[phantom] Guard against partially-written status descriptors
[people/dverkamp/gpxe.git] / src / drivers / net / phantom / phantom.c
index 93675e3..93fc079 100644 (file)
@@ -1445,9 +1445,20 @@ static void phantom_poll ( struct net_device *netdev ) {
 
                /* Check received opcode */
                sds_opcode = NX_GET ( sds, opcode );
-               switch ( sds_opcode ) {
-               case UNM_RXPKT_DESC:
-               case UNM_SYN_OFFLOAD:
+               if ( ( sds_opcode == UNM_RXPKT_DESC ) ||
+                    ( sds_opcode == UNM_SYN_OFFLOAD ) ) {
+
+                       /* Sanity check: ensure that all of the SDS
+                        * descriptor has been written.
+                        */
+                       if ( NX_GET ( sds, total_length ) == 0 ) {
+                               DBGC ( phantom, "Phantom %p port %d SDS %d "
+                                      "incomplete; deferring\n", phantom,
+                                      phantom_port->port, sds_consumer_idx );
+                               /* Leave for next poll() */
+                               break;
+                       }
+
                        /* Process received packet */
                        sds_handle = NX_GET ( sds, handle );
                        iobuf = phantom_port->rds_iobuf[sds_handle];
@@ -1459,25 +1470,27 @@ static void phantom_poll ( struct net_device *netdev ) {
                                phantom, phantom_port->port, sds_handle );
                        netdev_rx ( netdev, iobuf );
                        phantom_port->rds_iobuf[sds_handle] = NULL;
-                       break;
-               default:
+
+                       /* Update RDS consumer counter.  This is a
+                        * lower bound for the number of descriptors
+                        * that have been read by the hardware, since
+                        * the hardware must have read at least one
+                        * descriptor for each completion that we
+                        * receive.
+                        */
+                       rds_consumer_idx =
+                               ( ( rds_consumer_idx + 1 ) % PHN_NUM_RDS );
+                       phantom_port->rds_consumer_idx = rds_consumer_idx;
+
+               } else {
+
                        DBGC ( phantom, "Phantom %p port %d unexpected SDS "
                               "opcode %02x\n",
                               phantom, phantom_port->port, sds_opcode );
                        DBGC_HDA ( phantom, virt_to_bus ( sds ),
                                   sds, sizeof ( *sds ) );
-                       break;
                }
                        
-               /* Update RDS consumer counter.  This is a lower bound
-                * for the number of descriptors that have been read
-                * by the hardware, since the hardware must have read
-                * at least one descriptor for each completion that we
-                * receive.
-                */
-               rds_consumer_idx = ( ( rds_consumer_idx + 1 ) % PHN_NUM_RDS );
-               phantom_port->rds_consumer_idx = rds_consumer_idx;
-
                /* Clear status descriptor */
                memset ( sds, 0, sizeof ( *sds ) );