diff mbox series

[Openvpn-devel,v2] dco_linux: enable extended netlink error reporting

Message ID 20250609100216.3997-1-gert@greenie.muc.de
State Accepted
Headers show
Series [Openvpn-devel,v2] dco_linux: enable extended netlink error reporting | expand

Commit Message

Gert Doering June 9, 2025, 10:02 a.m. UTC 
From: Antonio Quartulli <antonio@mandelbit.com>

The ovpn netlink code reports more verbose error
strings to help userspace understand what went wrong,
rather than just returning, for example, -EINVAL.

However, userspace must instruct the kernel netlink
subsystem that it wants to receive such strings.

code for parsing such strings has always been present
but it was never used.

Set the socket option which enables such reporting.

Change-Id: I4457b1d7262e0a39c275d33aaef6c4bcbeae6ab3
Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
---

This change was reviewed on Gerrit and approved by at least one
developer. I request to merge it to master.

Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1040
This mail reflects revision 2 of this Change.

Acked-by according to Gerrit (reflected above):
Gert Doering <gert@greenie.muc.de>

Comments

Gert Doering June 9, 2025, 5:46 p.m. UTC | #1 
Tested, makes sense - I intentionally broke some code parts in dco_linux.c
that set up a peer, and instead of a not very helpful "-7" userspace now
gets a proper error string.  Discovered the extra "\n" testing this, so
thanks for the v2 fix :-)

Your patch has been applied to the master branch.

commit ddbfbeca603eedddc12556b28e5cd9b022e9ea63
Author: Antonio Quartulli
Date:   Mon Jun 9 12:02:10 2025 +0200

     dco_linux: enable extended netlink error reporting

     Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>
     Acked-by: Gert Doering <gert@greenie.muc.de>
     Message-Id: <20250609100216.3997-1-gert@greenie.muc.de>
     URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg31885.html
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering
diff mbox series

Patch

diff --git a/src/openvpn/dco_linux.c b/src/openvpn/dco_linux.c
index 49dbdad..0345413 100644
--- a/src/openvpn/dco_linux.c
+++ b/src/openvpn/dco_linux.c
@@ -367,19 +367,19 @@ 
     {
         len = strnlen((char *)nla_data(tb_msg[NLMSGERR_ATTR_MSG]),
                       nla_len(tb_msg[NLMSGERR_ATTR_MSG]));
-        msg(M_WARN, "kernel error: %*s\n", len,
+        msg(M_WARN, "kernel error: %*s", len,
             (char *)nla_data(tb_msg[NLMSGERR_ATTR_MSG]));
     }
 
     if (tb_msg[OVPN_NLMSGERR_ATTR_MISS_NEST])
     {
-        msg(M_WARN, "kernel error: missing required nesting type %u\n",
+        msg(M_WARN, "kernel error: missing required nesting type %u",
             nla_get_u32(tb_msg[OVPN_NLMSGERR_ATTR_MISS_NEST]));
     }
 
     if (tb_msg[OVPN_NLMSGERR_ATTR_MISS_TYPE])
     {
-        msg(M_WARN, "kernel error: missing required attribute type %u\n",
+        msg(M_WARN, "kernel error: missing required attribute type %u",
             nla_get_u32(tb_msg[OVPN_NLMSGERR_ATTR_MISS_TYPE]));
     }
 
@@ -405,6 +405,11 @@ 
             nl_geterror(ret));
     }
 
+    /* enable Extended ACK for detailed error reporting */
+    ret = 1;
+    setsockopt(nl_socket_get_fd(dco->nl_sock), SOL_NETLINK, NETLINK_EXT_ACK,
+               &ret, sizeof(ret));
+
     /* set close on exec and non-block on the netlink socket */
     set_cloexec(nl_socket_get_fd(dco->nl_sock));
     set_nonblock(nl_socket_get_fd(dco->nl_sock));