From ba0dc5f6e0ba5a5d2f575bcdb35e5d1960cf7c04 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 12 Apr 2017 14:34:06 +0200 Subject: netlink: allow sending extended ACK with cookie on success Now that we have extended error reporting and a new message format for netlink ACK messages, also extend this to be able to return arbitrary cookie data on success. This will allow, for example, nl80211 to not send an extra message for cookies identifying newly created objects, but return those directly in the ACK message. The cookie data size is currently limited to 20 bytes (since Jamal talked about using SHA1 for identifiers.) Thanks to Jamal Hadi Salim for bringing up this idea during the discussions. Signed-off-by: Johannes Berg Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) (limited to 'net') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index c1564768000e..ee841f00a6ec 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2311,6 +2311,10 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, } } else { flags |= NLM_F_CAPPED; + + if (nlk->flags & NETLINK_F_EXT_ACK && + extack && extack->cookie_len) + tlvlen += nla_total_size(extack->cookie_len); } if (tlvlen) @@ -2337,17 +2341,24 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, errmsg->error = err; memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); - if (err && nlk->flags & NETLINK_F_EXT_ACK && extack) { - 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 + - in_skb->len)) - WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, - (u8 *)extack->bad_attr - - in_skb->data)); + if (nlk->flags & NETLINK_F_EXT_ACK && extack) { + 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 + + in_skb->len)) + WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, + (u8 *)extack->bad_attr - + in_skb->data)); + } else { + if (extack->cookie_len) + WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, + extack->cookie_len, + extack->cookie)); + } } nlmsg_end(skb, rep); -- cgit v1.2.3-59-g8ed1b