rtnl/ipv4: 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>

1 files changed, 89 insertions, 4 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 2a6abc163ed2..020fdd2e6e19 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -55,6 +55,7 @@
 #include <linux/sysctl.h>
 #endif
 #include <linux/kmod.h>
+#include <linux/netconf.h>
 
 #include <net/arp.h>
 #include <net/ip.h>
@@ -1442,6 +1443,73 @@ static int inet_set_link_af(struct net_device *dev, const struct nlattr *nla)
         return 0;
 }
 
+static int inet_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 inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
+                                     struct ipv4_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_INET;
+
+        if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
+                goto nla_put_failure;
+
+        if (type == NETCONFA_FORWARDING &&
+            nla_put_s32(skb, NETCONFA_FORWARDING,
+                        IPV4_DEVCONF(*devconf, FORWARDING)) < 0)
+                goto nla_put_failure;
+
+        return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+        nlmsg_cancel(skb, nlh);
+        return -EMSGSIZE;
+}
+
+static void inet_netconf_notify_devconf(struct net *net, int type, int ifindex,
+                                        struct ipv4_devconf *devconf)
+{
+        struct sk_buff *skb;
+        int err = -ENOBUFS;
+
+        skb = nlmsg_new(inet_netconf_msgsize_devconf(type), GFP_ATOMIC);
+        if (skb == NULL)
+                goto errout;
+
+        err = inet_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
+                                        RTM_NEWNETCONF, 0, type);
+        if (err < 0) {
+                /* -EMSGSIZE implies BUG in inet_netconf_msgsize_devconf() */
+                WARN_ON(err == -EMSGSIZE);
+                kfree_skb(skb);
+                goto errout;
+        }
+        rtnl_notify(skb, net, 0, RTNLGRP_IPV4_NETCONF, NULL, GFP_ATOMIC);
+        return;
+errout:
+        if (err < 0)
+                rtnl_set_sk_err(net, RTNLGRP_IPV4_NETCONF, err);
+}
+
 #ifdef CONFIG_SYSCTL
 
 static void devinet_copy_dflt_conf(struct net *net, int i)
@@ -1467,6 +1535,12 @@ static void inet_forward_change(struct net *net)
 
         IPV4_DEVCONF_ALL(net, ACCEPT_REDIRECTS) = !on;
         IPV4_DEVCONF_DFLT(net, FORWARDING) = on;
+        inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
+                                    NETCONFA_IFINDEX_ALL,
+                                    net->ipv4.devconf_all);
+        inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
+                                    NETCONFA_IFINDEX_DEFAULT,
+                                    net->ipv4.devconf_dflt);
 
         for_each_netdev(net, dev) {
                 struct in_device *in_dev;
@@ -1474,8 +1548,11 @@ static void inet_forward_change(struct net *net)
                         dev_disable_lro(dev);
                 rcu_read_lock();
                 in_dev = __in_dev_get_rcu(dev);
-                if (in_dev)
+                if (in_dev) {
                         IN_DEV_CONF_SET(in_dev, FORWARDING, on);
+                        inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
+                                                    dev->ifindex, &in_dev->cnf);
+                }
                 rcu_read_unlock();
         }
 }
@@ -1527,15 +1604,23 @@ static int devinet_sysctl_forward(ctl_table *ctl, int write,
                         }
                         if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
                                 inet_forward_change(net);
-                        } else if (*valp) {
+                        } else {
                                 struct ipv4_devconf *cnf = ctl->extra1;
                                 struct in_device *idev =
                                         container_of(cnf, struct in_device, cnf);
-                                dev_disable_lro(idev->dev);
+                                if (*valp)
+                                        dev_disable_lro(idev->dev);
+                                inet_netconf_notify_devconf(net,
+                                                            NETCONFA_FORWARDING,
+                                                            idev->dev->ifindex,
+                                                            cnf);
                         }
                         rtnl_unlock();
                         rt_cache_flush(net);
-                }
+                } else
+                        inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
+                                                    NETCONFA_IFINDEX_DEFAULT,
+                                                    net->ipv4.devconf_dflt);
         }
 
         return ret;