batman-adv: network coding - code and transmit packets if possible

Before adding forward-skbs to the coding buffer, the buffer is searched
for a potential coding opportunity. If one is found, the two packets are
network coded and transmitted right away. If not, the forward-skb is
added to the buffer.

Network coded packets are transmitted with information about the two
receivers and the two coded packets. The first receiver is given by the
MAC header, while the second is given in the payload/bat-header. The
second receiver uses promiscuous mode to receive the packet and check
the second destination.

Signed-off-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/net/batman-adv/packet.h b/net/batman-adv/packet.h
index ed0aa89bbf8b..a07995834b84 100644
--- a/net/batman-adv/packet.h
+++ b/net/batman-adv/packet.h
@@ -30,6 +30,7 @@ enum batadv_packettype {
         BATADV_TT_QUERY         = 0x07,
         BATADV_ROAM_ADV         = 0x08,
         BATADV_UNICAST_4ADDR    = 0x09,
+        BATADV_CODED            = 0x0a,
 };
 
 /**
@@ -278,4 +279,36 @@ struct batadv_tt_change {
         uint8_t addr[ETH_ALEN];
 } __packed;
 
+/**
+ * struct batadv_coded_packet - network coded packet
+ * @header: common batman packet header and ttl of first included packet
+ * @reserved: Align following fields to 2-byte boundaries
+ * @first_source: original source of first included packet
+ * @first_orig_dest: original destinal of first included packet
+ * @first_crc: checksum of first included packet
+ * @first_ttvn: tt-version number of first included packet
+ * @second_ttl: ttl of second packet
+ * @second_dest: second receiver of this coded packet
+ * @second_source: original source of second included packet
+ * @second_orig_dest: original destination of second included packet
+ * @second_crc: checksum of second included packet
+ * @second_ttvn: tt version number of second included packet
+ * @coded_len: length of network coded part of the payload
+ */
+struct batadv_coded_packet {
+        struct batadv_header header;
+        uint8_t  first_ttvn;
+        /* uint8_t  first_dest[ETH_ALEN]; - saved in mac header destination */
+        uint8_t  first_source[ETH_ALEN];
+        uint8_t  first_orig_dest[ETH_ALEN];
+        __be32   first_crc;
+        uint8_t  second_ttl;
+        uint8_t  second_ttvn;
+        uint8_t  second_dest[ETH_ALEN];
+        uint8_t  second_source[ETH_ALEN];
+        uint8_t  second_orig_dest[ETH_ALEN];
+        __be32   second_crc;
+        uint16_t coded_len;
+};
+
 #endif /* _NET_BATMAN_ADV_PACKET_H_ */