diff mbox series

[Openvpn-devel,v1] Fix broken DHCP options

Message ID 20250730180527.25339-1-gert@greenie.muc.de
State Accepted
Headers show
Series [Openvpn-devel,v1] Fix broken DHCP options | expand

Commit Message

Gert Doering July 30, 2025, 6:04 p.m. UTC 
From: Lev Stipakov <lev@openvpn.net>

Commit

  2dfc4f ("dns: deal with --dhcp-options when --dns is active")

broke support for --dhcp-options. It removed the setting of the
DHCP_OPTIONS_DHCP_OPTIONAL flag for some DHCP options. This flag is
required for those options to be applied correctly, as it is used
when building the DHCP options string that is passed to the TAP driver.

This commit fixes the issue by restoring the setting of this flag.

GitHub: fixes OpenVPN/openvpn#791

Change-Id: I0d75efcceb826d06e74abd003d5377468ff9fe3b
Signed-off-by: Lev Stipakov <lev@openvpn.net>
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/+/1090
This mail reflects revision 1 of this Change.

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

Comments

Gert Doering July 30, 2025, 6:15 p.m. UTC | #1 
Thanks.  I've ran into this myself with 2.7_alpha2 and a setup that 
ended up doing DHCP on TAP, so thanks for the fix :-)

I have not tested it beyond "does it compile", but looking at the code
flow and finding tt->options.dhcp_options in tun.c, this is "obviously
correct".  The dance with the helper variable is unavoidable due to
the platform-dependent nature of the options.c code here... ("or you
get 3 extra #ifdefs").

Your patch has been applied to the master branch.

commit 040e0d1c308a587ae9a26295eeaa070561befa0d
Author: Lev Stipakov
Date:   Wed Jul 30 20:04:26 2025 +0200

     Fix broken DHCP options

     Signed-off-by: Lev Stipakov <lev@openvpn.net>
     Acked-by: Gert Doering <gert@greenie.muc.de>
     Message-Id: <20250730180527.25339-1-gert@greenie.muc.de>
     URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg32427.html
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering
diff mbox series

Patch

diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 0662b49..4ba9243 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -8310,9 +8310,12 @@ 
 #endif
         VERIFY_PERMISSION(OPT_P_DHCPDNS);
 
+        bool dhcp_optional = false;
+
         if ((streq(p[1], "DOMAIN") || streq(p[1], "ADAPTER_DOMAIN_SUFFIX")) && p[2] && !p[3])
         {
             dhcp->domain = p[2];
+            dhcp_optional = true;
         }
         else if (streq(p[1], "DOMAIN-SEARCH") && p[2] && !p[3])
         {
@@ -8325,6 +8328,7 @@ 
                 msg(msglevel, "--dhcp-option %s: maximum of %d search entries can be specified",
                     p[1], N_SEARCH_LIST_LEN);
             }
+            dhcp_optional = true;
         }
         else if ((streq(p[1], "DNS") || streq(p[1], "DNS6")) && p[2] && !p[3]
                  && (!strstr(p[2], ":") || ipv6_addr_safe(p[2])))
@@ -8336,6 +8340,7 @@ 
             else
             {
                 dhcp_option_address_parse("DNS", p[2], dhcp->dns, &dhcp->dns_len, msglevel);
+                dhcp_optional = true;
             }
         }
 #if defined(_WIN32) || defined(TARGET_ANDROID)
@@ -8359,6 +8364,7 @@ 
         else if (streq(p[1], "WINS") && p[2] && !p[3])
         {
             dhcp_option_address_parse("WINS", p[2], o->wins, &o->wins_len, msglevel);
+            o->dhcp_options |= DHCP_OPTIONS_DHCP_OPTIONAL;
         }
         else if (streq(p[1], "NTP") && p[2] && !p[3])
         {
@@ -8390,6 +8396,13 @@ 
 #else /* if defined(_WIN32) || defined(TARGET_ANDROID) */
         setenv_foreign_option(options, (const char **)p, 3, es);
 #endif /* if defined(_WIN32) || defined(TARGET_ANDROID) */
+
+        if (dhcp_optional)
+        {
+#if defined(_WIN32) || defined(TARGET_ANDROID)
+            o->dhcp_options |= DHCP_OPTIONS_DHCP_OPTIONAL;
+#endif
+        }
     }
 #ifdef _WIN32
     else if (streq(p[0], "show-adapters") && !p[1])