feat: Allow specifying vmnet network UUID to disable DHCP (on vmnet.h…

README.md

@@ -12,27 +12,29 @@ Unlike `vde_vmnet`, `socket_vmnet` does not depend on VDE.
 <!-- START doctoc generated TOC please keep comment here to allow auto update -->
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
 
-- [Install](#install)
-  - [From binary](#from-binary)
-  - [From source](#from-source)
-  - [From Homebrew](#from-homebrew)
-  - [From MacPorts](#from-macports)
-- [Usage](#usage)
-  - [QEMU](#qemu)
-  - [Lima](#lima)
-- [Advanced usage](#advanced-usage)
-  - [Multi VM](#multi-vm)
-  - [Bridged mode](#bridged-mode)
-- [FAQs](#faqs)
-  - [Why does `socket_vmnet` require root?](#why-does-socket_vmnet-require-root)
-  - [Is it possible to run `socket_vmnet` with SETUID?](#is-it-possible-to-run-socket_vmnet-with-setuid)
-  - [How is socket_vmnet related to vde_vmnet?](#how-is-socket_vmnet-related-to-vde_vmnet)
-  - [How is socket_vmnet related to QEMU-builtin vmnet support?](#how-is-socket_vmnet-related-to-qemu-builtin-vmnet-support)
-  - [How to use static IP addresses?](#how-to-use-static-ip-addresses)
-  - [How to reserve DHCP addresses?](#how-to-reserve-dhcp-addresses)
-  - [IP address is not assigned](#ip-address-is-not-assigned)
-- [Links](#links)
-- [Troubleshooting](#troubleshooting)
+- [socket_vmnet: vmnet.framework support for rootless and VDE-less QEMU](#socket_vmnet-vmnetframework-support-for-rootless-and-vde-less-qemu)
+  - [Install](#install)
+    - [From binary](#from-binary)
+    - [From source](#from-source)
+    - [From Homebrew](#from-homebrew)
+    - [From MacPorts](#from-macports)
+  - [Usage](#usage)
+    - [QEMU](#qemu)
+    - [Lima](#lima)
+  - [Advanced usage](#advanced-usage)
+    - [Multi VM](#multi-vm)
+    - [Bridged mode](#bridged-mode)
+  - [FAQs](#faqs)
+    - [Why does `socket_vmnet` require root?](#why-does-socket_vmnet-require-root)
+    - [Is it possible to run `socket_vmnet` with SETUID?](#is-it-possible-to-run-socket_vmnet-with-setuid)
+    - [How is socket_vmnet related to vde_vmnet?](#how-is-socket_vmnet-related-to-vde_vmnet)
+    - [How is socket_vmnet related to QEMU-builtin vmnet support?](#how-is-socket_vmnet-related-to-qemu-builtin-vmnet-support)
+    - [How to use static IP addresses?](#how-to-use-static-ip-addresses)
+    - [How to reserve DHCP addresses?](#how-to-reserve-dhcp-addresses)
+    - [IP address is not assigned](#ip-address-is-not-assigned)
+    - [How to setup a vmnet host network without DHCP?](#how-to-setup-a-vmnet-host-network-without-dhcp)
+  - [Links](#links)
+  - [Troubleshooting](#troubleshooting)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
@@ -122,8 +124,7 @@ Run the following command to start the daemon:
 sudo /opt/socket_vmnet/bin/socket_vmnet --vmnet-gateway=192.168.105.1 /var/run/socket_vmnet
 ```
 
-> [!TIP]
-> `sudo make install` is also available in addition to `sudo make install.bin`.
+> [!TIP] > `sudo make install` is also available in addition to `sudo make install.bin`.
 > The former one installs the launchd service (see below) too.
 
 <details>
@@ -430,6 +431,17 @@ sudo /usr/libexec/ApplicationFirewall/socketfilterfw --add /usr/libexec/bootpd
 /usr/libexec/ApplicationFirewall/socketfilterfw --unblock /usr/libexec/bootpd
 ```
 
+### How to setup a vmnet host network without DHCP?
+
+You may need to disable the vmnet framework's DHCP to:
+
+- Create a host network where all VMs have static IPs.
+- Run a custom DHCP server on one VM to assign IPs to others on the same network.
+
+To disable the macOS DHCP you must use `--vmnet-mode=host` and provide a `--vmnet-network-idenfitier` UUID.
+You **_must not_** provide `--vmnet-gateway`. That is the signal to Apple's vmnet.framework to enable MacOS DHCP.
+You can use `--vmnet-network-idenfitier=random` to get a random UUID assigned.
+
 ## Links
 
 - https://developer.apple.com/documentation/vmnet

cli.c

@@ -48,6 +48,12 @@ static void print_usage(const char *argv0) {
          "specified\n");
   printf("--vmnet-interface-id=UUID           vmnet interface ID (default: "
          "random)\n");
+  printf("--vmnet-network-identifier=UUID     vmnet network identifier (UUID string, \"random\", "
+         "or \"\")\n"
+         "                                    When vmnet mode is \"host\" and --vmnet-gateway is "
+         "not set, the internal DHCP will be disabled.\n"
+         "                                    (default: \"\")\n");
+
   printf("--vmnet-nat66-prefix=PREFIX::       The IPv6 prefix to use with "
          "shared mode.\n");
   printf("                                    The prefix must be a ULA i.e. "
@@ -72,6 +78,7 @@ enum {
   CLI_OPT_VMNET_MASK,
   CLI_OPT_VMNET_INTERFACE_ID,
   CLI_OPT_VMNET_NAT66_PREFIX,
+  CLI_OPT_VMNET_NETWORK_IDENTIFIER,
 };
 
 struct cli_options *cli_options_parse(int argc, char *argv[]) {
@@ -82,18 +89,19 @@ struct cli_options *cli_options_parse(int argc, char *argv[]) {
   }
 
   const struct option longopts[] = {
-      {"socket-group",       required_argument, NULL, CLI_OPT_SOCKET_GROUP      },
-      {"vmnet-mode",         required_argument, NULL, CLI_OPT_VMNET_MODE        },
-      {"vmnet-interface",    required_argument, NULL, CLI_OPT_VMNET_INTERFACE   },
-      {"vmnet-gateway",      required_argument, NULL, CLI_OPT_VMNET_GATEWAY     },
-      {"vmnet-dhcp-end",     required_argument, NULL, CLI_OPT_VMNET_DHCP_END    },
-      {"vmnet-mask",         required_argument, NULL, CLI_OPT_VMNET_MASK        },
-      {"vmnet-interface-id", required_argument, NULL, CLI_OPT_VMNET_INTERFACE_ID},
-      {"vmnet-nat66-prefix", required_argument, NULL, CLI_OPT_VMNET_NAT66_PREFIX},
-      {"pidfile",            required_argument, NULL, 'p'                       },
-      {"help",               no_argument,       NULL, 'h'                       },
-      {"version",            no_argument,       NULL, 'v'                       },
-      {0,                    0,                 0,    0                         },
+      {"socket-group",             required_argument, NULL, CLI_OPT_SOCKET_GROUP            },
+      {"vmnet-mode",               required_argument, NULL, CLI_OPT_VMNET_MODE              },
+      {"vmnet-interface",          required_argument, NULL, CLI_OPT_VMNET_INTERFACE         },
+      {"vmnet-gateway",            required_argument, NULL, CLI_OPT_VMNET_GATEWAY           },
+      {"vmnet-dhcp-end",           required_argument, NULL, CLI_OPT_VMNET_DHCP_END          },
+      {"vmnet-mask",               required_argument, NULL, CLI_OPT_VMNET_MASK              },
+      {"vmnet-interface-id",       required_argument, NULL, CLI_OPT_VMNET_INTERFACE_ID      },
+      {"vmnet-nat66-prefix",       required_argument, NULL, CLI_OPT_VMNET_NAT66_PREFIX      },
+      {"vmnet-network-identifier", required_argument, NULL, CLI_OPT_VMNET_NETWORK_IDENTIFIER},
+      {"pidfile",                  required_argument, NULL, 'p'                             },
+      {"help",                     no_argument,       NULL, 'h'                             },
+      {"version",                  no_argument,       NULL, 'v'                             },
+      {0,                          0,                 0,    0                               },
   };
   int opt = 0;
   while ((opt = getopt_long(argc, argv, "hvp:", longopts, NULL)) != -1) {
@@ -134,6 +142,16 @@ struct cli_options *cli_options_parse(int argc, char *argv[]) {
     case CLI_OPT_VMNET_NAT66_PREFIX:
       res->vmnet_nat66_prefix = strdup(optarg);
       break;
+    case CLI_OPT_VMNET_NETWORK_IDENTIFIER:
+      if (strcmp(optarg, "random") == 0) {
+        uuid_generate_random(res->vmnet_network_identifier);
+      } else if (strcmp(optarg, "") == 0) {
+        uuid_clear(res->vmnet_network_identifier);
+      } else if (uuid_parse(optarg, res->vmnet_network_identifier) < 0) {
+        ERRORF("Failed to parse UUID \"%s\"", optarg);
+        goto error;
+      }
+      break;
     case 'p':
       res->pidfile = strdup(optarg);
       break;
@@ -191,7 +209,7 @@ struct cli_options *cli_options_parse(int argc, char *argv[]) {
     goto error;
   }
   if (res->vmnet_gateway == NULL) {
-    if (res->vmnet_mode != VMNET_BRIDGED_MODE) {
+    if (res->vmnet_mode != VMNET_BRIDGED_MODE && res->vmnet_mode != VMNET_HOST_MODE) {
       WARN("--vmnet-gateway=IP should be explicitly specified to "
            "avoid conflicting with other applications");
     }

cli.h

@@ -20,6 +20,8 @@ struct cli_options {
   char *vmnet_mask;
   // --vmnet-interface-id, corresponds to vmnet_interface_id_key
   uuid_t vmnet_interface_id;
+  // --vmnet-network-identifier, corresponds to vmnet_network_identifier_key
+  uuid_t vmnet_network_identifier;
   // --vmnet-nat66-prefix, corresponds to vmnet_nat66_prefix_key
   char *vmnet_nat66_prefix;
   // -p, --pidfile; writes pidfile using permissions of socket_vmnet

main.c

@@ -230,10 +230,23 @@ static interface_ref start(struct state *state, struct cli_options *cliopt) {
     INFOF("Using network interface \"%s\"", cliopt->vmnet_interface);
     xpc_dictionary_set_string(dict, vmnet_shared_interface_name_key, cliopt->vmnet_interface);
   }
-  if (cliopt->vmnet_gateway != NULL) {
-    xpc_dictionary_set_string(dict, vmnet_start_address_key, cliopt->vmnet_gateway);
-    xpc_dictionary_set_string(dict, vmnet_end_address_key, cliopt->vmnet_dhcp_end);
-    xpc_dictionary_set_string(dict, vmnet_subnet_mask_key, cliopt->vmnet_mask);
+
+  // no dhcp
+  if (cliopt->vmnet_mode == VMNET_HOST_MODE && cliopt->vmnet_gateway == NULL) {
+    if (!uuid_is_null(cliopt->vmnet_network_identifier)) {
+      xpc_dictionary_set_uuid(dict, vmnet_network_identifier_key, cliopt->vmnet_network_identifier);
+      uuid_string_t uuid_str;
+      uuid_unparse(cliopt->vmnet_network_identifier, uuid_str);
+      INFOF("Using network identifier \"%s\" and no vmnet gateway -> NO DHCP will be enabled on "
+            "this vmnet",
+            uuid_str);
+    }
+  } else {
+    if (cliopt->vmnet_gateway != NULL) {
+      xpc_dictionary_set_string(dict, vmnet_start_address_key, cliopt->vmnet_gateway);
+      xpc_dictionary_set_string(dict, vmnet_end_address_key, cliopt->vmnet_dhcp_end);
+      xpc_dictionary_set_string(dict, vmnet_subnet_mask_key, cliopt->vmnet_mask);
+    }
   }
 
   xpc_dictionary_set_uuid(dict, vmnet_interface_id_key, cliopt->vmnet_interface_id);