2 files changed, 63 insertions, 0 deletions

diff --git a/gatchat/ppp_cp.c b/gatchat/ppp_cp.c
index 98c6635d..1c86bee4 100644
--- a/gatchat/ppp_cp.c
+++ b/gatchat/ppp_cp.c
@@ -217,6 +217,52 @@ static struct pppcp_packet *pppcp_packet_new(struct pppcp_data *data,
 	return packet;
 }
 
+void ppp_option_iter_init(struct ppp_option_iter *iter,
+					const struct pppcp_packet *packet)
+{
+	iter->max = ntohs(packet->length) - CP_HEADER_SZ;
+	iter->pdata = packet->data;
+	iter->pos = 0;
+	iter->type = 0;
+	iter->len = 0;
+	iter->option_data = NULL;
+}
+
+gboolean ppp_option_iter_next(struct ppp_option_iter *iter)
+{
+	const guint8 *cur = iter->pdata + iter->pos;
+	const guint8 *end = iter->pdata + iter->max;
+
+	if (cur + 1 > end)
+		return FALSE;
+
+	if (cur + cur[1] > end)
+		return FALSE;
+
+	iter->type = cur[0];
+	iter->len = cur[1] - 2;
+	iter->option_data = cur + 2;
+
+	iter->pdata += cur[1];
+
+	return TRUE;
+}
+
+guint8 ppp_option_iter_get_type(struct ppp_option_iter *iter)
+{
+	return iter->type;
+}
+
+guint8 ppp_option_iter_get_length(struct ppp_option_iter *iter)
+{
+	return iter->len;
+}
+
+const guint8 *ppp_option_iter_get_data(struct ppp_option_iter *iter)
+{
+	return iter->option_data;
+}
+
 static gboolean pppcp_timeout(gpointer user_data)
 {
 	struct pppcp_timer_data *timer_data = user_data;
diff --git a/gatchat/ppp_cp.h b/gatchat/ppp_cp.h
index 913df0f8..407cbd7e 100644
--- a/gatchat/ppp_cp.h
+++ b/gatchat/ppp_cp.h
@@ -20,6 +20,7 @@
  */
 
 struct pppcp_data;
+struct ppp_option_iter;
 
 /* option format */
 struct ppp_option {
@@ -48,6 +49,15 @@ enum pppcp_code {
 	PPPCP_CODE_TYPE_DISCARD_REQUEST
 };
 
+struct ppp_option_iter {
+	guint16 max;
+	guint16 pos;
+	const guint8 *pdata;
+	guint8 type;
+	guint8 len;
+	const guint8 *option_data;
+};
+
 struct pppcp_action {
 	void (*this_layer_up)(struct pppcp_data *data);
 	void (*this_layer_down)(struct pppcp_data *data);
@@ -66,6 +76,13 @@ struct pppcp_packet {
 	guint8 data[0];
 } __attribute__((packed));
 
+void ppp_option_iter_init(struct ppp_option_iter *iter,
+					const struct pppcp_packet *packet);
+gboolean ppp_option_iter_next(struct ppp_option_iter *iter);
+guint8 ppp_option_iter_get_type(struct ppp_option_iter *iter);
+guint8 ppp_option_iter_get_length(struct ppp_option_iter *iter);
+const guint8 *ppp_option_iter_get_data(struct ppp_option_iter *iter);
+
 struct pppcp_data *pppcp_new(GAtPPP *ppp, guint16 proto,
 				const struct pppcp_action *action);
 void pppcp_free(struct pppcp_data *data);