I thought perhaps "use_oif_addr_only" was a slightly clearer sysctl name.
(Maybe it should be plural, "use_oif_addrs_only"?)
On 20 July 2015 at 16:04, Erik Kline wrote:
> 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: Erik Kline
> ---
> Documentation/networking/ip-sysctl.txt | 7 +++
> include/linux/ipv6.h | 1 +
> include/uapi/linux/ipv6.h | 1 +
> net/ipv6/addrconf.c| 22 +++---
> 4 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/networking/ip-sysctl.txt
> b/Documentation/networking/ip-sysctl.txt
> index f63aeef..e710369 100644
> --- a/Documentation/networking/ip-sysctl.txt
> +++ b/Documentation/networking/ip-sysctl.txt
> @@ -1460,6 +1460,13 @@ router_solicitations - INTEGER
> routers are present.
> Default: 3
>
> +use_oif_addr_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
> diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
> index 1319a6b..28e4837 100644
> --- a/include/linux/ipv6.h
> +++ b/include/linux/ipv6.h
> @@ -57,6 +57,7 @@ struct ipv6_devconf {
> bool initialized;
> struct in6_addr secret;
> } stable_secret;
> + __s32 use_oif_addr_only;
> void*sysctl;
> };
>
> diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
> index 5efa54a..6fcb256 100644
> --- a/include/uapi/linux/ipv6.h
> +++ b/include/uapi/linux/ipv6.h
> @@ -171,6 +171,7 @@ enum {
> DEVCONF_USE_OPTIMISTIC,
> DEVCONF_ACCEPT_RA_MTU,
> DEVCONF_STABLE_SECRET,
> + DEVCONF_USE_OIF_ADDR_ONLY,
> DEVCONF_MAX
> };
>
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 32153c2..ebfb38a 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -211,7 +211,8 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
> .accept_ra_mtu = 1,
> .stable_secret = {
> .initialized = false,
> - }
> + },
> + .use_oif_addr_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_addr_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) {
> + idev = __in6_dev_get(dst_dev);
> if ((dst_type & IPV6_ADDR_MULTICAST) ||
> - dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL) {
> - idev = __in6_dev_get(dst_dev);
> + dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL ||
> + (idev && idev->cnf.use_oif_addr_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_ADDR_ONLY] = cnf->use_oif_addr_only;
> }
>
> static inline size_t inet6_ifla6_size(void)
> @@ -5606,6 +5614,14 @@ static struct addrconf_sysctl_table
> .proc_handler = addrconf_sysctl_stable_secret,
> },
> {
> + .procname = "use_oif_addr_only",
> + .data = &ipv6_devconf.use_oif_addr_only,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
> +
> + },
> + {
> /* sentinel */
>
