Re: [PATCH] ppp: silently discard packets if needed

[Gustavo F. Padovan <gustavo@padovan.org>]

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Hi Kristen,

* Kristen Carlson Accardi <kristen@linux.intel.com> [2010-04-27 13:26:49 -0700]:

> When receiving a packet, check the protocol and the phase to see
> if the packet should be dropped.
> ---
>  gatchat/gatppp.c |   31 ++++++++++++++++++++++++++-----
>  1 files changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/gatchat/gatppp.c b/gatchat/gatppp.c
> index c7bf089..933cbec 100644
> --- a/gatchat/gatppp.c
> +++ b/gatchat/gatppp.c
> @@ -173,17 +173,38 @@ static struct frame_buffer *ppp_encode(GAtPPP *ppp, guint8 *data, int len)
>  	return fb;
>  }
>  
> +/*
> + * Silently discard packets which are received when they shouldn't be
> + */
> +static inline gboolean drop_packet(GAtPPP *ppp, guint16 protocol)
> +{
> +	switch (ppp->phase) {
> +	case PPP_PHASE_ESTABLISHMENT:
> +	case PPP_PHASE_TERMINATION:
> +		if (protocol != LCP_PROTOCOL)
> +			return TRUE;
> +		break;
> +	case PPP_PHASE_AUTHENTICATION:
> +		if (protocol != LCP_PROTOCOL && protocol != CHAP_PROTOCOL)
> +			return TRUE;
> +		break;
> +	case PPP_PHASE_DEAD:
> +		return TRUE;
> +		break;

You have a return and a break on the same case. You'll never reach the
break here.

> +	case PPP_PHASE_NETWORK:
> +		break;
> +	}
> +
> +	return FALSE;
> +}
> +
>  /* called when we have received a complete ppp frame */
>  static void ppp_recv(GAtPPP *ppp, struct frame_buffer *frame)
>  {
>  	guint16 protocol = ppp_proto(frame->bytes);
>  	guint8 *packet = ppp_info(frame->bytes);
>  
> -	/*
> -	 * Any non-LCP packets received during Link Establishment
> -	 * phase must be silently discarded.
> -	 */
> -	if (ppp->phase == PPP_PHASE_ESTABLISHMENT && protocol != LCP_PROTOCOL)
> +	if (drop_packet(ppp, protocol))
>  		return;
>  
>  	switch (protocol) {
> -- 
> 1.6.6.1
> 
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-- 
Gustavo F. Padovan
http://padovan.org