Commit 3985e8a3 authored by Erik Kline's avatar Erik Kline Committed by David S. Miller

ipv6: sysctl to restrict candidate source addresses

Per RFC 6724, section 4, "Candidate Source Addresses":

    It is RECOMMENDED that the candidate source addresses be the set
    of unicast addresses assigned to the interface that will be used
    to send to the destination (the "outgoing" interface).

Add a sysctl to enable this behaviour.
Signed-off-by: default avatarErik Kline <ek@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fb02eb4a
......@@ -1460,6 +1460,13 @@ router_solicitations - INTEGER
routers are present.
Default: 3
use_oif_addrs_only - BOOLEAN
When enabled, the candidate source addresses for destinations
routed via this interface are restricted to the set of addresses
configured on this interface (vis. RFC 6724, section 4).
Default: false
use_tempaddr - INTEGER
Preference for Privacy Extensions (RFC3041).
<= 0 : disable Privacy Extensions
......
......@@ -57,6 +57,7 @@ struct ipv6_devconf {
bool initialized;
struct in6_addr secret;
} stable_secret;
__s32 use_oif_addrs_only;
void *sysctl;
};
......
......@@ -171,6 +171,7 @@ enum {
DEVCONF_USE_OPTIMISTIC,
DEVCONF_ACCEPT_RA_MTU,
DEVCONF_STABLE_SECRET,
DEVCONF_USE_OIF_ADDRS_ONLY,
DEVCONF_MAX
};
......
......@@ -211,7 +211,8 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
.accept_ra_mtu = 1,
.stable_secret = {
.initialized = false,
}
},
.use_oif_addrs_only = 0,
};
static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
......@@ -253,6 +254,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
.stable_secret = {
.initialized = false,
},
.use_oif_addrs_only = 0,
};
/* Check if a valid qdisc is available */
......@@ -1472,11 +1474,16 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
* include addresses assigned to interfaces
* belonging to the same site as the outgoing
* interface.)
* - "It is RECOMMENDED that the candidate source addresses
* be the set of unicast addresses assigned to the
* interface that will be used to send to the destination
* (the 'outgoing' interface)." (RFC 6724)
*/
if (dst_dev) {
if ((dst_type & IPV6_ADDR_MULTICAST) ||
dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL) {
idev = __in6_dev_get(dst_dev);
if ((dst_type & IPV6_ADDR_MULTICAST) ||
dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL ||
(idev && idev->cnf.use_oif_addrs_only)) {
use_oif_addr = true;
}
}
......@@ -4607,6 +4614,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local;
array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu;
/* we omit DEVCONF_STABLE_SECRET for now */
array[DEVCONF_USE_OIF_ADDRS_ONLY] = cnf->use_oif_addrs_only;
}
static inline size_t inet6_ifla6_size(void)
......@@ -5605,6 +5613,14 @@ static struct addrconf_sysctl_table
.mode = 0600,
.proc_handler = addrconf_sysctl_stable_secret,
},
{
.procname = "use_oif_addrs_only",
.data = &ipv6_devconf.use_oif_addrs_only,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
/* sentinel */
}
......
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