On Wed, 15 May 2024 at 15:41, Abhiram Tilak <atp.exp@gmail.com> wrote:

The current way of updating a network configuration uses `virsh
net-update` to add, delete or modify entries. But with such a mechansim
one should know if an entry with current info already exists. Adding
modify-or-add option automatically performs either modify or add
depending on the current state.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/363
Signed-off-by: Abhiram Tilak <atp.exp@gmail.com>
---
Changes in v2:
- Removed the modify-or-add functionality for sections
where modify is not applicable.
- Changed the existing implementation of `UpdateIPDHCPHost`,
to avoid code duplication.
- Changed the implementation of modify-or-delete to reassign
the `command` variable instead of using multiple nested conditions.

docs/manpages/virsh.rst | 5 +-
include/libvirt/libvirt-network.h | 12 +--
src/conf/network_conf.c | 134 +++++++++++++++++++++---------
tools/virsh-network.c | 6 +-
4 files changed, 110 insertions(+), 47 deletions(-)

diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
index 115b802c45..0da3827f6b 100644
--- a/docs/manpages/virsh.rst
+++ b/docs/manpages/virsh.rst
@@ -5908,7 +5908,10 @@ changes optionally taking effect immediately, without needing to
destroy and re-start the network.

*command* is one of "add-first", "add-last", "add" (a synonym for
-add-last), "delete", or "modify".
+add-last), "delete", "modify", "modify-or-add" (modify + add-last), or
+"modify-or-add-first". The 'modify-or-add*' commands perform modify or
+add operation depending on the given state, and can be useful for
+scripting.

*section* is one of "bridge", "domain", "ip", "ip-dhcp-host",
"ip-dhcp-range", "forward", "forward-interface", "forward-pf",
diff --git a/include/libvirt/libvirt-network.h b/include/libvirt/libvirt-network.h
index 58591be7ac..bb4468b160 100644
--- a/include/libvirt/libvirt-network.h
+++ b/include/libvirt/libvirt-network.h
@@ -176,11 +176,13 @@ int virNetworkUndefine (virNetworkPtr network);
* Since: 0.10.2
*/
typedef enum {
- VIR_NETWORK_UPDATE_COMMAND_NONE = 0, /* invalid (Since: 0.10.2) */
- VIR_NETWORK_UPDATE_COMMAND_MODIFY = 1, /* modify an existing element (Since: 0.10.2) */
- VIR_NETWORK_UPDATE_COMMAND_DELETE = 2, /* delete an existing element (Since: 0.10.2) */
- VIR_NETWORK_UPDATE_COMMAND_ADD_LAST = 3, /* add an element at end of list (Since: 0.10.2) */
- VIR_NETWORK_UPDATE_COMMAND_ADD_FIRST = 4, /* add an element at start of list (Since: 0.10.2) */
+ VIR_NETWORK_UPDATE_COMMAND_NONE = 0, /* invalid (Since: 0.10.2) */
+ VIR_NETWORK_UPDATE_COMMAND_MODIFY = 1, /* modify an existing element (Since: 0.10.2) */
+ VIR_NETWORK_UPDATE_COMMAND_DELETE = 2, /* delete an existing element (Since: 0.10.2) */
+ VIR_NETWORK_UPDATE_COMMAND_ADD_LAST = 3, /* add an element at end of list (Since: 0.10.2) */
+ VIR_NETWORK_UPDATE_COMMAND_ADD_FIRST = 4, /* add an element at start of list (Since: 0.10.2) */
+ VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST = 5, /* conditionally modify or add an element at end (Since: 10.4.0) */
+ VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST = 6, /* conditionally modify or add an element at start (Since: 10.4.0) */
# ifdef VIR_ENUM_SENTINELS
VIR_NETWORK_UPDATE_COMMAND_LAST /* (Since: 0.10.2) */
# endif
diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
index cc92ed0b03..a7c3dea163 100644
--- a/src/conf/network_conf.c
+++ b/src/conf/network_conf.c
@@ -2720,6 +2720,7 @@ virNetworkDefUpdateIPDHCPHost(virNetworkDef *def,
virNetworkIPDef *ipdef = virNetworkIPDefByIndex(def, parentIndex);
virNetworkDHCPHostDef host = { 0 };
bool partialOkay = (command == VIR_NETWORK_UPDATE_COMMAND_DELETE);
+ int foundMatchedEntry = -1, foundExactEntry = -1;

if (virNetworkDefUpdateCheckElementName(def, ctxt->node, "host") < 0)
goto cleanup;
@@ -2740,22 +2741,47 @@ virNetworkDefUpdateIPDHCPHost(virNetworkDef *def,
goto cleanup;
}

- if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY) {
+ /* check if the entry already exsits */
+ for (i = 0; i < ipdef->nhosts; i++) {

- /* search for the entry with this (ip|mac|name),
- * and update the IP+(mac|name) */
- for (i = 0; i < ipdef->nhosts; i++) {
- if ((host.mac && ipdef->hosts[i].mac &&
- !virMacAddrCompare(host.mac, ipdef->hosts[i].mac)) ||
- (VIR_SOCKET_ADDR_VALID(&host.ip) &&
- virSocketAddrEqual(&host.ip, &ipdef->hosts[i].ip)) ||
- (host.name &&
- STREQ_NULLABLE(host.name, ipdef->hosts[i].name))) {
- break;
- }
+ /* try to match any of (ip|mac|name) attributes */
+ if ((host.mac && ipdef->hosts[i].mac &&
+ !virMacAddrCompare(host.mac, ipdef->hosts[i].mac)) ||
+ (VIR_SOCKET_ADDR_VALID(&host.ip) &&
+ virSocketAddrEqual(&host.ip, &ipdef->hosts[i].ip)) ||
+ (host.name &&
+ STREQ_NULLABLE(host.name, ipdef->hosts[i].name))) {
+ foundMatchedEntry = i;
+ }
+
+ /* find exact entry - all specified attributes must match */
+ if ((!host.mac || !ipdef->hosts[i].mac ||
+ !virMacAddrCompare(host.mac, ipdef->hosts[i].mac)) &&
+ (!host.name ||
+ STREQ_NULLABLE(host.name, ipdef->hosts[i].name)) &&
+ (!VIR_SOCKET_ADDR_VALID(&host.ip) ||
+ virSocketAddrEqual(&host.ip, &ipdef->hosts[i].ip))) {
+ foundExactEntry = i;
+ break;
}
+ }
+
+ /* modify-or-add: convert command to add or modify based on foundEntry */
+ if (foundEntry == -1) {
+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST)
+ command = VIR_NETWORK_UPDATE_COMMAND_ADD_FIRST;
+ else if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST)
+ command = VIR_NETWORK_UPDATE_COMMAND_ADD_LAST;
+ } else if (foundEntry >= 0) {
+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST ||
+ command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST)
+ command = VIR_NETWORK_UPDATE_COMMAND_MODIFY;
+ }
+
+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY) {

- if (i == ipdef->nhosts) {
+ /* log error if no such entry exists to be modified */
+ if (foundMatchedEntry == -1) {
g_autofree char *ip = virSocketAddrFormat(&host.ip);
virReportError(VIR_ERR_OPERATION_INVALID,
_("couldn't locate an existing dhcp host entry with \"mac='%1$s'\" \"name='%2$s'\" \"ip='%3$s'\" in network '%4$s'"),
@@ -2779,21 +2805,13 @@ virNetworkDefUpdateIPDHCPHost(virNetworkDef *def,
goto cleanup;

/* log error if an entry with same name/address/ip already exists */
- for (i = 0; i < ipdef->nhosts; i++) {
- if ((host.mac && ipdef->hosts[i].mac &&
- !virMacAddrCompare(host.mac, ipdef->hosts[i].mac)) ||
- (host.name &&
- STREQ_NULLABLE(host.name, ipdef->hosts[i].name)) ||
- (VIR_SOCKET_ADDR_VALID(&host.ip) &&
- virSocketAddrEqual(&host.ip, &ipdef->hosts[i].ip))) {
- g_autofree char *ip = virSocketAddrFormat(&host.ip);
+ if (foundMatchedEntry >= 0) {
+ virReportError(VIR_ERR_OPERATION_INVALID,
+ _("there is an existing dhcp host entry in network '%1$s' that matches \"<host mac='%2$s' name='%3$s' ip='%4$s'/>\""),
+ def->name, host.mac ? host.mac : _("unknown"),
+ host.name, ip ? ip : _("unknown"));
+ goto cleanup;

- virReportError(VIR_ERR_OPERATION_INVALID,
- _("there is an existing dhcp host entry in network '%1$s' that matches \"<host mac='%2$s' name='%3$s' ip='%4$s'/>\""),
- def->name, host.mac ? host.mac : _("unknown"),
- host.name, ip ? ip : _("unknown"));
- goto cleanup;
- }
}

/* add to beginning/end of list */
@@ -2804,18 +2822,8 @@ virNetworkDefUpdateIPDHCPHost(virNetworkDef *def,
goto cleanup;
} else if (command == VIR_NETWORK_UPDATE_COMMAND_DELETE) {

- /* find matching entry - all specified attributes must match */
- for (i = 0; i < ipdef->nhosts; i++) {
- if ((!host.mac || !ipdef->hosts[i].mac ||
- !virMacAddrCompare(host.mac, ipdef->hosts[i].mac)) &&
- (!host.name ||
- STREQ_NULLABLE(host.name, ipdef->hosts[i].name)) &&
- (!VIR_SOCKET_ADDR_VALID(&host.ip) ||
- virSocketAddrEqual(&host.ip, &ipdef->hosts[i].ip))) {
- break;
- }
- }
- if (i == ipdef->nhosts) {
+ /* log error if there is no entry with exact match*/
+ if (foundExactEntry == -1) {
virReportError(VIR_ERR_OPERATION_INVALID,
_("couldn't locate a matching dhcp host entry in network '%1$s'"),
def->name);
@@ -2865,6 +2873,14 @@ virNetworkDefUpdateIPDHCPRange(virNetworkDef *def,
return -1;
}

+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST ||
+ command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST) {
+
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("dhcp ranges cannot be modified, use add command instead of modify-or-add"));
+ return -1;
+ }
+
if (virNetworkDHCPRangeDefParseXML(def->name, ipdef, ctxt->node, &range) < 0)
return -1;

@@ -2964,6 +2980,13 @@ virNetworkDefUpdateForwardInterface(virNetworkDef *def,
goto cleanup;
}

+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST ||
+ command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("forward interface entries cannot be modified, use add command instead of modify-or-add"));
+ goto cleanup;
+ }
+
/* parsing this is so simple that it doesn't have its own function */
iface.type = VIR_NETWORK_FORWARD_HOSTDEV_DEVICE_NETDEV;
if (!(iface.device.dev = virXMLPropString(ctxt->node, "dev"))) {
@@ -3085,6 +3108,18 @@ virNetworkDefUpdatePortGroup(virNetworkDef *def,
goto cleanup;
}

+ /* modify-or-add: convert command to add or modify based on foundName */
+ if (foundName == -1) {
+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST)
+ command = VIR_NETWORK_UPDATE_COMMAND_ADD_FIRST;
+ else if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST)
+ command = VIR_NETWORK_UPDATE_COMMAND_ADD_LAST;
+ } else if (foundName >= 0) {
+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST ||
+ command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST)
+ command = VIR_NETWORK_UPDATE_COMMAND_MODIFY;
+ }
+
/* if there is already a different default, we can't make this
* one the default.
*/
@@ -3153,6 +3188,13 @@ virNetworkDefUpdateDNSHost(virNetworkDef *def,
goto cleanup;
}

+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST ||
+ command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("DNS HOST records cannot be modified, use add instead of modify-or-add"));
+ goto cleanup;
+ }
+
if (virNetworkDefUpdateCheckElementName(def, ctxt->node, "host") < 0)
goto cleanup;

@@ -3249,6 +3291,13 @@ virNetworkDefUpdateDNSSrv(virNetworkDef *def,
goto cleanup;
}

+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST ||
+ command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("DNS SRV records cannot be modified, use add command instead of modify-or-add"));
+ goto cleanup;
+ }
+
if (virNetworkDefUpdateCheckElementName(def, ctxt->node, "srv") < 0)
goto cleanup;

@@ -3330,6 +3379,13 @@ virNetworkDefUpdateDNSTxt(virNetworkDef *def,
goto cleanup;
}

+ if (command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_FIRST ||
+ command == VIR_NETWORK_UPDATE_COMMAND_MODIFY_ADD_LAST) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("DNS TXT records cannot be modified, use add command instead of modify-or-add"));
+ goto cleanup;
+ }
+
if (virNetworkDefUpdateCheckElementName(def, ctxt->node, "txt") < 0)
goto cleanup;

diff --git a/tools/virsh-network.c b/tools/virsh-network.c
index 597e3d4530..d7dc5df5a8 100644
--- a/tools/virsh-network.c
+++ b/tools/virsh-network.c
@@ -1231,7 +1231,8 @@ static const vshCmdOptDef opts_network_update[] = {
.positional = true,
.required = true,
.completer = virshNetworkUpdateCommandCompleter,
- .help = N_("type of update (add-first, add-last (add), delete, or modify)")
+ .help = N_("type of update (add-first, add-last (add), delete, modify,"
+ "modify-or-add, or modify-or-add-first)")
},
{.name = "section",
.type = VSH_OT_STRING,
@@ -1260,7 +1261,8 @@ static const vshCmdOptDef opts_network_update[] = {

VIR_ENUM_IMPL(virshNetworkUpdateCommand,
VIR_NETWORK_UPDATE_COMMAND_LAST,
- "none", "modify", "delete", "add-last", "add-first");
+ "none", "modify", "delete", "add-last", "add-first", "modify-or-add",
+ "modify-or-add-first");

VIR_ENUM_IMPL(virshNetworkSection,
VIR_NETWORK_SECTION_LAST,
--
2.42.1