/*------------------------------------------------------------------- * * Name: ax25_pad.h * * Purpose: Header file for using ax25_pad.c * *------------------------------------------------------------------*/ #ifndef AX25_PAD_H #define AX25_PAD_H 1 #define AX25_MAX_REPEATERS 8 #define AX25_MIN_ADDRS 2 /* Destinatin & Source. */ #define AX25_MAX_ADDRS 10 /* Destination, Source, 8 digipeaters. */ #define AX25_DESTINATION 0 /* Address positions in frame. */ #define AX25_SOURCE 1 #define AX25_REPEATER_1 2 #define AX25_REPEATER_2 3 #define AX25_REPEATER_3 4 #define AX25_REPEATER_4 5 #define AX25_REPEATER_5 6 #define AX25_REPEATER_6 7 #define AX25_REPEATER_7 8 #define AX25_REPEATER_8 9 #define AX25_MAX_ADDR_LEN 12 /* In theory, you would expect the maximum length */ /* to be 6 letters, dash, 2 digits, and nul for a */ /* total of 10. However, object labels can be 10 */ /* characters so throw in a couple extra bytes */ /* to be safe. */ #define AX25_MIN_INFO_LEN 0 /* Previously 1 when considering only APRS. */ #define AX25_MAX_INFO_LEN 2048 /* Maximum size for APRS. */ /* AX.25 starts out with 256 as the default max */ /* length but the end stations can negotiate */ /* something different. */ /* version 0.8: Change from 256 to 2028 to */ /* handle the larger paclen for Linux AX25. */ /* These don't include the 2 bytes for the */ /* HDLC frame FCS. */ /* * Previously, for APRS only. * #define AX25_MIN_PACKET_LEN ( 2 * 7 + 2 + AX25_MIN_INFO_LEN) * #define AX25_MAX_PACKET_LEN ( AX25_MAX_ADDRS * 7 + 2 + AX25_MAX_INFO_LEN) */ /* The more general case. */ /* An AX.25 frame can have a control byte and no protocol. */ #define AX25_MIN_PACKET_LEN ( 2 * 7 + 1 ) #define AX25_MAX_PACKET_LEN ( AX25_MAX_ADDRS * 7 + 2 + 3 + AX25_MAX_INFO_LEN) /* * packet_t is a pointer to a packet object. * * The actual implementation is not visible outside ax25_pad.c. */ #define AX25_UI_FRAME 3 /* Control field value. */ #define AX25_PID_NO_LAYER_3 0xf0 /* protocol ID used for APRS */ #define AX25_PID_SEGMENTATION_FRAGMENT 0x08 #define AX25_PID_ESCAPE_CHARACTER 0xff #ifdef AX25_PAD_C /* Keep this hidden - implementation could change. */ struct packet_s { int magic1; /* for error checking. */ int seq; /* unique sequence number for debugging. */ double release_time; /* Time stamp in format returned by dtime_now(). */ /* When to release from the SATgate mode delay queue. */ #define MAGIC 0x41583235 struct packet_s *nextp; /* Pointer to next in queue. */ int num_addr; /* Number of addresses in frame. */ /* Range of AX25_MIN_ADDRS .. AX25_MAX_ADDRS for AX.25. */ /* It will be 0 if it doesn't look like AX.25. */ /* -1 is used temporarily at allocation to mean */ /* not determined yet. */ /* * The 7th octet of each address contains: * * Bits: H R R SSID 0 * * H for digipeaters set to 0 intially. * Changed to 1 when position has been used. * * for source & destination it is called * command/response. Normally both 1 for APRS. * They should be opposites for connected mode. * * R R Reserved. Normally set to 1 1. * * SSID Substation ID. Range of 0 - 15. * * 0 Usually 0 but 1 for last address. */ #define SSID_H_MASK 0x80 #define SSID_H_SHIFT 7 #define SSID_RR_MASK 0x60 #define SSID_RR_SHIFT 5 #define SSID_SSID_MASK 0x1e #define SSID_SSID_SHIFT 1 #define SSID_LAST_MASK 0x01 int frame_len; /* Frame length without CRC. */ int modulo; /* I & S frames have sequence numbers of either 3 bits (modulo 8) */ /* or 7 bits (modulo 128). This is conveyed by either 1 or 2 */ /* control bytes. Unfortunately, we can't determine this by looking */ /* at an isolated frame. We need to know about the context. If we */ /* are part of the conversation, we would know. But if we are */ /* just listening to others, this would be more difficult to determine. */ /* For U frames: set to 0 - not applicable */ /* For I & S frames: 8 or 128 if known. 0 if unknown. */ unsigned char frame_data[AX25_MAX_PACKET_LEN+1]; /* Raw frame contents, without the CRC. */ int magic2; /* Will get stomped on if above overflows. */ }; #else /* Public view. */ struct packet_s { int secret; }; #endif typedef struct packet_s *packet_t; typedef enum cmdres_e { cr_00 = 2, cr_cmd = 1, cr_res = 0, cr_11 = 3 } cmdres_t; extern packet_t ax25_new (void); #ifdef AX25_PAD_C /* Keep this hidden - implementation could change. */ /* * APRS always has one control octet of 0x03 but the more * general AX.25 case is one or two control bytes depending on * whether "modulo 128 operation" is in effect. */ //#define DEBUGX 1 static inline int ax25_get_control_offset (packet_t this_p) { return (this_p->num_addr*7); } static inline int ax25_get_num_control (packet_t this_p) { int c; c = this_p->frame_data[ax25_get_control_offset(this_p)]; if ( (c & 0x01) == 0 ) { /* I xxxx xxx0 */ #if DEBUGX dw_printf ("ax25_get_num_control, %02x is I frame, returns %d\n", c, (this_p->modulo == 128) ? 2 : 1); #endif return ((this_p->modulo == 128) ? 2 : 1); } if ( (c & 0x03) == 1 ) { /* S xxxx xx01 */ #if DEBUGX dw_printf ("ax25_get_num_control, %02x is S frame, returns %d\n", c, (this_p->modulo == 128) ? 2 : 1); #endif return ((this_p->modulo == 128) ? 2 : 1); } #if DEBUGX dw_printf ("ax25_get_num_control, %02x is U frame, always returns 1.\n", c); #endif return (1); /* U xxxx xx11 */ } /* * APRS always has one protocol octet of 0xF0 meaning no level 3 * protocol but the more general case is 0, 1 or 2 protocol ID octets. */ static inline int ax25_get_pid_offset (packet_t this_p) { return (ax25_get_control_offset (this_p) + ax25_get_num_control(this_p)); } static int ax25_get_num_pid (packet_t this_p) { int c; int pid; c = this_p->frame_data[ax25_get_control_offset(this_p)]; if ( (c & 0x01) == 0 || /* I xxxx xxx0 */ c == 0x03 || c == 0x13) { /* UI 000x 0011 */ pid = this_p->frame_data[ax25_get_pid_offset(this_p)]; #if DEBUGX dw_printf ("ax25_get_num_pid, %02x is I or UI frame, pid = %02x, returns %d\n", c, pid, (pid==AX25_PID_ESCAPE_CHARACTER) ? 2 : 1); #endif if (pid == AX25_PID_ESCAPE_CHARACTER) { return (2); /* pid 1111 1111 means another follows. */ } return (1); } #if DEBUGX dw_printf ("ax25_get_num_pid, %02x is neither I nor UI frame, returns 0\n", c); #endif return (0); } /* * AX.25 has info field for 5 frame types depending on the control field. * * xxxx xxx0 I * 000x 0011 UI (which includes APRS) * 101x 1111 XID * 111x 0011 TEST * 100x 0111 FRMR * * APRS always has an Information field with at least one octet for the Data Type Indicator. */ static inline int ax25_get_info_offset (packet_t this_p) { int offset = ax25_get_control_offset (this_p) + ax25_get_num_control(this_p) + ax25_get_num_pid(this_p); #if DEBUGX dw_printf ("ax25_get_info_offset, returns %d\n", offset); #endif return (offset); } static inline int ax25_get_num_info (packet_t this_p) { int len; /* assuming AX.25 frame. */ len = this_p->frame_len - this_p->num_addr * 7 - ax25_get_num_control(this_p) - ax25_get_num_pid(this_p); if (len < 0) { len = 0; /* print error? */ } return (len); } #endif typedef enum ax25_modulo_e { modulo_unknown = 0, modulo_8 = 8, modulo_128 = 128 } ax25_modulo_t; typedef enum ax25_frame_type_e { frame_type_I = 0, // Information frame_type_S_RR, // Receive Ready - System Ready To Receive frame_type_S_RNR, // Receive Not Ready - TNC Buffer Full frame_type_S_REJ, // Reject Frame - Out of Sequence or Duplicate frame_type_S_SREJ, // Selective Reject - Request single frame repeat frame_type_U_SABME, // Set Async Balanced Mode, Extended frame_type_U_SABM, // Set Async Balanced Mode frame_type_U_DISC, // Disconnect frame_type_U_DM, // Disconnect Mode frame_type_U_UA, // Unnumbered Acknowledge frame_type_U_FRMR, // Frame Reject frame_type_U_UI, // Unnumbered Information frame_type_U_XID, // Exchange Identification frame_type_U_TEST, // Test frame_type_U, // other Unnumbered, not used by AX.25. frame_not_AX25 // Could not get control byte from frame. // This must be last because value plus 1 is // for the size of an array. } ax25_frame_type_t; /* * Originally this was a single number. * Let's try something new in version 1.2. * Also collect AGC values from the mark and space filters. */ typedef struct alevel_s { int rec; int mark; int space; //float ms_ratio; // TODO: take out after temporary investigation. } alevel_t; #ifndef AXTEST // TODO: remove this? #define AX25MEMDEBUG 1 #endif #if AX25MEMDEBUG // to investigate a memory leak problem extern void ax25memdebug_set(void); extern int ax25memdebug_get (void); extern int ax25memdebug_seq (packet_t this_p); extern packet_t ax25_from_text_debug (char *monitor, int strict, char *src_file, int src_line); #define ax25_from_text(m,s) ax25_from_text_debug(m,s,__FILE__,__LINE__) extern packet_t ax25_from_frame_debug (unsigned char *data, int len, alevel_t alevel, char *src_file, int src_line); #define ax25_from_frame(d,l,a) ax25_from_frame_debug(d,l,a,__FILE__,__LINE__); extern packet_t ax25_dup_debug (packet_t copy_from, char *src_file, int src_line); #define ax25_dup(p) ax25_dup_debug(p,__FILE__,__LINE__); extern void ax25_delete_debug (packet_t pp, char *src_file, int src_line); #define ax25_delete(p) ax25_delete_debug(p,__FILE__,__LINE__); #else extern packet_t ax25_from_text (char *monitor, int strict); extern packet_t ax25_from_frame (unsigned char *data, int len, alevel_t alevel); extern packet_t ax25_dup (packet_t copy_from); extern void ax25_delete (packet_t pp); #endif extern int ax25_parse_addr (int position, char *in_addr, int strict, char *out_addr, int *out_ssid, int *out_heard); extern int ax25_check_addresses (packet_t pp); extern packet_t ax25_unwrap_third_party (packet_t from_pp); extern void ax25_set_addr (packet_t pp, int, char *); extern void ax25_insert_addr (packet_t this_p, int n, char *ad); extern void ax25_remove_addr (packet_t this_p, int n); extern int ax25_get_num_addr (packet_t pp); extern int ax25_get_num_repeaters (packet_t this_p); extern void ax25_get_addr_with_ssid (packet_t pp, int n, char *station); extern void ax25_get_addr_no_ssid (packet_t pp, int n, char *station); extern int ax25_get_ssid (packet_t pp, int n); extern void ax25_set_ssid (packet_t this_p, int n, int ssid); extern int ax25_get_h (packet_t pp, int n); extern void ax25_set_h (packet_t pp, int n); extern int ax25_get_heard(packet_t this_p); extern int ax25_get_first_not_repeated(packet_t pp); extern int ax25_get_rr (packet_t this_p, int n); extern int ax25_get_info (packet_t pp, unsigned char **paddr); extern void ax25_set_nextp (packet_t this_p, packet_t next_p); extern int ax25_get_dti (packet_t this_p); extern packet_t ax25_get_nextp (packet_t this_p); extern void ax25_set_release_time (packet_t this_p, double release_time); extern double ax25_get_release_time (packet_t this_p); extern void ax25_set_modulo (packet_t this_p, int modulo); extern void ax25_format_addrs (packet_t pp, char *); extern int ax25_pack (packet_t pp, unsigned char result[AX25_MAX_PACKET_LEN]); extern ax25_frame_type_t ax25_frame_type (packet_t this_p, cmdres_t *cr, char *desc, int *pf, int *nr, int *ns); extern void ax25_hex_dump (packet_t this_p); extern int ax25_is_aprs (packet_t pp); extern int ax25_is_null_frame (packet_t this_p); extern int ax25_get_control (packet_t this_p); extern int ax25_get_c2 (packet_t this_p); extern int ax25_get_pid (packet_t this_p); extern unsigned short ax25_dedupe_crc (packet_t pp); extern unsigned short ax25_m_m_crc (packet_t pp); extern void ax25_safe_print (char *, int, int ascii_only); #define AX25_ALEVEL_TO_TEXT_SIZE 32 // overkill but safe. extern int ax25_alevel_to_text (alevel_t alevel, char text[AX25_ALEVEL_TO_TEXT_SIZE]); #endif /* AX25_PAD_H */ /* end ax25_pad.h */