[Dnsmasq-discuss] Failure of dnsmasq v2.81 in docker (qemu emulated armhf hardware)

[Geert Stappers]

On Sun, Apr 19, 2020 at 07:19:10AM +0200, Dominik wrote:
> On Wed, 2020-04-15 at 21:34 +0200, Dominik wrote:
> > A possible solution seems to be what Petr Gotthard suggested
> > (dnsmasq-discuss /Thu Mar 19 13:16:11 GMT 2020/):
> > 
> > > +#ifdef NETLINK_NO_ENOBUFS
> > >        setsockopt(daemon->netlinkfd, SOL_NETLINK,
> > > NETLINK_NO_ENOBUFS, &opt, sizeof(opt)) == -1 ||
> > > +#endif
> 
> Patch attached which restored dnsmasq operation for us.
> 
> Have a nice weekend!

    ;-)


> Best regards,
> Dominik

> From 59e38c1e81e3ec479866a47cadb92d53b9f86022 Mon Sep 17 00:00:00 2001
> From: Dominik Derigs <dl6er at dl6er.de>
> Date: Sun, 19 Apr 2020 07:15:00 +0200
> Subject: [PATCH] Don't try setsockopt of non-existing NETLINK_NO_ENOBUFS option to prevent dnsmasq from failing in docker qemu emulation.

FWIW  git commit summary is supposed to be less then 53 characters

> ---
>  src/netlink.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/src/netlink.c b/src/netlink.c
> index 3af54c4..21e84ef 100644
> --- a/src/netlink.c
> +++ b/src/netlink.c
> @@ -27,10 +27,6 @@
>  #define SOL_NETLINK 270
>  #endif
>  
> -#ifndef NETLINK_NO_ENOBUFS

Tests on    "not defined"


> -#define NETLINK_NO_ENOBUFS 5

Pushes (very (rude)) the value to 5


> -#endif
> -
>  /* linux 2.6.19 buggers up the headers, patch it up here. */ 
>  #ifndef IFA_RTA
>  #  define IFA_RTA(r)  \
> @@ -83,7 +79,9 @@ void netlink_init(void)
>    
>    if (daemon->netlinkfd == -1 || 
>        (daemon->kernel_version >= KERNEL_VERSION(2,6,30) &&
> +#ifdef NETLINK_NO_ENOBUFS

in case it is defined


>         setsockopt(daemon->netlinkfd, SOL_NETLINK, NETLINK_NO_ENOBUFS, &opt, sizeof(opt)) == -1) ||

use it with value as set in proper place


> +#endif
>        getsockname(daemon->netlinkfd, (struct sockaddr *)&addr, &slen) == -1)
>      die(_("cannot create netlink socket: %s"), NULL, EC_MISC);
>    


My apologies for not tested on "Yes, with that patch it still works for me"


Groeten
Geert Stappers
-- 
Silence is hard to parse