rtnl/ipv6: use netconf msg to advertise forwarding status

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 79 insertions, 0 deletions

diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 0043b413b8bc..a4d75ea868ed 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -592,6 +592,8 @@ enum rtnetlink_groups {
 #define RTNLGRP_PHONET_ROUTE    RTNLGRP_PHONET_ROUTE
         RTNLGRP_DCB,
 #define RTNLGRP_DCB             RTNLGRP_DCB
+        RTNLGRP_IPV6_NETCONF,
+#define RTNLGRP_IPV6_NETCONF    RTNLGRP_IPV6_NETCONF
         __RTNLGRP_MAX
 };
 #define RTNLGRP_MAX     (__RTNLGRP_MAX - 1)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 0424e4e27414..0c57a8f67715 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -81,6 +81,7 @@
 #include <net/pkt_sched.h>
 #include <linux/if_tunnel.h>
 #include <linux/rtnetlink.h>
+#include <linux/netconf.h>
 
 #ifdef CONFIG_IPV6_PRIVACY
 #include <linux/random.h>
@@ -460,6 +461,72 @@ static struct inet6_dev *ipv6_find_idev(struct net_device *dev)
         return idev;
 }
 
+static int inet6_netconf_msgsize_devconf(int type)
+{
+        int size =  NLMSG_ALIGN(sizeof(struct netconfmsg))
+                    + nla_total_size(4);        /* NETCONFA_IFINDEX */
+
+        if (type == NETCONFA_FORWARDING)
+                size += nla_total_size(4);
+
+        return size;
+}
+
+static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
+                                      struct ipv6_devconf *devconf, u32 portid,
+                                      u32 seq, int event, unsigned int flags,
+                                      int type)
+{
+        struct nlmsghdr  *nlh;
+        struct netconfmsg *ncm;
+
+        nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct netconfmsg),
+                        flags);
+        if (nlh == NULL)
+                return -EMSGSIZE;
+
+        ncm = nlmsg_data(nlh);
+        ncm->ncm_family = AF_INET6;
+
+        if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
+                goto nla_put_failure;
+
+        if (type == NETCONFA_FORWARDING &&
+            nla_put_s32(skb, NETCONFA_FORWARDING, devconf->forwarding) < 0)
+                goto nla_put_failure;
+
+        return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+        nlmsg_cancel(skb, nlh);
+        return -EMSGSIZE;
+}
+
+static void inet6_netconf_notify_devconf(struct net *net, int type, int ifindex,
+                                         struct ipv6_devconf *devconf)
+{
+        struct sk_buff *skb;
+        int err = -ENOBUFS;
+
+        skb = nlmsg_new(inet6_netconf_msgsize_devconf(type), GFP_ATOMIC);
+        if (skb == NULL)
+                goto errout;
+
+        err = inet6_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
+                                         RTM_NEWNETCONF, 0, type);
+        if (err < 0) {
+                /* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
+                WARN_ON(err == -EMSGSIZE);
+                kfree_skb(skb);
+                goto errout;
+        }
+        rtnl_notify(skb, net, 0, RTNLGRP_IPV6_NETCONF, NULL, GFP_ATOMIC);
+        return;
+errout:
+        if (err < 0)
+                rtnl_set_sk_err(net, RTNLGRP_IPV6_NETCONF, err);
+}
+
 #ifdef CONFIG_SYSCTL
 static void dev_forward_change(struct inet6_dev *idev)
 {
@@ -486,6 +553,8 @@ static void dev_forward_change(struct inet6_dev *idev)
                 else
                         addrconf_leave_anycast(ifa);
         }
+        inet6_netconf_notify_devconf(dev_net(dev), NETCONFA_FORWARDING,
+                                     dev->ifindex, &idev->cnf);
 }
 
 
@@ -518,6 +587,10 @@ static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int newf)
         *p = newf;
 
         if (p == &net->ipv6.devconf_dflt->forwarding) {
+                if ((!newf) ^ (!old))
+                        inet6_netconf_notify_devconf(net, NETCONFA_FORWARDING,
+                                                     NETCONFA_IFINDEX_DEFAULT,
+                                                     net->ipv6.devconf_dflt);
                 rtnl_unlock();
                 return 0;
         }
@@ -525,6 +598,10 @@ static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int newf)
         if (p == &net->ipv6.devconf_all->forwarding) {
                 net->ipv6.devconf_dflt->forwarding = newf;
                 addrconf_forward_change(net, newf);
+                if ((!newf) ^ (!old))
+                        inet6_netconf_notify_devconf(net, NETCONFA_FORWARDING,
+                                                     NETCONFA_IFINDEX_ALL,
+                                                     net->ipv6.devconf_all);
         } else if ((!newf) ^ (!old))
                 dev_forward_change((struct inet6_dev *)table->extra1);
         rtnl_unlock();