[PATCH] RFC: Support network interface downscript

[Chen Hanxiao]

https://gitlab.com/libvirt/libvirt/-/issues/13

Add support for downscript:

<interface type='ethernet'>
    <mac address='00:11:22:33:44:55'/>
    <script path='/etc/qemu-ifup'/>
    <downscript path='/path/to/my/downscript'/>
</interface>

But -net ...,script=/etc/qemu-ifup has some limitation:
https://github.com/qemu/qemu/blob/035b448b84f3557206abc44d786c5d3db2638f7d/net/tap.c#L818
Maybe virNetDevRunEthernetScript is another choice.

Signed-off-by: Chen Hanxiao <chen_han_xiao at 126.com>
---
 src/conf/domain_conf.c    | 7 +++++++
 src/conf/domain_conf.h    | 1 +
 src/qemu/qemu_extdevice.c | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index c201fc9..5cb39a3 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -2520,6 +2520,7 @@ virDomainNetDefClear(virDomainNetDefPtr def)
     VIR_FREE(def->teaming.persistent);
     VIR_FREE(def->virtPortProfile);
     VIR_FREE(def->script);
+    VIR_FREE(def->downscript);
     VIR_FREE(def->domain_name);
     VIR_FREE(def->ifname);
     VIR_FREE(def->ifname_guest);
@@ -11977,6 +11978,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
     g_autofree char *ifname_guest = NULL;
     g_autofree char *ifname_guest_actual = NULL;
     g_autofree char *script = NULL;
+    g_autofree char *downscript = NULL;
     g_autofree char *address = NULL;
     g_autofree char *port = NULL;
     g_autofree char *localaddr = NULL;
@@ -12149,6 +12151,9 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
             } else if (!script &&
                        virXMLNodeNameEqual(cur, "script")) {
                 script = virXMLPropString(cur, "path");
+            } else if (!downscript &&
+                       virXMLNodeNameEqual(cur, "downscript")) {
+                downscript = virXMLPropString(cur, "path");
             } else if (!domain_name &&
                        virXMLNodeNameEqual(cur, "backenddomain")) {
                 domain_name = virXMLPropString(cur, "name");
@@ -12482,6 +12487,8 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
 
     if (script != NULL)
         def->script = g_steal_pointer(&script);
+    if (downscript != NULL)
+        def->downscript = g_steal_pointer(&downscript);
     if (domain_name != NULL)
         def->domain_name = g_steal_pointer(&domain_name);
     if (ifname != NULL)
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index ddc75d8..e152c59 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1055,6 +1055,7 @@ struct _virDomainNetDef {
         unsigned long sndbuf;
     } tune;
     char *script;
+    char *downscript;
     char *domain_name; /* backend domain name */
     char *ifname; /* interface name on the host (<target dev='x'/>) */
     int managed_tap; /* enum virTristateBool - ABSENT == YES */
diff --git a/src/qemu/qemu_extdevice.c b/src/qemu/qemu_extdevice.c
index 2096272..f8e440a 100644
--- a/src/qemu/qemu_extdevice.c
+++ b/src/qemu/qemu_extdevice.c
@@ -234,6 +234,8 @@ qemuExtDevicesStop(virQEMUDriverPtr driver,
 
         if (slirp)
             qemuSlirpStop(slirp, vm, driver, net);
+        if (net->downscript)
+            virNetDevRunEthernetScript(net->ifname, net->downscript);
     }
 
     for (i = 0; i < def->nfss; i++) {
-- 
1.8.3.1