6.6 KiB
ABNF from rfc2812:
message = [ ":" prefix SPACE ] command [ params ] crlf
prefix = servername / ( nickname [ [ "!" user ] "@" host ] )
command = 1*letter / 3digit
params = *14( SPACE middle ) [ SPACE ":" trailing ]
=/ 14( SPACE middle ) [ SPACE [ ":" ] trailing ]
nospcrlfcl = %x01-09 / %x0B-0C / %x0E-1F / %x21-39 / %x3B-FF
; any octet except NUL, CR, LF, " " and ":"
middle = nospcrlfcl *( ":" / nospcrlfcl )
trailing = *( ":" / " " / nospcrlfcl )
SPACE = %x20 ; space character
crlf = %x0D %x0A ; "carriage return" "linefeed"
target = nickname / server
msgtarget = msgto *( "," msgto )
msgto = channel / ( user [ "%" host ] "@" servername )
msgto =/ ( user "%" host ) / targetmask
msgto =/ nickname / ( nickname "!" user "@" host )
channel = ( "#" / "+" / ( "!" channelid ) / "&" ) chanstring
[ ":" chanstring ]
servername = hostname
host = hostname / hostaddr
hostname = shortname *( "." shortname )
shortname = ( letter / digit ) *( letter / digit / "-" )
*( letter / digit )
; as specified in RFC 1123 [HNAME]
hostaddr = ip4addr / ip6addr
ip4addr = 1*3digit "." 1*3digit "." 1*3digit "." 1*3digit
ip6addr = 1*hexdigit 7( ":" 1*hexdigit )
ip6addr =/ "0:0:0:0:0:" ( "0" / "FFFF" ) ":" ip4addr
nickname = ( letter / special ) *8( letter / digit / special / "-" )
targetmask = ( "$" / "#" ) mask
; see details on allowed masks in section 3.3.1
chanstring = %x01-07 / %x08-09 / %x0B-0C / %x0E-1F / %x21-2B
chanstring =/ %x2D-39 / %x3B-FF
; any octet except NUL, BELL, CR, LF, " ", "," and ":"
channelid = 5( %x41-5A / digit ) ; 5( A-Z / 0-9 )
user = 1*( %x01-09 / %x0B-0C / %x0E-1F / %x21-3F / %x41-FF )
; any octet except NUL, CR, LF, " " and "@"
key = 1*23( %x01-05 / %x07-08 / %x0C / %x0E-1F / %x21-7F )
; any 7-bit US_ASCII character,
; except NUL, CR, LF, FF, h/v TABs, and " "
letter = %x41-5A / %x61-7A ; A-Z / a-z
digit = %x30-39 ; 0-9
hexdigit = digit / "A" / "B" / "C" / "D" / "E" / "F"
special = %x5B-60 / %x7B-7D
; "[", "]", "\", "`", "_", "^", "{", "|", "}"
mask = *( nowild / noesc wildone / noesc wildmany )
wildone = %x3F
wildmany = %x2A
nowild = %x01-29 / %x2B-3E / %x40-FF
; any octet except NUL, "*", "?"
noesc = %x01-5B / %x5D-FF
; any octet except NUL and "\"
matchone = %x01-FF
; matches wildone
matchmany = *matchone
; matches wildmany
Examples:
a?c ; Matches any string of 3 characters in length starting
with "a" and ending with "c"
a*c ; Matches any string of at least 2 characters in length
starting with "a" and ending with "c"
Server State
-
List of local connections, which may belong to clients (users and services) or other servers
-
List of servers in the network
- Server name, max of 63 chars
- Hostmasks can group servers with matching names into a 'virtual server' seen by non-matching servers
- Hopcount
- Peer identifier token
- Link flags
-
List of clients in the network
- Network-unique identifier; format depends on type
- Server to which the client is connected
-
List of users in the network
- Has a unique nickname on the network (std says 9 chars max)
- Name of the host the user is running on
- Username of user on that host
- Server the user is connected to
-
List of services in the network known by the server
- Service name = nickname + server name
- Service type
-
List of channels in the network known by the server
- Channel name (prefix + up to 49 other chars)
- Channel members
- Channel modes
-
Recent nickname changes
-
Nickname re-use delay
Connection State
-
A new connection starts out as Unregistered
-
A password before registering is optional
-
Connection can register as a user, service, or server
-
Once registered, a client is told the id it was registered with
-
Idle connections are periodically sent a PING and are disconnected if a PONG is not received in reply
-
Flood control applicability and timer information
User State
-
User has a nickname that is first set during registration, but can later change.
-
User has mode flags that can also be set during registration and change during operation.
- a: away (set by AWAY, not MODE)
- i: invisible
- w: receives wallops
- r: restricted connection (can't be cleared with MODE, but can be set)
- o: operator (set by OPER, cleared with MODE)
- O: local operator (set by OPER, cleared with MODE)
- s: receives server notices
-
User has a user name, hostname, and real name. These are set at registration and do not change thereafter.
-
User has a hopcount to determine distance from local server
-
Connection by which user can be sent messages
Service State
-
Service name
-
Servertoken
-
Distribution mask
-
Hopcount
-
Type
Channel State
-
Channels are typically created when users join them
-
Services cannot join channels
-
A channel has a name
- Up to 50 chars, first char is prefix
- &: local to single server
- #: normal distribution
- +: no channel modes
- !: safe channels
-
A channel (that is not a local-only channel) may have a channel mask to limit distribution
-
A channel has a topic
-
A channel has a set of joined users
-
Channels may require keys to join
-
Channels have modes, some of which are flags and some of which are records of management-related data, such as a list of channel ops.
-
Channels may keep track of users that have been invited when they are set +i (invite-only)
Connection Registration
Valid combinations of registration commands are:
NICK -> USER
PASS -> NICK -> USER
NICK -> PASS -> USER
PASS -> SERVICE
SERVICE
When registration succeeds for a user, the server sends the following:
RPL_WELCOME
RPL_YOURHOST
RPL_CREATED
RPL_MYINFO
LUSER
MOTD
When registration succeds for a service, the server sends the following:
RPL_YOURESERVICE
RPL_YOURHOST
RPL_MYINFO
The server then informs any other servers it is connected to of the new client.