mirror of https://github.com/wb2osz/direwolf.git
299 lines
7.3 KiB
C
299 lines
7.3 KiB
C
/*-------------------------------------------------------------------
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*
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* Name: ax25_pad.h
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*
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* Purpose: Header file for using ax25_pad.c
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*
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*------------------------------------------------------------------*/
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#ifndef AX25_PAD_H
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#define AX25_PAD_H 1
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#define AX25_MAX_REPEATERS 8
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#define AX25_MIN_ADDRS 2 /* Destinatin & Source. */
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#define AX25_MAX_ADDRS 10 /* Destination, Source, 8 digipeaters. */
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#define AX25_DESTINATION 0 /* Address positions in frame. */
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#define AX25_SOURCE 1
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#define AX25_REPEATER_1 2
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#define AX25_REPEATER_2 3
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#define AX25_REPEATER_3 4
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#define AX25_REPEATER_4 5
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#define AX25_REPEATER_5 6
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#define AX25_REPEATER_6 7
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#define AX25_REPEATER_7 8
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#define AX25_REPEATER_8 9
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#define AX25_MAX_ADDR_LEN 12 /* In theory, you would expect the maximum length */
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/* to be 6 letters, dash, 2 digits, and nul for a */
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/* total of 10. However, object labels can be 10 */
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/* characters so throw in a couple extra bytes */
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/* to be safe. */
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#define AX25_MIN_INFO_LEN 0 /* Previously 1 when considering only APRS. */
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#define AX25_MAX_INFO_LEN 2048 /* Maximum size for APRS. */
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/* AX.25 starts out with 256 as the default max */
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/* length but the end stations can negotiate */
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/* something different. */
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/* version 0.8: Change from 256 to 2028 to */
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/* handle the larger paclen for Linux AX25. */
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/* These don't include the 2 bytes for the */
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/* HDLC frame FCS. */
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/*
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* Previously, for APRS only.
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* #define AX25_MIN_PACKET_LEN ( 2 * 7 + 2 + AX25_MIN_INFO_LEN)
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* #define AX25_MAX_PACKET_LEN ( AX25_MAX_ADDRS * 7 + 2 + AX25_MAX_INFO_LEN)
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*/
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/* the more general case. */
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#define AX25_MIN_PACKET_LEN ( 2 * 7 + 1 )
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#define AX25_MAX_PACKET_LEN ( AX25_MAX_ADDRS * 7 + 2 + 3 + AX25_MAX_INFO_LEN)
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/*
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* packet_t is a pointer to a packet object.
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*
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* The actual implementation is not visible outside ax25_pad.c.
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*/
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#define AX25_UI_FRAME 3 /* Control field value. */
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#define AX25_NO_LAYER_3 0xf0 /* protocol ID */
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#ifdef AX25_PAD_C /* Keep this hidden - implementation could change. */
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struct packet_s {
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int magic1; /* for error checking. */
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#define MAGIC 0x41583235
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struct packet_s *nextp; /* Pointer to next in queue. */
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int num_addr; /* Number of elements used in two below. */
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/* Range of 0 .. AX25_MAX_ADDRS. */
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char addrs[AX25_MAX_ADDRS][AX25_MAX_ADDR_LEN];
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/* Contains the address without the ssid. */
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/* Why is it larger than 7? */
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/* Messages from an IGate server can have longer */
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/* addresses after qAC. Up to 9 observed so far. */
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/* usual human readable form. e.g. WB20SZ-15 */
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unsigned char ssid_etc[AX25_MAX_ADDRS]; /* SSID octet from each address. */
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/*
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* Bits: H R R SSID 0
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*
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* H for digipeaters set to 0 intially.
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* Changed to 1 when position has been used.
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*
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* for source & destination it is called
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* command/response and is normally 1.
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*
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* R R Reserved. Normally set to 1 1.
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*
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* SSID Substation ID. Range of 0 - 15.
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*
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* 0 Usually 0 but 1 for last address.
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*/
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#define SSID_H_MASK 0x80
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#define SSID_H_SHIFT 7
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#define SSID_RR_MASK 0x60
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#define SSID_RR_SHIFT 5
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#define SSID_SSID_MASK 0x1e
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#define SSID_SSID_SHIFT 1
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#define SSID_LAST_MASK 0x01
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int the_rest_len; /* Frame length minus the address part. */
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unsigned char the_rest[2 + 3 + AX25_MAX_INFO_LEN + 1];
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/* The rest after removing the addresses. */
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/* Includes control, protocol ID, Information, */
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/* and throw in one more for a character */
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/* string nul terminator. */
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int magic2; /* Will get stomped on if above overflows. */
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};
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#else /* Public view. */
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struct packet_s {
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int secret;
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};
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#endif
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typedef struct packet_s *packet_t;
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#ifdef AX25_PAD_C /* Keep this hidden - implementation could change. */
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/*
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* APRS always has one control octet of 0x03 but the more
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* general AX.25 case is one or two control bytes depending on
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* "modulo 128 operation" is in effect. Unfortunately, it seems
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* this can be determined only by examining the XID frames and
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* keeping this information for each connection.
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* We can assume 1 for our purposes.
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*/
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static inline int ax25_get_control_offset (packet_t this_p)
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{
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return (0);
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}
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static inline int ax25_get_num_control (packet_t this_p)
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{
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return (1);
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}
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/*
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* APRS always has one protocol octet of 0xF0 meaning no level 3
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* protocol but the more general case is 0, 1 or 2 protocol ID octets.
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*/
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static inline int ax25_get_pid_offset (packet_t this_p)
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{
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return (ax25_get_num_control(this_p));
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}
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static int ax25_get_num_pid (packet_t this_p)
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{
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int c;
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int pid;
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c = this_p->the_rest[ax25_get_control_offset(this_p)];
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if ( (c & 0x01) == 0 || /* I xxxx xxx0 */
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c == 0x03 || c == 0x13) { /* UI 000x 0011 */
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pid = this_p->the_rest[ax25_get_pid_offset(this_p)];
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if (pid == 0xff) {
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return (2); /* pid 1111 1111 means another follows. */
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}
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return (1);
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}
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return (0);
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}
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/*
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* APRS always has an Information field with at least one octet for the
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* Data Type Indicator. AX.25 has this for only 5 frame types depending
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* on the control field.
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* xxxx xxx0 I
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* 000x 0011 UI
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* 101x 1111 XID
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* 111x 0011 TEST
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* 100x 0111 FRMR
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*/
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static inline int ax25_get_info_offset (packet_t this_p)
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{
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return (ax25_get_num_control(this_p) + ax25_get_num_pid(this_p));
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}
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static int ax25_get_num_info (packet_t this_p)
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{
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int len;
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len = this_p->the_rest_len - ax25_get_num_control(this_p) - ax25_get_num_pid(this_p);
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if (len < 0) {
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len = 0; /* print error? */
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}
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return (len);
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}
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#endif
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//static packet_t ax25_new (void);
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extern void ax25_delete (packet_t pp);
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extern void ax25_clear (packet_t pp);
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extern packet_t ax25_from_text (char *, int strict);
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extern packet_t ax25_from_frame (unsigned char *data, int len, int alevel);
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extern packet_t ax25_dup (packet_t copy_from);
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extern int ax25_parse_addr (char *in_addr, int strict, char *out_addr, int *out_ssid, int *out_heard);
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extern packet_t ax25_unwrap_third_party (packet_t from_pp);
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extern void ax25_set_addr (packet_t pp, int, char *);
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extern void ax25_insert_addr (packet_t this_p, int n, char *ad);
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extern void ax25_remove_addr (packet_t this_p, int n);
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extern int ax25_get_num_addr (packet_t pp);
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extern int ax25_get_num_repeaters (packet_t this_p);
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extern void ax25_get_addr_with_ssid (packet_t pp, int n, char *);
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extern int ax25_get_ssid (packet_t pp, int n);
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extern void ax25_set_ssid (packet_t this_p, int n, int ssid);
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extern int ax25_get_h (packet_t pp, int n);
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extern void ax25_set_h (packet_t pp, int n);
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extern int ax25_get_heard(packet_t this_p);
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extern int ax25_get_first_not_repeated(packet_t pp);
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extern int ax25_get_info (packet_t pp, unsigned char **paddr);
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extern void ax25_set_nextp (packet_t this_p, packet_t next_p);
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extern int ax25_get_dti (packet_t this_p);
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extern packet_t ax25_get_nextp (packet_t this_p);
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extern void ax25_format_addrs (packet_t pp, char *);
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extern int ax25_pack (packet_t pp, unsigned char result[AX25_MAX_PACKET_LEN]);
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extern int ax25_is_aprs (packet_t pp);
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extern int ax25_get_control (packet_t this_p);
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extern int ax25_get_pid (packet_t this_p);
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extern unsigned short ax25_dedupe_crc (packet_t pp);
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extern unsigned short ax25_m_m_crc (packet_t pp);
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extern void ax25_safe_print (char *, int, int ascii_only);
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#endif /* AX25_PAD_H */
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/* end ax25_pad.h */
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