should discard packet when received AUTH header length < 20 ?

[WANG Tinggong]

hi all,
	
in src/main/listen.c , auth_socket_recv function, rad_recv_header uses MSG_PEEK
flag. in case 0 <= rcode < 20, malfromed request still in the receive queue, 
should it be cleaned before line 757 ?

 751         rcode = rad_recv_header(listener->fd, &src_ipaddr, &src_port, &code     ); 
 752         if (rcode < 0) return 0;
 753    
 754         RAD_STATS_TYPE_INC(listener, total_requests);
 755    
 756         if (rcode < 20) {       /* AUTH_HDR_LEN */
 757                 RAD_STATS_TYPE_INC(listener, total_malformed_requests);
 758                 return 0;
 759         }

here is my patch against branch v2.1.x , does it make sense? 

thanks
Tinggong

---
 src/main/listen.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/src/main/listen.c b/src/main/listen.c
index 59ff314..855ee9c 100644
--- a/src/main/listen.c
+++ b/src/main/listen.c
@@ -754,6 +754,7 @@ static int auth_socket_recv(rad_listen_t *listener,
        RAD_STATS_TYPE_INC(listener, total_requests);
 
        if (rcode < 20) {       /* AUTH_HDR_LEN */
+               rad_recv_discard(listener->fd);
                RAD_STATS_TYPE_INC(listener, total_malformed_requests);
                return 0;
        }