IRCv3 SASL capability + PLAIN method

Only plain, no other methods. We don't have built-in SSL to implement
EXTERNAL (certfp) and nothing else is worth implementing.

The actual authentication is pretty much like sending a server password
(when the server's authmode isn't closed), which means it happens in
cmd_identify, but this code also calls storage_check_pass() to send the
required success/failure replies.

SASL doesn't give us much benefit other than standards compliance, but
some clients might appreciate it.

And having a fifth way to do the same thing doesn't hurt! Now we have:

- identify in &bitlbee
- identify to nickserv (alias for root)
- 'nickserv' and 'ns' irc commands
- server password
- sasl plain

1 files changed, 7 insertions, 0 deletions

diff --git a/irc_cap.c b/irc_cap.c
index 79732409..4cfc158b 100644
--- a/irc_cap.c
+++ b/irc_cap.c
@@ -37,6 +37,7 @@ typedef struct {
 } cap_info_t;
 
 static const cap_info_t supported_caps[] = {
+	{"sasl", CAP_SASL},
 	{"multi-prefix", CAP_MULTI_PREFIX},
 	{NULL},
 };
@@ -169,6 +170,12 @@ void irc_cmd_cap(irc_t *irc, char **cmd)
 
 	} else if (g_strcasecmp(cmd[1], "END") == 0) {
 		irc->status &= ~USTATUS_CAP_PENDING;
+
+		if (irc->status & USTATUS_SASL_PLAIN_PENDING) {
+			irc_send_num(irc, 906, ":SASL authentication aborted");
+			irc->status &= ~USTATUS_SASL_PLAIN_PENDING;
+		}
+
 		irc_check_login(irc);
 
 	} else {