RFC 9000 §5.1.1 + §19.15: a client SHOULD advertise spare source
CIDs to the peer via NEW_CONNECTION_ID frames so the peer has
DCIDs available for path migration / NAT rebind. Strict server
stacks (quic-go, picoquic, msquic, mvfst) refuse to validate a new
client path until they have a spare DCID — server log shows
"skipping validation of new path … since no connection ID is
available". Quinn migrates on src-port-change alone, which is why
rebind-port / rebind-addr passed against quinn pre-fix and failed
against the others.
Adds:
- IssuedSourceConnectionIdEntry (data class) — sequence + CID +
stateless-reset token tuple.
- QuicConnection.issuedSourceConnectionIds (LinkedHashMap) — pool
of currently-active issued SCIDs, seeded with seq=0 (the
initial CID, no token because the stateless_reset_token TP is
server-only per RFC 9000 §18.2).
- QuicConnection.issueOwnConnectionIdsLocked(count) — drives the
initial issuance once handshake is confirmed; appends recovery
tokens to pendingOwnNewConnectionIdEmits for the writer to emit.
- QuicConnection.issueOwnReplacementSourceCidLocked() — top-up
after each peer RETIRE_CONNECTION_ID so the pool stays at
full capacity for repeated migrations.
- QuicConnectionWriter — once handshakeConfirmed flips, calls
issueOwnConnectionIdsLocked with `peer.activeConnectionIdLimit
- 1` (cap 7); drains pendingOwnNewConnectionIdEmits as fresh
NEW_CONNECTION_ID frames; the existing pendingNewConnectionId
map continues to handle loss-recovery retransmits.
- applyPeerRetireConnectionIdLocked — three cases: in-pool seq
is freed and replaced; below-next-seq missing seq is benign
retransmit; above-next-seq is PROTOCOL_VIOLATION (peer
retiring something we never advertised).
Verified against the live interop runner:
- quic-go rebind-port: 2/2 (was 0/N — Task 2). Now passes in ~64s.
- quic-go rebind-addr: 2/2 (was 0/N). Now passes in ~125-138s.
- picoquic rebind-port: 2/2.
- picoquic rebind-addr: 1/2 (flaky — separate investigation;
one run the connection migrates correctly, the other times
out at 110s; not blocking the rebind-port / quic-go win).
- picoquic connectionmigration: 0/2 still failing (the runner's
"active migration" testcase exercises a more sophisticated
migration shape — TBD; tracked separately).
Tests: IssuedSourceConnectionIdTest (5 cases pinning the
post-handshake emission, peer-RETIRE replacement, retransmit
tolerance, and protocol-violation closure for above-next-seq retires).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Vitor Pamplona
0920aba2b8