Add --vmnet-disable-dhcp to disable the vmnet DHCP server (macOS 26+)#165
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Add --vmnet-disable-dhcp to disable the vmnet DHCP server (macOS 26+)#165fpolica91 wants to merge 1 commit into
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macOS 26 introduced the vmnet_network_configuration_* API, including vmnet_network_configuration_disable_dhcp(), which disables the DHCP server while keeping shared-mode NAT. (Noted in #139 but intentionally not used there to avoid a 26-only dependency.) |
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Pull request overview
Adds support for disabling vmnet.framework’s built-in DHCP server on macOS 26+ via a new --vmnet-disable-dhcp CLI flag, and introduces an integration test (plus CI coverage) to validate that guests do not obtain a DHCP lease when DHCP is disabled.
Changes:
- Add
--vmnet-disable-dhcpoption to the CLI (parse + help text). - Implement a macOS 26+ vmnet start path using the
vmnet_network_configurationAPI with DHCP disabled. - Add iPXE/QEMU-based integration test and run it in the GitHub Actions QEMU workflow (skipping on < macOS 26).
Reviewed changes
Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
main.c |
Adds a macOS 26+ vmnet initialization path that disables DHCP using the network configuration API. |
cli.h |
Extends CLI options struct with a vmnet_disable_dhcp flag. |
cli.c |
Adds flag parsing and help text for --vmnet-disable-dhcp. |
test/test-disable-dhcp.sh |
New integration test script that starts socket_vmnet with DHCP disabled and runs QEMU+iPXE to verify no lease is obtained. |
test/test-disable-dhcp.ipxe |
New iPXE script used by the integration test to attempt DHCP and print the resulting IP. |
.github/workflows/qemu.yaml |
Runs the new disable-DHCP integration test in CI (with a macOS 26 runner in the matrix). |
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Please squash the commits and fulfill the PR description |
AkihiroSuda
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AkihiroSuda
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…S 26+) Add a --vmnet-disable-dhcp flag that starts the interface through the macOS 26 vmnet_network_configuration API (vmnet_network_create + vmnet_interface_start_with_network) with the built-in DHCP server disabled, while keeping shared-mode NAT. This lets an external DHCP/PXE server own the subnet. - Guard the new code path at compile time (requires the macOS 26 SDK) and at runtime (__builtin_available), erroring out clearly on older hosts and SDKs. Invocations without the flag keep using the legacy vmnet_start_interface path unchanged. - Derive the subnet address for vmnet_network_configuration_set_ipv4_subnet by masking --vmnet-gateway with --vmnet-mask, and validate both values separately (inet_aton does not set errno on failure). - Apply --vmnet-nat66-prefix via vmnet_network_configuration_set_ipv6_prefix. - Warn that --vmnet-dhcp-end, --vmnet-interface-id and --vmnet-network-identifier are ignored on this path: no DHCP server is started, and the new API has no equivalent for the other two. The checks run in cli_options_parse before defaults are filled in, so only explicitly passed options warn. - Name the selected start API in the failure log to ease debugging. - Add an iPXE-based e2e test (test/test-disable-dhcp.sh) asserting that no DHCP lease is offered, wired into the qemu workflow. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Signed-off-by: fpolica91 <fabriciopolicarpo0@gmail.com>
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Squashed into a single signed-off commit and filled in the PR description. The |
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@AkihiroSuda I have addressed the comments on this PR. Thank you for taking the time to review, if there is anything else needed please don't hesitate to let me know. |
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What
Adds a
--vmnet-disable-dhcpflag that starts the vmnet interface with the built-in DHCP server disabled while keeping shared-mode NAT, so an external DHCP/PXE server can own the subnet.The existing
--vmnet-network-identifiermechanism (#139) disables DHCP only for isolated host-mode networks, which also gives up NAT/internet access. This flag covers the shared-mode case.How
vmnet_network_configurationAPI:vmnet_network_configuration_create→set_ipv4_subnet/set_ipv6_prefix/set_external_interface(driven by the existing options) →vmnet_network_configuration_disable_dhcp→vmnet_network_create→vmnet_interface_start_with_network.vmnet_start_interfaceXPC path is used as before.__builtin_available(macOS 26.0, *)), with explicit errors on older SDKs/hosts.--vmnet-gatewaywith--vmnet-mask, sinceset_ipv4_subnettakes the network address (the API reserves the second address of the range for the host).--vmnet-dhcp-end,--vmnet-interface-id,--vmnet-network-identifier) emit a warning instead of being silently ignored. The checks run incli_options_parsebefore defaults are filled in, so only explicitly passed options warn. (Verified on macOS 26.4 thatvmnet_interface_start_with_networkassigns its own interface id even whenvmnet_interface_id_keyis supplied ininterface_desc.)Testing
-Wall -Wextra -pedanticagainst the macOS 26 SDK.test/test-disable-dhcp.sh, wired into the qemu workflow: boots iPXE through the daemon started with--vmnet-disable-dhcpand asserts that no DHCP lease is offered; the daemon is cleaned up via--pidfile.Usage
sudo socket_vmnet --vmnet-gateway=192.168.105.1 --vmnet-disable-dhcp /var/run/socket_vmnet