net: lwm2m: introduce getter/setter for OPAQUE data

Each content formatter should have a way of handling opaque data.

For instance TLV data will individually be able to specify a length
but plain text will take up the rest of the packet.

Signed-off-by: Michael Scott <michael.scott@linaro.org>

subsys/net/lib/lwm2m/lwm2m_engine.c

@@ -1834,6 +1834,30 @@ static int lwm2m_read_handler(struct lwm2m_engine_obj_inst *obj_inst,
 	return 0;
 }
 
+size_t lwm2m_engine_get_opaque_more(struct lwm2m_input_context *in,
+				    u8_t *buf, size_t buflen, bool *last_block)
+{
+	u16_t in_len = in->opaque_len;
+
+	if (in_len > buflen) {
+		in_len = buflen;
+	}
+
+	in->opaque_len -= in_len;
+	if (in->opaque_len == 0) {
+		*last_block = true;
+	}
+
+	in->frag = net_frag_read(in->frag, in->offset, &in->offset, in_len,
+				 buf);
+	if (!in->frag && in->offset == 0xffff) {
+		*last_block = true;
+		return 0;
+	}
+
+	return (size_t)in_len;
+}
+
 /* This function is exposed for the content format writers */
 int lwm2m_write_handler(struct lwm2m_engine_obj_inst *obj_inst,
 			struct lwm2m_engine_res_inst *res,

subsys/net/lib/lwm2m/lwm2m_engine.h

@@ -112,6 +112,9 @@ enum coap_block_size lwm2m_default_block_size(void);
 
 int lwm2m_engine_add_service(void (*service)(void), u32_t period_ms);
 
+size_t lwm2m_engine_get_opaque_more(struct lwm2m_input_context *in,
+				    u8_t *buf, size_t buflen, bool *last_block);
+
 #if defined(CONFIG_LWM2M_FIRMWARE_UPDATE_OBJ_SUPPORT)
 u8_t lwm2m_firmware_get_update_state(void);
 void lwm2m_firmware_set_update_state(u8_t state);

subsys/net/lib/lwm2m/lwm2m_object.h

@@ -229,6 +229,9 @@ struct lwm2m_input_context {
 
 	/* length of incoming coap/lwm2m payload */
 	u16_t payload_len;
+
+	/* length of incoming opaque */
+	u16_t opaque_len;
 };
 
 /* LWM2M format writer for the various formats supported */
@@ -265,6 +268,9 @@ struct lwm2m_writer {
 	size_t (*put_bool)(struct lwm2m_output_context *out,
 			   struct lwm2m_obj_path *path,
 			   bool value);
+	size_t (*put_opaque)(struct lwm2m_output_context *out,
+			     struct lwm2m_obj_path *path,
+			     char *buf, size_t buflen);
 };
 
 struct lwm2m_reader {
@@ -280,6 +286,8 @@ struct lwm2m_reader {
 				 float64_value_t *value);
 	size_t (*get_bool)(struct lwm2m_input_context *in,
 			   bool *value);
+	size_t (*get_opaque)(struct lwm2m_input_context *in,
+			     u8_t *buf, size_t buflen, bool *last_block);
 };
 
 /* LWM2M engine context */
@@ -388,6 +396,17 @@ static inline size_t engine_put_bool(struct lwm2m_output_context *out,
 	return out->writer->put_bool(out, path, value);
 }
 
+static inline size_t engine_put_opaque(struct lwm2m_output_context *out,
+				       struct lwm2m_obj_path *path,
+				       char *buf, size_t buflen)
+{
+	if (out->writer->put_opaque) {
+		return out->writer->put_opaque(out, path, buf, buflen);
+	}
+
+	return 0;
+}
+
 static inline size_t engine_get_s32(struct lwm2m_input_context *in,
 				    s32_t *value)
 {
@@ -424,4 +443,15 @@ static inline size_t engine_get_bool(struct lwm2m_input_context *in,
 	return in->reader->get_bool(in, value);
 }
 
+static inline size_t engine_get_opaque(struct lwm2m_input_context *in,
+				       u8_t *buf, size_t buflen,
+				       bool *last_block)
+{
+	if (in->reader->get_opaque) {
+		return in->reader->get_opaque(in, buf, buflen, last_block);
+	}
+
+	return 0;
+}
+
 #endif /* LWM2M_OBJECT_H_ */

subsys/net/lib/lwm2m/lwm2m_rw_json.c

@@ -462,7 +462,8 @@ const struct lwm2m_writer json_writer = {
 	put_string,
 	put_float32fix,
 	put_float64fix,
-	put_bool
+	put_bool,
+	NULL
 };
 
 static int parse_path(const u8_t *buf, u16_t buflen,

subsys/net/lib/lwm2m/lwm2m_rw_oma_tlv.c

@@ -699,6 +699,16 @@ static size_t get_bool(struct lwm2m_input_context *in, bool *value)
 	return size;
 }
 
+static size_t get_opaque(struct lwm2m_input_context *in,
+			 u8_t *value, size_t buflen, bool *last_block)
+{
+	struct oma_tlv tlv;
+
+	oma_tlv_get(&tlv, in, false);
+	in->opaque_len = tlv.length;
+	return lwm2m_engine_get_opaque_more(in, value, buflen, last_block);
+}
+
 const struct lwm2m_writer oma_tlv_writer = {
 	NULL,
 	NULL,
@@ -711,7 +721,8 @@ const struct lwm2m_writer oma_tlv_writer = {
 	put_string,
 	put_float32fix,
 	put_float64fix,
-	put_bool
+	put_bool,
+	NULL
 };
 
 const struct lwm2m_reader oma_tlv_reader = {
@@ -720,7 +731,8 @@ const struct lwm2m_reader oma_tlv_reader = {
 	get_string,
 	get_float32fix,
 	get_float64fix,
-	get_bool
+	get_bool,
+	get_opaque
 };
 
 static int do_write_op_tlv_item(struct lwm2m_engine_context *context)

subsys/net/lib/lwm2m/lwm2m_rw_plain_text.c

@@ -301,6 +301,13 @@ static size_t get_bool(struct lwm2m_input_context *in,
 	return 0;
 }
 
+static size_t get_opaque(struct lwm2m_input_context *in,
+			 u8_t *value, size_t buflen, bool *last_block)
+{
+	in->opaque_len = pkt_length_left(in);
+	return lwm2m_engine_get_opaque_more(in, value, buflen, last_block);
+}
+
 const struct lwm2m_writer plain_text_writer = {
 	NULL,
 	NULL,
@@ -313,7 +320,8 @@ const struct lwm2m_writer plain_text_writer = {
 	put_string,
 	put_float32fix,
 	put_float64fix,
-	put_bool
+	put_bool,
+	NULL
 };
 
 const struct lwm2m_reader plain_text_reader = {
@@ -322,7 +330,8 @@ const struct lwm2m_reader plain_text_reader = {
 	get_string,
 	get_float32fix,
 	get_float64fix,
-	get_bool
+	get_bool,
+	get_opaque
 };
 
 int do_write_op_plain_text(struct lwm2m_engine_obj *obj,