net/ipv4: Add support for dumping addresses for a specific device

If an RTM_GETADDR dump request has ifa_index set in the ifaddrmsg
header, then return only the addresses for that device.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 67f382c..63d5b58 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -109,6 +109,7 @@ struct inet_fill_args {
        int event;
        unsigned int flags;
        int netnsid;
+       int ifindex;
 };
 
 #define IN4_ADDR_HSIZE_SHIFT   8
@@ -1663,8 +1664,9 @@ nla_put_failure:
 static int inet_valid_dump_ifaddr_req(const struct nlmsghdr *nlh,
                                      struct inet_fill_args *fillargs,
                                      struct net **tgt_net, struct sock *sk,
-                                     struct netlink_ext_ack *extack)
+                                     struct netlink_callback *cb)
 {
+       struct netlink_ext_ack *extack = cb->extack;
        struct nlattr *tb[IFA_MAX+1];
        struct ifaddrmsg *ifm;
        int err, i;
@@ -1679,9 +1681,11 @@ static int inet_valid_dump_ifaddr_req(const struct nlmsghdr *nlh,
                NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for address dump request");
                return -EINVAL;
        }
-       if (ifm->ifa_index) {
-               NL_SET_ERR_MSG(extack, "ipv4: Filter by device index not supported for address dump");
-               return -EINVAL;
+
+       fillargs->ifindex = ifm->ifa_index;
+       if (fillargs->ifindex) {
+               cb->answer_flags |= NLM_F_DUMP_FILTERED;
+               fillargs->flags |= NLM_F_DUMP_FILTERED;
        }
 
        err = nlmsg_parse_strict(nlh, sizeof(*ifm), tb, IFA_MAX,
@@ -1765,9 +1769,22 @@ static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
 
        if (cb->strict_check) {
                err = inet_valid_dump_ifaddr_req(nlh, &fillargs, &tgt_net,
-                                                skb->sk, cb->extack);
+                                                skb->sk, cb);
                if (err < 0)
                        return err;
+
+               if (fillargs.ifindex) {
+                       dev = __dev_get_by_index(tgt_net, fillargs.ifindex);
+                       if (!dev)
+                               return -ENODEV;
+
+                       in_dev = __in_dev_get_rtnl(dev);
+                       if (in_dev) {
+                               err = in_dev_dump_addr(in_dev, skb, cb, s_ip_idx,
+                                                      &fillargs);
+                       }
+                       goto put_tgt_net;
+               }
        }
 
        for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
@@ -1800,6 +1817,7 @@ cont:
 done:
        cb->args[0] = h;
        cb->args[1] = idx;
+put_tgt_net:
        if (fillargs.netnsid >= 0)
                put_net(tgt_net);