Skip to content

Commit

Permalink
gre: Add netlink interface
Browse files Browse the repository at this point in the history 
This patch adds a netlink interface that will eventually displace
the existing ioctl interface.  It utilises the elegant rtnl_link_ops
mechanism.

This also means that user-space no longer needs to rely on the
tunnel interface being of type GRE to identify GRE tunnels.  The
identification can now occur using rtnl_link_ops.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
Herbert Xu authored and David S. Miller committed Oct 9, 2008
1 parent 42aa916 commit c19e654
Show file tree
Hide file tree
Showing 2 changed files with 262 additions and 4 deletions.
19 changes: 19 additions & 0 deletions include/linux/if_tunnel.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
#define _IF_TUNNEL_H_

#include <linux/types.h>
#include <linux/ip.h>

#define SIOCGETTUNNEL (SIOCDEVPRIVATE + 0)
#define SIOCADDTUNNEL (SIOCDEVPRIVATE + 1)
Expand Down Expand Up @@ -47,4 +48,22 @@ struct ip_tunnel_prl {
/* PRL flags */
#define PRL_DEFAULT 0x0001

enum
{
IFLA_GRE_UNSPEC,
IFLA_GRE_LINK,
IFLA_GRE_IFLAGS,
IFLA_GRE_OFLAGS,
IFLA_GRE_IKEY,
IFLA_GRE_OKEY,
IFLA_GRE_LOCAL,
IFLA_GRE_REMOTE,
IFLA_GRE_TTL,
IFLA_GRE_TOS,
IFLA_GRE_PMTUDISC,
__IFLA_GRE_MAX,
};

#define IFLA_GRE_MAX (__IFLA_GRE_MAX - 1)

#endif /* _IF_TUNNEL_H_ */
247 changes: 243 additions & 4 deletions net/ipv4/ip_gre.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/rtnetlink.h>

#ifdef CONFIG_IPV6
#include <net/ipv6.h>
Expand Down Expand Up @@ -117,6 +118,7 @@
Alexey Kuznetsov.
*/

static struct rtnl_link_ops ipgre_link_ops __read_mostly;
static int ipgre_tunnel_init(struct net_device *dev);
static void ipgre_tunnel_setup(struct net_device *dev);
static int ipgre_tunnel_bind_dev(struct net_device *dev);
Expand Down Expand Up @@ -286,9 +288,9 @@ static struct ip_tunnel * ipgre_tunnel_locate(struct net *net,
goto failed_free;
}

dev->init = ipgre_tunnel_init;
nt = netdev_priv(dev);
nt->parms = *parms;
dev->rtnl_link_ops = &ipgre_link_ops;

dev->mtu = ipgre_tunnel_bind_dev(dev);

Expand Down Expand Up @@ -1087,6 +1089,7 @@ static int ipgre_close(struct net_device *dev)

static void ipgre_tunnel_setup(struct net_device *dev)
{
dev->init = ipgre_tunnel_init;
dev->uninit = ipgre_tunnel_uninit;
dev->destructor = free_netdev;
dev->hard_start_xmit = ipgre_tunnel_xmit;
Expand Down Expand Up @@ -1196,6 +1199,7 @@ static int ipgre_init_net(struct net *net)

ign->fb_tunnel_dev->init = ipgre_fb_tunnel_init;
dev_net_set(ign->fb_tunnel_dev, net);
ign->fb_tunnel_dev->rtnl_link_ops = &ipgre_link_ops;

if ((err = register_netdev(ign->fb_tunnel_dev)))
goto err_reg_dev;
Expand Down Expand Up @@ -1228,6 +1232,229 @@ static struct pernet_operations ipgre_net_ops = {
.exit = ipgre_exit_net,
};

static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
{
__be16 flags;

if (!data)
return 0;

flags = 0;
if (data[IFLA_GRE_IFLAGS])
flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
if (data[IFLA_GRE_OFLAGS])
flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
if (flags & (GRE_VERSION|GRE_ROUTING))
return -EINVAL;

return 0;
}

static void ipgre_netlink_parms(struct nlattr *data[],
struct ip_tunnel_parm *parms)
{
memset(parms, 0, sizeof(parms));

parms->iph.protocol = IPPROTO_GRE;

if (!data)
return;

if (data[IFLA_GRE_LINK])
parms->link = nla_get_u32(data[IFLA_GRE_LINK]);

if (data[IFLA_GRE_IFLAGS])
parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]);

if (data[IFLA_GRE_OFLAGS])
parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]);

if (data[IFLA_GRE_IKEY])
parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);

if (data[IFLA_GRE_OKEY])
parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);

if (data[IFLA_GRE_LOCAL])
memcpy(&parms->iph.saddr, nla_data(data[IFLA_GRE_LOCAL]), 4);

if (data[IFLA_GRE_REMOTE])
memcpy(&parms->iph.daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);

if (data[IFLA_GRE_TTL])
parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);

if (data[IFLA_GRE_TOS])
parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);

if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC]))
parms->iph.frag_off = htons(IP_DF);
}

static int ipgre_newlink(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[])
{
struct ip_tunnel *nt;
struct net *net = dev_net(dev);
struct ipgre_net *ign = net_generic(net, ipgre_net_id);
int mtu;
int err;

nt = netdev_priv(dev);
ipgre_netlink_parms(data, &nt->parms);

if (ipgre_tunnel_locate(net, &nt->parms, 0))
return -EEXIST;

mtu = ipgre_tunnel_bind_dev(dev);
if (!tb[IFLA_MTU])
dev->mtu = mtu;

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

dev_hold(dev);
ipgre_tunnel_link(ign, nt);

out:
return err;
}

static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[])
{
struct ip_tunnel *t, *nt;
struct net *net = dev_net(dev);
struct ipgre_net *ign = net_generic(net, ipgre_net_id);
struct ip_tunnel_parm p;
int mtu;

if (dev == ign->fb_tunnel_dev)
return -EINVAL;

nt = netdev_priv(dev);
ipgre_netlink_parms(data, &p);

t = ipgre_tunnel_locate(net, &p, 0);

if (t) {
if (t->dev != dev)
return -EEXIST;
} else {
unsigned nflags = 0;

t = nt;

if (ipv4_is_multicast(p.iph.daddr))
nflags = IFF_BROADCAST;
else if (p.iph.daddr)
nflags = IFF_POINTOPOINT;

if ((dev->flags ^ nflags) &
(IFF_POINTOPOINT | IFF_BROADCAST))
return -EINVAL;

ipgre_tunnel_unlink(ign, t);
t->parms.iph.saddr = p.iph.saddr;
t->parms.iph.daddr = p.iph.daddr;
t->parms.i_key = p.i_key;
memcpy(dev->dev_addr, &p.iph.saddr, 4);
memcpy(dev->broadcast, &p.iph.daddr, 4);
ipgre_tunnel_link(ign, t);
netdev_state_change(dev);
}

t->parms.o_key = p.o_key;
t->parms.iph.ttl = p.iph.ttl;
t->parms.iph.tos = p.iph.tos;
t->parms.iph.frag_off = p.iph.frag_off;

if (t->parms.link != p.link) {
t->parms.link = p.link;
mtu = ipgre_tunnel_bind_dev(dev);
if (!tb[IFLA_MTU])
dev->mtu = mtu;
netdev_state_change(dev);
}

return 0;
}

static size_t ipgre_get_size(const struct net_device *dev)
{
return
/* IFLA_GRE_LINK */
nla_total_size(4) +
/* IFLA_GRE_IFLAGS */
nla_total_size(2) +
/* IFLA_GRE_OFLAGS */
nla_total_size(2) +
/* IFLA_GRE_IKEY */
nla_total_size(4) +
/* IFLA_GRE_OKEY */
nla_total_size(4) +
/* IFLA_GRE_LOCAL */
nla_total_size(4) +
/* IFLA_GRE_REMOTE */
nla_total_size(4) +
/* IFLA_GRE_TTL */
nla_total_size(1) +
/* IFLA_GRE_TOS */
nla_total_size(1) +
/* IFLA_GRE_PMTUDISC */
nla_total_size(1) +
0;
}

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;

NLA_PUT_U32(skb, IFLA_GRE_LINK, p->link);
NLA_PUT_BE16(skb, IFLA_GRE_IFLAGS, p->i_flags);
NLA_PUT_BE16(skb, IFLA_GRE_OFLAGS, p->o_flags);
NLA_PUT_BE32(skb, IFLA_GRE_IFLAGS, p->i_flags);
NLA_PUT_BE32(skb, IFLA_GRE_OFLAGS, p->o_flags);
NLA_PUT(skb, IFLA_GRE_LOCAL, 4, &p->iph.saddr);
NLA_PUT(skb, IFLA_GRE_REMOTE, 4, &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)));

return 0;

nla_put_failure:
return -EMSGSIZE;
}

static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
[IFLA_GRE_LINK] = { .type = NLA_U32 },
[IFLA_GRE_IFLAGS] = { .type = NLA_U16 },
[IFLA_GRE_OFLAGS] = { .type = NLA_U16 },
[IFLA_GRE_IKEY] = { .type = NLA_U32 },
[IFLA_GRE_OKEY] = { .type = NLA_U32 },
[IFLA_GRE_LOCAL] = { .len = 4 },
[IFLA_GRE_REMOTE] = { .len = 4 },
[IFLA_GRE_TTL] = { .type = NLA_U8 },
[IFLA_GRE_TOS] = { .type = NLA_U8 },
[IFLA_GRE_PMTUDISC] = { .type = NLA_U8 },
};

static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
.kind = "gre",
.maxtype = IFLA_GRE_MAX,
.policy = ipgre_policy,
.priv_size = sizeof(struct ip_tunnel),
.setup = ipgre_tunnel_setup,
.validate = ipgre_tunnel_validate,
.newlink = ipgre_newlink,
.changelink = ipgre_changelink,
.get_size = ipgre_get_size,
.fill_info = ipgre_fill_info,
};

/*
* And now the modules code and kernel interface.
*/
Expand All @@ -1245,19 +1472,31 @@ static int __init ipgre_init(void)

err = register_pernet_gen_device(&ipgre_net_id, &ipgre_net_ops);
if (err < 0)
inet_del_protocol(&ipgre_protocol, IPPROTO_GRE);
goto gen_device_failed;

err = rtnl_link_register(&ipgre_link_ops);
if (err < 0)
goto rtnl_link_failed;

out:
return err;

rtnl_link_failed:
unregister_pernet_gen_device(ipgre_net_id, &ipgre_net_ops);
gen_device_failed:
inet_del_protocol(&ipgre_protocol, IPPROTO_GRE);
goto out;
}

static void __exit ipgre_fini(void)
{
rtnl_link_unregister(&ipgre_link_ops);
unregister_pernet_gen_device(ipgre_net_id, &ipgre_net_ops);
if (inet_del_protocol(&ipgre_protocol, IPPROTO_GRE) < 0)
printk(KERN_INFO "ipgre close: can't remove protocol\n");

unregister_pernet_gen_device(ipgre_net_id, &ipgre_net_ops);
}

module_init(ipgre_init);
module_exit(ipgre_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS("rtnl-link-gre");

0 comments on commit c19e654

Please sign in to comment.