Decompiled ifxjdbc.jar (4.50.JC10, build 146, 2023-03-07) with CFR 0.152
into build/jdbc-src/. The decompiled tree is gitignored — it's a
clean-room understanding reference, not shipped code.
Findings landed in two artifacts:
JDBC_NOTES.md — the reverse-lookup index:
- JAR identity (SHA256, manifest, line counts)
- Package layout (com.informix.{asf,jdbc,lang} are the load-bearing
packages; org.bson and the JDBC API surface get ignored)
- Class index mapping each wire-protocol concern to the responsible
Java class. Highlights:
- com.informix.asf.Connection (the wire transport / login PDU)
- com.informix.asf.IfxData{Input,Output}Stream (framing primitives)
- com.informix.jdbc.IfxMessageTypes (140+ message-tag constants)
- com.informix.lang.JavaToIfxType / IfxToJavaType (codecs)
- com.informix.jdbc.IfxSqli / IfxSqliConnect (the SQLI state machine)
- Auth landscape: plain-password is inline in the binary login PDU;
PAM is a server-initiated post-login challenge/response; CSM is
removed from this driver (literally throws an error if you try)
PROTOCOL_NOTES.md — the byte-level wire-format reference:
- Endianness: big-endian, network byte order (confirmed from
JavaToIfxInt source)
- Width table: SmallInt 2B, Int 4B, BigInt 8B, plus the legacy 10-byte
LongInt that we skip for MVP
- 16-bit alignment requirement for variable-length payloads — every
string/decimal/datetime is 0-padded if odd-length, missing this
desynchronizes the parser
- Login PDU structure decoded byte-by-byte from encodeAscBinary():
SLheader (6 bytes) + PFheader with markers 100/101/104/106/107/
108/116/127, capability bitfield, env vars, process info, app name
- Disconnection: bare [short SQ_EXIT=56] both directions, no header
- Post-login messages have NO header — protocol is stream-oriented:
[short tag][payload][short tag][payload]...
- Message-type tag table categorized by purpose
- Open questions list and cross-check matrix tracking what's
JDBC-derived vs PCAP-confirmed
DECISION_LOG.md additions:
- ifxjdbc.jar 4.50.JC10 selected as JDBC reference; CFR 0.152 as decompiler
- CSM is officially dead — never plan for it
- Plain-password auth is single-round-trip (no challenge/response)
- Wire-framing primitives locked in for _protocol.py
- Container credentials: user=informix, password=in4mix, on port 9088,
TLS off
Phase 0 exit gate: criteria #1 (login layout), #2 (message-type tags),
#3 (SELECT 1 hypothesis) are derived from JDBC. PCAP capture (task #7)
and cross-reference (task #2) remaining to corroborate.
Ryan Malloy
1a149074d4