Re: netlink socket does not accept SOCK_DGRAM

> On 15 Jan 2023, at 02:26, User Ngor <ihor@antonovs.family> wrote:
> 
> man 4 rtnetlink says:
> 
>     int socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
> 
> 
> 
> The following snippet fails
> 
>    int fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
>    if (fd < 0) {
>        perror("Failed to open netlink socket");
>        return -1;
>    }
>    printf("all good\n");
>    close(fd);
>    return 0;
> 
> I get: Failed to open netlink socket: Protocol wrong type for socket
> 
> 
> but if I change
> int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
> 
> I get "all good"
> 
> Am I doing something wrong or is this a bug?
It’s a bug. The manage should state SOCK_RAW, but both options should be supported, which is not the case ATM.
I’ll fix it in a couple of days.
Meanwhile it may be worth looking into snl(3) which abstracts issues like this one.
> 
> 
> 
> $ uname -a FreeBSD zen.hq 14.0-CURRENT FreeBSD 14.0-CURRENT #0 main-n259967-11b5b9e8a520: Sat Jan  7 16:39:30 UTC 2023 root@releng1.nyi.freebsd.org:/usr/obj/usr/src/amd64.amd64/sys/GENERIC amd64
> 
> $ kldstat | grep netl
> 39    1 0xffffffff839fc000    14af8 netlink.ko
> 
> 
> -- 
> Ihor Antonov
> 
>