netdev - Re: [PATCH net-next v12 09/12] virtio_net: Implement IPv4 ethtool flow rules

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Message-ID: <73140271-6218-4201-96c4-7de563da965e@nvidia.com>
Date: Mon, 24 Nov 2025 16:41:44 -0600
From: Dan Jurgens <danielj@...dia.com>
To: "Michael S. Tsirkin" <mst@...hat.com>
Cc: netdev@...r.kernel.org, jasowang@...hat.com, pabeni@...hat.com,
 virtualization@...ts.linux.dev, parav@...dia.com, shshitrit@...dia.com,
 yohadt@...dia.com, xuanzhuo@...ux.alibaba.com, eperezma@...hat.com,
 jgg@...pe.ca, kevin.tian@...el.com, kuba@...nel.org, andrew+netdev@...n.ch,
 edumazet@...gle.com
Subject: Re: [PATCH net-next v12 09/12] virtio_net: Implement IPv4 ethtool
 flow rules

On 11/24/25 3:51 PM, Michael S. Tsirkin wrote:
> On Wed, Nov 19, 2025 at 01:15:20PM -0600, Daniel Jurgens wrote:
>> Add support for IP_USER type rules from ethtool.
>>
>> Example:
>> $ ethtool -U ens9 flow-type ip4 src-ip 192.168.51.101 action -1
>> Added rule with ID 1
>>
>> The example rule will drop packets with the source IP specified.
>>
>> Signed-off-by: Daniel Jurgens <danielj@...dia.com>
>> Reviewed-by: Parav Pandit <parav@...dia.com>
>> Reviewed-by: Shahar Shitrit <shshitrit@...dia.com>
>> Reviewed-by: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
>> ---
>> v4:
>>     - Fixed bug in protocol check of parse_ip4
>>     - (u8 *) to (void *) casting.
>>     - Alignment issues.
>>
>> v12
>>     - refactor calculate_flow_sizes to remove goto. MST
>>     - refactor build_and_insert to remove goto validate. MST
>>     - Move parse_ip4 l3_mask check to TCP/UDP patch. MST
>>     - Check saddr/daddr mask before copying in parse_ip4. MST
>>     - Remove tos check in setup_ip_key_mask.
> 
> So if user attempts to set a filter by tos now, what blocks it?
> because parse_ip4 seems to ignore it ...
> 
>>     - check l4_4_bytes mask is 0 in setup_ip_key_mask. MST
>>     - changed return of setup_ip_key_mask to -EINVAL.
>>     - BUG_ON if key overflows u8 size in calculate_flow_sizes. MST
>> ---
>> ---
>>  drivers/net/virtio_net.c | 119 +++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 113 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 5e49cd78904f..b0b9972fe624 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -5894,6 +5894,34 @@ static bool validate_eth_mask(const struct virtnet_ff *ff,
>>  	return true;
>>  }
>>  
>> +static bool validate_ip4_mask(const struct virtnet_ff *ff,
>> +			      const struct virtio_net_ff_selector *sel,
>> +			      const struct virtio_net_ff_selector *sel_cap)
>> +{
>> +	bool partial_mask = !!(sel_cap->flags & VIRTIO_NET_FF_MASK_F_PARTIAL_MASK);
>> +	struct iphdr *cap, *mask;
>> +
>> +	cap = (struct iphdr *)&sel_cap->mask;
>> +	mask = (struct iphdr *)&sel->mask;
>> +
>> +	if (mask->saddr &&
>> +	    !check_mask_vs_cap(&mask->saddr, &cap->saddr,
>> +			       sizeof(__be32), partial_mask))
>> +		return false;
>> +
>> +	if (mask->daddr &&
>> +	    !check_mask_vs_cap(&mask->daddr, &cap->daddr,
>> +			       sizeof(__be32), partial_mask))
>> +		return false;
>> +
>> +	if (mask->protocol &&
>> +	    !check_mask_vs_cap(&mask->protocol, &cap->protocol,
>> +			       sizeof(u8), partial_mask))
>> +		return false;
>> +
>> +	return true;
>> +}
>> +
>>  static bool validate_mask(const struct virtnet_ff *ff,
>>  			  const struct virtio_net_ff_selector *sel)
>>  {
>> @@ -5905,11 +5933,36 @@ static bool validate_mask(const struct virtnet_ff *ff,
>>  	switch (sel->type) {
>>  	case VIRTIO_NET_FF_MASK_TYPE_ETH:
>>  		return validate_eth_mask(ff, sel, sel_cap);
>> +
>> +	case VIRTIO_NET_FF_MASK_TYPE_IPV4:
>> +		return validate_ip4_mask(ff, sel, sel_cap);
>>  	}
>>  
>>  	return false;
>>  }
>>  
>> +static void parse_ip4(struct iphdr *mask, struct iphdr *key,
>> +		      const struct ethtool_rx_flow_spec *fs)
>> +{
>> +	const struct ethtool_usrip4_spec *l3_mask = &fs->m_u.usr_ip4_spec;
>> +	const struct ethtool_usrip4_spec *l3_val  = &fs->h_u.usr_ip4_spec;
>> +
>> +	if (mask->saddr) {
>> +		mask->saddr = l3_mask->ip4src;
>> +		key->saddr = l3_val->ip4src;
>> +	}
> 
> So if mast->saddr is already set you over-write it?
> 
> But what sets it? Don't you really mean l3_mask->ip4src maybe?

Yes your right. My abbreviated test was only checking filtering by port
number on ipv4. Will fix that as well.

> 
> 
> 
>> +
>> +	if (mask->daddr) {
>> +		mask->daddr = l3_mask->ip4dst;
>> +		key->daddr = l3_val->ip4dst;
>> +	}
>> +}
> 
> 
> Same question.
> 
> 
>