Re: [PATCH net] r8169: fix multicast tx issue with macvlan interface

[Heiner Kallweit <hkallweit1@gmail.com>]

On 07.04.2020 01:20, Eric Dumazet wrote:
> 
> 
> On 4/6/20 3:16 PM, Heiner Kallweit wrote:
> 
>>
>> In a similar context Realtek made me aware of a hw issue if IP header
>> has the options field set. You mentioned problems with multicast packets,
>> and based on the following code the root cause may be related.
>>
>> br_ip4_multicast_alloc_query()
>> -> iph->ihl = 6;
>>
>> I'd appreciate if you could test (with HW tx checksumming enabled)
>> whether this experimental patch fixes the issue with invalid/lost
>> multicasts.
>>
>>
>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
>> index e40e8eaeb..dd251ddb8 100644
>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>> @@ -4319,6 +4319,10 @@ static netdev_features_t rtl8169_features_check(struct sk_buff *skb,
>>  		    rtl_chip_supports_csum_v2(tp))
>>  			features &= ~NETIF_F_ALL_TSO;
>>  	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
>> +		if (ip_hdrlen(skb) > sizeof(struct iphdr)) {
> 
> Packet could be non IPv4 at this point. (IPv6 for instance)
> 
Right, I should have mentioned it:
This experimental patch is for IPv4 only. In a final version (if it indeed
fixes the issue) I had to extend the condition and check for IPv4.

>> +			pr_info("hk: iphdr has options field set\n");
>> +			features &= ~NETIF_F_CSUM_MASK;
>> +		}
>>  		if (skb->len < ETH_ZLEN) {
>>  			switch (tp->mac_version) {
>>  			case RTL_GIGA_MAC_VER_11:
>>