From 4e2f5dfa6484a90d8c01f5d5f9c46dddab8d86e9 Mon Sep 17 00:00:00 2001
From: Tuetuopay <tuetuopay@me.com>
Date: Mon, 9 Apr 2018 16:21:41 +0200
Subject: [PATCH 41/76] route/link: fix sequence number handling in
 rtnl_link_change()

When rtnl_link_change() fails with -NLE_OPNOTSUPP, it retries
with RTM_SETLINK operation. However, it also needs to re-adjust
the sequence number. Otherwise, the second request might fail
with NLE_SEQ_MISMATCH, although it actually succeeded.

[thaller@redhat.com: changed commit message]

https://github.com/thom311/libnl/issues/179
https://github.com/thom311/libnl/pull/184
---
 lib/route/link.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/route/link.c b/lib/route/link.c
index de3c393..40165e5 100644
--- a/lib/route/link.c
+++ b/lib/route/link.c
@@ -1772,6 +1772,10 @@ errout:
  * @note The link name can only be changed if the link has been put
  *       in opertional down state. (~IF_UP)
  *
+ * @note On versions up to 3.4.0, \c NLE_SEQ_MISMATCH would be returned if the
+ *       kernel does not supports \c RTM_NEWLINK. It is advised to ignore the
+ *       error code if you cannot upgrade the library.
+ *
  * @return 0 on success or a negative error code.
  */
 int rtnl_link_change(struct nl_sock *sk, struct rtnl_link *orig,
@@ -1792,6 +1796,7 @@ retry:
 	err = wait_for_ack(sk);
 	if (err == -NLE_OPNOTSUPP && msg->nm_nlh->nlmsg_type == RTM_NEWLINK) {
 		msg->nm_nlh->nlmsg_type = RTM_SETLINK;
+		msg->nm_nlh->nlmsg_seq = NL_AUTO_SEQ;
 		goto retry;
 	}
 
-- 
1.8.3.1

