diff --git a/src/libssh2_priv.h b/src/libssh2_priv.h
index d281c11..04741a7 100644
--- a/src/libssh2_priv.h
+++ b/src/libssh2_priv.h
@@ -178,7 +178,6 @@ static inline int writev(int sock, struct iovec *iov, int nvecs)
 
 typedef struct _LIBSSH2_KEX_METHOD LIBSSH2_KEX_METHOD;
 typedef struct _LIBSSH2_HOSTKEY_METHOD LIBSSH2_HOSTKEY_METHOD;
-typedef struct _LIBSSH2_MAC_METHOD LIBSSH2_MAC_METHOD;
 typedef struct _LIBSSH2_CRYPT_METHOD LIBSSH2_CRYPT_METHOD;
 typedef struct _LIBSSH2_COMP_METHOD LIBSSH2_COMP_METHOD;
 
@@ -310,7 +309,7 @@ struct _LIBSSH2_PACKET
 
     /* Where to start reading data from,
      * used for channel data that's been partially consumed */
-    unsigned long data_head;
+    size_t data_head;
 };
 
 typedef struct _libssh2_channel_data
@@ -319,7 +318,7 @@ typedef struct _libssh2_channel_data
     uint32_t id;
 
     /* Limits and restrictions */
-    unsigned long window_size_initial, window_size, packet_size;
+    uint32_t window_size_initial, window_size, packet_size;
 
     /* Set to 1 when CHANNEL_CLOSE / CHANNEL_EOF sent/received */
     char close, eof, extended_data_ignore_mode;
@@ -340,7 +339,7 @@ struct _LIBSSH2_CHANNEL
 
     libssh2_channel_data local, remote;
     /* Amount of bytes to be refunded to receive window (but not yet sent) */
-    unsigned long adjust_queue;
+    int adjust_queue;
 
     LIBSSH2_SESSION *session;
 
@@ -445,8 +444,8 @@ typedef struct _libssh2_endpoint_data
     const LIBSSH2_CRYPT_METHOD *crypt;
     void *crypt_abstract;
 
-    const LIBSSH2_MAC_METHOD *mac;
-    unsigned long seqno;
+    const struct _LIBSSH2_MAC_METHOD *mac;
+    uint32_t seqno;
     void *mac_abstract;
 
     const LIBSSH2_COMP_METHOD *comp;
@@ -499,7 +498,7 @@ struct transportpacket
 struct _LIBSSH2_PUBLICKEY
 {
     LIBSSH2_CHANNEL *channel;
-    unsigned long version;
+    uint32_t version;
 
     /* State variables used in libssh2_publickey_packet_receive() */
     libssh2_nonblocking_states receive_state;
@@ -560,7 +559,7 @@ struct _LIBSSH2_SESSION
     int burn_optimistic_kexinit:1;
 
     unsigned char *session_id;
-    unsigned long session_id_len;
+    uint32_t session_id_len;
 
     /* this is set to TRUE if a blocking API behavior is requested */
     int api_block_mode;
@@ -573,7 +572,7 @@ struct _LIBSSH2_SESSION
      * Or read from server in (eg) KEXDH_INIT (for client mode)
      */
     unsigned char *server_hostkey;
-    unsigned long server_hostkey_len;
+    uint32_t server_hostkey_len;
 #if LIBSSH2_MD5
     unsigned char server_hostkey_md5[MD5_DIGEST_LENGTH];
 #endif                          /* ! LIBSSH2_MD5 */
@@ -592,7 +591,7 @@ struct _LIBSSH2_SESSION
     /* Active connection channels */
     struct list_head channels;
 
-    unsigned long next_channel;
+    uint32_t next_channel;
 
     struct list_head listeners; /* list of LIBSSH2_LISTENER structs */
 
@@ -720,8 +719,8 @@ struct _LIBSSH2_SESSION
     /* State variables used in libssh2_channel_forward_listen_ex() */
     libssh2_nonblocking_states fwdLstn_state;
     unsigned char *fwdLstn_packet;
-    unsigned long fwdLstn_host_len;
-    unsigned long fwdLstn_packet_len;
+    uint32_t fwdLstn_host_len;
+    uint32_t fwdLstn_packet_len;
     packet_requirev_state_t fwdLstn_packet_requirev_state;
 
     /* State variables used in libssh2_publickey_init() */
@@ -759,9 +758,9 @@ struct _LIBSSH2_SESSION
     /* State variables used in libssh2_scp_recv() */
     libssh2_nonblocking_states scpRecv_state;
     unsigned char *scpRecv_command;
-    unsigned long scpRecv_command_len;
+    size_t scpRecv_command_len;
     unsigned char scpRecv_response[LIBSSH2_SCP_RESPONSE_BUFLEN];
-    unsigned long scpRecv_response_len;
+    size_t scpRecv_response_len;
     long scpRecv_mode;
 #if defined(HAVE_LONGLONG) && defined(HAVE_STRTOLL)
     /* we have the type and we can parse such numbers */
@@ -778,9 +777,9 @@ struct _LIBSSH2_SESSION
     /* State variables used in libssh2_scp_send_ex() */
     libssh2_nonblocking_states scpSend_state;
     unsigned char *scpSend_command;
-    unsigned long scpSend_command_len;
+    size_t scpSend_command_len;
     unsigned char scpSend_response[LIBSSH2_SCP_RESPONSE_BUFLEN];
-    unsigned long scpSend_response_len;
+    size_t scpSend_response_len;
     LIBSSH2_CHANNEL *scpSend_channel;
 
     /* Keepalive variables used by keepalive.c. */
@@ -886,26 +885,6 @@ struct _LIBSSH2_COMP_METHOD
     int (*dtor) (LIBSSH2_SESSION * session, int compress, void **abstract);
 };
 
-struct _LIBSSH2_MAC_METHOD
-{
-    const char *name;
-
-    /* The length of a given MAC packet */
-    int mac_len;
-
-    /* integrity key length */
-    int key_len;
-
-    /* Message Authentication Code Hashing algo */
-    int (*init) (LIBSSH2_SESSION * session, unsigned char *key, int *free_key,
-                 void **abstract);
-    int (*hash) (LIBSSH2_SESSION * session, unsigned char *buf,
-                 unsigned long seqno, const unsigned char *packet,
-                 unsigned long packet_len, const unsigned char *addtl,
-                 unsigned long addtl_len, void **abstract);
-    int (*dtor) (LIBSSH2_SESSION * session, void **abstract);
-};
-
 #ifdef LIBSSH2DEBUG
 void _libssh2_debug(LIBSSH2_SESSION * session, int context, const char *format,
                     ...);
diff --git a/src/mac.c b/src/mac.c
index 4045910..76894fc 100644
--- a/src/mac.c
+++ b/src/mac.c
@@ -44,9 +44,9 @@
  */
 static int
 mac_none_MAC(LIBSSH2_SESSION * session, unsigned char *buf,
-             unsigned long seqno, const unsigned char *packet,
-             unsigned long packet_len, const unsigned char *addtl,
-             unsigned long addtl_len, void **abstract)
+             uint32_t seqno, const unsigned char *packet,
+             uint32_t packet_len, const unsigned char *addtl,
+             uint32_t addtl_len, void **abstract)
 {
     return 0;
 }
@@ -101,11 +101,11 @@ mac_method_common_dtor(LIBSSH2_SESSION * session, void **abstract)
  */
 static int
 mac_method_hmac_sha1_hash(LIBSSH2_SESSION * session,
-                          unsigned char *buf, unsigned long seqno,
+                          unsigned char *buf, uint32_t seqno,
                           const unsigned char *packet,
-                          unsigned long packet_len,
+                          uint32_t packet_len,
                           const unsigned char *addtl,
-                          unsigned long addtl_len, void **abstract)
+                          uint32_t addtl_len, void **abstract)
 {
     libssh2_hmac_ctx ctx;
     unsigned char seqno_buf[4];
@@ -141,11 +141,11 @@ static const LIBSSH2_MAC_METHOD mac_method_hmac_sha1 = {
  */
 static int
 mac_method_hmac_sha1_96_hash(LIBSSH2_SESSION * session,
-                             unsigned char *buf, unsigned long seqno,
+                             unsigned char *buf, uint32_t seqno,
                              const unsigned char *packet,
-                             unsigned long packet_len,
+                             uint32_t packet_len,
                              const unsigned char *addtl,
-                             unsigned long addtl_len, void **abstract)
+                             uint32_t addtl_len, void **abstract)
 {
     unsigned char temp[SHA_DIGEST_LENGTH];
 
@@ -173,11 +173,11 @@ static const LIBSSH2_MAC_METHOD mac_method_hmac_sha1_96 = {
  */
 static int
 mac_method_hmac_md5_hash(LIBSSH2_SESSION * session, unsigned char *buf,
-                         unsigned long seqno,
+                         uint32_t seqno,
                          const unsigned char *packet,
-                         unsigned long packet_len,
+                         uint32_t packet_len,
                          const unsigned char *addtl,
-                         unsigned long addtl_len, void **abstract)
+                         uint32_t addtl_len, void **abstract)
 {
     libssh2_hmac_ctx ctx;
     unsigned char seqno_buf[4];
@@ -213,11 +213,11 @@ static const LIBSSH2_MAC_METHOD mac_method_hmac_md5 = {
  */
 static int
 mac_method_hmac_md5_96_hash(LIBSSH2_SESSION * session,
-                            unsigned char *buf, unsigned long seqno,
+                            unsigned char *buf, uint32_t seqno,
                             const unsigned char *packet,
-                            unsigned long packet_len,
+                            uint32_t packet_len,
                             const unsigned char *addtl,
-                            unsigned long addtl_len, void **abstract)
+                            uint32_t addtl_len, void **abstract)
 {
     unsigned char temp[MD5_DIGEST_LENGTH];
     mac_method_hmac_md5_hash(session, temp, seqno, packet, packet_len,
@@ -244,11 +244,11 @@ static const LIBSSH2_MAC_METHOD mac_method_hmac_md5_96 = {
  */
 static int
 mac_method_hmac_ripemd160_hash(LIBSSH2_SESSION * session,
-                               unsigned char *buf, unsigned long seqno,
+                               unsigned char *buf, uint32_t seqno,
                                const unsigned char *packet,
-                               unsigned long packet_len,
+                               uint32_t packet_len,
                                const unsigned char *addtl,
-                               unsigned long addtl_len,
+                               uint32_t addtl_len,
                                void **abstract)
 {
     libssh2_hmac_ctx ctx;
diff --git a/src/mac.h b/src/mac.h
index efccf9d..66d3e61 100644
--- a/src/mac.h
+++ b/src/mac.h
@@ -1,7 +1,7 @@
 #ifndef __LIBSSH2_MAC_H
 #define __LIBSSH2_MAC_H
 
-/* Copyright (C) 2009 by Daniel Stenberg
+/* Copyright (C) 2009-2010 by Daniel Stenberg
  *
  * Redistribution and use in source and binary forms,
  * with or without modification, are permitted provided
@@ -40,6 +40,28 @@
 
 #include "libssh2_priv.h"
 
+struct _LIBSSH2_MAC_METHOD
+{
+    const char *name;
+
+    /* The length of a given MAC packet */
+    int mac_len;
+
+    /* integrity key length */
+    int key_len;
+
+    /* Message Authentication Code Hashing algo */
+    int (*init) (LIBSSH2_SESSION * session, unsigned char *key, int *free_key,
+                 void **abstract);
+    int (*hash) (LIBSSH2_SESSION * session, unsigned char *buf,
+                 uint32_t seqno, const unsigned char *packet,
+                 uint32_t packet_len, const unsigned char *addtl,
+                 uint32_t addtl_len, void **abstract);
+    int (*dtor) (LIBSSH2_SESSION * session, void **abstract);
+};
+
+typedef struct _LIBSSH2_MAC_METHOD LIBSSH2_MAC_METHOD;
+
 const LIBSSH2_MAC_METHOD **_libssh2_mac_methods(void);
 
 #endif /* __LIBSSH2_MAC_H */
diff --git a/src/session.c b/src/session.c
index fd852ff..62e5640 100644
--- a/src/session.c
+++ b/src/session.c
@@ -55,6 +55,7 @@
 #include "transport.h"
 #include "session.h"
 #include "channel.h"
+#include "mac.h"
 
 /* libssh2_default_alloc
  */
diff --git a/src/transport.c b/src/transport.c
index a027ff1..cbe49df 100644
--- a/src/transport.c
+++ b/src/transport.c
@@ -49,6 +49,7 @@
 #include <assert.h>
 
 #include "transport.h"
+#include "mac.h"
 
 #define MAX_BLOCKSIZE 32    /* MUST fit biggest crypto block size we use/get */
 #define MAX_MACSIZE 20      /* MUST fit biggest MAC length we support */