batman-adv: fix header alignment by unrolling batadv_header

The size of the batadv_header of 3 is problematic on some architectures
which automatically pad all structures to a 32 bit boundary. To not lose
performance by packing this struct, better embed it into the various
host structures.

Reported-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

1 files changed, 53 insertions, 21 deletions

diff --git a/net/batman-adv/packet.h b/net/batman-adv/packet.h
index 10597a6729a6..175ce7d721d6 100644
--- a/net/batman-adv/packet.h
+++ b/net/batman-adv/packet.h
@@ -164,23 +164,18 @@ struct batadv_bla_claim_dst {
         __be16 group;           /* group id */
 };
 
-struct batadv_header {
-        uint8_t  packet_type;
-        uint8_t  version;  /* batman version field */
-        uint8_t  ttl;
-        /* the parent struct has to add a byte after the header to make
-         * everything 4 bytes aligned again
-         */
-};
-
 /**
  * struct batadv_ogm_packet - ogm (routing protocol) packet
- * @header: common batman packet header
+ * @packet_type: batman-adv packet type, part of the general header
+ * @version: batman-adv protocol version, part of the genereal header
+ * @ttl: time to live for this packet, part of the genereal header
  * @flags: contains routing relevant flags - see enum batadv_iv_flags
  * @tvlv_len: length of tvlv data following the ogm header
  */
 struct batadv_ogm_packet {
-        struct batadv_header header;
+        uint8_t  packet_type;
+        uint8_t  version;
+        uint8_t  ttl;
         uint8_t  flags;
         __be32   seqno;
         uint8_t  orig[ETH_ALEN];
@@ -197,14 +192,18 @@ struct batadv_ogm_packet {
 
 /**
  * batadv_icmp_header - common ICMP header
- * @header: common batman header
+ * @packet_type: batman-adv packet type, part of the general header
+ * @version: batman-adv protocol version, part of the genereal header
+ * @ttl: time to live for this packet, part of the genereal header
  * @msg_type: ICMP packet type
  * @dst: address of the destination node
  * @orig: address of the source node
  * @uid: local ICMP socket identifier
  */
 struct batadv_icmp_header {
-        struct batadv_header header;
+        uint8_t  packet_type;
+        uint8_t  version;
+        uint8_t  ttl;
         uint8_t  msg_type; /* see ICMP message types above */
         uint8_t  dst[ETH_ALEN];
         uint8_t  orig[ETH_ALEN];
@@ -253,8 +252,18 @@ struct batadv_icmp_packet_rr {
  */
 #pragma pack(2)
 
+/**
+ * struct batadv_unicast_packet - unicast packet for network payload
+ * @packet_type: batman-adv packet type, part of the general header
+ * @version: batman-adv protocol version, part of the genereal header
+ * @ttl: time to live for this packet, part of the genereal header
+ * @ttvn: translation table version number
+ * @dest: originator destination of the unicast packet
+ */
 struct batadv_unicast_packet {
-        struct batadv_header header;
+        uint8_t  packet_type;
+        uint8_t  version;
+        uint8_t  ttl;
         uint8_t  ttvn; /* destination translation table version number */
         uint8_t  dest[ETH_ALEN];
         /* "4 bytes boundary + 2 bytes" long to make the payload after the
@@ -280,7 +289,9 @@ struct batadv_unicast_4addr_packet {
 
 /**
  * struct batadv_frag_packet - fragmented packet
- * @header: common batman packet header with type, compatversion, and ttl
+ * @packet_type: batman-adv packet type, part of the general header
+ * @version: batman-adv protocol version, part of the genereal header
+ * @ttl: time to live for this packet, part of the genereal header
  * @dest: final destination used when routing fragments
  * @orig: originator of the fragment used when merging the packet
  * @no: fragment number within this sequence
@@ -289,7 +300,9 @@ struct batadv_unicast_4addr_packet {
  * @total_size: size of the merged packet
  */
 struct batadv_frag_packet {
-        struct  batadv_header header;
+        uint8_t packet_type;
+        uint8_t version;  /* batman version field */
+        uint8_t ttl;
 #if defined(__BIG_ENDIAN_BITFIELD)
         uint8_t no:4;
         uint8_t reserved:4;
@@ -305,8 +318,19 @@ struct batadv_frag_packet {
         __be16  total_size;
 };
 
+/**
+ * struct batadv_bcast_packet - broadcast packet for network payload
+ * @packet_type: batman-adv packet type, part of the general header
+ * @version: batman-adv protocol version, part of the genereal header
+ * @ttl: time to live for this packet, part of the genereal header
+ * @reserved: reserved byte for alignment
+ * @seqno: sequence identification
+ * @orig: originator of the broadcast packet
+ */
 struct batadv_bcast_packet {
-        struct batadv_header header;
+        uint8_t  packet_type;
+        uint8_t  version;  /* batman version field */
+        uint8_t  ttl;
         uint8_t  reserved;
         __be32   seqno;
         uint8_t  orig[ETH_ALEN];
@@ -317,7 +341,9 @@ struct batadv_bcast_packet {
 
 /**
  * struct batadv_coded_packet - network coded packet
- * @header: common batman packet header and ttl of first included packet
+ * @packet_type: batman-adv packet type, part of the general header
+ * @version: batman-adv protocol version, part of the genereal header
+ * @ttl: time to live for this packet, part of the genereal header
  * @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
@@ -332,7 +358,9 @@ struct batadv_bcast_packet {
  * @coded_len: length of network coded part of the payload
  */
 struct batadv_coded_packet {
-        struct batadv_header header;
+        uint8_t  packet_type;
+        uint8_t  version;  /* batman version field */
+        uint8_t  ttl;
         uint8_t  first_ttvn;
         /* uint8_t  first_dest[ETH_ALEN]; - saved in mac header destination */
         uint8_t  first_source[ETH_ALEN];
@@ -351,7 +379,9 @@ struct batadv_coded_packet {
 
 /**
  * struct batadv_unicast_tvlv - generic unicast packet with tvlv payload
- * @header: common batman packet header
+ * @packet_type: batman-adv packet type, part of the general header
+ * @version: batman-adv protocol version, part of the genereal header
+ * @ttl: time to live for this packet, part of the genereal header
  * @reserved: reserved field (for packet alignment)
  * @src: address of the source
  * @dst: address of the destination
@@ -359,7 +389,9 @@ struct batadv_coded_packet {
  * @align: 2 bytes to align the header to a 4 byte boundry
  */
 struct batadv_unicast_tvlv_packet {
-        struct batadv_header header;
+        uint8_t  packet_type;
+        uint8_t  version;  /* batman version field */
+        uint8_t  ttl;
         uint8_t  reserved;
         uint8_t  dst[ETH_ALEN];
         uint8_t  src[ETH_ALEN];