rtnl/ipv4: add support of RTM_GETNETCONF

This message allows to get the devconf for an interface.

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

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 020fdd2e6e1927bc972c378c1f81ed6c891eb76d..f8b1e0494d7539fc864c373a6eefb41108aa2a88 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1448,7 +1448,8 @@ 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)
+       /* type -1 is used for ALL */
+       if (type == -1 || type == NETCONFA_FORWARDING)
                size += nla_total_size(4);
 
        return size;
@@ -1473,7 +1474,8 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
        if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
                goto nla_put_failure;
 
-       if (type == NETCONFA_FORWARDING &&
+       /* type -1 is used for ALL */
+       if ((type == -1 || type == NETCONFA_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_FORWARDING,
                        IPV4_DEVCONF(*devconf, FORWARDING)) < 0)
                goto nla_put_failure;
@@ -1510,6 +1512,73 @@ errout:
                rtnl_set_sk_err(net, RTNLGRP_IPV4_NETCONF, err);
 }
 
+static const struct nla_policy devconf_ipv4_policy[NETCONFA_MAX+1] = {
+       [NETCONFA_IFINDEX]      = { .len = sizeof(int) },
+       [NETCONFA_FORWARDING]   = { .len = sizeof(int) },
+};
+
+static int inet_netconf_get_devconf(struct sk_buff *in_skb,
+                                   struct nlmsghdr *nlh,
+                                   void *arg)
+{
+       struct net *net = sock_net(in_skb->sk);
+       struct nlattr *tb[NETCONFA_MAX+1];
+       struct netconfmsg *ncm;
+       struct sk_buff *skb;
+       struct ipv4_devconf *devconf;
+       struct in_device *in_dev;
+       struct net_device *dev;
+       int ifindex;
+       int err;
+
+       err = nlmsg_parse(nlh, sizeof(*ncm), tb, NETCONFA_MAX,
+                         devconf_ipv4_policy);
+       if (err < 0)
+               goto errout;
+
+       err = EINVAL;
+       if (!tb[NETCONFA_IFINDEX])
+               goto errout;
+
+       ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]);
+       switch (ifindex) {
+       case NETCONFA_IFINDEX_ALL:
+               devconf = net->ipv4.devconf_all;
+               break;
+       case NETCONFA_IFINDEX_DEFAULT:
+               devconf = net->ipv4.devconf_dflt;
+               break;
+       default:
+               dev = __dev_get_by_index(net, ifindex);
+               if (dev == NULL)
+                       goto errout;
+               in_dev = __in_dev_get_rtnl(dev);
+               if (in_dev == NULL)
+                       goto errout;
+               devconf = &in_dev->cnf;
+               break;
+       }
+
+       err = -ENOBUFS;
+       skb = nlmsg_new(inet_netconf_msgsize_devconf(-1), GFP_ATOMIC);
+       if (skb == NULL)
+               goto errout;
+
+       err = inet_netconf_fill_devconf(skb, ifindex, devconf,
+                                       NETLINK_CB(in_skb).portid,
+                                       nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
+                                       -1);
+       if (err < 0) {
+               /* -EMSGSIZE implies BUG in inet_netconf_msgsize_devconf() */
+               WARN_ON(err == -EMSGSIZE);
+               kfree_skb(skb);
+               goto errout;
+       }
+       err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
+errout:
+       return err;
+}
+
 #ifdef CONFIG_SYSCTL
 
 static void devinet_copy_dflt_conf(struct net *net, int i)
@@ -1894,5 +1963,7 @@ void __init devinet_init(void)
        rtnl_register(PF_INET, RTM_NEWADDR, inet_rtm_newaddr, NULL, NULL);
        rtnl_register(PF_INET, RTM_DELADDR, inet_rtm_deladdr, NULL, NULL);
        rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, NULL);
+       rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf,
+                     NULL, NULL);
 }