net/ipv6: 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.

Since inet6_dump_addr is reused for multicast and anycast addresses,
this adds support for device specfic dumps of RTM_GETMULTICAST and
RTM_GETANYCAST as well.

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

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6b65984..45b84dd 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4821,6 +4821,7 @@ struct inet6_fill_args {
        int event;
        unsigned int flags;
        int netnsid;
+       int ifindex;
        enum addr_type_t type;
 };
 
@@ -5018,8 +5019,9 @@ next:
 static int inet6_valid_dump_ifaddr_req(const struct nlmsghdr *nlh,
                                       struct inet6_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;
@@ -5034,9 +5036,11 @@ static int inet6_valid_dump_ifaddr_req(const struct nlmsghdr *nlh,
                NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for address dump request");
                return -EINVAL;
        }
-       if (ifm->ifa_index) {
-               NL_SET_ERR_MSG_MOD(extack, "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,
@@ -5094,9 +5098,21 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
                int err;
 
                err = inet6_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;
+                       idev = __in6_dev_get(dev);
+                       if (idev) {
+                               err = in6_dump_addrs(idev, skb, cb, s_ip_idx,
+                                                    &fillargs);
+                       }
+                       goto put_tgt_net;
+               }
        }
 
        rcu_read_lock();
@@ -5124,6 +5140,7 @@ done:
        rcu_read_unlock();
        cb->args[0] = h;
        cb->args[1] = idx;
+put_tgt_net:
        if (fillargs.netnsid >= 0)
                put_net(tgt_net);