Add support for TAGMSG and client message tags

Previously we dropped all TAGMSG as well as any client message tag sent
from downstream.

This adds support for properly forwarding TAGMSG and client message tags
from downstreams and upstreams.

TAGMSG messages are intentionally not logged, because they are currently
typically used for +typing, which can generate a lot of traffic and is
only useful for a few seconds after it is sent.

downstream.go

@@ -250,6 +250,9 @@ func (dc *downstreamConn) readMessages(ch chan<- event) error {
 // This can only called from the user goroutine.
 func (dc *downstreamConn) SendMessage(msg *irc.Message) {
 	if !dc.caps["message-tags"] {
+		if msg.Command == "TAGMSG" {
+			return
+		}
 		msg = msg.Copy()
 		for name := range msg.Tags {
 			supported := false
@@ -274,7 +277,7 @@ func (dc *downstreamConn) marshalMessage(msg *irc.Message, net *network) *irc.Me
 	msg.Prefix = dc.marshalUserPrefix(net, msg.Prefix)
 
 	switch msg.Command {
-	case "PRIVMSG", "NOTICE":
+	case "PRIVMSG", "NOTICE", "TAGMSG":
 		msg.Params[0] = dc.marshalEntity(net, msg.Params[0])
 	case "NICK":
 		// Nick change for another user
@@ -1397,6 +1400,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 		if err := parseMessageParams(msg, &targetsStr, &text); err != nil {
 			return err
 		}
+		tags := copyClientTags(msg.Tags)
 
 		for _, name := range strings.Split(targetsStr, ",") {
 			if name == serviceNick {
@@ -1418,14 +1422,15 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				unmarshaledText = dc.unmarshalText(uc, text)
 			}
 			uc.SendMessageLabeled(dc.id, &irc.Message{
+				Tags:    tags,
 				Command: "PRIVMSG",
 				Params:  []string{upstreamName, unmarshaledText},
 			})
 
+			echoTags := tags.Copy()
+			echoTags["time"] = irc.TagValue(time.Now().UTC().Format(serverTimeLayout))
 			echoMsg := &irc.Message{
-				Tags: irc.Tags{
+				Tags: echoTags,
-					"time": irc.TagValue(time.Now().UTC().Format(serverTimeLayout)),
-				},
 				Prefix: &irc.Prefix{
 					Name: uc.nick,
 					User: uc.username,
@@ -1440,6 +1445,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 		if err := parseMessageParams(msg, &targetsStr, &text); err != nil {
 			return err
 		}
+		tags := copyClientTags(msg.Tags)
 
 		for _, name := range strings.Split(targetsStr, ",") {
 			uc, upstreamName, err := dc.unmarshalEntity(name)
@@ -1452,10 +1458,30 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				unmarshaledText = dc.unmarshalText(uc, text)
 			}
 			uc.SendMessageLabeled(dc.id, &irc.Message{
+				Tags:    tags,
 				Command: "NOTICE",
 				Params:  []string{upstreamName, unmarshaledText},
 			})
 		}
+	case "TAGMSG":
+		var targetsStr string
+		if err := parseMessageParams(msg, &targetsStr); err != nil {
+			return err
+		}
+		tags := copyClientTags(msg.Tags)
+
+		for _, name := range strings.Split(targetsStr, ",") {
+			uc, upstreamName, err := dc.unmarshalEntity(name)
+			if err != nil {
+				return err
+			}
+
+			uc.SendMessageLabeled(dc.id, &irc.Message{
+				Tags:    tags,
+				Command: "TAGMSG",
+				Params:  []string{upstreamName},
+			})
+		}
 	case "INVITE":
 		var user, channel string
 		if err := parseMessageParams(msg, &user, &channel); err != nil {

irc.go

@@ -274,6 +274,16 @@ func parseMessageParams(msg *irc.Message, out ...*string) error {
 	return nil
 }
 
+func copyClientTags(tags irc.Tags) irc.Tags {
+	t := make(irc.Tags, len(tags))
+	for k, v := range tags {
+		if strings.HasPrefix(k, "+") {
+			t[k] = v
+		}
+	}
+	return t
+}
+
 type batch struct {
 	Type   string
 	Params []string

upstream.go

@@ -320,14 +320,20 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			Params:  msg.Params,
 		})
 		return nil
-	case "NOTICE", "PRIVMSG":
+	case "NOTICE", "PRIVMSG", "TAGMSG":
 		if msg.Prefix == nil {
 			return fmt.Errorf("expected a prefix")
 		}
 
 		var entity, text string
-		if err := parseMessageParams(msg, &entity, &text); err != nil {
+		if msg.Command != "TAGMSG" {
-			return err
+			if err := parseMessageParams(msg, &entity, &text); err != nil {
+				return err
+			}
+		} else {
+			if err := parseMessageParams(msg, &entity); err != nil {
+				return err
+			}
 		}
 
 		if msg.Prefix.Name == serviceNick {
@@ -341,7 +347,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 
 		if msg.Prefix.User == "" && msg.Prefix.Host == "" { // server message
 			uc.produce("", msg, nil)
-		} else { // regular user NOTICE or PRIVMSG
+		} else { // regular user message
 			target := entity
 			if target == uc.nick {
 				target = msg.Prefix.Name
@@ -1274,8 +1280,6 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 				})
 			})
 		}
-	case "TAGMSG":
-		// TODO: relay to downstream connections that accept message-tags
 	case "ACK":
 		// Ignore
 	case irc.RPL_NOWAWAY, irc.RPL_UNAWAY:
@@ -1487,6 +1491,15 @@ func (uc *upstreamConn) readMessages(ch chan<- event) error {
 	return nil
 }
 
+func (uc *upstreamConn) SendMessage(msg *irc.Message) {
+	if !uc.caps["message-tags"] {
+		msg = msg.Copy()
+		msg.Tags = nil
+	}
+
+	uc.conn.SendMessage(msg)
+}
+
 func (uc *upstreamConn) SendMessageLabeled(downstreamID uint64, msg *irc.Message) {
 	if uc.caps["labeled-response"] {
 		if msg.Tags == nil {