Re: [PATCH v2] net/cadence_gem: Updating the GEM MAC IP to properly filter out multicast addresses.

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Fri, Nov 29, 2019 at 01:52:16PM +0500, bilalwasim676@gmail.com wrote:
> From: bwasim <bilal_wasim@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..

Thanks Bilal,

Sorry, just one more thing I had missed, we need to update
gem_transmit_updatestats() aswell, in a similar way as we did with
gem_receive_updatestats().

Cheers,
Edgar


> 
> Signed-off-by: Bilal Wasim <bilal_wasim@mentor.com>
> ---
>  hw/net/cadence_gem.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
> index b8be73dc55..042188c1ba 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;
>              }
>          }
>      }
> -- 
> 2.19.1.windows.1
>