From 7a9e9dfb182451b26846f5595dd8470d13042769 Mon Sep 17 00:00:00 2001
From: Adam Julis <ajulis@redhat.com>
Date: Tue, 9 Jul 2024 17:23:31 +0200
Subject: [PATCH] network: allow "modify" option for DNS-Txt records

The "modify" command allows to replace an existing record (its
text value). The primary key is the name of the record. If
duplicity or missing record detected, throw error.

Tests in networkxml2xmlupdatetest.c contain replacements of an
existing DNS-text record and failure due to non-existing record.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/639
Signed-off-by: Adam Julis <ajulis@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/conf/network_conf.c                       | 18 ++++++++-----
 .../dns-txt-record-modify-fail.xml            |  1 +
 .../dns-txt-record-modify-success.xml         |  1 +
 .../nat-network-dns-txt-modify-ok.xml         | 26 +++++++++++++++++++
 tests/networkxml2xmlupdatetest.c              |  9 +++++++
 5 files changed, 49 insertions(+), 6 deletions(-)
 create mode 100644 tests/networkxml2xmlupdatein/dns-txt-record-modify-fail.xml
 create mode 100644 tests/networkxml2xmlupdatein/dns-txt-record-modify-success.xml
 create mode 100644 tests/networkxml2xmlupdateout/nat-network-dns-txt-modify-ok.xml

diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
index 8e7a739d78..68eee367c4 100644
--- a/src/conf/network_conf.c
+++ b/src/conf/network_conf.c
@@ -3353,12 +3353,6 @@ virNetworkDefUpdateDNSTxt(virNetworkDef *def,
     bool isAdd = (command == VIR_NETWORK_UPDATE_COMMAND_ADD_FIRST ||
                   command == VIR_NETWORK_UPDATE_COMMAND_ADD_LAST);
 
-    if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY) {
-        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
-                       _("DNS TXT records cannot be modified, only added or deleted"));
-        goto cleanup;
-    }
-
     if (virNetworkDefUpdateCheckElementName(def, ctxt->node, "txt") < 0)
         goto cleanup;
 
@@ -3397,6 +3391,18 @@ virNetworkDefUpdateDNSTxt(virNetworkDef *def,
         virNetworkDNSTxtDefClear(&dns->txts[foundIdx]);
         VIR_DELETE_ELEMENT(dns->txts, foundIdx, dns->ntxts);
 
+    } else if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY) {
+
+        if (foundIdx == dns->ntxts) {
+            virReportError(VIR_ERR_OPERATION_INVALID,
+                           _("couldn't locate a matching DNS TXT record in network %1$s"),
+                           def->name);
+            goto cleanup;
+        }
+
+        VIR_FREE(dns->txts[foundIdx].value);
+        dns->txts[foundIdx].value = g_steal_pointer(&txt.value);
+
     } else {
         virNetworkDefUpdateUnknownCommand(command);
         goto cleanup;
diff --git a/tests/networkxml2xmlupdatein/dns-txt-record-modify-fail.xml b/tests/networkxml2xmlupdatein/dns-txt-record-modify-fail.xml
new file mode 100644
index 0000000000..75ed475fe1
--- /dev/null
+++ b/tests/networkxml2xmlupdatein/dns-txt-record-modify-fail.xml
@@ -0,0 +1 @@
+<txt name='notexisted' value='modified example'/>
diff --git a/tests/networkxml2xmlupdatein/dns-txt-record-modify-success.xml b/tests/networkxml2xmlupdatein/dns-txt-record-modify-success.xml
new file mode 100644
index 0000000000..e16c352253
--- /dev/null
+++ b/tests/networkxml2xmlupdatein/dns-txt-record-modify-success.xml
@@ -0,0 +1 @@
+<txt name='example' value='modified example'/>
diff --git a/tests/networkxml2xmlupdateout/nat-network-dns-txt-modify-ok.xml b/tests/networkxml2xmlupdateout/nat-network-dns-txt-modify-ok.xml
new file mode 100644
index 0000000000..4b4dda094a
--- /dev/null
+++ b/tests/networkxml2xmlupdateout/nat-network-dns-txt-modify-ok.xml
@@ -0,0 +1,26 @@
+<network>
+  <name>default</name>
+  <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid>
+  <forward dev='eth1' mode='nat'>
+    <interface dev='eth1'/>
+  </forward>
+  <bridge name='virbr0' stp='on' delay='0'/>
+  <dns>
+    <txt name='example' value='modified example'/>
+  </dns>
+  <ip address='192.168.122.1' netmask='255.255.255.0'>
+    <dhcp>
+      <range start='192.168.122.2' end='192.168.122.254'/>
+      <host mac='00:16:3e:77:e2:ed' name='a.example.com' ip='192.168.122.10'/>
+      <host mac='00:16:3e:3e:a9:1a' name='b.example.com' ip='192.168.122.11'/>
+    </dhcp>
+  </ip>
+  <ip family='ipv4' address='192.168.123.1' netmask='255.255.255.0'>
+  </ip>
+  <ip family='ipv6' address='2001:db8:ac10:fe01::1' prefix='64'>
+  </ip>
+  <ip family='ipv6' address='2001:db8:ac10:fd01::1' prefix='64'>
+  </ip>
+  <ip family='ipv4' address='10.24.10.1'>
+  </ip>
+</network>
diff --git a/tests/networkxml2xmlupdatetest.c b/tests/networkxml2xmlupdatetest.c
index 59e6ce98e5..875cede035 100644
--- a/tests/networkxml2xmlupdatetest.c
+++ b/tests/networkxml2xmlupdatetest.c
@@ -306,6 +306,15 @@ mymain(void)
                  "dns-txt-record-snowman",
                  "nat-network-dns-txt-record",
                  VIR_NETWORK_UPDATE_COMMAND_DELETE);
+    DO_TEST("modify-dns-txt-record",
+            "dns-txt-record-modify-success",
+            "nat-network-dns-txt-record",
+            "nat-network-dns-txt-modify-ok",
+            VIR_NETWORK_UPDATE_COMMAND_MODIFY);
+    DO_TEST_FAIL("modify-missing-dns-txt-record",
+            "dns-txt-record-modify-fail",
+            "nat-network-dns-txt-record",
+            VIR_NETWORK_UPDATE_COMMAND_MODIFY);
 
 
     section = VIR_NETWORK_SECTION_DNS_SRV;