batman-adv: Explicitly mark the common header structure

All batman-adv packets have a common 3 byte header. It can be used to share
some code between different code paths, but it was never explicit stated that
this header has to be always the same for all packets. Therefore, new code
changes always have the problem that they may accidently introduce regressions
by moving some elements around.

A new structure is introduced that contains the common header and makes it
easier visible that these 3 bytes have to be the same for all on-wire packets.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

1 files changed, 13 insertions, 25 deletions

diff --git a/net/batman-adv/packet.h b/net/batman-adv/packet.h
index 4d9e54c57a36..88c717b9344d 100644
--- a/net/batman-adv/packet.h
+++ b/net/batman-adv/packet.h
@@ -90,10 +90,14 @@ enum tt_client_flags {
         TT_CLIENT_PENDING = 1 << 10
 };
 
-struct batman_ogm_packet {
+struct batman_header {
         uint8_t  packet_type;
         uint8_t  version;  /* batman version field */
         uint8_t  ttl;
+} __packed;
+
+struct batman_ogm_packet {
+        struct batman_header header;
         uint8_t  flags;    /* 0x40: DIRECTLINK flag, 0x20 VIS_SERVER flag... */
         uint32_t seqno;
         uint8_t  orig[6];
@@ -108,9 +112,7 @@ struct batman_ogm_packet {
 #define BATMAN_OGM_LEN sizeof(struct batman_ogm_packet)
 
 struct icmp_packet {
-        uint8_t  packet_type;
-        uint8_t  version;  /* batman version field */
-        uint8_t  ttl;
+        struct batman_header header;
         uint8_t  msg_type; /* see ICMP message types above */
         uint8_t  dst[6];
         uint8_t  orig[6];
@@ -124,9 +126,7 @@ struct icmp_packet {
 /* icmp_packet_rr must start with all fields from imcp_packet
  * as this is assumed by code that handles ICMP packets */
 struct icmp_packet_rr {
-        uint8_t  packet_type;
-        uint8_t  version;  /* batman version field */
-        uint8_t  ttl;
+        struct batman_header header;
         uint8_t  msg_type; /* see ICMP message types above */
         uint8_t  dst[6];
         uint8_t  orig[6];
@@ -137,17 +137,13 @@ struct icmp_packet_rr {
 } __packed;
 
 struct unicast_packet {
-        uint8_t  packet_type;
-        uint8_t  version;  /* batman version field */
-        uint8_t  ttl;
+        struct batman_header header;
         uint8_t  ttvn; /* destination translation table version number */
         uint8_t  dest[6];
 } __packed;
 
 struct unicast_frag_packet {
-        uint8_t  packet_type;
-        uint8_t  version;  /* batman version field */
-        uint8_t  ttl;
+        struct batman_header header;
         uint8_t  ttvn; /* destination translation table version number */
         uint8_t  dest[6];
         uint8_t  flags;
@@ -157,18 +153,14 @@ struct unicast_frag_packet {
 } __packed;
 
 struct bcast_packet {
-        uint8_t  packet_type;
-        uint8_t  version;  /* batman version field */
-        uint8_t  ttl;
+        struct batman_header header;
         uint8_t  reserved;
         uint32_t seqno;
         uint8_t  orig[6];
 } __packed;
 
 struct vis_packet {
-        uint8_t  packet_type;
-        uint8_t  version;        /* batman version field */
-        uint8_t  ttl;            /* TTL */
+        struct batman_header header;
         uint8_t  vis_type;       /* which type of vis-participant sent this? */
         uint32_t seqno;          /* sequence number */
         uint8_t  entries;        /* number of entries behind this struct */
@@ -179,9 +171,7 @@ struct vis_packet {
 } __packed;
 
 struct tt_query_packet {
-        uint8_t  packet_type;
-        uint8_t  version;  /* batman version field */
-        uint8_t  ttl;
+        struct batman_header header;
         /* the flag field is a combination of:
          * - TT_REQUEST or TT_RESPONSE
          * - TT_FULL_TABLE */
@@ -202,9 +192,7 @@ struct tt_query_packet {
 } __packed;
 
 struct roam_adv_packet {
-        uint8_t  packet_type;
-        uint8_t  version;
-        uint8_t  ttl;
+        struct batman_header header;
         uint8_t  reserved;
         uint8_t  dst[ETH_ALEN];
         uint8_t  src[ETH_ALEN];