Re: [PATCH iproute2-next] iplink: add support for setting IPv4 devconf parameters

[Fernando Fernandez Mancera <fmancera@suse.de>]

On 6/2/26 9:36 PM, David Ahern wrote:
> On 6/1/26 8:32 AM, Fernando Fernandez Mancera wrote:
>> Currently, modifying IPv4 interface configuration parameters requires
>> interacting with sysctl (/proc/sys/net/ipv4/conf/*). While
>> ip-netconf exists for monitoring these values, there has been no native
>> way to set them directly through iproute2.
>>
>> This patch introduces the support for that via 'inet' at the 'ip link
>> set'. It uses IFLA_INET_CONF netlink attribute to set the parameter.
>>
>> Example to enable forwarding on an interface:
>>
>> ip link set dev enp8s0 inet forwarding on
> 
> If an attribute can be set this way, then ip link show needs to show the
> values. What's the plan on that front?
> 

I could introduce it in a follow-up patch. I guess it makes sense to 
introduce it for ip -d link show only, right? I am happy to work on it 
anyway.

>>
>> Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
>> ---
>>   ip/iplink.c           | 354 ++++++++++++++++++++++++++++++++++++++++++
>>   man/man8/ip-link.8.in |  81 ++++++++++
>>   2 files changed, 435 insertions(+)
>>
> 
> ...
> 
>>   		"		[ gso_max_size BYTES ] [ gso_ipv4_max_size BYTES ] [ gso_max_segs PACKETS ]\n"
>> @@ -551,6 +569,339 @@ static int iplink_parse_vf(int vf, int *argcp, char ***argvp,
>>   	return 0;
>>   }
>>   
>> +static int iplink_parse_inet(int *argcp, char ***argvp, struct iplink_req *req)
>> +{
>> +	struct rtattr *afs, *afinet, *inet_devconf;
>> +	char **argv = *argvp;
>> +	int argc = *argcp;
>> +	int ret;
>> +
>> +	afs = addattr_nest(&req->n, sizeof(*req), IFLA_AF_SPEC);
>> +	afinet = addattr_nest(&req->n, sizeof(*req), AF_INET);
>> +	inet_devconf = addattr_nest(&req->n, sizeof(*req), IFLA_INET_CONF);
>> +
>> +	while (NEXT_ARG_OK()) {
>> +		NEXT_ARG();
>> +		if (matches(*argv, "forwarding") == 0) {
> 
> new uses of matches are not allowed. If s/matches/strcmp/ is the only
> comment, I can fix up before applying.
> 

Sorry I didn't know this. Thanks.