static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
struct ip_tunnel *t = netdev_priv(dev);
struct ip_tunnel_parm *p = &t->parms;
if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
nla_put_be16(skb, IFLA_GRE_IFLAGS, tnl_flags_to_gre_flags(p->i_flags)) ||
nla_put_be16(skb, IFLA_GRE_OFLAGS, tnl_flags_to_gre_flags(p->o_flags)) ||
nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
nla_put_be32(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
nla_put_be32(skb, IFLA_GRE_REMOTE, p->iph.daddr) ||
nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) ||
nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) ||
nla_put_u8(skb, IFLA_GRE_PMTUDISC,
!!(p->iph.frag_off & htons(IP_DF))))
goto nla_put_failure;
if (nla_put_u16(skb, IFLA_GRE_ENCAP_TYPE,
t->encap.type) ||
nla_put_u16(skb, IFLA_GRE_ENCAP_SPORT,
t->encap.sport) ||
nla_put_u16(skb, IFLA_GRE_ENCAP_DPORT,
t->encap.dport) ||
nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS,
t->encap.dport))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int ipgre_tunnel_ioctl(struct net_device *dev,
struct ifreq *ifr, int cmd)
{
int err;
struct ip_tunnel_parm p;
if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
return -EFAULT;
if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
return -EINVAL;
}
p.i_flags = gre_flags_to_tnl_flags(p.i_flags);
p.o_flags = gre_flags_to_tnl_flags(p.o_flags);
err = ip_tunnel_ioctl(dev, &p, cmd);
if (err)
return err;
p.i_flags = tnl_flags_to_gre_flags(p.i_flags);
p.o_flags = tnl_flags_to_gre_flags(p.o_flags);
if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
return -EFAULT;
return 0;
}
void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
int hdr_len)
{
struct gre_base_hdr *greh;
skb_push(skb, hdr_len);
greh = (struct gre_base_hdr *)skb->data;
greh->flags = tnl_flags_to_gre_flags(tpi->flags);
greh->protocol = tpi->proto;
if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) {
__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
if (tpi->flags&TUNNEL_SEQ) {
*ptr = tpi->seq;
ptr--;
}
if (tpi->flags&TUNNEL_KEY) {
*ptr = tpi->key;
ptr--;
}
if (tpi->flags&TUNNEL_CSUM &&
!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE)) {
*ptr = 0;
*(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
skb->len, 0));
}
}
}
/* Nice toy. Unfortunately, useless in real life :-)
It allows to construct virtual multiprotocol broadcast "LAN"
over the Internet, provided multicast routing is tuned.
I have no idea was this bicycle invented before me,
so that I had to set ARPHRD_IPGRE to a random value.
I have an impression, that Cisco could make something similar,
but this feature is apparently missing in IOS<=11.2(8).
I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
ping -t 255 224.66.66.66
If nobody answers, mbone does not work.
ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
ip addr add 10.66.66.<somewhat>/24 dev Universe
ifconfig Universe up
ifconfig Universe add fe80::<Your_real_addr>/10
ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
ftp 10.66.66.66
...
ftp fec0:6666:6666::193.233.7.65
...
*/
static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
unsigned short type,
const void *daddr, const void *saddr, unsigned int len)
{
struct ip_tunnel *t = netdev_priv(dev);
struct iphdr *iph;
struct gre_base_hdr *greh;
iph = (struct iphdr *)skb_push(skb, t->hlen + sizeof(*iph));
greh = (struct gre_base_hdr *)(iph+1);
greh->flags = tnl_flags_to_gre_flags(t->parms.o_flags);
greh->protocol = htons(type);
memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
/* Set the source hardware address. */
if (saddr)
memcpy(&iph->saddr, saddr, 4);
if (daddr)
memcpy(&iph->daddr, daddr, 4);
if (iph->daddr)
return t->hlen + sizeof(*iph);
return -(t->hlen + sizeof(*iph));
}
static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,
__be16 proto, __be32 key, __be32 seq)
{
struct gre_base_hdr *greh;
skb_push(skb, hdr_len);
skb_reset_transport_header(skb);
greh = (struct gre_base_hdr *)skb->data;
greh->flags = tnl_flags_to_gre_flags(flags);
greh->protocol = proto;
if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
if (flags & TUNNEL_SEQ) {
*ptr = seq;
ptr--;
}
if (flags & TUNNEL_KEY) {
*ptr = key;
ptr--;
}
if (flags & TUNNEL_CSUM &&
!(skb_shinfo(skb)->gso_type &
(SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
*ptr = 0;
*(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
skb->len, 0));
}
}
}
