Extend IGMP slice implementation

[JulianSchmid]

Summary by CodeRabbit

• New Features

  • Added IGMP v1/v2/v3 support for parsing and building packets, including access to IGMP headers via transport handling.
  • Added zero-copy, typed IGMP message views (queries, membership reports, leave-group, and unknown IGMP) plus IGMPv3 source/group record iteration.

• Documentation

  • Updated README, crate docs, changelog, and examples to reflect IGMP support and new serialization helpers.

• Tests

  • Expanded slicing, checksum, transport decoding, and packet-composition test coverage for IGMP.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 9dd9d248-0aa3-4247-a9fc-6db266f14259

📥 Commits

Reviewing files that changed from the base of the PR and between ea3f6d3 and 4459414.

📒 Files selected for processing (2)

• etherparse/src/transport/igmp/membership_query_with_sources_slice.rs
• etherparse/src/transport/igmp/membership_report_v2_slice.rs

🚧 Files skipped from review as they are similar to previous changes (2)

• etherparse/src/transport/igmp/membership_report_v2_slice.rs
• etherparse/src/transport/igmp/membership_query_with_sources_slice.rs

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📝 Walkthrough

Walkthrough

IGMP support is extended across typed zero-copy message slices, transport parsing, packet building, payload representations, composition tests, examples, and documentation. IGMPv1/v2/v3 messages now have typed accessors, iterator support, checksum handling, and IPv4/IPv6 transport integration.

Changes

IGMP protocol integration

Layer / File(s)	Summary
Typed IGMP slices and validation etherparse/src/transport/igmp/*slice.rs, etherparse/src/transport/igmp_slice.rs, etherparse/src/transport/igmp/mod.rs	IgmpSlice is now a typed enum covering query, report, leave-group, and unknown messages, with zero-copy accessors and IGMPv3 source/group-record iteration.
Transport parsing and payload variants etherparse/src/transport/transport_*.rs, etherparse/src/sliced_packet_cursor.rs, etherparse/src/lax_*.rs, etherparse/src/packet_headers.rs, etherparse/src/payload_slice.rs	IGMP is represented in transport and payload enums, parsed by packet cursors and header readers, and reported with IGMP-specific length errors.
Packet construction etherparse/src/packet_builder.rs, etherparse/src/transport/igmp_header.rs	PacketBuilder adds IGMP transitions and serialization methods, maps IGMP into IPv4/IPv6 protocol fields, and includes IGMP header sizing and writing.
Composition and support coverage etherparse/src/compositions_tests.rs, etherparse/src/test_gens/mod.rs, etherparse/src/test_packet.rs, etherparse/proptest-regressions/*, etherparse/src/*packet.rs	Composition tests, generators, regression data, and packet helpers now include IGMP transport headers, payloads, protocol values, and round trips.
Documentation and examples README.md, changelog.md, etherparse/src/lib.rs, etherparse/examples/read_by_slicing.rs, etherparse/src/lax_packet_headers.rs	Protocol lists, API references, changelog entries, examples, and parsing documentation describe IGMP support.

Estimated code review effort: 4 (Complex) | ~60 minutes

Possibly related PRs

• JulianSchmid/etherparse#135: Related packet-builder serialization and writer changes.
• JulianSchmid/etherparse#142: Related IGMP header and transport groundwork.
• JulianSchmid/etherparse#148: Related IGMP zero-copy slice and group-record work.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: expanding the IGMP slice implementation and related support.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch igmp-slice-continue

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@etherparse/src/transport/igmp/membership_query_with_sources_slice.rs`:
- Around line 35-38: Update the # Safety documentation for from_slice_unchecked
to require that slice contains the complete declared payload: at least 12 +
num_of_sources * 4 bytes, where num_of_sources is read from the header. Retain
the existing minimum header-length requirement while explicitly covering all
source addresses used by source_addrs_bytes().

In `@etherparse/src/transport/igmp/membership_report_v2_slice.rs`:
- Line 9: Correct the ASCII diagram’s Type field in the IGMPv2 membership report
documentation to 0x16, matching the struct’s documented message type and the
IgmpSlice::from_slice dispatch constant.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 281c47a7-06e9-4b77-b005-a14e393985f6

📥 Commits

Reviewing files that changed from the base of the PR and between f56e12a and ea3f6d3.

📒 Files selected for processing (33)

• README.md
• changelog.md
• etherparse/examples/read_by_slicing.rs
• etherparse/proptest-regressions/compositions_tests.txt
• etherparse/src/compositions_tests.rs
• etherparse/src/lax_packet_headers.rs
• etherparse/src/lax_payload_slice.rs
• etherparse/src/lax_sliced_packet.rs
• etherparse/src/lax_sliced_packet_cursor.rs
• etherparse/src/lib.rs
• etherparse/src/net/ipv6_fragment_header.rs
• etherparse/src/packet_builder.rs
• etherparse/src/packet_headers.rs
• etherparse/src/payload_slice.rs
• etherparse/src/sliced_packet.rs
• etherparse/src/sliced_packet_cursor.rs
• etherparse/src/test_gens/mod.rs
• etherparse/src/test_packet.rs
• etherparse/src/transport/igmp/igmp_unknown_slice.rs
• etherparse/src/transport/igmp/leave_group_slice.rs
• etherparse/src/transport/igmp/membership_query_slice.rs
• etherparse/src/transport/igmp/membership_query_with_sources_slice.rs
• etherparse/src/transport/igmp/membership_report_v1_slice.rs
• etherparse/src/transport/igmp/membership_report_v2_slice.rs
• etherparse/src/transport/igmp/membership_report_v3_slice.rs
• etherparse/src/transport/igmp/mod.rs
• etherparse/src/transport/igmp/report_group_record_v3_slice.rs
• etherparse/src/transport/igmp_header.rs
• etherparse/src/transport/igmp_slice.rs
• etherparse/src/transport/transport_header.rs
• etherparse/src/transport/transport_slice.rs
• etherparse/tests/transport/icmpv4.rs
• etherparse/tests/transport/icmpv6.rs