From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next] libbpf: add function to setup XDP
Date: Tue, 12 Dec 2017 10:53:50 -0500 (EST)
Message-ID: <20171212.105350.1862932376620064454.davem@davemloft.net>
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        <c1be066a-eb39-c9e0-b21b-4bb4da280b26@lab.ntt.co.jp>
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To: makita.toshiaki@lab.ntt.co.jp
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From: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
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@regit.org>
> ...
>> +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.