i386/linux/linux-2.3.21/include/net/llc_frame.h

   1 /* if_ether.h needed for definition of ETH_DATA_LEN and ETH_ALEN
   2  */
   3 #include "linux/if_ether.h"
   4
   5 /* frame layout based on par3.2 "LLC PDU format"
   6  */
   7 typedef union {                 /* pdu layout from pages 40 & 44 */
   8     struct {                    /* general header, all pdu types */
   9         unsigned dsap : 8;      /* dest service access point */
  10         unsigned ssap : 8;      /* source service access point */
  11         unsigned f1 : 1;        /* I- U- or S- format id bits */
  12         unsigned f2 : 1;
  13         unsigned : 6;
  14         unsigned : 8;
  15    } pdu_hdr;
  16    struct {
  17         char dummy1[2];         /* dsap + ssap */
  18         char byte1;
  19         char byte2;
  20    } pdu_cntl;                  /* unformatted control bytes */
  21    struct {                     /* header of an Information pdu */
  22         unsigned char dummy2[2];
  23         unsigned : 1;
  24         unsigned ns : 7;
  25         unsigned i_pflag : 1;   /* poll/final bit */
  26         unsigned nr : 7;        /* N(R)  */
  27         unsigned char is_info[ ETH_DATA_LEN ];
  28    }  i_hdr;
  29    struct {                     /* header of a Supervisory pdu */
  30         unsigned char dummy3[2];
  31         unsigned : 2;
  32         unsigned ss : 2;        /* supervisory function bits */
  33         unsigned : 4;
  34         unsigned s_pflag : 1;   /* poll/final bit  */
  35         unsigned nr : 7;        /* N(R)  */
  36    } s_hdr;
  37
  38 /* when accessing the P/F bit or the N(R) field there's no need to distinguish
  39    I pdus from S pdus i_pflag and s_pflag / i_nr and s_nr map to the same
  40    physical location.
  41  */
  42    struct {                     /* header of an Unnumbered pdu */
  43         unsigned char dummy4[2];
  44         unsigned : 2;
  45         unsigned mm1 : 2;       /* modifier function part1 */
  46         unsigned u_pflag : 1;    /* P/F for U- pdus */
  47         unsigned mm2 : 3;       /* modifier function part2 */
  48         unsigned char u_info[ ETH_DATA_LEN-1];
  49    } u_hdr;
  50    struct {                     /* mm field in an Unnumbered pdu */
  51         unsigned char dummy5[2];
  52         unsigned : 2;
  53         unsigned mm : 6;        /* must be masked to get ridd of P/F !  */
  54    } u_mm;
  55
  56 } frame_type, *frameptr;
  57
  58 /* frame format test macros: */
  59
  60 #define IS_UFRAME( fr ) ( ( (fr)->pdu_hdr.f1) & ( (fr)->pdu_hdr.f2) )
  61
  62 #define IS_IFRAME( fr ) ( !( (fr)->pdu_hdr.f1) )
  63
  64 #define IS_SFRAME( fr ) ( ( (fr)->pdu_hdr.f1) & !( (fr)->pdu_hdr.f2) )
  65
  66 #define IS_RSP( fr ) ( fr->pdu_hdr.ssap & 0x01 )
  67
  68
  69 /* The transition table, the _encode tables and some tests in the
  70    source code depend on the numeric order of these values.
  71    Think twice before changing.
  72  */
  73
  74 /* frame names for TYPE 2 operation: */
  75 #define I_CMD           0
  76 #define RR_CMD          1
  77 #define RNR_CMD         2
  78 #define REJ_CMD         3
  79 #define DISC_CMD        4
  80 #define SABME_CMD       5
  81 #define I_RSP           6
  82 #define RR_RSP          7
  83 #define RNR_RSP         8
  84 #define REJ_RSP         9
  85 #define UA_RSP          10
  86 #define DM_RSP          11
  87 #define FRMR_RSP        12
  88
  89 /* junk frame name: */
  90 #define BAD_FRAME       13
  91 #define NO_FRAME        13
  92
  93 /* frame names for TYPE 1 operation: */
  94 #define UI_CMD          14
  95 #define XID_CMD         15
  96 #define TEST_CMD        16
  97 #define XID_RSP         17
  98 #define TEST_RSP        18