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>

1 files changed, 73 insertions, 2 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 020fdd2e6e19..f8b1e0494d75 100644
--- 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);
 }