// Copyright (c) Liam Stanley <me@liamstanley.io>. All rights reserved. Use
// of this source code is governed by the MIT license that can be found in
// the LICENSE file.
package girc
import (
"encoding/json"
"strings"
"sync"
)
// CMode represents a single step of a given mode change.
type CMode struct {
add bool // if it's a +, or -.
name byte // character representation of the given mode.
setting bool // if it's a setting (should be stored) or temporary (op/voice/etc).
args string // arguments to the mode, if arguments are supported.
}
// Short returns a short representation of a mode without arguments. E.g. "+a",
// or "-b".
func (c *CMode) Short() string {
var status string
if c.add {
status = "+"
} else {
status = "-"
}
return status + string(c.name)
}
// String returns a string representation of a mode, including optional
// arguments. E.g. "+b user*!ident@host.*.com"
func (c *CMode) String() string {
if len(c.args) == 0 {
return c.Short()
}
return c.Short() + " " + c.args
}
// CModes is a representation of a set of modes. This may be the given state
// of a channel/user, or the given state changes to a given channel/user.
type CModes struct {
raw string // raw supported modes.
modesListArgs string // modes that add/remove users from lists and support args.
modesArgs string // modes that support args.
modesSetArgs string // modes that support args ONLY when set.
modesNoArgs string // modes that do not support args.
prefixes string // user permission prefixes. these aren't a CMode.setting.
modes []CMode // the list of modes for this given state.
}
// Copy returns a deep copy of CModes.
func (c *CModes) Copy() (nc CModes) {
nc = CModes{}
nc = *c
nc.modes = make([]CMode, len(c.modes))
// Copy modes.
for i := 0; i < len(c.modes); i++ {
nc.modes[i] = c.modes[i]
}
return nc
}
// String returns a complete set of modes for this given state (change?). For
// example, "+a-b+cde some-arg".
func (c *CModes) String() string {
var out string
var args string
if len(c.modes) > 0 {
out += "+"
}
for i := 0; i < len(c.modes); i++ {
out += string(c.modes[i].name)
if len(c.modes[i].args) > 0 {
args += " " + c.modes[i].args
}
}
return out + args
}
// HasMode checks if the CModes state has a given mode. E.g. "m", or "I".
func (c *CModes) HasMode(mode string) bool {
for i := 0; i < len(c.modes); i++ {
if string(c.modes[i].name) == mode {
return true
}
}
return false
}
// Get returns the arguments for a given mode within this session, if it
// supports args.
func (c *CModes) Get(mode string) (args string, ok bool) {
for i := 0; i < len(c.modes); i++ {
if string(c.modes[i].name) == mode {
if len(c.modes[i].args) == 0 {
return "", false
}
return c.modes[i].args, true
}
}
return "", false
}
// hasArg checks to see if the mode supports arguments. What ones support this?:
// A = Mode that adds or removes a nick or address to a list. Always has a parameter.
// B = Mode that changes a setting and always has a parameter.
// C = Mode that changes a setting and only has a parameter when set.
// D = Mode that changes a setting and never has a parameter.
// Note: Modes of type A return the list when there is no parameter present.
// Note: Some clients assumes that any mode not listed is of type D.
// Note: Modes in PREFIX are not listed but could be considered type B.
func (c *CModes) hasArg(set bool, mode byte) (hasArgs, isSetting bool) {
if len(c.raw) < 1 {
return false, true
}
if strings.IndexByte(c.modesListArgs, mode) > -1 {
return true, false
}
if strings.IndexByte(c.modesArgs, mode) > -1 {
return true, true
}
if strings.IndexByte(c.modesSetArgs, mode) > -1 {
if set {
return true, true
}
return false, true
}
if strings.IndexByte(c.prefixes, mode) > -1 {
return true, false
}
return false, true
}
// Apply merges two state changes, or one state change into a state of modes.
// For example, the latter would mean applying an incoming MODE with the modes
// stored for a channel.
func (c *CModes) Apply(modes []CMode) {
var new []CMode
for j := 0; j < len(c.modes); j++ {
isin := false
for i := 0; i < len(modes); i++ {
if !modes[i].setting {
continue
}
if c.modes[j].name == modes[i].name && modes[i].add {
new = append(new, modes[i])
isin = true
break
}
}
if !isin {
new = append(new, c.modes[j])
}
}
for i := 0; i < len(modes); i++ {
if !modes[i].setting || !modes[i].add {
continue
}
isin := false
for j := 0; j < len(new); j++ {
if modes[i].name == new[j].name {
isin = true
break
}
}
if !isin {
new = append(new, modes[i])
}
}
c.modes = new
}
// Parse parses a set of flags and args, returning the necessary list of
// mappings for the mode flags.
func (c *CModes) Parse(flags string, args []string) (out []CMode) {
// add is the mode state we're currently in. Adding, or removing modes.
add := true
var argCount int
for i := 0; i < len(flags); i++ {
if flags[i] == '+' {
add = true
continue
}
if flags[i] == '-' {
add = false
continue
}
mode := CMode{
name: flags[i],
add: add,
}
hasArgs, isSetting := c.hasArg(add, flags[i])
if hasArgs && len(args) >= argCount+1 {
mode.args = args[argCount]
argCount++
}
mode.setting = isSetting
out = append(out, mode)
}
return out
}
// NewCModes returns a new CModes reference. channelModes and userPrefixes
// would be something you see from the server's "CHANMODES" and "PREFIX"
// ISUPPORT capability messages (alternatively, fall back to the standard)
// DefaultPrefixes and ModeDefaults.
func NewCModes(channelModes, userPrefixes string) CModes {
split := strings.SplitN(channelModes, ",", 4)
if len(split) != 4 {
for i := len(split); i < 4; i++ {
split = append(split, "")
}
}
return CModes{
raw: channelModes,
modesListArgs: split[0],
modesArgs: split[1],
modesSetArgs: split[2],
modesNoArgs: split[3],
prefixes: userPrefixes,
modes: []CMode{},
}
}
// IsValidChannelMode validates a channel mode (CHANMODES).
func IsValidChannelMode(raw string) bool {
if len(raw) < 1 {
return false
}
for i := 0; i < len(raw); i++ {
// Allowed are: ",", A-Z and a-z.
if raw[i] != ',' && (raw[i] < 'A' || raw[i] > 'Z') && (raw[i] < 'a' || raw[i] > 'z') {
return false
}
}
return true
}
// isValidUserPrefix validates a list of ISUPPORT-style user prefixes (PREFIX).
func isValidUserPrefix(raw string) bool {
if len(raw) < 1 {
return false
}
if raw[0] != '(' {
return false
}
var keys, rep int
var passedKeys bool
// Skip the first one as we know it's (.
for i := 1; i < len(raw); i++ {
if raw[i] == ')' {
passedKeys = true
continue
}
if passedKeys {
rep++
} else {
keys++
}
}
return keys == rep
}
// parsePrefixes parses the mode character mappings from the symbols of a
// ISUPPORT-style user prefixes list (PREFIX).
func parsePrefixes(raw string) (modes, prefixes string) {
if !isValidUserPrefix(raw) {
return modes, prefixes
}
i := strings.Index(raw, ")")
if i < 1 {
return modes, prefixes
}
return raw[1:i], raw[i+1:]
}
// handleMODE handles incoming MODE messages, and updates the tracking
// information for each channel, as well as if any of the modes affect user
// permissions.
func handleMODE(c *Client, e Event) {
// Check if it's a RPL_CHANNELMODEIS.
if e.Command == RPL_CHANNELMODEIS && len(e.Params) > 2 {
// RPL_CHANNELMODEIS sends the user as the first param, skip it.
e.Params = e.Params[1:]
}
// Should be at least MODE <target> <flags>, to be useful. As well, only
// tracking channel modes at the moment.
if len(e.Params) < 2 || !IsValidChannel(e.Params[0]) {
return
}
c.state.RLock()
channel := c.state.lookupChannel(e.Params[0])
if channel == nil {
c.state.RUnlock()
return
}
flags := e.Params[1]
var args []string
if len(e.Params) > 2 {
args = append(args, e.Params[2:]...)
}
modes := channel.Modes.Parse(flags, args)
channel.Modes.Apply(modes)
// Loop through and update users modes as necessary.
for i := 0; i < len(modes); i++ {
if modes[i].setting || len(modes[i].args) == 0 {
continue
}
user := c.state.lookupUser(modes[i].args)
if user != nil {
perms, _ := user.Perms.Lookup(channel.Name)
perms.setFromMode(modes[i])
user.Perms.set(channel.Name, perms)
}
}
c.state.RUnlock()
c.state.notify(c, UPDATE_STATE)
}
// chanModes returns the ISUPPORT list of server-supported channel modes,
// alternatively falling back to ModeDefaults.
func (s *state) chanModes() string {
if modes, ok := s.serverOptions["CHANMODES"]; ok && IsValidChannelMode(modes) {
return modes
}
return ModeDefaults
}
// userPrefixes returns the ISUPPORT list of server-supported user prefixes.
// This includes mode characters, as well as user prefix symbols. Falls back
// to DefaultPrefixes if not server-supported.
func (s *state) userPrefixes() string {
if prefix, ok := s.serverOptions["PREFIX"]; ok && isValidUserPrefix(prefix) {
return prefix
}
return DefaultPrefixes
}
// UserPerms contains all of the permissions for each channel the user is
// in.
type UserPerms struct {
mu sync.RWMutex
channels map[string]Perms
}
// Copy returns a deep copy of the channel permissions.
func (p *UserPerms) Copy() (perms *UserPerms) {
np := &UserPerms{
channels: make(map[string]Perms),
}
p.mu.RLock()
for key := range p.channels {
np.channels[key] = p.channels[key]
}
p.mu.RUnlock()
return np
}
// MarshalJSON implements json.Marshaler.
func (p *UserPerms) MarshalJSON() ([]byte, error) {
p.mu.Lock()
out, err := json.Marshal(&p.channels)
p.mu.Unlock()
return out, err
}
// Lookup looks up the users permissions for a given channel. ok is false
// if the user is not in the given channel.
func (p *UserPerms) Lookup(channel string) (perms Perms, ok bool) {
p.mu.RLock()
perms, ok = p.channels[ToRFC1459(channel)]
p.mu.RUnlock()
return perms, ok
}
func (p *UserPerms) set(channel string, perms Perms) {
p.mu.Lock()
p.channels[ToRFC1459(channel)] = perms
p.mu.Unlock()
}
func (p *UserPerms) remove(channel string) {
p.mu.Lock()
delete(p.channels, ToRFC1459(channel))
p.mu.Unlock()
}
// Perms contains all channel-based user permissions. The minimum op, and
// voice should be supported on all networks. This also supports non-rfc
// Owner, Admin, and HalfOp, if the network has support for it.
type Perms struct {
// Owner (non-rfc) indicates that the user has full permissions to the
// channel. More than one user can have owner permission.
Owner bool `json:"owner"`
// Admin (non-rfc) is commonly given to users that are trusted enough
// to manage channel permissions, as well as higher level service settings.
Admin bool `json:"admin"`
// Op is commonly given to trusted users who can manage a given channel
// by kicking, and banning users.
Op bool `json:"op"`
// HalfOp (non-rfc) is commonly used to give users permissions like the
// ability to kick, without giving them greater abilities to ban all users.
HalfOp bool `json:"half_op"`
// Voice indicates the user has voice permissions, commonly given to known
// users, with very light trust, or to indicate a user is active.
Voice bool `json:"voice"`
}
// IsAdmin indicates that the user has banning abilities, and are likely a
// very trustable user (e.g. op+).
func (m Perms) IsAdmin() bool {
if m.Owner || m.Admin || m.Op {
return true
}
return false
}
// IsTrusted indicates that the user at least has modes set upon them, higher
// than a regular joining user.
func (m Perms) IsTrusted() bool {
if m.IsAdmin() || m.HalfOp || m.Voice {
return true
}
return false
}
// reset resets the modes of a user.
func (m *Perms) reset() {
m.Owner = false
m.Admin = false
m.Op = false
m.HalfOp = false
m.Voice = false
}
// set translates raw prefix characters into proper permissions. Only
// use this function when you have a session lock.
func (m *Perms) set(prefix string, append bool) {
if !append {
m.reset()
}
for i := 0; i < len(prefix); i++ {
switch string(prefix[i]) {
case OwnerPrefix:
m.Owner = true
case AdminPrefix:
m.Admin = true
case OperatorPrefix:
m.Op = true
case HalfOperatorPrefix:
m.HalfOp = true
case VoicePrefix:
m.Voice = true
}
}
}
// setFromMode sets user-permissions based on channel user mode chars. E.g.
// "o" being oper, "v" being voice, etc.
func (m *Perms) setFromMode(mode CMode) {
switch string(mode.name) {
case ModeOwner:
m.Owner = mode.add
case ModeAdmin:
m.Admin = mode.add
case ModeOperator:
m.Op = mode.add
case ModeHalfOperator:
m.HalfOp = mode.add
case ModeVoice:
m.Voice = mode.add
}
}
// parseUserPrefix parses a raw mode line, like "@user" or "@+user".
func parseUserPrefix(raw string) (modes, nick string, success bool) {
for i := 0; i < len(raw); i++ {
char := string(raw[i])
if char == OwnerPrefix || char == AdminPrefix || char == HalfOperatorPrefix ||
char == OperatorPrefix || char == VoicePrefix {
modes += char
continue
}
// Assume we've gotten to the nickname part.
return modes, raw[i:], true
}
return
}