[NETLINK]: Introduce NLMSG_NEW macro to better handle netlink flags

Introduces a new macro NLMSG_NEW which extends NLMSG_PUT but takes
a flags argument. NLMSG_PUT stays there for compatibility but now
calls NLMSG_NEW with flags == 0. NLMSG_PUT_ANSWER is renamed to
NLMSG_NEW_ANSWER which now also takes a flags argument.

Also converts the users of NLMSG_PUT_ANSWER to use NLMSG_NEW_ANSWER
and fixes the two direct users of __nlmsg_put to either provide
the flags or use NLMSG_NEW(_ANSWER).

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 7 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 2296a145fb78..0fb742e228cc 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1590,8 +1590,8 @@ static int neightbl_fill_info(struct neigh_table *tbl, struct sk_buff *skb,
         struct nlmsghdr *nlh;
         struct ndtmsg *ndtmsg;
 
-        nlh = NLMSG_PUT_ANSWER(skb, cb, RTM_NEWNEIGHTBL, sizeof(struct ndtmsg));
-        nlh->nlmsg_flags |= NLM_F_MULTI;
+        nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWNEIGHTBL, sizeof(struct ndtmsg),
+                               NLM_F_MULTI);
 
         ndtmsg = NLMSG_DATA(nlh);
 
@@ -1675,8 +1675,8 @@ static int neightbl_fill_param_info(struct neigh_table *tbl,
         struct ndtmsg *ndtmsg;
         struct nlmsghdr *nlh;
 
-        nlh = NLMSG_PUT_ANSWER(skb, cb, RTM_NEWNEIGHTBL, sizeof(struct ndtmsg));
-        nlh->nlmsg_flags |= NLM_F_MULTI;
+        nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWNEIGHTBL, sizeof(struct ndtmsg),
+                               NLM_F_MULTI);
 
         ndtmsg = NLMSG_DATA(nlh);
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index e41ce458c2a9..70bcd4744d93 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1095,8 +1095,7 @@ static int netlink_dump(struct sock *sk)
                 return 0;
         }
 
-        nlh = __nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq, NLMSG_DONE, sizeof(int));
-        nlh->nlmsg_flags |= NLM_F_MULTI;
+        nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
         memcpy(NLMSG_DATA(nlh), &len, sizeof(len));
         skb_queue_tail(&sk->sk_receive_queue, skb);
         sk->sk_data_ready(sk, skb->len);
@@ -1107,6 +1106,9 @@ static int netlink_dump(struct sock *sk)
 
         netlink_destroy_callback(cb);
         return 0;
+
+nlmsg_failure:
+        return -ENOBUFS;
 }
 
 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
@@ -1178,7 +1180,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
         }
 
         rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
-                          NLMSG_ERROR, sizeof(struct nlmsgerr));
+                          NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
         errmsg = NLMSG_DATA(rep);
         errmsg->error = err;
         memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr));