diff --git a/gtp/gtp.h b/gtp/gtp.h
index d1f0e22..7e09f6d 100644
--- a/gtp/gtp.h
+++ b/gtp/gtp.h
@@ -153,67 +153,67 @@
  *   redundant because the header also includes flow. */
 
 struct gtp0_header {    /*    Descriptions from 3GPP 09.60 */
-  u_int8_t  flags;      /* 01 bitfield, with typical values */
+  uint8_t  flags;      /* 01 bitfield, with typical values */
                         /*    000..... Version: 1 (0) */
                         /*    ...1111. Spare (7) */
                         /*    .......0 SNDCP N-PDU Number flag (0) */
-  u_int8_t  type;	        /* 02 Message type. T-PDU = 0xff */
-  u_int16_t length;	/* 03 Length (of G-PDU excluding header) */
-  u_int16_t seq;	        /* 05 Sequence Number */
-  u_int16_t flow;	        /* 07 Flow Label ( = 0 for signalling) */
-  u_int8_t  number;	/* 09 SNDCP N-PDU LCC Number ( 0 = 0xff) */
-  u_int8_t  spare1;	/* 10 Spare */
-  u_int8_t  spare2;	/* 11 Spare */
-  u_int8_t  spare3;	/* 12 Spare */
-  u_int64_t tid;	/* 13 Tunnel ID */
+  uint8_t  type;	        /* 02 Message type. T-PDU = 0xff */
+  uint16_t length;	/* 03 Length (of G-PDU excluding header) */
+  uint16_t seq;	        /* 05 Sequence Number */
+  uint16_t flow;	        /* 07 Flow Label ( = 0 for signalling) */
+  uint8_t  number;	/* 09 SNDCP N-PDU LCC Number ( 0 = 0xff) */
+  uint8_t  spare1;	/* 10 Spare */
+  uint8_t  spare2;	/* 11 Spare */
+  uint8_t  spare3;	/* 12 Spare */
+  uint64_t tid;	/* 13 Tunnel ID */
 };                      /* 20 */
 
 struct gtp1_header_short { /*    Descriptions from 3GPP 29060 */
-  u_int8_t  flags;         /* 01 bitfield, with typical values */
+  uint8_t  flags;         /* 01 bitfield, with typical values */
                            /*    001..... Version: 1 */
                            /*    ...1.... Protocol Type: GTP=1, GTP'=0 */
                            /*    ....0... Spare = 0 */
                            /*    .....0.. Extension header flag: 0 */
                            /*    ......0. Sequence number flag: 0 */
                            /*    .......0 PN: N-PDU Number flag */
-  u_int8_t  type;	   /* 02 Message type. T-PDU = 0xff */
-  u_int16_t length;	   /* 03 Length (of IP packet or signalling) */
-  u_int32_t tei;           /* 05 - 08 Tunnel Endpoint ID */
+  uint8_t  type;	   /* 02 Message type. T-PDU = 0xff */
+  uint16_t length;	   /* 03 Length (of IP packet or signalling) */
+  uint32_t tei;           /* 05 - 08 Tunnel Endpoint ID */
 };
 
 struct gtp1_header_long {  /*    Descriptions from 3GPP 29060 */
-  u_int8_t  flags;         /* 01 bitfield, with typical values */
+  uint8_t  flags;         /* 01 bitfield, with typical values */
                            /*    001..... Version: 1 */
                            /*    ...1.... Protocol Type: GTP=1, GTP'=0 */
                            /*    ....0... Spare = 0 */
                            /*    .....0.. Extension header flag: 0 */
                            /*    ......1. Sequence number flag: 1 */
                            /*    .......0 PN: N-PDU Number flag */
-  u_int8_t  type;	   /* 02 Message type. T-PDU = 0xff */
-  u_int16_t length;	   /* 03 Length (of IP packet or signalling) */
-  u_int32_t tei;	   /* 05 Tunnel Endpoint ID */
-  u_int16_t seq;	   /* 10 Sequence Number */
-  u_int8_t  npdu;	   /* 11 N-PDU Number */
-  u_int8_t  next;	   /* 12 Next extension header type. Empty = 0 */
+  uint8_t  type;	   /* 02 Message type. T-PDU = 0xff */
+  uint16_t length;	   /* 03 Length (of IP packet or signalling) */
+  uint32_t tei;	   /* 05 Tunnel Endpoint ID */
+  uint16_t seq;	   /* 10 Sequence Number */
+  uint8_t  npdu;	   /* 11 N-PDU Number */
+  uint8_t  next;	   /* 12 Next extension header type. Empty = 0 */
 };
 
 struct gtp0_packet {
   struct gtp0_header h;
-  u_int8_t p[GTP_MAX];
+  uint8_t p[GTP_MAX];
 } __attribute__((packed));
 
 struct gtp1_packet_short {
   struct gtp1_header_short h;
-  u_int8_t p[GTP_MAX];
+  uint8_t p[GTP_MAX];
 } __attribute__((packed));
 
 struct gtp1_packet_long {
   struct gtp1_header_long h;
-  u_int8_t p[GTP_MAX];
+  uint8_t p[GTP_MAX];
 } __attribute__((packed));
 
 union gtp_packet {
-  u_int8_t flags;
+  uint8_t flags;
   struct gtp0_packet        gtp0;
   struct gtp1_packet_short  gtp1s;
   struct gtp1_packet_long   gtp1l;