Re: [PATCH_v2 1/2] GAtPPP: Add ACFC option support

[Denis Kenzior <denkenz@gmail.com>]

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Hi Guillaume,

On 06/27/2011 11:15 AM, Guillaume Zajac wrote:
> ---
>  gatchat/gatppp.c  |   79 ++++++++++++++++++++++++++++++++++++++++++++++-------
>  gatchat/gatppp.h  |    2 +
>  gatchat/ppp.h     |    8 +++++
>  gatchat/ppp_lcp.c |   28 ++++++++++++++++---
>  4 files changed, 103 insertions(+), 14 deletions(-)
> 
> diff --git a/gatchat/gatppp.c b/gatchat/gatppp.c
> index 5fb4146..2640985 100644
> --- a/gatchat/gatppp.c
> +++ b/gatchat/gatppp.c
> @@ -83,6 +83,8 @@ struct _GAtPPP {
>  	int fd;
>  	guint guard_timeout_source;
>  	gboolean suspended;
> +	gboolean force_acfc_off;

You don't need this variable, see below for more

> +	gboolean acfc;

Please name this xmit_acfc.

>  };
>  
>  void ppp_debug(GAtPPP *ppp, const char *str)
> @@ -168,8 +170,19 @@ static inline gboolean ppp_drop_packet(GAtPPP *ppp, guint16 protocol)
>  static void ppp_receive(const unsigned char *buf, gsize len, void *data)
>  {
>  	GAtPPP *ppp = data;
> -	guint16 protocol = ppp_proto(buf);
> -	const guint8 *packet = ppp_info(buf);
> +	struct ppp_header *header = (struct ppp_header *) buf;
> +	gboolean acfc_frame = (header->address != PPP_ADDR_FIELD
> +			|| header->control != PPP_CTRL);
> +	guint16 protocol;
> +	const guint8 *packet;
> +
> +	if (acfc_frame) {
> +		protocol = ppp_acfc_proto(buf);
> +		packet = ppp_acfc_info(buf);
> +	} else {
> +		protocol = ppp_proto(buf);
> +		packet = ppp_info(buf);
> +	}
>  
>  	if (ppp_drop_packet(ppp, protocol))
>  		return;
> @@ -196,17 +209,11 @@ static void ppp_receive(const unsigned char *buf, gsize len, void *data)
>  	};
>  }
>  
> -/*
> - * transmit out through the lower layer interface
> - *
> - * infolen - length of the information part of the packet
> - */
> -void ppp_transmit(GAtPPP *ppp, guint8 *packet, guint infolen)
> +static void ppp_send_common_frame(GAtPPP *ppp, guint8 *packet, guint infolen,
> +					gboolean lcp)

Shouldn't this be called send_lcp_frame?

>  {
>  	struct ppp_header *header = (struct ppp_header *) packet;
> -	guint16 proto = ppp_proto(packet);
>  	guint8 code;
> -	gboolean lcp = (proto == LCP_PROTOCOL);
>  	guint32 xmit_accm = 0;
>  	gboolean sta = FALSE;
>  
> @@ -251,6 +258,44 @@ void ppp_transmit(GAtPPP *ppp, guint8 *packet, guint infolen)
>  		g_at_hdlc_set_xmit_accm(ppp->hdlc, xmit_accm);
>  }
>  
> +static void ppp_send_acfc_frame(GAtPPP *ppp, guint8 *packet,
> +					guint infolen)
> +{
> +	struct ppp_header *header = (struct ppp_header *) packet;
> +	guint offset = 0;
> +
> +	if (ppp->acfc)
> +		offset = 2;
> +	else
> +		offset = 0;
> +
> +	if (g_at_hdlc_send(ppp->hdlc, packet + offset,
> +				infolen + sizeof(*header) - offset)
> +			== FALSE)
> +		DBG(ppp, "Failed to send a frame\n");
> +}
> +
> +/*
> + * transmit out through the lower layer interface
> + *
> + * infolen - length of the information part of the packet
> + */
> +void ppp_transmit(GAtPPP *ppp, guint8 *packet, guint infolen)
> +{
> +	guint16 proto = ppp_proto(packet);
> +
> +	switch (proto) {
> +	case LCP_PROTOCOL:
> +		ppp_send_common_frame(ppp, packet, infolen, TRUE);
> +		break;
> +	case CHAP_PROTOCOL:
> +	case IPCP_PROTO:
> +	case PPP_IP_PROTO:
> +		ppp_send_acfc_frame(ppp, packet, infolen);
> +		break;
> +	}
> +}
> +
>  static inline void ppp_enter_phase(GAtPPP *ppp, enum ppp_phase phase)
>  {
>  	DBG(ppp, "%d", phase);
> @@ -390,6 +435,14 @@ void ppp_set_mtu(GAtPPP *ppp, const guint8 *data)
>  	ppp->mtu = mtu;
>  }
>  
> +void ppp_set_acfc_enabled(GAtPPP *ppp, gboolean acfc)

Please name this function ppp_set_xmit_acfc(GAtPPP *ppp, gboolean acfc)

> +{
> +	if (ppp->force_acfc_off)
> +		ppp->acfc = FALSE;
> +	else
> +		ppp->acfc = acfc;

And set ppp->xmit_acfc directly from acfc...

> +}
> +
>  static void io_disconnect(gpointer user_data)
>  {
>  	GAtPPP *ppp = user_data;
> @@ -658,6 +711,12 @@ void g_at_ppp_set_server_info(GAtPPP *ppp, const char *remote,
>  	ipcp_set_server_info(ppp->ipcp, r, d1, d2);
>  }
>  
> +void g_at_ppp_force_acfc_off(GAtPPP *ppp, gboolean off)

Please name this function g_at_ppp_set_acfc_enabled(GAtPPP *ppp,
gboolean enabled)

> +{
> +	ppp->force_acfc_off = off;
> +	lcp_turn_off_acfc(ppp->lcp);

To help in regression testing lets turn off ACFC by default, and only
enable it if someone has asked for it.

> +}
> +
>  static GAtPPP *ppp_init_common(gboolean is_server, guint32 ip)
>  {
>  	GAtPPP *ppp;
> diff --git a/gatchat/gatppp.h b/gatchat/gatppp.h
> index f0930a7..d0231fc 100644
> --- a/gatchat/gatppp.h
> +++ b/gatchat/gatppp.h
> @@ -79,6 +79,8 @@ void g_at_ppp_set_recording(GAtPPP *ppp, const char *filename);
>  void g_at_ppp_set_server_info(GAtPPP *ppp, const char *remote_ip,
>  				const char *dns1, const char *dns2);
>  
> +void g_at_ppp_force_acfc_off(GAtPPP *ppp, gboolean off);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/gatchat/ppp.h b/gatchat/ppp.h
> index 023d779..116b5db 100644
> --- a/gatchat/ppp.h
> +++ b/gatchat/ppp.h
> @@ -85,10 +85,17 @@ static inline void __put_unaligned_short(void *p, guint16 val)
>  #define ppp_proto(packet) \
>  	(get_host_short(packet + 2))
>  
> +#define ppp_acfc_info(packet) \
> +	(packet + 2)
> +
> +#define ppp_acfc_proto(packet) \
> +	(get_host_short(packet))
> +
>  /* LCP related functions */
>  struct pppcp_data *lcp_new(GAtPPP *ppp, gboolean dormant);
>  void lcp_free(struct pppcp_data *lcp);
>  void lcp_protocol_reject(struct pppcp_data *lcp, guint8 *packet, gsize len);
> +void lcp_turn_off_acfc(struct pppcp_data *pppcp);
>  
>  /* IPCP related functions */
>  struct pppcp_data *ipcp_new(GAtPPP *ppp, gboolean is_server, guint32 ip);
> @@ -125,4 +132,5 @@ void ppp_lcp_finished_notify(GAtPPP *ppp);
>  void ppp_set_recv_accm(GAtPPP *ppp, guint32 accm);
>  void ppp_set_xmit_accm(GAtPPP *ppp, guint32 accm);
>  void ppp_set_mtu(GAtPPP *ppp, const guint8 *data);
> +void ppp_set_acfc_enabled(GAtPPP *ppp, gboolean acfc);
>  struct ppp_header *ppp_packet_new(gsize infolen, guint16 protocol);
> diff --git a/gatchat/ppp_lcp.c b/gatchat/ppp_lcp.c
> index ce9dae2..3814ddf 100644
> --- a/gatchat/ppp_lcp.c
> +++ b/gatchat/ppp_lcp.c
> @@ -58,11 +58,12 @@ enum lcp_options {
>  	ACFC			= 8,
>  };
>  
> -/* Maximum size of all options, we only ever request ACCM and MRU */ 
> -#define MAX_CONFIG_OPTION_SIZE 10
> +/* Maximum size of all options, we only ever request ACCM, MRU and ACFC */
> +#define MAX_CONFIG_OPTION_SIZE 12
>  
>  #define REQ_OPTION_ACCM	0x1
>  #define REQ_OPTION_MRU	0x2
> +#define REQ_OPTION_ACFC	0x4
>  
>  struct lcp_data {
>  	guint8 options[MAX_CONFIG_OPTION_SIZE];
> @@ -100,13 +101,20 @@ static void lcp_generate_config_options(struct lcp_data *lcp)
>  		len += 4;
>  	}
>  
> +	if (lcp->req_options & REQ_OPTION_ACFC) {
> +		lcp->options[len] = ACFC;
> +		lcp->options[len + 1] = 2;
> +
> +		len += 2;
> +	}
> +
>  	lcp->options_len = len;
>  }
>  
>  static void lcp_reset_config_options(struct lcp_data *lcp)
>  {
>  	/* Using the default ACCM */
> -
> +	lcp->req_options |= REQ_OPTION_ACFC;
>  	lcp_generate_config_options(lcp);
>  }
>  
> @@ -286,9 +294,11 @@ static enum rcr_result lcp_rcr(struct pppcp_data *pppcp,
>  			break;
>  		case MAGIC_NUMBER:
>  		case PFC:
> -		case ACFC:
>  			/* don't care */
>  			break;
> +		case ACFC:
> +			ppp_set_acfc_enabled(ppp, TRUE);

You can check whether we turned on ACFC by checking whether ACFC option
is being advertised to the peer.  E.g. lcp->req_options & REQ_OPTION_ACFC...

> +			break;
>  		}
>  	}
>  
> @@ -338,3 +348,13 @@ struct pppcp_data *lcp_new(GAtPPP *ppp, gboolean is_server)
>  
>  	return pppcp;
>  }
> +
> +void lcp_turn_off_acfc(struct pppcp_data *pppcp)
> +{
> +	struct lcp_data *lcp = pppcp_get_data(pppcp);
> +
> +	lcp->req_options &= ~REQ_OPTION_ACFC;
> +	lcp_generate_config_options(lcp);
> +
> +	pppcp_set_local_options(pppcp, lcp->options, lcp->options_len);
> +}

Regards,
-Denis