u32 *info, int offset)
{
const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) skb->data;
struct ip6_tnl *t;
int rel_msg = 0;
u8 rel_type = ICMPV6_DEST_UNREACH;
u8 rel_code = ICMPV6_ADDR_UNREACH;
__u32 rel_info = 0;
__u16 len;
int err = -ENOENT;
/* If the packet doesn't contain the original IPv6 header we are
in trouble since we might need the source address for further
processing of the error. */
rcu_read_lock();
if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr,
&ipv6h->saddr)) == NULL)
goto out;
if (t->parms.proto != ipproto && t->parms.proto != 0)
goto out;
err = 0;
switch (*type) {
__u32 teli;
struct ipv6_tlv_tnl_enc_lim *tel;
__u32 mtu;
case ICMPV6_DEST_UNREACH:
net_warn_ratelimited("%s: Path to destination invalid or inactive!\n",
t->parms.name);
rel_msg = 1;
break;
case ICMPV6_TIME_EXCEED:
if ((*code) == ICMPV6_EXC_HOPLIMIT) {
net_warn_ratelimited("%s: Too small hop limit or routing loop in tunnel!\n",
t->parms.name);
rel_msg = 1;
}
break;
case ICMPV6_PARAMPROB:
teli = 0;
if ((*code) == ICMPV6_HDR_FIELD)
teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);
if (teli && teli == *info - 2) {
tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
if (tel->encap_limit == 0) {
net_warn_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
t->parms.name);
rel_msg = 1;
}
} else {
net_warn_ratelimited("%s: Recipient unable to parse tunneled packet!\n",
t->parms.name);
}
break;
case ICMPV6_PKT_TOOBIG:
mtu = *info - offset;
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
t->dev->mtu = mtu;
if ((len = sizeof (*ipv6h) + ntohs(ipv6h->payload_len)) > mtu) {
rel_type = ICMPV6_PKT_TOOBIG;
rel_code = 0;
rel_info = mtu;
rel_msg = 1;
}
break;
}
*type = rel_type;
*code = rel_code;
*info = rel_info;
*msg = rel_msg;
out:
rcu_read_unlock();
return err;
}
static int
ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
int rel_msg = 0;
u8 rel_type = type;
u8 rel_code = code;
__u32 rel_info = ntohl(info);
int err;
struct sk_buff *skb2;
const struct iphdr *eiph;
struct rtable *rt;
struct flowi4 fl4;
err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code,
&rel_msg, &rel_info, offset);
if (err < 0)
return err;
if (rel_msg == 0)
return 0;
switch (rel_type) {
case ICMPV6_DEST_UNREACH:
if (rel_code != ICMPV6_ADDR_UNREACH)
return 0;
rel_type = ICMP_DEST_UNREACH;
rel_code = ICMP_HOST_UNREACH;
break;
case ICMPV6_PKT_TOOBIG:
if (rel_code != 0)
return 0;
rel_type = ICMP_DEST_UNREACH;
rel_code = ICMP_FRAG_NEEDED;
break;
case NDISC_REDIRECT:
rel_type = ICMP_REDIRECT;
rel_code = ICMP_REDIR_HOST;
default:
return 0;
}
if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))
return 0;
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
return 0;
skb_dst_drop(skb2);
skb_pull(skb2, offset);
skb_reset_network_header(skb2);
eiph = ip_hdr(skb2);
/* Try to guess incoming interface */
rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
eiph->saddr, 0,
0, 0,
IPPROTO_IPIP, RT_TOS(eiph->tos), 0);
if (IS_ERR(rt))
goto out;
skb2->dev = rt->dst.dev;
/* route "incoming" packet */
if (rt->rt_flags & RTCF_LOCAL) {
ip_rt_put(rt);
rt = NULL;
rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
eiph->daddr, eiph->saddr,
0, 0,
IPPROTO_IPIP,
RT_TOS(eiph->tos), 0);
if (IS_ERR(rt) ||
rt->dst.dev->type != ARPHRD_TUNNEL) {
if (!IS_ERR(rt))
ip_rt_put(rt);
goto out;
}
skb_dst_set(skb2, &rt->dst);
} else {
ip_rt_put(rt);
if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
skb2->dev) ||
skb_dst(skb2)->dev->type != ARPHRD_TUNNEL)
goto out;
}
/* change mtu on this route */
if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) {
if (rel_info > dst_mtu(skb_dst(skb2)))
goto out;
skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
}
if (rel_type == ICMP_REDIRECT)
skb_dst(skb2)->ops->redirect(skb_dst(skb2), NULL, skb2);
icmp_send(skb2, rel_type, rel_code, htonl(rel_info));
out:
kfree_skb(skb2);
return 0;
}
static int
ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
int rel_msg = 0;
u8 rel_type = type;
u8 rel_code = code;
__u32 rel_info = ntohl(info);
int err;
err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,
&rel_msg, &rel_info, offset);
if (err < 0)
return err;
if (rel_msg && pskb_may_pull(skb, offset + sizeof(struct ipv6hdr))) {
struct rt6_info *rt;
struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
return 0;
skb_dst_drop(skb2);
skb_pull(skb2, offset);
skb_reset_network_header(skb2);
/* Try to guess incoming interface */
rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr,
NULL, 0, 0);
if (rt && rt->dst.dev)
skb2->dev = rt->dst.dev;
icmpv6_send(skb2, rel_type, rel_code, rel_info);
ip6_rt_put(rt);
kfree_skb(skb2);
}
return 0;
}
static int ip4ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
const struct ipv6hdr *ipv6h,
struct sk_buff *skb)
{
__u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK;
if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, dsfield);
return IP6_ECN_decapsulate(ipv6h, skb);
}
static int ip6ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
const struct ipv6hdr *ipv6h,
struct sk_buff *skb)
{
if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
ipv6_copy_dscp(ipv6_get_dsfield(ipv6h), ipv6_hdr(skb));
return IP6_ECN_decapsulate(ipv6h, skb);
}
__u32 ip6_tnl_get_cap(struct ip6_tnl *t,
const struct in6_addr *laddr,
const struct in6_addr *raddr)
{
struct __ip6_tnl_parm *p = &t->parms;
int ltype = ipv6_addr_type(laddr);
int rtype = ipv6_addr_type(raddr);
__u32 flags = 0;
if (ltype == IPV6_ADDR_ANY || rtype == IPV6_ADDR_ANY) {
flags = IP6_TNL_F_CAP_PER_PACKET;
} else if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
!((ltype|rtype) & IPV6_ADDR_LOOPBACK) &&
(!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) {
if (ltype&IPV6_ADDR_UNICAST)
flags |= IP6_TNL_F_CAP_XMIT;
if (rtype&IPV6_ADDR_UNICAST)
flags |= IP6_TNL_F_CAP_RCV;
}
return flags;
}
EXPORT_SYMBOL(ip6_tnl_get_cap);
/* called with rcu_read_lock() */
int ip6_tnl_rcv_ctl(struct ip6_tnl *t,
const struct in6_addr *laddr,
const struct in6_addr *raddr)
{
struct __ip6_tnl_parm *p = &t->parms;
int ret = 0;
struct net *net = t->net;
if ((p->flags & IP6_TNL_F_CAP_RCV) ||
((p->flags & IP6_TNL_F_CAP_PER_PACKET) &&
(ip6_tnl_get_cap(t, laddr, raddr) & IP6_TNL_F_CAP_RCV))) {
struct net_device *ldev = NULL;
if (p->link)
ldev = dev_get_by_index_rcu(net, p->link);
if ((ipv6_addr_is_multicast(laddr) ||
likely(ipv6_chk_addr(net, laddr, ldev, 0))) &&
likely(!ipv6_chk_addr(net, raddr, NULL, 0)))
ret = 1;
}
return ret;
}
EXPORT_SYMBOL_GPL(ip6_tnl_rcv_ctl);
/**
* ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
* @skb: received socket buffer
* @protocol: ethernet protocol ID
* @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN
*
* Return: 0
**/
static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
__u8 ipproto,
int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
const struct ipv6hdr *ipv6h,
struct sk_buff *skb))
{
struct ip6_tnl *t;
const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
int err;
rcu_read_lock();
if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr,
&ipv6h->daddr)) != NULL) {
struct pcpu_sw_netstats *tstats;
if (t->parms.proto != ipproto && t->parms.proto != 0) {
rcu_read_unlock();
goto discard;
}
if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
rcu_read_unlock();
goto discard;
}
if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
t->dev->stats.rx_dropped++;
rcu_read_unlock();
goto discard;
}
skb->mac_header = skb->network_header;
skb_reset_network_header(skb);
skb->protocol = htons(protocol);
memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
__skb_tunnel_rx(skb, t->dev, t->net);
err = dscp_ecn_decapsulate(t, ipv6h, skb);
if (unlikely(err)) {
if (log_ecn_error)
net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
&ipv6h->saddr,
ipv6_get_dsfield(ipv6h));
if (err > 1) {
++t->dev->stats.rx_frame_errors;
++t->dev->stats.rx_errors;
rcu_read_unlock();
goto discard;
}
}
tstats = this_cpu_ptr(t->dev->tstats);
u64_stats_update_begin(&tstats->syncp);
tstats->rx_packets++;
tstats->rx_bytes += skb->len;
u64_stats_update_end(&tstats->syncp);
netif_rx(skb);
rcu_read_unlock();
return 0;
}
rcu_read_unlock();
return 1;
discard:
kfree_skb(skb);
return 0;
}
static int ip4ip6_rcv(struct sk_buff *skb)
{
return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP,
ip4ip6_dscp_ecn_decapsulate);
}
static int ip6ip6_rcv(struct sk_buff *skb)
{
return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6,
ip6ip6_dscp_ecn_decapsulate);
}
struct ipv6_tel_txoption {
struct ipv6_txoptions ops;
__u8 dst_opt[8];
};
static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
{
memset(opt, 0, sizeof(struct ipv6_tel_txoption));
opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
opt->dst_opt[3] = 1;
opt->dst_opt[4] = encap_limit;
opt->dst_opt[5] = IPV6_TLV_PADN;
opt->dst_opt[6] = 1;
opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
opt->ops.opt_nflen = 8;
}
/**
* ip6_tnl_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
ip6_tnl_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
{
return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
}
int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
{
struct __ip6_tnl_parm *p = &t->parms;
int ret = 0;
struct net *net = t->net;
if (p->flags & IP6_TNL_F_CAP_XMIT) {
struct net_device *ldev = NULL;
rcu_read_lock();
if (p->link)
ldev = dev_get_by_index_rcu(net, p->link);
if (unlikely(!ipv6_chk_addr(net, &p->laddr, ldev, 0)))
pr_warn("%s xmit: Local address not yet configured!\n",
p->name);
else if (!ipv6_addr_is_multicast(&p->raddr) &&
unlikely(ipv6_chk_addr(net, &p->raddr, NULL, 0)))
pr_warn("%s xmit: Routing loop! Remote address found on this node!\n",
p->name);
else
ret = 1;
rcu_read_unlock();
}
return ret;
}
EXPORT_SYMBOL_GPL(ip6_tnl_xmit_ctl);
/**
* ip6_tnl_xmit2 - encapsulate packet and send
* @skb: the outgoing socket buffer
* @dev: the outgoing tunnel device
* @dsfield: dscp code for outer header
* @fl: flow of tunneled packet
* @encap_limit: encapsulation limit
* @pmtu: Path MTU is stored if packet is too big
*
* Description:
* Build new header and do some sanity checks on the packet before sending
* it.
*
* Return:
* 0 on success
* -1 fail
* %-EMSGSIZE message too big. return mtu in this case.
**/
static int ip6_tnl_xmit2(struct sk_buff *skb,
struct net_device *dev,
__u8 dsfield,
struct flowi6 *fl6,
int encap_limit,
__u32 *pmtu)
{
struct ip6_tnl *t = netdev_priv(dev);
struct net *net = t->net;
struct net_device_stats *stats = &t->dev->stats;
struct ipv6hdr *ipv6h = ipv6_hdr(skb);
struct ipv6_tel_txoption opt;
struct dst_entry *dst = NULL, *ndst = NULL;
struct net_device *tdev;
int mtu;
unsigned int max_headroom = sizeof(struct ipv6hdr);
u8 proto;
int err = -1;
if (!fl6->flowi6_mark)
dst = ip6_tnl_dst_check(t);
if (!dst) {
ndst = ip6_route_output(net, NULL, fl6);
if (ndst->error)
goto tx_err_link_failure;
ndst = xfrm_lookup(net, ndst, flowi6_to_flowi(fl6), NULL, 0);
if (IS_ERR(ndst)) {
err = PTR_ERR(ndst);
ndst = NULL;
goto tx_err_link_failure;
}
dst = ndst;
}
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;
}
mtu = dst_mtu(dst) - sizeof (*ipv6h);
if (encap_limit >= 0) {
max_headroom += 8;
mtu -= 8;
}
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
if (skb_dst(skb))
skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);