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CONTACTS.md

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Supported Chaosnet protocols

The following Chaosnet contacts (protocol names) have built-in support in the bridge program. Additional protocols may be supported through the NCP.

DUMP-ROUTING-TABLE

The bridge responds to the DUMP-ROUTING-TABLE contact, which sends the routing table (for subnets up to nr 122). This is used by e.g. the functions CHAOS:SHOW-ROUTING-PATH and CHAOS:SHOW-ROUTING-TABLE on LMI systems, the CHAOS:PRINT-ROUTING-TABLE function on Symbolics systems, and if you're lucky, the DUMP-ROUTING-TABLE command of the CHATST program in ITS.

STATUS

It also responds to the STATUS protocol (see AI Memo 628), using the host name from the "myname" configuration parameter (defaults to the DNS name of the configured Chaosnet address (the "chaddr" parameter), or the "real" host name, up to first period).

TIME and UPTIME

It also responds to TIME and UPTIME contacts. Note that UPTIME is wrt the start of the bridge program, which is more interesting than the host uptime (e.g. wrt the STATUS statistics).

LASTCN

A non-standard contact LASTCN is also supported, which reponds with info about which hosts the bridge has received packets from, from what other host (e.g. another router) and how long ago. Each entry consists of the following 16-bit words:

  1. length of entry in 16-bit words (8)
  2. host addr which was seen
  3. # input pkts from that (least significant 16 bits)
  4. (most significant 16 bits)
  5. address the host was last seen from (e.g. a bridge)
  6. how many seconds ago was the host seen (LSB 16 bits)
  7. (MSB 16 bits)
  8. the forwarding count field of the last seen packet

DNS

A non-standard contact DNS is also supported, which responds to a "simple" protocol. The contact string is "DNS" followed by a space and then the DNS query packet. The cbridge process, if configured for it, forwards the query to a DNS server (over IP/UDP) and sends the response as an ANS packet to the (Chaosnet) requester. Because of the packet size limit, queries and responses are also limited in size.

There is also a (separate) server for the DOMAIN contact which allows DNS queries over a stream connection, lifting the size limit. This is more standard, used by Symbolics lisp machines, and (soon) by the Bogodyne lisp system.

A client implementation (for both protocols) for the LambdaDelta lisp machine exists, which could prossibly be ported to the CADR system (which doesn't have IP).

See also https://chaosnet.net for info about DNS for Chaosnet data.