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linux/net/ipv6/ip6_tunnel.c
Denis V. Lunev f206351a50 [NETNS]: Add namespace parameter to ip_route_output_key. 
Needed to propagate it down to the ip_route_output_flow.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:11:07 -08:00

1462 lines
33 KiB
C
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/*
* IPv6 tunneling device
* Linux INET6 implementation
*
* Authors:
* Ville Nuorvala <vnuorval@tcs.hut.fi>
* Yasuyuki Kozakai <kozakai@linux-ipv6.org>
*
* $Id$
*
* 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.
*
*/
#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/if_tunnel.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 <asm/uaccess.h>
#include <asm/atomic.h>
#include <net/icmp.h>
#include <net/ip.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>
MODULE_AUTHOR("Ville Nuorvala");
MODULE_DESCRIPTION("IPv6 tunneling device");
MODULE_LICENSE("GPL");
#define IPV6_TLV_TEL_DST_SIZE 8
#ifdef IP6_TNL_DEBUG
#define IP6_TNL_TRACE(x...) printk(KERN_DEBUG "%s:" x "\n", __FUNCTION__)
#else
#define IP6_TNL_TRACE(x...) do {;} while(0)
#endif
#define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK)
#define IPV6_TCLASS_SHIFT 20
#define HASH_SIZE 32
#define HASH(addr) ((__force u32)((addr)->s6_addr32[0] ^ (addr)->s6_addr32[1] ^ \
(addr)->s6_addr32[2] ^ (addr)->s6_addr32[3]) & \
(HASH_SIZE - 1))
static int ip6_fb_tnl_dev_init(struct net_device *dev);
static int ip6_tnl_dev_init(struct net_device *dev);
static void ip6_tnl_dev_setup(struct net_device *dev);
/* the IPv6 tunnel fallback device */
static struct net_device *ip6_fb_tnl_dev;
/* lists for storing tunnels in use */
static struct ip6_tnl *tnls_r_l[HASH_SIZE];
static struct ip6_tnl *tnls_wc[1];
static struct ip6_tnl **tnls[2] = { tnls_wc, tnls_r_l };
/* lock for the tunnel lists */
static DEFINE_RWLOCK(ip6_tnl_lock);
static inline 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;
}
static inline void ip6_tnl_dst_reset(struct ip6_tnl *t)
{
dst_release(t->dst_cache);
t->dst_cache = NULL;
}
static inline 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;
}
/**
* 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
**/
static struct ip6_tnl *
ip6_tnl_lookup(struct in6_addr *remote, struct in6_addr *local)
{
unsigned h0 = HASH(remote);
unsigned h1 = HASH(local);
struct ip6_tnl *t;
for (t = tnls_r_l[h0 ^ h1]; t; t = t->next) {
if (ipv6_addr_equal(local, &t->parms.laddr) &&
ipv6_addr_equal(remote, &t->parms.raddr) &&
(t->dev->flags & IFF_UP))
return t;
}
if ((t = tnls_wc[0]) != NULL && (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 **
ip6_tnl_bucket(struct ip6_tnl_parm *p)
{
struct in6_addr *remote = &p->raddr;
struct in6_addr *local = &p->laddr;
unsigned h = 0;
int prio = 0;
if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
prio = 1;
h = HASH(remote) ^ HASH(local);
}
return &tnls[prio][h];
}
/**
* ip6_tnl_link - add tunnel to hash table
* @t: tunnel to be added
**/
static void
ip6_tnl_link(struct ip6_tnl *t)
{
struct ip6_tnl **tp = ip6_tnl_bucket(&t->parms);
t->next = *tp;
write_lock_bh(&ip6_tnl_lock);
*tp = t;
write_unlock_bh(&ip6_tnl_lock);
}
/**
* ip6_tnl_unlink - remove tunnel from hash table
* @t: tunnel to be removed
**/
static void
ip6_tnl_unlink(struct ip6_tnl *t)
{
struct ip6_tnl **tp;
for (tp = ip6_tnl_bucket(&t->parms); *tp; tp = &(*tp)->next) {
if (t == *tp) {
write_lock_bh(&ip6_tnl_lock);
*tp = t->next;
write_unlock_bh(&ip6_tnl_lock);
break;
}
}
}
/**
* 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 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 {
int i;
for (i = 1; i < IP6_TNL_MAX; i++) {
sprintf(name, "ip6tnl%d", i);
if (__dev_get_by_name(&init_net, name) == NULL)
break;
}
if (i == IP6_TNL_MAX)
goto failed;
}
dev = alloc_netdev(sizeof (*t), name, ip6_tnl_dev_setup);
if (dev == NULL)
goto failed;
t = netdev_priv(dev);
dev->init = ip6_tnl_dev_init;
t->parms = *p;
if ((err = register_netdevice(dev)) < 0) {
free_netdev(dev);
goto failed;
}
dev_hold(dev);
ip6_tnl_link(t);
return t;
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 ip6_tnl_parm *p, int create)
{
struct in6_addr *remote = &p->raddr;
struct in6_addr *local = &p->laddr;
struct ip6_tnl *t;
for (t = *ip6_tnl_bucket(p); t; t = 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(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);
if (dev == ip6_fb_tnl_dev) {
write_lock_bh(&ip6_tnl_lock);
tnls_wc[0] = NULL;
write_unlock_bh(&ip6_tnl_lock);
} else {
ip6_tnl_unlink(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
**/
static __u16
parse_tlv_tnl_enc_lim(struct sk_buff *skb, __u8 * raw)
{
struct ipv6hdr *ipv6h = (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;
}
/**
* 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,
int *type, int *code, int *msg, __u32 *info, int offset)
{
struct ipv6hdr *ipv6h = (struct ipv6hdr *) skb->data;
struct ip6_tnl *t;
int rel_msg = 0;
int rel_type = ICMPV6_DEST_UNREACH;
int 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. */
read_lock(&ip6_tnl_lock);
if ((t = ip6_tnl_lookup(&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:
if (net_ratelimit())
printk(KERN_WARNING
"%s: Path to destination invalid "
"or inactive!\n", t->parms.name);
rel_msg = 1;
break;
case ICMPV6_TIME_EXCEED:
if ((*code) == ICMPV6_EXC_HOPLIMIT) {
if (net_ratelimit())
printk(KERN_WARNING
"%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 = parse_tlv_tnl_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) {
if (net_ratelimit())
printk(KERN_WARNING
"%s: Too small encapsulation "
"limit or routing loop in "
"tunnel!\n", t->parms.name);
rel_msg = 1;
}
} else if (net_ratelimit()) {
printk(KERN_WARNING
"%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:
read_unlock(&ip6_tnl_lock);
return err;
}
static int
ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
int type, int code, int offset, __be32 info)
{
int rel_msg = 0;
int rel_type = type;
int rel_code = code;
__u32 rel_info = ntohl(info);
int err;
struct sk_buff *skb2;
struct iphdr *eiph;
struct flowi fl;
struct rtable *rt;
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;
default:
return 0;
}
if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))
return 0;
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
return 0;
dst_release(skb2->dst);
skb2->dst = NULL;
skb_pull(skb2, offset);
skb_reset_network_header(skb2);
eiph = ip_hdr(skb2);
/* Try to guess incoming interface */
memset(&fl, 0, sizeof(fl));
fl.fl4_dst = eiph->saddr;
fl.fl4_tos = RT_TOS(eiph->tos);
fl.proto = IPPROTO_IPIP;
if (ip_route_output_key(&init_net, &rt, &fl))
goto out;
skb2->dev = rt->u.dst.dev;
/* route "incoming" packet */
if (rt->rt_flags & RTCF_LOCAL) {
ip_rt_put(rt);
rt = NULL;
fl.fl4_dst = eiph->daddr;
fl.fl4_src = eiph->saddr;
fl.fl4_tos = eiph->tos;
if (ip_route_output_key(&init_net, &rt, &fl) ||
rt->u.dst.dev->type != ARPHRD_TUNNEL) {
ip_rt_put(rt);
goto out;
}
} else {
ip_rt_put(rt);
if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
skb2->dev) ||
skb2->dst->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(skb2->dst))
goto out;
skb2->dst->ops->update_pmtu(skb2->dst, rel_info);
}
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,
int type, int code, int offset, __be32 info)
{
int rel_msg = 0;
int rel_type = type;
int 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;
dst_release(skb2->dst);
skb2->dst = NULL;
skb_pull(skb2, offset);
skb_reset_network_header(skb2);
/* Try to guess incoming interface */
rt = rt6_lookup(&ipv6_hdr(skb2)->saddr, NULL, 0, 0);
if (rt && rt->rt6i_dev)
skb2->dev = rt->rt6i_dev;
icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
if (rt)
dst_release(&rt->u.dst);
kfree_skb(skb2);
}
return 0;
}
static void ip4ip6_dscp_ecn_decapsulate(struct ip6_tnl *t,
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);
if (INET_ECN_is_ce(dsfield))
IP_ECN_set_ce(ip_hdr(skb));
}
static void ip6ip6_dscp_ecn_decapsulate(struct ip6_tnl *t,
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));
if (INET_ECN_is_ce(ipv6_get_dsfield(ipv6h)))
IP6_ECN_set_ce(ipv6_hdr(skb));
}
static inline int ip6_tnl_rcv_ctl(struct ip6_tnl *t)
{
struct ip6_tnl_parm *p = &t->parms;
int ret = 0;
if (p->flags & IP6_TNL_F_CAP_RCV) {
struct net_device *ldev = NULL;
if (p->link)
ldev = dev_get_by_index(&init_net, p->link);
if ((ipv6_addr_is_multicast(&p->laddr) ||
likely(ipv6_chk_addr(&init_net, &p->laddr, ldev, 0))) &&
likely(!ipv6_chk_addr(&init_net, &p->raddr, NULL, 0)))
ret = 1;
if (ldev)
dev_put(ldev);
}
return ret;
}
/**
* 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,
void (*dscp_ecn_decapsulate)(struct ip6_tnl *t,
struct ipv6hdr *ipv6h,
struct sk_buff *skb))
{
struct ip6_tnl *t;
struct ipv6hdr *ipv6h = ipv6_hdr(skb);
read_lock(&ip6_tnl_lock);
if ((t = ip6_tnl_lookup(&ipv6h->saddr, &ipv6h->daddr)) != NULL) {
if (t->parms.proto != ipproto && t->parms.proto != 0) {
read_unlock(&ip6_tnl_lock);
goto discard;
}
if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
read_unlock(&ip6_tnl_lock);
goto discard;
}
if (!ip6_tnl_rcv_ctl(t)) {
t->stat.rx_dropped++;
read_unlock(&ip6_tnl_lock);
goto discard;
}
secpath_reset(skb);
skb->mac_header = skb->network_header;
skb_reset_network_header(skb);
skb->protocol = htons(protocol);
skb->pkt_type = PACKET_HOST;
memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
skb->dev = t->dev;
dst_release(skb->dst);
skb->dst = NULL;
nf_reset(skb);
dscp_ecn_decapsulate(t, ipv6h, skb);
t->stat.rx_packets++;
t->stat.rx_bytes += skb->len;
netif_rx(skb);
read_unlock(&ip6_tnl_lock);
return 0;
}
read_unlock(&ip6_tnl_lock);
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 int
ip6_tnl_addr_conflict(struct ip6_tnl *t, struct ipv6hdr *hdr)
{
return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
}
static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
{
struct ip6_tnl_parm *p = &t->parms;
int ret = 0;
if (p->flags & IP6_TNL_F_CAP_XMIT) {
struct net_device *ldev = NULL;
if (p->link)
ldev = dev_get_by_index(&init_net, p->link);
if (unlikely(!ipv6_chk_addr(&init_net, &p->laddr, ldev, 0)))
printk(KERN_WARNING
"%s xmit: Local address not yet configured!\n",
p->name);
else if (!ipv6_addr_is_multicast(&p->raddr) &&
unlikely(ipv6_chk_addr(&init_net, &p->raddr, NULL, 0)))
printk(KERN_WARNING
"%s xmit: Routing loop! "
"Remote address found on this node!\n",
p->name);
else
ret = 1;
if (ldev)
dev_put(ldev);
}
return ret;
}
/**
* 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 flowi *fl,
int encap_limit,
__u32 *pmtu)
{
struct ip6_tnl *t = netdev_priv(dev);
struct net_device_stats *stats = &t->stat;
struct ipv6hdr *ipv6h = ipv6_hdr(skb);
struct ipv6_tel_txoption opt;
struct dst_entry *dst;
struct net_device *tdev;
int mtu;
unsigned int max_headroom = sizeof(struct ipv6hdr);
u8 proto;
int err = -1;
int pkt_len;
if ((dst = ip6_tnl_dst_check(t)) != NULL)
dst_hold(dst);
else {
dst = ip6_route_output(NULL, fl);
if (dst->error || xfrm_lookup(&dst, fl, NULL, 0) < 0)
goto tx_err_link_failure;
}
tdev = dst->dev;
if (tdev == dev) {
stats->collisions++;
if (net_ratelimit())
printk(KERN_WARNING
"%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->dst->ops->update_pmtu(skb->dst, mtu);
if (skb->len > mtu) {
*pmtu = mtu;
err = -EMSGSIZE;
goto tx_err_dst_release;
}
/*
* Okay, now see if we can stuff it in the buffer as-is.
*/
max_headroom += LL_RESERVED_SPACE(tdev);
if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
(skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
struct sk_buff *new_skb;
if (!(new_skb = skb_realloc_headroom(skb, max_headroom)))
goto tx_err_dst_release;
if (skb->sk)
skb_set_owner_w(new_skb, skb->sk);
kfree_skb(skb);
skb = new_skb;
}
dst_release(skb->dst);
skb->dst = dst_clone(dst);
skb->transport_header = skb->network_header;
proto = fl->proto;
if (encap_limit >= 0) {
init_tel_txopt(&opt, encap_limit);
ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
}
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
ipv6h = ipv6_hdr(skb);
*(__be32*)ipv6h = fl->fl6_flowlabel | htonl(0x60000000);
dsfield = INET_ECN_encapsulate(0, dsfield);
ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield);
ipv6h->hop_limit = t->parms.hop_limit;
ipv6h->nexthdr = proto;
ipv6_addr_copy(&ipv6h->saddr, &fl->fl6_src);
ipv6_addr_copy(&ipv6h->daddr, &fl->fl6_dst);
nf_reset(skb);
pkt_len = skb->len;
err = ip6_local_out(skb);
if (net_xmit_eval(err) == 0) {
stats->tx_bytes += pkt_len;
stats->tx_packets++;
} else {
stats->tx_errors++;
stats->tx_aborted_errors++;
}
ip6_tnl_dst_store(t, dst);
return 0;
tx_err_link_failure:
stats->tx_carrier_errors++;
dst_link_failure(skb);
tx_err_dst_release:
dst_release(dst);
return err;
}
static inline int
ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
struct iphdr *iph = ip_hdr(skb);
int encap_limit = -1;
struct flowi fl;
__u8 dsfield;
__u32 mtu;
int err;
if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) ||
!ip6_tnl_xmit_ctl(t))
return -1;
if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
encap_limit = t->parms.encap_limit;
memcpy(&fl, &t->fl, sizeof (fl));
fl.proto = IPPROTO_IPIP;
dsfield = ipv4_get_dsfield(iph);
if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
fl.fl6_flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
& IPV6_TCLASS_MASK;
err = ip6_tnl_xmit2(skb, dev, dsfield, &fl, encap_limit, &mtu);
if (err != 0) {
/* XXX: send ICMP error even if DF is not set. */
if (err == -EMSGSIZE)
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
htonl(mtu));
return -1;
}
return 0;
}
static inline int
ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
struct ipv6hdr *ipv6h = ipv6_hdr(skb);
int encap_limit = -1;
__u16 offset;
struct flowi fl;
__u8 dsfield;
__u32 mtu;
int err;
if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
!ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h))
return -1;
offset = parse_tlv_tnl_enc_lim(skb, skb_network_header(skb));
if (offset > 0) {
struct ipv6_tlv_tnl_enc_lim *tel;
tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
if (tel->encap_limit == 0) {
icmpv6_send(skb, ICMPV6_PARAMPROB,
ICMPV6_HDR_FIELD, offset + 2, skb->dev);
return -1;
}
encap_limit = tel->encap_limit - 1;
} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
encap_limit = t->parms.encap_limit;
memcpy(&fl, &t->fl, sizeof (fl));
fl.proto = IPPROTO_IPV6;
dsfield = ipv6_get_dsfield(ipv6h);
if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
if ((t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL))
fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK);
err = ip6_tnl_xmit2(skb, dev, dsfield, &fl, encap_limit, &mtu);
if (err != 0) {
if (err == -EMSGSIZE)
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
return -1;
}
return 0;
}
static int
ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
struct net_device_stats *stats = &t->stat;
int ret;
if (t->recursion++) {
t->stat.collisions++;
goto tx_err;
}
switch (skb->protocol) {
case __constant_htons(ETH_P_IP):
ret = ip4ip6_tnl_xmit(skb, dev);
break;
case __constant_htons(ETH_P_IPV6):
ret = ip6ip6_tnl_xmit(skb, dev);
break;
default:
goto tx_err;
}
if (ret < 0)
goto tx_err;
t->recursion--;
return 0;
tx_err:
stats->tx_errors++;
stats->tx_dropped++;
kfree_skb(skb);
t->recursion--;
return 0;
}
static void ip6_tnl_set_cap(struct ip6_tnl *t)
{
struct ip6_tnl_parm *p = &t->parms;
int ltype = ipv6_addr_type(&p->laddr);
int rtype = ipv6_addr_type(&p->raddr);
p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV);
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)
p->flags |= IP6_TNL_F_CAP_XMIT;
if (rtype&IPV6_ADDR_UNICAST)
p->flags |= IP6_TNL_F_CAP_RCV;
}
}
static void ip6_tnl_link_config(struct ip6_tnl *t)
{
struct net_device *dev = t->dev;
struct ip6_tnl_parm *p = &t->parms;
struct flowi *fl = &t->fl;
memcpy(&dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
memcpy(&dev->broadcast, &p->raddr, sizeof(struct in6_addr));
/* Set up flowi template */
ipv6_addr_copy(&fl->fl6_src, &p->laddr);
ipv6_addr_copy(&fl->fl6_dst, &p->raddr);
fl->oif = p->link;
fl->fl6_flowlabel = 0;
if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
fl->fl6_flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
fl->fl6_flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
ip6_tnl_set_cap(t);
if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
dev->flags |= IFF_POINTOPOINT;
else
dev->flags &= ~IFF_POINTOPOINT;
dev->iflink = p->link;
if (p->flags & IP6_TNL_F_CAP_XMIT) {
int strict = (ipv6_addr_type(&p->raddr) &
(IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
struct rt6_info *rt = rt6_lookup(&p->raddr, &p->laddr,
p->link, strict);
if (rt == NULL)
return;
if (rt->rt6i_dev) {
dev->hard_header_len = rt->rt6i_dev->hard_header_len +
sizeof (struct ipv6hdr);
dev->mtu = rt->rt6i_dev->mtu - sizeof (struct ipv6hdr);
if (dev->mtu < IPV6_MIN_MTU)
dev->mtu = IPV6_MIN_MTU;
}
dst_release(&rt->u.dst);
}
}
/**
* ip6_tnl_change - update the tunnel parameters
* @t: tunnel to be changed
* @p: tunnel configuration parameters
* @active: != 0 if tunnel is ready for use
*
* Description:
* ip6_tnl_change() updates the tunnel parameters
**/
static int
ip6_tnl_change(struct ip6_tnl *t, struct ip6_tnl_parm *p)
{
ipv6_addr_copy(&t->parms.laddr, &p->laddr);
ipv6_addr_copy(&t->parms.raddr, &p->raddr);
t->parms.flags = p->flags;
t->parms.hop_limit = p->hop_limit;
t->parms.encap_limit = p->encap_limit;
t->parms.flowinfo = p->flowinfo;
t->parms.link = p->link;
t->parms.proto = p->proto;
ip6_tnl_dst_reset(t);
ip6_tnl_link_config(t);
return 0;
}
/**
* ip6_tnl_ioctl - configure ipv6 tunnels from userspace
* @dev: virtual device associated with tunnel
* @ifr: parameters passed from userspace
* @cmd: command to be performed
*
* Description:
* ip6_tnl_ioctl() is used for managing IPv6 tunnels
* from userspace.
*
* The possible commands are the following:
* %SIOCGETTUNNEL: get tunnel parameters for device
* %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
* %SIOCCHGTUNNEL: change tunnel parameters to those given
* %SIOCDELTUNNEL: delete tunnel
*
* The fallback device "ip6tnl0", created during module
* initialization, can be used for creating other tunnel devices.
*
* Return:
* 0 on success,
* %-EFAULT if unable to copy data to or from userspace,
* %-EPERM if current process hasn't %CAP_NET_ADMIN set
* %-EINVAL if passed tunnel parameters are invalid,
* %-EEXIST if changing a tunnel's parameters would cause a conflict
* %-ENODEV if attempting to change or delete a nonexisting device
**/
static int
ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
int err = 0;
struct ip6_tnl_parm p;
struct ip6_tnl *t = NULL;
switch (cmd) {
case SIOCGETTUNNEL:
if (dev == ip6_fb_tnl_dev) {
if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) {
err = -EFAULT;
break;
}
t = ip6_tnl_locate(&p, 0);
}
if (t == NULL)
t = netdev_priv(dev);
memcpy(&p, &t->parms, sizeof (p));
if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof (p))) {
err = -EFAULT;
}
break;
case SIOCADDTUNNEL:
case SIOCCHGTUNNEL:
err = -EPERM;
if (!capable(CAP_NET_ADMIN))
break;
err = -EFAULT;
if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
break;
err = -EINVAL;
if (p.proto != IPPROTO_IPV6 && p.proto != IPPROTO_IPIP &&
p.proto != 0)
break;
t = ip6_tnl_locate(&p, cmd == SIOCADDTUNNEL);
if (dev != ip6_fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
if (t != NULL) {
if (t->dev != dev) {
err = -EEXIST;
break;
}
} else
t = netdev_priv(dev);
ip6_tnl_unlink(t);
err = ip6_tnl_change(t, &p);
ip6_tnl_link(t);
netdev_state_change(dev);
}
if (t) {
err = 0;
if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof (p)))
err = -EFAULT;
} else
err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
break;
case SIOCDELTUNNEL:
err = -EPERM;
if (!capable(CAP_NET_ADMIN))
break;
if (dev == ip6_fb_tnl_dev) {
err = -EFAULT;
if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
break;
err = -ENOENT;
if ((t = ip6_tnl_locate(&p, 0)) == NULL)
break;
err = -EPERM;
if (t->dev == ip6_fb_tnl_dev)
break;
dev = t->dev;
}
err = 0;
unregister_netdevice(dev);
break;
default:
err = -EINVAL;
}
return err;
}
/**
* ip6_tnl_get_stats - return the stats for tunnel device
* @dev: virtual device associated with tunnel
*
* Return: stats for device
**/
static struct net_device_stats *
ip6_tnl_get_stats(struct net_device *dev)
{
return &(((struct ip6_tnl *)netdev_priv(dev))->stat);
}
/**
* ip6_tnl_change_mtu - change mtu manually for tunnel device
* @dev: virtual device associated with tunnel
* @new_mtu: the new mtu
*
* Return:
* 0 on success,
* %-EINVAL if mtu too small
**/
static int
ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
{
if (new_mtu < IPV6_MIN_MTU) {
return -EINVAL;
}
dev->mtu = new_mtu;
return 0;
}
/**
* ip6_tnl_dev_setup - setup virtual tunnel device
* @dev: virtual device associated with tunnel
*
* Description:
* Initialize function pointers and device parameters
**/
static void ip6_tnl_dev_setup(struct net_device *dev)
{
dev->uninit = ip6_tnl_dev_uninit;
dev->destructor = free_netdev;
dev->hard_start_xmit = ip6_tnl_xmit;
dev->get_stats = ip6_tnl_get_stats;
dev->do_ioctl = ip6_tnl_ioctl;
dev->change_mtu = ip6_tnl_change_mtu;
dev->type = ARPHRD_TUNNEL6;
dev->hard_header_len = LL_MAX_HEADER + sizeof (struct ipv6hdr);
dev->mtu = ETH_DATA_LEN - sizeof (struct ipv6hdr);
dev->flags |= IFF_NOARP;
dev->addr_len = sizeof(struct in6_addr);
}
/**
* ip6_tnl_dev_init_gen - general initializer for all tunnel devices
* @dev: virtual device associated with tunnel
**/
static inline void
ip6_tnl_dev_init_gen(struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
t->dev = dev;
strcpy(t->parms.name, dev->name);
}
/**
* ip6_tnl_dev_init - initializer for all non fallback tunnel devices
* @dev: virtual device associated with tunnel
**/
static int
ip6_tnl_dev_init(struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
ip6_tnl_dev_init_gen(dev);
ip6_tnl_link_config(t);
return 0;
}
/**
* ip6_fb_tnl_dev_init - initializer for fallback tunnel device
* @dev: fallback device
*
* Return: 0
**/
static int
ip6_fb_tnl_dev_init(struct net_device *dev)
{
struct ip6_tnl *t = netdev_priv(dev);
ip6_tnl_dev_init_gen(dev);
t->parms.proto = IPPROTO_IPV6;
dev_hold(dev);
tnls_wc[0] = t;
return 0;
}
static struct xfrm6_tunnel ip4ip6_handler = {
.handler = ip4ip6_rcv,
.err_handler = ip4ip6_err,
.priority = 1,
};
static struct xfrm6_tunnel ip6ip6_handler = {
.handler = ip6ip6_rcv,
.err_handler = ip6ip6_err,
.priority = 1,
};
/**
* ip6_tunnel_init - register protocol and reserve needed resources
*
* Return: 0 on success
**/
static int __init ip6_tunnel_init(void)
{
int err;
if (xfrm6_tunnel_register(&ip4ip6_handler, AF_INET)) {
printk(KERN_ERR "ip6_tunnel init: can't register ip4ip6\n");
err = -EAGAIN;
goto out;
}
if (xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6)) {
printk(KERN_ERR "ip6_tunnel init: can't register ip6ip6\n");
err = -EAGAIN;
goto unreg_ip4ip6;
}
ip6_fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
ip6_tnl_dev_setup);
if (!ip6_fb_tnl_dev) {
err = -ENOMEM;
goto fail;
}
ip6_fb_tnl_dev->init = ip6_fb_tnl_dev_init;
if ((err = register_netdev(ip6_fb_tnl_dev))) {
free_netdev(ip6_fb_tnl_dev);
goto fail;
}
return 0;
fail:
xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6);
unreg_ip4ip6:
xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);
out:
return err;
}
static void __exit ip6_tnl_destroy_tunnels(void)
{
int h;
struct ip6_tnl *t;
for (h = 0; h < HASH_SIZE; h++) {
while ((t = tnls_r_l[h]) != NULL)
unregister_netdevice(t->dev);
}
t = tnls_wc[0];
unregister_netdevice(t->dev);
}
/**
* ip6_tunnel_cleanup - free resources and unregister protocol
**/
static void __exit ip6_tunnel_cleanup(void)
{
if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET))
printk(KERN_INFO "ip6_tunnel close: can't deregister ip4ip6\n");
if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6))
printk(KERN_INFO "ip6_tunnel close: can't deregister ip6ip6\n");
rtnl_lock();
ip6_tnl_destroy_tunnels();
rtnl_unlock();
}
module_init(ip6_tunnel_init);
module_exit(ip6_tunnel_cleanup);
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