* fix(dns): resolve CNAME chains and prevent invalid IP parsing
- Add automated in-band CNAME chain resolution to extract final A/AAAA IP addresses.
- Replace `MaxResponseAnswers` with `MaxIPs` and `MaxCNAMEs` to explicitly bound resource decoding and prevent memory exhaustion.
- Bound CNAME chain traversal to prevent infinite loops from cyclic records.
* refactor(dns): eagerly decode CNAME target into r.data, drop target field
Address review feedback on #189:
- Remove Resource.target: Resource.Decode expands CNAME RDATA in place
into r.data (uncompressed wire format) while the full message is still
available and updates header.Length, storing the name bytes exactly once.
- Add Resource.CNAMEView returning a length-bounded view of the expanded
target; Message.WriteAnswers uses it.
- Rename matchesHost to ResourceHeader.pertainsTo.
- Make ResolveConfig.MaxCNAMEs explicit: drop the silent default in
Client.StartResolve and let callers opt in (x/xnet).
- Reduce test suite to regression coverage only.
refs #189
* dns: simplify @hnw function and additional fixes
---------
Co-authored-by: Yoshio HANAWA <y@hnw.jp>
* pcap: reuse Frame memory
* slog: reduce heap allocations of addresses; also prevent heap alloc of dhcp options in pcap
* dns: heapless improvement; add StackAsync buffer for more heapless operation; start thinking of errors
* errors: begin standardise errors in lneto
* errors: finish standardization of errors
* fix merge issues
* add more lneto errors to rest of package
* format errors.go
Pat Whittingslow