linux-stable/net/ipv6/sysctl_net_ipv6.c
FX Le Bail 509aba3b0d IPv6: add the option to use anycast addresses as source addresses in echo reply
This change allows to follow a recommandation of RFC4942.

- Add "anycast_src_echo_reply" sysctl to control the use of anycast addresses
  as source addresses for ICMPv6 echo reply. This sysctl is false by default
  to preserve existing behavior.
- Add inline check ipv6_anycast_destination().
- Use them in icmpv6_echo_reply().

Reference:
RFC4942 - IPv6 Transition/Coexistence Security Considerations
   (http://tools.ietf.org/html/rfc4942#section-2.1.6)

2.1.6. Anycast Traffic Identification and Security

   [...]
   To avoid exposing knowledge about the internal structure of the
   network, it is recommended that anycast servers now take advantage of
   the ability to return responses with the anycast address as the
   source address if possible.

Signed-off-by: Francois-Xavier Le Bail <fx.lebail@yahoo.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-07 15:51:39 -05:00

150 lines
3.5 KiB
C

/*
* sysctl_net_ipv6.c: sysctl interface to net IPV6 subsystem.
*
* Changes:
* YOSHIFUJI Hideaki @USAGI: added icmp sysctl table.
*/
#include <linux/mm.h>
#include <linux/sysctl.h>
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <net/ndisc.h>
#include <net/ipv6.h>
#include <net/addrconf.h>
#include <net/inet_frag.h>
static struct ctl_table ipv6_table_template[] = {
{
.procname = "bindv6only",
.data = &init_net.ipv6.sysctl.bindv6only,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec
},
{
.procname = "anycast_src_echo_reply",
.data = &init_net.ipv6.anycast_src_echo_reply,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec
},
{ }
};
static struct ctl_table ipv6_rotable[] = {
{
.procname = "mld_max_msf",
.data = &sysctl_mld_max_msf,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec
},
{ }
};
static int __net_init ipv6_sysctl_net_init(struct net *net)
{
struct ctl_table *ipv6_table;
struct ctl_table *ipv6_route_table;
struct ctl_table *ipv6_icmp_table;
int err;
err = -ENOMEM;
ipv6_table = kmemdup(ipv6_table_template, sizeof(ipv6_table_template),
GFP_KERNEL);
if (!ipv6_table)
goto out;
ipv6_table[0].data = &net->ipv6.sysctl.bindv6only;
ipv6_table[1].data = &net->ipv6.anycast_src_echo_reply;
ipv6_route_table = ipv6_route_sysctl_init(net);
if (!ipv6_route_table)
goto out_ipv6_table;
ipv6_icmp_table = ipv6_icmp_sysctl_init(net);
if (!ipv6_icmp_table)
goto out_ipv6_route_table;
net->ipv6.sysctl.hdr = register_net_sysctl(net, "net/ipv6", ipv6_table);
if (!net->ipv6.sysctl.hdr)
goto out_ipv6_icmp_table;
net->ipv6.sysctl.route_hdr =
register_net_sysctl(net, "net/ipv6/route", ipv6_route_table);
if (!net->ipv6.sysctl.route_hdr)
goto out_unregister_ipv6_table;
net->ipv6.sysctl.icmp_hdr =
register_net_sysctl(net, "net/ipv6/icmp", ipv6_icmp_table);
if (!net->ipv6.sysctl.icmp_hdr)
goto out_unregister_route_table;
err = 0;
out:
return err;
out_unregister_route_table:
unregister_net_sysctl_table(net->ipv6.sysctl.route_hdr);
out_unregister_ipv6_table:
unregister_net_sysctl_table(net->ipv6.sysctl.hdr);
out_ipv6_icmp_table:
kfree(ipv6_icmp_table);
out_ipv6_route_table:
kfree(ipv6_route_table);
out_ipv6_table:
kfree(ipv6_table);
goto out;
}
static void __net_exit ipv6_sysctl_net_exit(struct net *net)
{
struct ctl_table *ipv6_table;
struct ctl_table *ipv6_route_table;
struct ctl_table *ipv6_icmp_table;
ipv6_table = net->ipv6.sysctl.hdr->ctl_table_arg;
ipv6_route_table = net->ipv6.sysctl.route_hdr->ctl_table_arg;
ipv6_icmp_table = net->ipv6.sysctl.icmp_hdr->ctl_table_arg;
unregister_net_sysctl_table(net->ipv6.sysctl.icmp_hdr);
unregister_net_sysctl_table(net->ipv6.sysctl.route_hdr);
unregister_net_sysctl_table(net->ipv6.sysctl.hdr);
kfree(ipv6_table);
kfree(ipv6_route_table);
kfree(ipv6_icmp_table);
}
static struct pernet_operations ipv6_sysctl_net_ops = {
.init = ipv6_sysctl_net_init,
.exit = ipv6_sysctl_net_exit,
};
static struct ctl_table_header *ip6_header;
int ipv6_sysctl_register(void)
{
int err = -ENOMEM;
ip6_header = register_net_sysctl(&init_net, "net/ipv6", ipv6_rotable);
if (ip6_header == NULL)
goto out;
err = register_pernet_subsys(&ipv6_sysctl_net_ops);
if (err)
goto err_pernet;
out:
return err;
err_pernet:
unregister_net_sysctl_table(ip6_header);
goto out;
}
void ipv6_sysctl_unregister(void)
{
unregister_net_sysctl_table(ip6_header);
unregister_pernet_subsys(&ipv6_sysctl_net_ops);
}