[PATCH v3 11/11] net: cadence_gem: Fix RX address filtering

[Sai Pavan Boddu]

From: Tong Ho <address@hidden>

Two defects are fixed:

1/ Detection of multicast frames
2/ Treating drop of mis-addressed frames as non-error

Signed-off-by: Tong Ho <address@hidden>
Signed-off-by: Edgar E. Iglesias <address@hidden>
Signed-off-by: Sai Pavan Boddu <address@hidden>
Reviewed-by: Edgar E. Iglesias <address@hidden>
---
 hw/net/cadence_gem.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index f8cea63..ccd087d 100644
--- a/hw/net/cadence_gem.c
+++ b/hw/net/cadence_gem.c
@@ -34,6 +34,7 @@
 #include "qemu/module.h"
 #include "sysemu/dma.h"
 #include "net/checksum.h"
+#include "net/eth.h"
 
 #define CADENCE_GEM_ERR_DEBUG 0
 #define DB_PRINT(...) do {\
@@ -682,7 +683,7 @@ static unsigned calc_mac_hash(const uint8_t *mac)
 static int gem_mac_address_filter(CadenceGEMState *s, const uint8_t *packet)
 {
     uint8_t *gem_spaddr;
-    int i;
+    int i, is_mc;
 
     /* Promiscuous mode? */
     if (s->regs[GEM_NWCFG] & GEM_NWCFG_PROMISC) {
@@ -698,22 +699,17 @@ static int gem_mac_address_filter(CadenceGEMState *s, 
const uint8_t *packet)
     }
 
     /* Accept packets -w- hash match? */
-    if ((packet[0] == 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_MCAST_HASH)) ||
-        (packet[0] != 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_UCAST_HASH))) {
+    is_mc = is_multicast_ether_addr(packet);
+    if ((is_mc && (s->regs[GEM_NWCFG] & GEM_NWCFG_MCAST_HASH)) ||
+        (!is_mc && (s->regs[GEM_NWCFG] & GEM_NWCFG_UCAST_HASH))) {
+        uint64_t buckets;
         unsigned hash_index;
 
         hash_index = calc_mac_hash(packet);
-        if (hash_index < 32) {
-            if (s->regs[GEM_HASHLO] & (1<<hash_index)) {
-                return packet[0] == 0x01 ? GEM_RX_MULTICAST_HASH_ACCEPT :
-                                           GEM_RX_UNICAST_HASH_ACCEPT;
-            }
-        } else {
-            hash_index -= 32;
-            if (s->regs[GEM_HASHHI] & (1<<hash_index)) {
-                return packet[0] == 0x01 ? GEM_RX_MULTICAST_HASH_ACCEPT :
-                                           GEM_RX_UNICAST_HASH_ACCEPT;
-            }
+        buckets = ((uint64_t)s->regs[GEM_HASHHI] << 32) | s->regs[GEM_HASHLO];
+        if ((buckets >> hash_index) & 1) {
+            return is_mc ? GEM_RX_MULTICAST_HASH_ACCEPT
+                         : GEM_RX_UNICAST_HASH_ACCEPT;
         }
     }
 
@@ -938,7 +934,7 @@ static ssize_t gem_receive(NetClientState *nc, const 
uint8_t *buf, size_t size)
     /* Is this destination MAC address "for us" ? */
     maf = gem_mac_address_filter(s, buf);
     if (maf == GEM_RX_REJECT) {
-        return -1;
+        return size;  /* no, drop siliently b/c it's not an error */
     }
 
     /* Discard packets with receive length error enabled ? */
-- 
2.7.4