Add SSZ-REST as an alternative Engine API transport alongside JSON-RPC.
When enabled via --authrpc.ssz-rest (alias: --rest), Geth starts an
additional HTTP server that accepts SSZ-encoded payloads over REST,
cutting wire size ~50% and eliminating JSON encode/decode overhead.
New files:
- beacon/engine/ssz.go: SSZ encoding/decoding for all Engine API types
- beacon/engine/ssz_test.go: round-trip tests for SSZ codecs
- eth/catalyst/ssz_rest.go: SSZ-REST HTTP server with JWT auth
- eth/catalyst/ssz_rest_test.go: server unit tests
Modified files:
- beacon/engine/types.go: CommunicationChannel, ExchangeCapabilitiesV2Response
- eth/catalyst/api.go: ExchangeCapabilitiesV2, getSupportedProtocols, server wiring
- node/config.go, defaults.go: SszRestEnabled, SszRestPort config
- node/jwt_handler.go: exported NewJWTHandler for reuse
- cmd/utils/flags.go, cmd/geth/main.go: CLI flags
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
