Re: [PATCH net-next] libbpf: add function to setup XDP

[David Miller]

From: Toshiaki Makita <makita.toshiaki@xxxxxxxxxxxxx>
Date: Mon, 11 Dec 2017 11:24:12 +0900

> On 2017/12/09 23:43, Eric Leblond wrote:
>> Most of the code is taken from set_link_xdp_fd() in bpf_load.c and
>> slightly modified to be library compliant.
>> 
>> Signed-off-by: Eric Leblond <eric@xxxxxxxxx>
> ...
>> +int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
> ...
>> +	for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
>> +	     nh = NLMSG_NEXT(nh, len)) {
>> +		if (nh->nlmsg_pid != getpid()) {
> 
> Generally nlmsg_pid should not be compared with process id.
> See man netlink and
> https://github.com/iovisor/bcc/pull/1275/commits/69ce96a54c55960c8de3392061254c97b6306a6d

Right.  I wish we had never named this "pid", it gets misinterpreted
way too easily.