include/net/gen/vjhc.h

   1 /*
   2 net/gen/vjhc.h
   3
   4 Defines for Van Jacobson TCP/IP Header Compression as defined in RFC-1144
   5
   6 Created:        Nov 15, 1993 by Philip Homburg <philip@cs.vu.nl>
   7 */
   8
   9 #ifndef __NET__GEN__VJHC_H__
  10 #define __NET__GEN__VJHC_H__
  11
  12 #define VJHC_FLAG_U     0x01
  13 #define VJHC_FLAG_W     0x02
  14 #define VJHC_FLAG_A     0x04
  15 #define VJHC_FLAG_S     0x08
  16 #define VJHC_FLAG_P     0x10
  17 #define VJHC_FLAG_I     0x20
  18 #define VJHC_FLAG_C     0x40
  19
  20 #define VJHC_SPEC_I     (VJHC_FLAG_S | VJHC_FLAG_W | VJHC_FLAG_U)
  21 #define VJHC_SPEC_D     (VJHC_FLAG_S | VJHC_FLAG_A | VJHC_FLAG_W | VJHC_FLAG_U)
  22 #define VJHC_SPEC_MASK  (VJHC_FLAG_S | VJHC_FLAG_A | VJHC_FLAG_W | VJHC_FLAG_U)
  23
  24 #define VJHC_ENCODE(cp, n) \
  25 { \
  26         if ((u16_t)(n) >= 256) \
  27         { \
  28                 *(cp)++= 0; \
  29                 *(cp)++= (n >> 8); \
  30                 *(cp)++= (n); \
  31         } \
  32         else \
  33                 *(cp)++= (n); \
  34 }
  35
  36 #define VJHC_ENCODEZ(cp, n) \
  37 { \
  38         if ((u16_t)(n) == 0 || (u16_t)(n) >= 256) \
  39         { \
  40                 *(cp)++= 0; \
  41                 *(cp)++= (n >> 8); \
  42                 *(cp)++= (n); \
  43         } \
  44         else \
  45                 *(cp)++= (n); \
  46 }
  47
  48 #define VJHC_DECODEL(cp, l) \
  49 { \
  50         if (*(cp) == 0) \
  51         { \
  52                 (l)= htonl(ntohl((l)) + (((cp)[1] << 8) | (cp)[2])); \
  53                 (cp) += 3; \
  54         } \
  55         else \
  56                 (l)= htonl(ntohl((l)) + (u32_t)*(cp)++); \
  57 }
  58
  59 #define VJHC_DECODES(cp, s) \
  60 { \
  61         if (*(cp) == 0) \
  62         { \
  63                 (s)= htons(ntohs((s)) + (((cp)[1] << 8) | (cp)[2])); \
  64                 (cp) += 3; \
  65         } \
  66         else \
  67                 (s)= htons(ntohs((s)) + (u16_t)*(cp)++); \
  68 }
  69
  70 #define VJHC_DECODEU(cp, s) \
  71 { \
  72         if (*(cp) == 0) \
  73         { \
  74                 (s)= htons(((cp)[1] << 8) | (cp)[2]); \
  75                 (cp) += 3; \
  76         } \
  77         else \
  78                 (s)= htons((u16_t)*(cp)++); \
  79 }
  80
  81 #endif /* __NET__GEN__VJHC_H__ */
  82
  83 /*
  84  * $PchId: vjhc.h,v 1.2 1995/11/17 22:14:46 philip Exp $
  85  */