[PATCH v3] net/cadence_gem: Updating the GEM MAC IP to properly filter out multicast addresses.

[bilalwasim676]

From: bwasim <bilal_wa...@mentor.com>

The current code makes a bad assumption that the most-significant byte
of the MAC address is used to determine if the address is multicast or
unicast, but in reality only a single bit is used to determine this.
This caused IPv6 to not work.. Fix is now in place and has been tested
with ZCU102-A53 / IPv6 on a TAP interface. Works well..

Signed-off-by: Bilal Wasim <bilal_wa...@mentor.com>
---
 hw/net/cadence_gem.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index b8be73dc55..6400b3653b 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"
 
 #ifdef CADENCE_GEM_ERR_DEBUG
 #define DB_PRINT(...) do { \
@@ -601,7 +602,7 @@ static void gem_receive_updatestats(CadenceGEMState *s, 
const uint8_t *packet,
     }
 
     /* Error-free Multicast Frames counter */
-    if (packet[0] == 0x01) {
+    if (is_multicast_ether_addr(packet)) {
         s->regs[GEM_RXMULTICNT]++;
     }
 
@@ -690,21 +691,25 @@ 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))) {
+    if ((is_multicast_ether_addr(packet)
+        && (s->regs[GEM_NWCFG] & GEM_NWCFG_MCAST_HASH)) ||
+        (is_unicast_ether_addr(packet)
+        && (s->regs[GEM_NWCFG] & GEM_NWCFG_UCAST_HASH))) {
         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;
+                return is_multicast_ether_addr(packet) ?
+                       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;
+                return is_multicast_ether_addr(packet) ?
+                       GEM_RX_MULTICAST_HASH_ACCEPT :
+                       GEM_RX_UNICAST_HASH_ACCEPT;
             }
         }
     }
@@ -1083,7 +1088,7 @@ static void gem_transmit_updatestats(CadenceGEMState *s, 
const uint8_t *packet,
     }
 
     /* Error-free Multicast Frames counter */
-    if (packet[0] == 0x01) {
+    if (is_multicast_ether_addr(packet)) {
         s->regs[GEM_TXMCNT]++;
     }
 
-- 
2.19.1.windows.1