Re: [PATCH 01/11] tap: Don't quit if pasta gets EIO on writev() to tap, interface might be down

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 1457 bytes --]

On Wed, Jul 24, 2024 at 11:50:07PM +0200, Stefano Brivio wrote:
> If we start pasta with some ports forwarded, but no --config-net, say:
> 
>   $ ./pasta -u 10001
> 
> and then use a local, non-loopback address to send traffic to that
> port, say:
> 
>   $ socat -u FILE:test UDP4:192.0.2.1:10001
> 
> pasta writes to the tap file descriptor, but if the interface is down,
> we get EIO and terminate.
> 
> By itself, what I'm doing in this case is not very useful (I simply
> forgot to pass --config-net), but if we happen to have a DHCP client
> in the network namespace, the interface might still be down while
> somebody tries to send traffic to it, and exiting in that case is not
> really helpful.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>


> ---
>  tap.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tap.c b/tap.c
> index 32a7b09..6930ad8 100644
> --- a/tap.c
> +++ b/tap.c
> @@ -324,6 +324,7 @@ static size_t tap_send_frames_pasta(const struct ctx *c,
>  			case EINTR:
>  			case ENOBUFS:
>  			case ENOSPC:
> +			case EIO:		/* interface down? */
>  				break;
>  			default:
>  				die("Write error on tap device, exiting");

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]