GAtPPP: Add ACFC option support

gatchat/gatppp.c

@@ -83,6 +83,7 @@ struct _GAtPPP {
 	int fd;
 	guint guard_timeout_source;
 	gboolean suspended;
+	gboolean xmit_acfc;
 };
 
 void ppp_debug(GAtPPP *ppp, const char *str)
@@ -168,8 +169,19 @@ 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);
+	struct ppp_header *header = (struct ppp_header *) buf;
-	const guint8 *packet = ppp_info(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;
@@ -196,37 +208,29 @@ static void ppp_receive(const unsigned char *buf, gsize len, void *data)
 	};
 }
 
-/*
+static void ppp_send_lcp_frame(GAtPPP *ppp, guint8 *packet, guint infolen)
- * 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)
 {
 	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;
+	gboolean lcp;
 
 	/*
 	 * all LCP Link Configuration, Link Termination, and Code-Reject
 	 * packets must be sent with the default sending ACCM
 	 */
-	if (lcp) {
+	code = pppcp_get_code(packet);
-		code = pppcp_get_code(packet);
+	lcp = code > 0 && code < 8;
-		lcp = code > 0 && code < 8;
 
-		/*
+	/*
-		 * If we're going down, we try to make sure to send the final
+	 * If we're going down, we try to make sure to send the final
-		 * ack before informing the upper layers via the ppp_disconnect
+	 * ack before informing the upper layers via the ppp_disconnect
-		 * function.  Once we enter PPP_DEAD phase, no further packets
+	 * function.  Once we enter PPP_DEAD phase, no further packets
-		 * will be sent
+	 * will be sent
-		 */
+	 */
-		if (code == PPPCP_CODE_TYPE_TERMINATE_ACK)
+	if (code == PPPCP_CODE_TYPE_TERMINATE_ACK)
-			sta = TRUE;
+		sta = TRUE;
-	}
 
 	if (lcp) {
 		xmit_accm = g_at_hdlc_get_xmit_accm(ppp->hdlc);
@@ -251,6 +255,42 @@ 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->xmit_acfc)
+		offset = 2;
+
+	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_lcp_frame(ppp, packet, infolen);
+		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 +430,11 @@ void ppp_set_mtu(GAtPPP *ppp, const guint8 *data)
 	ppp->mtu = mtu;
 }
 
+void ppp_set_xmit_acfc(GAtPPP *ppp, gboolean acfc)
+{
+	ppp->xmit_acfc = acfc;
+}
+
 static void io_disconnect(gpointer user_data)
 {
 	GAtPPP *ppp = user_data;
@@ -658,6 +703,11 @@ 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_set_acfc_enabled(GAtPPP *ppp, gboolean enabled)
+{
+	lcp_set_acfc_enabled(ppp->lcp, enabled);
+}
+
 static GAtPPP *ppp_init_common(gboolean is_server, guint32 ip)
 {
 	GAtPPP *ppp;

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_set_acfc_enabled(GAtPPP *ppp, gboolean enabled);
+
 #ifdef __cplusplus
 }
 #endif

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_set_acfc_enabled(struct pppcp_data *pppcp, gboolean enabled);
 
 /* 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_xmit_acfc(GAtPPP *ppp, gboolean acfc);
 struct ppp_header *ppp_packet_new(gsize infolen, guint16 protocol);

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 */ 
+/* Maximum size of all options, we only ever request ACCM, MRU and ACFC */
-#define MAX_CONFIG_OPTION_SIZE 10
+#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];
@@ -100,6 +101,13 @@ 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;
 }
 
@@ -286,9 +294,17 @@ static enum rcr_result lcp_rcr(struct pppcp_data *pppcp,
 			break;
 		case MAGIC_NUMBER:
 		case PFC:
-		case ACFC:
 			/* don't care */
 			break;
+		case ACFC:
+		{
+			struct lcp_data *lcp = pppcp_get_data(pppcp);
+
+			if (lcp->req_options & REQ_OPTION_ACFC)
+				ppp_set_xmit_acfc(ppp, TRUE);
+
+			break;
+		}
 		}
 	}
 
@@ -338,3 +354,16 @@ struct pppcp_data *lcp_new(GAtPPP *ppp, gboolean is_server)
 
 	return pppcp;
 }
+
+void lcp_set_acfc_enabled(struct pppcp_data *pppcp, gboolean enabled)
+{
+	struct lcp_data *lcp = pppcp_get_data(pppcp);
+
+	if (enabled == TRUE)
+		lcp->req_options |= REQ_OPTION_ACFC;
+	else
+		lcp->req_options &= ~REQ_OPTION_ACFC;
+
+	lcp_generate_config_options(lcp);
+	pppcp_set_local_options(pppcp, lcp->options, lcp->options_len);
+}