Using pinned maps within a network namespace

[John McDowall <jmcdowall@xxxxxxxxxxxxxxxxxxxx>]

Hi everyone,

This may be a dumb question, I have set up a simple test environment
with multiple network namespaces running on a ubuntu 20.04 vagrant
box, with the latest github libbpf.

I want to use a pinned map, I can make /sys/fs/bpf shared by:

$ mount mount --make-shared /sys/fs/bpf
$ mount --bind /sys/fs/bpf /sys/fs/bpf

but when I try access the maps from a C program running in a namespace
using bpf I get

 Access to /sys/fs/bpf/lwtconfig map failed obj_pin errno: No such
file or directory

The code snippet is:

mapfd = bpf_obj_pin(pin_fd,CONFIG_MAP_PATH);
        if (mapfd < 0) {
            jed_info(jed_logfile,"Access to %s map failed obj_pin ",
CONFIG_MAP_PATH);
            pin_fd = bpf_obj_get(CONFIG_MAP_PATH);
            if (pin_fd < 0){
             jed_error(jed_logfile,"Access to %s map failed with
obj_get ", CONFIG_MAP_PATH);
            }
        }

Is this possible, and if so what am I missing?

Regards

John