batman-adv: tvlv - basic infrastructure

The goal is to provide the infrastructure for sending, receiving and
parsing information 'containers' while preserving backward
compatibility. TVLV (based on the commonly known Type Length Value
technique) was chosen as the format for those containers. Even if a
node does not know the tvlv type of a certain container it can simply
skip the current container and proceed with the next. Past experience
has shown features evolve over time, so a 'version' field was added
right from the start to allow differentiating between feature
variants - hence the name: T(ype) V(ersion) L(ength) V(alue).

This patch introduces the basic TVLV infrastructure:
 * register / unregister tvlv containers to be sent with each OGM
   (on primary interfaces only)
 * register / unregister callback handlers to be called upon
   finding the corresponding tvlv type in a tvlv buffer
 * unicast tvlv send / receive API calls

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Spyros Gasteratos <morfeas3000@gmail.com>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/net/batman-adv/packet.h b/net/batman-adv/packet.h
index 11a22c8..b5c21c4 100644
--- a/net/batman-adv/packet.h
+++ b/net/batman-adv/packet.h
@@ -20,6 +20,10 @@
 #ifndef _NET_BATMAN_ADV_PACKET_H_
 #define _NET_BATMAN_ADV_PACKET_H_
 
+/**
+ * enum batadv_packettype - types for batman-adv encapsulated packets
+ * @BATADV_UNICAST_TVLV: unicast packet carrying TVLV containers
+ */
 enum batadv_packettype {
 	BATADV_IV_OGM		= 0x01,
 	BATADV_ICMP		= 0x02,
@@ -31,6 +35,7 @@ enum batadv_packettype {
 	BATADV_ROAM_ADV		= 0x08,
 	BATADV_UNICAST_4ADDR	= 0x09,
 	BATADV_CODED		= 0x0a,
+	BATADV_UNICAST_TVLV	= 0x0b,
 };
 
 /**
@@ -131,6 +136,11 @@ struct batadv_header {
 	 */
 };
 
+/**
+ * struct batadv_ogm_packet - ogm (routing protocol) packet
+ * @header: common batman packet header
+ * @tvlv_len: length of tvlv data following the ogm header
+ */
 struct batadv_ogm_packet {
 	struct batadv_header header;
 	uint8_t  flags;    /* 0x40: DIRECTLINK flag, 0x20 VIS_SERVER flag... */
@@ -142,6 +152,7 @@ struct batadv_ogm_packet {
 	uint8_t  tt_num_changes;
 	uint8_t  ttvn; /* translation table version number */
 	__be16   tt_crc;
+	__be16   tvlv_len;
 } __packed;
 
 #define BATADV_OGM_HLEN sizeof(struct batadv_ogm_packet)
@@ -311,4 +322,34 @@ struct batadv_coded_packet {
 	__be16   coded_len;
 };
 
+/**
+ * struct batadv_unicast_tvlv - generic unicast packet with tvlv payload
+ * @header: common batman packet header
+ * @reserved: reserved field (for packet alignment)
+ * @src: address of the source
+ * @dst: address of the destination
+ * @tvlv_len: length of tvlv data following the unicast tvlv header
+ * @align: 2 bytes to align the header to a 4 byte boundry
+ */
+struct batadv_unicast_tvlv_packet {
+	struct batadv_header header;
+	uint8_t  reserved;
+	uint8_t  dst[ETH_ALEN];
+	uint8_t  src[ETH_ALEN];
+	__be16   tvlv_len;
+	uint16_t align;
+};
+
+/**
+ * struct batadv_tvlv_hdr - base tvlv header struct
+ * @type: tvlv container type (see batadv_tvlv_type)
+ * @version: tvlv container version
+ * @len: tvlv container length
+ */
+struct batadv_tvlv_hdr {
+	uint8_t type;
+	uint8_t version;
+	__be16  len;
+};
+
 #endif /* _NET_BATMAN_ADV_PACKET_H_ */