ipv4: add support for linkdown sysctl to netconf

This kernel patch exports the value of the new
ignore_routes_with_linkdown via netconf.

v2: changes to notify userspace via netlink when sysctl values change
and proposed for 'net' since this could be considered a bugfix

Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Suggested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 14 insertions, 0 deletions

diff --git a/include/uapi/linux/netconf.h b/include/uapi/linux/netconf.h
index 669a1f0b1d97..23cbd34e4ac7 100644
--- a/include/uapi/linux/netconf.h
+++ b/include/uapi/linux/netconf.h
@@ -15,6 +15,7 @@ enum {
         NETCONFA_RP_FILTER,
         NETCONFA_MC_FORWARDING,
         NETCONFA_PROXY_NEIGH,
+        NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
         __NETCONFA_MAX
 };
 #define NETCONFA_MAX    (__NETCONFA_MAX - 1)
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 7498716e8f54..e813196c91c7 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1740,6 +1740,8 @@ static int inet_netconf_msgsize_devconf(int type)
                 size += nla_total_size(4);
         if (type == -1 || type == NETCONFA_PROXY_NEIGH)
                 size += nla_total_size(4);
+        if (type == -1 || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN)
+                size += nla_total_size(4);
 
         return size;
 }
@@ -1780,6 +1782,10 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
             nla_put_s32(skb, NETCONFA_PROXY_NEIGH,
                         IPV4_DEVCONF(*devconf, PROXY_ARP)) < 0)
                 goto nla_put_failure;
+        if ((type == -1 || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&
+            nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
+                        IPV4_DEVCONF(*devconf, IGNORE_ROUTES_WITH_LINKDOWN)) < 0)
+                goto nla_put_failure;
 
         nlmsg_end(skb, nlh);
         return 0;
@@ -1819,6 +1825,7 @@ static const struct nla_policy devconf_ipv4_policy[NETCONFA_MAX+1] = {
         [NETCONFA_FORWARDING]   = { .len = sizeof(int) },
         [NETCONFA_RP_FILTER]    = { .len = sizeof(int) },
         [NETCONFA_PROXY_NEIGH]  = { .len = sizeof(int) },
+        [NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN]  = { .len = sizeof(int) },
 };
 
 static int inet_netconf_get_devconf(struct sk_buff *in_skb,
@@ -2048,6 +2055,12 @@ static int devinet_conf_proc(struct ctl_table *ctl, int write,
                         inet_netconf_notify_devconf(net, NETCONFA_PROXY_NEIGH,
                                                     ifindex, cnf);
                 }
+                if (i == IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN - 1 &&
+                    new_value != old_value) {
+                        ifindex = devinet_conf_ifindex(net, cnf);
+                        inet_netconf_notify_devconf(net, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
+                                                    ifindex, cnf);
+                }
         }
 
         return ret;