Switch config

The switch config gives every machine its virtual address and says who may talk to whom. The conductor reads it from VNET_CONFIG_PATH and sends it to every switch (Configuration). vnet-roster writes it as switch.txt.

Format

One entry per line, two words separated by spaces or tabs. Blank lines and lines whose first non-blank character is # are ignored; anything after the second word is ignored. Windows line endings are accepted. Entries may come in any order.

<agent> <a.b.c.d>

Gives the agent this virtual address. Each agent and each address appears once.

<agent> <agent>

The two machines may talk to each other, in both directions, with any protocol and port.

<agent> ::internet:<a.b.c.d> or <agent> ::internet:<a.b.c.d/n>

The machine may reach this internet address, or every address in the prefix, and receive the replies. ::internet:0.0.0.0/0 is the whole internet.

Agent names are 1 to 10 characters from [A-Za-z0-9_-]. A rule may only name agents that have an address. Give every address inside the overlay prefix (10.0.0.0/8 unless VNET_OVERLAY_CIDR says otherwise).

Example

# virtual addresses
judge   10.0.0.1
c001    10.0.1.1
c002    10.0.1.2

# contestants reach the judge, not each other
c001    judge
c002    judge

# the judge reaches the internet; c001 one address
judge   ::internet:0.0.0.0/0
c001    ::internet:192.0.2.80

Errors

A file with an error is refused as a whole; at start the program stops, on a reload the previous config stays in force. The log names the line:

Message	Cause
line N: expected two tokens, got '...'	a line with one word
line N: invalid IPv4 '...'	0.0.0.0 as a virtual address
line N: agent name '...' must be 1 to 10 characters from [A-Za-z0-9_-]	a name too long or with other characters
line N: duplicate IP a.b.c.d	two machines with one address
line N: duplicate agent name '...'	one machine with two addresses
line N: unknown agent '...'	a rule names a machine that has no address line, or a misspelled address (10.0.1.300 is read as a name)
line N: invalid internet address in '...'	a malformed ::internet: address or prefix

When it parses, the program logs [Config] Loaded N agent(s), M with agent ACLs, K with internet ACLs.

Fingerprint

The fingerprint is a SHA-256 of the parsed entries in a fixed order: comments, blank lines, order and the direction in which a pair is written do not change it. The logs show its first 12 hex digits.