#
proc tls::callback {option args} {
    variable debug

    #log 2 [concat $option $args]

    switch -- $option {
	"error" {
	    foreach {chan msg} $args break

	    log 0 "TLS/$chan: error: $msg"
	}
	"info" {
	    # poor man's lassign
	    foreach {chan major minor state msg type} $args break

	    if {$msg != ""} {
		append state ": $msg"
	    }
	    # For tracing
	    upvar #0 tls::$chan cb
	    set cb($major) $minor

	    log 2 "TLS/$chan: $major/$minor: $state"
	}
	"session" {
	    foreach {session_id ticket lifetime} $args break

	    log 0 "TLS/$chan: error: $msg"
	}
	default	{
	    return -code error "bad option \"$option\":\
		    must be one of error, info, or session"
	}
    }
}

#
# Sample callback when return value is needed
#
proc tls::validate_command {option args} {
    variable debug

    #log 2 [concat $option $args]

    switch -- $option {
	"alpn" {
	    foreach {protocol} $args break

	    log 0 "TLS/$chan: alpn: $protocol"
	}
	"hello" {
	    foreach {servername} $args break

	    log 0 "TLS/$chan: hello: $servername"
	}
	"sni" {
	    foreach {servername} $args break

	    log 0 "TLS/$chan: sni: $servername"
	}
	"verify" {
	    # poor man's lassign
	    foreach {chan depth cert rc err} $args break

	    array set c $cert

	    if {$rc != "1"} {
		log 1 "TLS/$chan: verify/$depth: Bad Cert: $err (rc = $rc)"
	    } else {
		log 2 "TLS/$chan: verify/$depth: $c(subject)"
	    }
	    if {$debug > 0} {
		return 1;	# FORCE OK
	    } else {
		return $rc
	    }
	}













	default	{
	    return -code error "bad option \"$option\":\
		    must be one of alpn, info, or verify"
	}
    }
    return 1
}

proc tls::xhandshake {chan} {
    upvar #0 tls::$chan cb

    if {[info exists cb(handshake)] && \
	$cb(handshake) == "done"} {