netlink: Allow ext_ack to carry non-error messages

The NLMSGERR API already carries data (eg, a cookie) on the success path.
Allow a message string to be returned as well.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2017-10-27 17:37:12 -07:00 committed by David S. Miller
parent a7b216b1e1
commit 4f6265d485

View File

@ -2313,17 +2313,16 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
* requests to cap the error message, and get extra error data if
* requested.
*/
if (nlk_has_extack && extack && extack->_msg)
tlvlen += nla_total_size(strlen(extack->_msg) + 1);
if (err) {
if (!(nlk->flags & NETLINK_F_CAP_ACK))
payload += nlmsg_len(nlh);
else
flags |= NLM_F_CAPPED;
if (nlk_has_extack && extack) {
if (extack->_msg)
tlvlen += nla_total_size(strlen(extack->_msg) + 1);
if (extack->bad_attr)
tlvlen += nla_total_size(sizeof(u32));
}
if (nlk_has_extack && extack && extack->bad_attr)
tlvlen += nla_total_size(sizeof(u32));
} else {
flags |= NLM_F_CAPPED;
@ -2348,10 +2347,11 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
if (nlk_has_extack && extack) {
if (extack->_msg) {
WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
extack->_msg));
}
if (err) {
if (extack->_msg)
WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
extack->_msg));
if (extack->bad_attr &&
!WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
(u8 *)extack->bad_attr >= in_skb->data +