// // This file is part of Dire Wolf, an amateur radio packet TNC. // // Copyright (C) 2011 , 2013, 2014, 2015 John Langner, WB2OSZ // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 2 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program. If not, see . // /*------------------------------------------------------------------ * * Name: ax25_pad * * Purpose: Packet assembler and disasembler. * * This was written when I was only concerned about APRS which * uses only UI frames. ax25_pad2.c, added years later, has * functions for dealing with other types of frames. * * We can obtain AX.25 packets from different sources: * * (a) from an HDLC frame. * (b) from text representation. * (c) built up piece by piece. * * We also want to use a packet in different ways: * * (a) transmit as an HDLC frame. * (b) print in human-readable text. * (c) take it apart piece by piece. * * Looking at the more general case, we also want to modify * an existing packet. For instance an APRS repeater might * want to change "WIDE2-2" to "WIDE2-1" and retransmit it. * * * Description: * * * APRS uses only UI frames. * Each starts with 2-10 addressses (14-70 octets): * * * Destination Address (note: opposite order in printed format) * * * Source Address * * * 0-8 Digipeater Addresses (Could there ever be more as a result of * digipeaters inserting their own call for * the tracing feature? * NO. The limit is 8 when transmitting AX.25 over the * radio. * Communication with an IGate server could * have a longer VIA path but that is only in text form, * not as an AX.25 frame.) * * Each address is composed of: * * * 6 upper case letters or digits, blank padded. * These are shifted left one bit, leaving the LSB always 0. * * * a 7th octet containing the SSID and flags. * The LSB is always 0 except for the last octet of the address field. * * The final octet of the Destination has the form: * * C R R SSID 0, where, * * C = command/response = 1 * R R = Reserved = 1 1 * SSID = substation ID * 0 = zero * * The AX.25 spec states that the RR bits should be 11 if not used. * There are a couple documents talking about possible uses for APRS. * I'm ignoring them for now. * http://www.aprs.org/aprs12/preemptive-digipeating.txt * http://www.aprs.org/aprs12/RR-bits.txt * * I don't recall why I originally intended to set the source/destination C bits both to 1. * Reviewing this 5 years later, after spending more time delving into the * AX.25 spec, I think it should be 1 for destination and 0 for source. * In practice you see all four combinations being used by APRS stations * and no one really cares about these two bits. * * The final octet of the Source has the form: * * C R R SSID 0, where, * * C = command/response = 1 (originally, now I think it should be 0 for source.) * (Haven't gone back to check to see what code actually does.) * R R = Reserved = 1 1 * SSID = substation ID * 0 = zero (or 1 if no repeaters) * * The final octet of each repeater has the form: * * H R R SSID 0, where, * * H = has-been-repeated = 0 initially. * Set to 1 after this address has been used. * R R = Reserved = 1 1 * SSID = substation ID * 0 = zero (or 1 if last repeater in list) * * A digipeater would repeat this frame if it finds its address * with the "H" bit set to 0 and all earlier repeater addresses * have the "H" bit set to 1. * The "H" bit would be set to 1 in the repeated frame. * * In standard monitoring format, an asterisk is displayed after the last * digipeater with the "H" bit set. That indicates who you are hearing * over the radio. * (That is if digipeaters update the via path properly. Some don't so * we don't know who we are hearing. This is discussed in the User Guide.) * No asterisk means the source is being heard directly. * * Example, if we can hear all stations involved, * * SRC>DST,RPT1,RPT2,RPT3: -- we heard SRC * SRC>DST,RPT1*,RPT2,RPT3: -- we heard RPT1 * SRC>DST,RPT1,RPT2*,RPT3: -- we heard RPT2 * SRC>DST,RPT1,RPT2,RPT3*: -- we heard RPT3 * * * Next we have: * * * One byte Control Field - APRS uses 3 for UI frame * The more general AX.25 frame can have two. * * * One byte Protocol ID - APRS uses 0xf0 for no layer 3 * * Finally the Information Field of 1-256 bytes. * * And, of course, the 2 byte CRC. * * The descriptions above, for the C, H, and RR bits, are for APRS usage. * When operating as a KISS TNC we just pass everything along and don't * interpret or change them. * * * Constructors: ax25_init - Clear everything. * ax25_from_text - Tear apart a text string * ax25_from_frame - Tear apart an AX.25 frame. * Must be called before any other function. * * Get methods: .... - Extract destination, source, or digipeater * address from frame. * * Assumptions: CRC has already been verified to be correct. * *------------------------------------------------------------------*/ #define AX25_PAD_C /* this will affect behavior of ax25_pad.h */ #include "direwolf.h" #include #include #include #include #include #include "regex.h" #if __WIN32__ char *strtok_r(char *str, const char *delim, char **saveptr); #endif #include "textcolor.h" #include "ax25_pad.h" #include "fcs_calc.h" /* * Accumulate statistics. * If new_count gets much larger than delete_count plus the size of * the transmit queue we have a memory leak. */ static volatile int new_count = 0; static volatile int delete_count = 0; static volatile int last_seq_num = 0; #if AX25MEMDEBUG int ax25memdebug = 0; void ax25memdebug_set(void) { ax25memdebug = 1; } int ax25memdebug_get (void) { return (ax25memdebug); } int ax25memdebug_seq (packet_t this_p) { return (this_p->seq); } #endif #define CLEAR_LAST_ADDR_FLAG this_p->frame_data[this_p->num_addr*7-1] &= ~ SSID_LAST_MASK #define SET_LAST_ADDR_FLAG this_p->frame_data[this_p->num_addr*7-1] |= SSID_LAST_MASK /*------------------------------------------------------------------------------ * * Name: ax25_new * * Purpose: Allocate memory for a new packet object. * * Returns: Identifier for a new packet object. * In the current implementation this happens to be a pointer. * *------------------------------------------------------------------------------*/ packet_t ax25_new (void) { struct packet_s *this_p; #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf ("ax25_new(): before alloc, new=%d, delete=%d\n", new_count, delete_count); #endif last_seq_num++; new_count++; /* * check for memory leak. */ // version 1.4 push up the threshold. We could have considerably more with connected mode. //if (new_count > delete_count + 100) { if (new_count > delete_count + 256) { text_color_set(DW_COLOR_ERROR); dw_printf ("Report to WB2OSZ - Memory leak for packet objects. new=%d, delete=%d\n", new_count, delete_count); #if AX25MEMDEBUG // Force on debug option to gather evidence. ax25memdebug_set(); #endif } this_p = calloc(sizeof (struct packet_s), (size_t)1); if (this_p == NULL) { text_color_set(DW_COLOR_ERROR); dw_printf ("ERROR - can't allocate memory in ax25_new.\n"); } assert (this_p != NULL); this_p->magic1 = MAGIC; this_p->seq = last_seq_num; this_p->magic2 = MAGIC; this_p->num_addr = (-1); return (this_p); } /*------------------------------------------------------------------------------ * * Name: ax25_delete * * Purpose: Destroy a packet object, freeing up memory it was using. * *------------------------------------------------------------------------------*/ #if AX25MEMDEBUG void ax25_delete_debug (packet_t this_p, char *src_file, int src_line) #else void ax25_delete (packet_t this_p) #endif { #if DEBUG text_color_set(DW_COLOR_DEBUG); dw_printf ("ax25_delete(): before free, new=%d, delete=%d\n", new_count, delete_count); #endif if (this_p == NULL) { text_color_set(DW_COLOR_ERROR); dw_printf ("ERROR - NULL pointer passed to ax25_delete.\n"); return; } delete_count++; #if AX25MEMDEBUG if (ax25memdebug) { text_color_set(DW_COLOR_DEBUG); dw_printf ("ax25_delete, seq=%d, called from %s %d, new_count=%d, delete_count=%d\n", this_p->seq, src_file, src_line, new_count, delete_count); } #endif assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); this_p->magic1 = 0; this_p->magic1 = 0; //memset (this_p, 0, sizeof (struct packet_s)); free (this_p); } /*------------------------------------------------------------------------------ * * Name: ax25_from_text * * Purpose: Parse a frame in human-readable monitoring format and change * to internal representation. * * Input: monitor - "TNC-2" monitor format for packet. i.e. * source>dest[,repeater1,repeater2,...]:information * * The information part can have non-printable characters * in the form of <0xff>. This will be converted to single * bytes. e.g. <0x0d> is carriage return. * In version 1.4H we will allow nul characters which means * we have to maintain a length rather than using strlen(). * I maintain that it violates the spec but want to handle it * because it does happen and we want to preserve it when * acting as an IGate rather than corrupting it. * * strict - True to enforce rules for packets sent over the air. * False to be more lenient for packets from IGate server. * * Messages from an IGate server can have longer * addresses after qAC. Up to 9 observed so far. * * We can just truncate the name because we will only * end up discarding it. TODO: check on this. * * Returns: Pointer to new packet object in the current implementation. * * Outputs: Use the "get" functions to retrieve information in different ways. * *------------------------------------------------------------------------------*/ #if AX25MEMDEBUG packet_t ax25_from_text_debug (char *monitor, int strict, char *src_file, int src_line) #else packet_t ax25_from_text (char *monitor, int strict) #endif { /* * Tearing it apart is destructive so make our own copy first. */ char stuff[512]; char *pinfo; char *pa; char *saveptr; /* Used with strtok_r because strtok is not thread safe. */ int ssid_temp, heard_temp; char atemp[AX25_MAX_ADDR_LEN]; char info_part[AX25_MAX_INFO_LEN+1]; int info_len; packet_t this_p = ax25_new (); #if AX25MEMDEBUG if (ax25memdebug) { text_color_set(DW_COLOR_DEBUG); dw_printf ("ax25_from_text, seq=%d, called from %s %d\n", this_p->seq, src_file, src_line); } #endif /* Is it possible to have a nul character (zero byte) in the */ /* information field of an AX.25 frame? */ /* At this point, we have a normal C string. */ /* It is possible that will convert <0x00> to a nul character later. */ /* There we need to maintain a separate length and not use normal C string functions. */ strlcpy (stuff, monitor, sizeof(stuff)); /* * Initialize the packet structure with two addresses and control/pid * for APRS. */ memset (this_p->frame_data + AX25_DESTINATION*7, ' ' << 1, 6); this_p->frame_data[AX25_DESTINATION*7+6] = SSID_H_MASK | SSID_RR_MASK; memset (this_p->frame_data + AX25_SOURCE*7, ' ' << 1, 6); this_p->frame_data[AX25_SOURCE*7+6] = SSID_H_MASK | SSID_RR_MASK | SSID_LAST_MASK; this_p->frame_data[14] = AX25_UI_FRAME; this_p->frame_data[15] = AX25_PID_NO_LAYER_3; this_p->frame_len = 7 + 7 + 1 + 1; this_p->num_addr = (-1); assert (ax25_get_num_addr(this_p) == 2); /* * Separate the addresses from the rest. */ pinfo = strchr (stuff, ':'); if (pinfo == NULL) { ax25_delete (this_p); return (NULL); } *pinfo = '\0'; pinfo++; /* * Separate the addresses. * Note that source and destination order is swappped. */ /* * Source address. * Don't use traditional strtok because it is not thread safe. */ pa = strtok_r (stuff, ">", &saveptr); if (pa == NULL) { text_color_set(DW_COLOR_ERROR); dw_printf ("Failed to create packet from text. No source address\n"); ax25_delete (this_p); return (NULL); } if ( ! ax25_parse_addr (AX25_SOURCE, pa, strict, atemp, &ssid_temp, &heard_temp)) { text_color_set(DW_COLOR_ERROR); dw_printf ("Failed to create packet from text. Bad source address\n"); ax25_delete (this_p); return (NULL); } ax25_set_addr (this_p, AX25_SOURCE, atemp); ax25_set_h (this_p, AX25_SOURCE); // c/r in this position ax25_set_ssid (this_p, AX25_SOURCE, ssid_temp); /* * Destination address. */ pa = strtok_r (NULL, ",", &saveptr); if (pa == NULL) { text_color_set(DW_COLOR_ERROR); dw_printf ("Failed to create packet from text. No destination address\n"); ax25_delete (this_p); return (NULL); } if ( ! ax25_parse_addr (AX25_DESTINATION, pa, strict, atemp, &ssid_temp, &heard_temp)) { text_color_set(DW_COLOR_ERROR); dw_printf ("Failed to create packet from text. Bad destination address\n"); ax25_delete (this_p); return (NULL); } ax25_set_addr (this_p, AX25_DESTINATION, atemp); ax25_set_h (this_p, AX25_DESTINATION); // c/r in this position ax25_set_ssid (this_p, AX25_DESTINATION, ssid_temp); /* * VIA path. */ while (( pa = strtok_r (NULL, ",", &saveptr)) != NULL && this_p->num_addr < AX25_MAX_ADDRS ) { int k; k = this_p->num_addr; if ( ! ax25_parse_addr (k, pa, strict, atemp, &ssid_temp, &heard_temp)) { text_color_set(DW_COLOR_ERROR); dw_printf ("Failed to create packet from text. Bad digipeater address\n"); ax25_delete (this_p); return (NULL); } ax25_set_addr (this_p, k, atemp); ax25_set_ssid (this_p, k, ssid_temp); // Does it have an "*" at the end? // TODO: Complain if more than one "*". // Could also check for all has been repeated bits are adjacent. if (heard_temp) { for ( ; k >= AX25_REPEATER_1; k--) { ax25_set_h (this_p, k); } } } /* * Finally, process the information part. * * Translate hexadecimal values like <0xff> to single bytes. * MIC-E format uses 5 different non-printing characters. * We might want to manually generate UTF-8 characters such as degree. */ //#define DEBUG14H 1 #if DEBUG14H text_color_set(DW_COLOR_DEBUG); dw_printf ("BEFORE: %s\nSAFE: ", pinfo); ax25_safe_print (pinfo, -1, 0); dw_printf ("\n"); #endif info_len = 0; while (*pinfo != '\0' && info_len < AX25_MAX_INFO_LEN) { if (strlen(pinfo) >= 6 && pinfo[0] == '<' && pinfo[1] == '0' && pinfo[2] == 'x' && isxdigit(pinfo[3]) && isxdigit(pinfo[4]) && pinfo[5] == '>') { char *p; info_part[info_len] = strtol (pinfo + 3, &p, 16); info_len++; pinfo += 6; } else { info_part[info_len] = *pinfo; info_len++; pinfo++; } } info_part[info_len] = '\0'; #if DEBUG14H text_color_set(DW_COLOR_DEBUG); dw_printf ("AFTER: %s\nSAFE: ", info_part); ax25_safe_print (info_part, info_len, 0); dw_printf ("\n"); #endif /* * Append the info part. */ memcpy ((char*)(this_p->frame_data+this_p->frame_len), info_part, info_len); this_p->frame_len += info_len; return (this_p); } /*------------------------------------------------------------------------------ * * Name: ax25_from_frame * * Purpose: Split apart an HDLC frame to components. * * Inputs: fbuf - Pointer to beginning of frame. * * flen - Length excluding the two FCS bytes. * * alevel - Audio level of received signal. * Maximum range 0 - 100. * -1 might be used when not applicable. * * Returns: Pointer to new packet object or NULL if error. * * Outputs: Use the "get" functions to retrieve information in different ways. * *------------------------------------------------------------------------------*/ #if AX25MEMDEBUG packet_t ax25_from_frame_debug (unsigned char *fbuf, int flen, alevel_t alevel, char *src_file, int src_line) #else packet_t ax25_from_frame (unsigned char *fbuf, int flen, alevel_t alevel) #endif { packet_t this_p; /* * First make sure we have an acceptable length: * * We are not concerned with the FCS (CRC) because someone else checked it. * * Is is possible to have zero length for info? * * In the original version, assuming APRS, the answer was no. * We always had at least 3 octets after the address part: * control, protocol, and first byte of info part for data type. * * In later versions, this restriction was relaxed so other * variations of AX.25 could be used. Now the minimum length * is 7+7 for addresses plus 1 for control. * */ if (flen < AX25_MIN_PACKET_LEN || flen > AX25_MAX_PACKET_LEN) { text_color_set(DW_COLOR_ERROR); dw_printf ("Frame length %d not in allowable range of %d to %d.\n", flen, AX25_MIN_PACKET_LEN, AX25_MAX_PACKET_LEN); return (NULL); } this_p = ax25_new (); #if AX25MEMDEBUG if (ax25memdebug) { text_color_set(DW_COLOR_DEBUG); dw_printf ("ax25_from_frame, seq=%d, called from %s %d\n", this_p->seq, src_file, src_line); } #endif /* Copy the whole thing intact. */ memcpy (this_p->frame_data, fbuf, flen); this_p->frame_data[flen] = 0; this_p->frame_len = flen; /* Find number of addresses. */ this_p->num_addr = (-1); (void) ax25_get_num_addr (this_p); return (this_p); } /*------------------------------------------------------------------------------ * * Name: ax25_dup * * Purpose: Make a copy of given packet object. * * Inputs: copy_from - Existing packet object. * * Returns: Pointer to new packet object or NULL if error. * * *------------------------------------------------------------------------------*/ #if AX25MEMDEBUG packet_t ax25_dup_debug (packet_t copy_from, char *src_file, int src_line) #else packet_t ax25_dup (packet_t copy_from) #endif { int save_seq; packet_t this_p; this_p = ax25_new (); assert (this_p != NULL); save_seq = this_p->seq; memcpy (this_p, copy_from, sizeof (struct packet_s)); this_p->seq = save_seq; #if AX25MEMDEBUG if (ax25memdebug) { text_color_set(DW_COLOR_DEBUG); dw_printf ("ax25_dup, seq=%d, called from %s %d, clone of seq %d\n", this_p->seq, src_file, src_line, copy_from->seq); } #endif return (this_p); } /*------------------------------------------------------------------------------ * * Name: ax25_parse_addr * * Purpose: Parse address with optional ssid. * * Inputs: position - AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER_1... * Used for more specific error message. -1 if not used. * * in_addr - Input such as "WB2OSZ-15*" * * strict - 1 (true) for strict checking (6 characters, no lower case, * SSID must be in range of 0 to 15). * Strict is appropriate for packets sent * over the radio. Communication with IGate * allows lower case (e.g. "qAR") and two * alphanumeric characters for the SSID. * We also get messages like this from a server. * KB1POR>APU25N,TCPIP*,qAC,T2NUENGLD:... * * 2 (extra true) will complain if * is found at end. * * Outputs: out_addr - Address without any SSID. * Must be at least AX25_MAX_ADDR_LEN bytes. * * out_ssid - Numeric value of SSID. * * out_heard - True if "*" found. * * Returns: True (1) if OK, false (0) if any error. * When 0, out_addr, out_ssid, and out_heard are unpredictable. * * *------------------------------------------------------------------------------*/ static const char *position_name[1 + AX25_MAX_ADDRS] = { "", "Destination ", "Source ", "Digi1 ", "Digi2 ", "Digi3 ", "Digi4 ", "Digi5 ", "Digi6 ", "Digi7 ", "Digi8 " }; int ax25_parse_addr (int position, char *in_addr, int strict, char *out_addr, int *out_ssid, int *out_heard) { char *p; char sstr[8]; /* Should be 1 or 2 digits for SSID. */ int i, j, k; int maxlen; *out_addr = '\0'; *out_ssid = 0; *out_heard = 0; if (position < -1) position = -1; if (position > AX25_REPEATER_8) position = AX25_REPEATER_8; position++; /* Adjust for position_name above. */ if (strict && strlen(in_addr) >= 2 && strncmp(in_addr, "qA", 2) == 0) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sAddress \"%s\" is a \"q-construct\" used for communicating with\n", position_name[position], in_addr); dw_printf ("APRS Internet Servers. It should never appear when going over the radio.\n"); } //dw_printf ("ax25_parse_addr in: %s\n", in_addr); maxlen = strict ? 6 : (AX25_MAX_ADDR_LEN-1); p = in_addr; i = 0; for (p = in_addr; *p != '\0' && *p != '-' && *p != '*'; p++) { if (i >= maxlen) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sAddress is too long. \"%s\" has more than %d characters.\n", position_name[position], in_addr, maxlen); return 0; } if ( ! isalnum(*p)) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sAddress, \"%s\" contains character other than letter or digit in character position %d.\n", position_name[position], in_addr, (int)(long)(p-in_addr)+1); return 0; } out_addr[i++] = *p; out_addr[i] = '\0'; #if DECAMAIN // Hack when running in decode_aprs utility. // Exempt the "qA..." case because it was already mentioned. if (strict && islower(*p) && strncmp(in_addr, "qA", 2) != 0) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sAddress has lower case letters. \"%s\" must be all upper case.\n", position_name[position], in_addr); } #else if (strict && islower(*p)) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sAddress has lower case letters. \"%s\" must be all upper case.\n", position_name[position], in_addr); return 0; } #endif } j = 0; sstr[j] = '\0'; if (*p == '-') { for (p++; isalnum(*p); p++) { if (j >= 2) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sSSID is too long. SSID part of \"%s\" has more than 2 characters.\n", position_name[position], in_addr); return 0; } sstr[j++] = *p; sstr[j] = '\0'; if (strict && ! isdigit(*p)) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sSSID must be digits. \"%s\" has letters in SSID.\n", position_name[position], in_addr); return 0; } } k = atoi(sstr); if (k < 0 || k > 15) { text_color_set(DW_COLOR_ERROR); dw_printf ("%sSSID out of range. SSID of \"%s\" not in range of 0 to 15.\n", position_name[position], in_addr); return 0; } *out_ssid = k; } if (*p == '*') { *out_heard = 1; p++; if (strict == 2) { text_color_set(DW_COLOR_ERROR); dw_printf ("\"*\" is not allowed at end of address \"%s\" here.\n", in_addr); return 0; } } if (*p != '\0') { text_color_set(DW_COLOR_ERROR); dw_printf ("Invalid character \"%c\" found in %saddress \"%s\".\n", *p, position_name[position], in_addr); return 0; } //dw_printf ("ax25_parse_addr out: %s %d %d\n", out_addr, *out_ssid, *out_heard); return (1); } /* end ax25_parse_addr */ /*------------------------------------------------------------------- * * Name: ax25_check_addresses * * Purpose: Check addresses of given packet and print message if any issues. * We call this when receiving and transmitting. * * Inputs: pp - packet object pointer. * * Errors: Print error message. * * Returns: 1 for all valid. 0 if not. * * Examples: I was surprised to get this from an APRS-IS server with * a lower case source address. * * n1otx>APRS,TCPIP*,qAC,THIRD:@141335z4227.48N/07111.73W_348/005g014t044r000p000h60b10075.wview_5_20_2 * * I haven't gotten to the bottom of this yet but it sounds * like "q constructs" are somehow getting on to the air when * they should only appear in conversations with IGate servers. * * https://groups.yahoo.com/neo/groups/direwolf_packet/conversations/topics/678 * * WB0VGI-7>APDW12,W0YC-5*,qAR,AE0RF-10:}N0DZQ-10>APWW10,TCPIP,WB0VGI-7*:;145.230MN*080306z4607.62N/09230.58WrKE0ACL/R 145.230- T146.2 (Pine County ARES) * * Typical result: * * Digipeater WIDE2 (probably N3LEE-4) audio level = 28(10/6) [NONE] __||||||| * [0.5] VE2DJE-9>P_0_P?,VE2PCQ-3,K1DF-7,N3LEE-4,WIDE2*:'{S+l <0x1c>>/ * Invalid character "_" in MIC-E destination/latitude. * Invalid character "_" in MIC-E destination/latitude. * Invalid character "?" in MIC-E destination/latitude. * Invalid MIC-E N/S encoding in 4th character of destination. * Invalid MIC-E E/W encoding in 6th character of destination. * MIC-E, normal car (side view), Unknown manufacturer, Returning * N 00 00.0000, E 005 55.1500, 0 MPH * Invalid character "_" found in Destination address "P_0_P?". * * *** The origin and journey of this packet should receive some scrutiny. *** * *--------------------------------------------------------------------*/ int ax25_check_addresses (packet_t pp) { int n; char addr[AX25_MAX_ADDR_LEN]; char ignore1[AX25_MAX_ADDR_LEN]; int ignore2, ignore3; int all_ok = 1; for (n = 0; n < ax25_get_num_addr(pp); n++) { ax25_get_addr_with_ssid (pp, n, addr); all_ok &= ax25_parse_addr (n, addr, 1, ignore1, &ignore2, &ignore3); } if (! all_ok) { text_color_set(DW_COLOR_ERROR); dw_printf ("\n"); dw_printf ("*** The origin and journey of this packet should receive some scrutiny. ***\n"); dw_printf ("\n"); } return (all_ok); } /* end ax25_check_addresses */ /*------------------------------------------------------------------------------ * * Name: ax25_unwrap_third_party * * Purpose: Unwrap a third party messge from the header. * * Inputs: copy_from - Existing packet object. * * Returns: Pointer to new packet object or NULL if error. * * Example: Input: A>B,C:}D>E,F:info * Output: D>E,F:info * *------------------------------------------------------------------------------*/ packet_t ax25_unwrap_third_party (packet_t from_pp) { unsigned char *info_p; packet_t result_pp; if (ax25_get_dti(from_pp) != '}') { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error: ax25_unwrap_third_party: wrong data type.\n"); return (NULL); } (void) ax25_get_info (from_pp, &info_p); // Want strict because addresses should conform to AX.25 here. // That's not the case for something from an Internet Server. result_pp = ax25_from_text((char *)info_p + 1, 1); return (result_pp); } /*------------------------------------------------------------------------------ * * Name: ax25_set_addr * * Purpose: Add or change an address. * * Inputs: n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * Must be either an existing address or one greater * than the final which causes a new one to be added. * * ad - Address with optional dash and substation id. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * TODO: ax25_from_text could use this. * * Returns: None. * *------------------------------------------------------------------------------*/ void ax25_set_addr (packet_t this_p, int n, char *ad) { int ssid_temp, heard_temp; char atemp[AX25_MAX_ADDR_LEN]; int i; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); assert (n >= 0 && n < AX25_MAX_ADDRS); //dw_printf ("ax25_set_addr (%d, %s) num_addr=%d\n", n, ad, this_p->num_addr); if (n >= 0 && n < this_p->num_addr) { //dw_printf ("ax25_set_addr , existing case\n"); /* * Set existing address position. */ // Why aren't we setting 'strict' here? // Messages from IGate have q-constructs. // We use this to parse it and later remove unwanted parts. ax25_parse_addr (n, ad, 0, atemp, &ssid_temp, &heard_temp); memset (this_p->frame_data + n*7, ' ' << 1, 6); for (i=0; i<6 && atemp[i] != '\0'; i++) { this_p->frame_data[n*7+i] = atemp[i] << 1; } ax25_set_ssid (this_p, n, ssid_temp); } else if (n == this_p->num_addr) { //dw_printf ("ax25_set_addr , appending case\n"); /* * One beyond last position, process as insert. */ ax25_insert_addr (this_p, n, ad); } else { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error, ax25_set_addr, bad position %d for '%s'\n", n, ad); } //dw_printf ("------\n"); //dw_printf ("dump after ax25_set_addr (%d, %s)\n", n, ad); //ax25_hex_dump (this_p); //dw_printf ("------\n"); } /*------------------------------------------------------------------------------ * * Name: ax25_insert_addr * * Purpose: Insert address at specified position, shifting others up one * position. * This is used when a digipeater wants to insert its own call * for tracing purposes. * For example: * W1ABC>TEST,WIDE3-3 * Would become: * W1ABC>TEST,WB2OSZ-1*,WIDE3-2 * * Inputs: n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * ad - Address with optional dash and substation id. * * Bugs: Little validity or bounds checking is performed. Be careful. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: None. * * *------------------------------------------------------------------------------*/ void ax25_insert_addr (packet_t this_p, int n, char *ad) { int ssid_temp, heard_temp; char atemp[AX25_MAX_ADDR_LEN]; int i; int expect; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); assert (n >= AX25_REPEATER_1 && n < AX25_MAX_ADDRS); //dw_printf ("ax25_insert_addr (%d, %s)\n", n, ad); /* Don't do it if we already have the maximum number. */ /* Should probably return success/fail code but currently the caller doesn't care. */ if ( this_p->num_addr >= AX25_MAX_ADDRS) { return; } CLEAR_LAST_ADDR_FLAG; this_p->num_addr++; memmove (this_p->frame_data + (n+1)*7, this_p->frame_data + n*7, this_p->frame_len - (n*7)); memset (this_p->frame_data + n*7, ' ' << 1, 6); this_p->frame_len += 7; this_p->frame_data[n*7+6] = SSID_RR_MASK; SET_LAST_ADDR_FLAG; // Why aren't we setting 'strict' here? // Messages from IGate have q-constructs. // We use this to parse it and later remove unwanted parts. ax25_parse_addr (n, ad, 0, atemp, &ssid_temp, &heard_temp); memset (this_p->frame_data + n*7, ' ' << 1, 6); for (i=0; i<6 && atemp[i] != '\0'; i++) { this_p->frame_data[n*7+i] = atemp[i] << 1; } ax25_set_ssid (this_p, n, ssid_temp); // Sanity check after messing with number of addresses. expect = this_p->num_addr; this_p->num_addr = (-1); if (expect != ax25_get_num_addr (this_p)) { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error ax25_remove_addr expect %d, actual %d\n", expect, this_p->num_addr); } } /*------------------------------------------------------------------------------ * * Name: ax25_remove_addr * * Purpose: Remove address at specified position, shifting others down one position. * This is used when we want to remove something from the digipeater list. * * Inputs: n - Index of address. Use the symbols * AX25_REPEATER1, AX25_REPEATER2, etc. * * Bugs: Little validity or bounds checking is performed. Be careful. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: None. * * *------------------------------------------------------------------------------*/ void ax25_remove_addr (packet_t this_p, int n) { int expect; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); assert (n >= AX25_REPEATER_1 && n < AX25_MAX_ADDRS); /* Shift those beyond to fill this position. */ CLEAR_LAST_ADDR_FLAG; this_p->num_addr--; memmove (this_p->frame_data + n*7, this_p->frame_data + (n+1)*7, this_p->frame_len - ((n+1)*7)); this_p->frame_len -= 7; SET_LAST_ADDR_FLAG; // Sanity check after messing with number of addresses. expect = this_p->num_addr; this_p->num_addr = (-1); if (expect != ax25_get_num_addr (this_p)) { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error ax25_remove_addr expect %d, actual %d\n", expect, this_p->num_addr); } } /*------------------------------------------------------------------------------ * * Name: ax25_get_num_addr * * Purpose: Return number of addresses in current packet. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: Number of addresses in the current packet. * Should be in the range of 2 .. AX25_MAX_ADDRS. * * Version 0.9: Could be zero for a non AX.25 frame in KISS mode. * *------------------------------------------------------------------------------*/ int ax25_get_num_addr (packet_t this_p) { //unsigned char *pf; int a; int addr_bytes; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); /* Use cached value if already set. */ if (this_p->num_addr >= 0) { return (this_p->num_addr); } /* Otherwise, determine the number ofaddresses. */ this_p->num_addr = 0; /* Number of addresses extracted. */ addr_bytes = 0; for (a = 0; a < this_p->frame_len && addr_bytes == 0; a++) { if (this_p->frame_data[a] & SSID_LAST_MASK) { addr_bytes = a + 1; } } if (addr_bytes % 7 == 0) { int addrs = addr_bytes / 7; if (addrs >= AX25_MIN_ADDRS && addrs <= AX25_MAX_ADDRS) { this_p->num_addr = addrs; } } return (this_p->num_addr); } /*------------------------------------------------------------------------------ * * Name: ax25_get_num_repeaters * * Purpose: Return number of repeater addresses in current packet. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: Number of addresses in the current packet - 2. * Should be in the range of 0 .. AX25_MAX_ADDRS - 2. * *------------------------------------------------------------------------------*/ int ax25_get_num_repeaters (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (this_p->num_addr >= 2) { return (this_p->num_addr - 2); } return (0); } /*------------------------------------------------------------------------------ * * Name: ax25_get_addr_with_ssid * * Purpose: Return specified address with any SSID in current packet. * * Inputs: n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * Outputs: station - String representation of the station, including the SSID. * e.g. "WB2OSZ-15" * Usually variables will be AX25_MAX_ADDR_LEN bytes * but 10 would be adequate. * * Bugs: No bounds checking is performed. Be careful. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: Character string in usual human readable format, * * *------------------------------------------------------------------------------*/ void ax25_get_addr_with_ssid (packet_t this_p, int n, char *station) { int ssid; char sstr[8]; /* Should be 1 or 2 digits for SSID. */ int i; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (n < 0) { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error detected in ax25_get_addr_with_ssid, %s, line %d.\n", __FILE__, __LINE__); dw_printf ("Address index, %d, is less than zero.\n", n); strlcpy (station, "??????", 10); return; } if (n >= this_p->num_addr) { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error detected in ax25_get_addr_with_ssid, %s, line %d.\n", __FILE__, __LINE__); dw_printf ("Address index, %d, is too large for number of addresses, %d.\n", n, this_p->num_addr); strlcpy (station, "??????", 10); return; } // At one time this would stop at the first space, on the assumption we would have only trailing spaces. // Then there was a forum discussion where someone encountered the address " WIDE2" with a leading space. // In that case, we would have returned a zero length string here. // Now we return exactly what is in the address field and trim trailing spaces. // This will provide better information for troubleshooting. for (i=0; i<6; i++) { station[i] = (this_p->frame_data[n*7+i] >> 1) & 0x7f; } station[6] = '\0'; for (i=5; i>=0; i--) { if (station[i] == ' ') station[i] = '\0'; else break; } ssid = ax25_get_ssid (this_p, n); if (ssid != 0) { snprintf (sstr, sizeof(sstr), "-%d", ssid); strlcat (station, sstr, 10); } } /* end ax25_get_addr_with_ssid */ /*------------------------------------------------------------------------------ * * Name: ax25_get_addr_no_ssid * * Purpose: Return specified address WITHOUT any SSID. * * Inputs: n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * Outputs: station - String representation of the station, WITHOUT the SSID. * e.g. "WB2OSZ" * Usually variables will be AX25_MAX_ADDR_LEN bytes * but 7 would be adequate. * * Bugs: No bounds checking is performed. Be careful. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: Character string in usual human readable format, * * *------------------------------------------------------------------------------*/ void ax25_get_addr_no_ssid (packet_t this_p, int n, char *station) { int i; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (n < 0) { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error detected in ax25_get_addr_no_ssid, %s, line %d.\n", __FILE__, __LINE__); dw_printf ("Address index, %d, is less than zero.\n", n); strlcpy (station, "??????", 7); return; } if (n >= this_p->num_addr) { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error detected in ax25_get_no_with_ssid, %s, line %d.\n", __FILE__, __LINE__); dw_printf ("Address index, %d, is too large for number of addresses, %d.\n", n, this_p->num_addr); strlcpy (station, "??????", 7); return; } // At one time this would stop at the first space, on the assumption we would have only trailing spaces. // Then there was a forum discussion where someone encountered the address " WIDE2" with a leading space. // In that case, we would have returned a zero length string here. // Now we return exactly what is in the address field and trim trailing spaces. // This will provide better information for troubleshooting. for (i=0; i<6; i++) { station[i] = (this_p->frame_data[n*7+i] >> 1) & 0x7f; } station[6] = '\0'; for (i=5; i>=0; i--) { if (station[i] == ' ') station[i] = '\0'; else break; } } /* end ax25_get_addr_no_ssid */ /*------------------------------------------------------------------------------ * * Name: ax25_get_ssid * * Purpose: Return SSID of specified address in current packet. * * Inputs: n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: Substation id, as integer 0 .. 15. * *------------------------------------------------------------------------------*/ int ax25_get_ssid (packet_t this_p, int n) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (n >= 0 && n < this_p->num_addr) { return ((this_p->frame_data[n*7+6] & SSID_SSID_MASK) >> SSID_SSID_SHIFT); } else { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error: ax25_get_ssid(%d), num_addr=%d\n", n, this_p->num_addr); return (0); } } /*------------------------------------------------------------------------------ * * Name: ax25_set_ssid * * Purpose: Set the SSID of specified address in current packet. * * Inputs: n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * ssid - New SSID. Must be in range of 0 to 15. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Bugs: Rewrite to keep call and SSID separate internally. * *------------------------------------------------------------------------------*/ void ax25_set_ssid (packet_t this_p, int n, int ssid) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (n >= 0 && n < this_p->num_addr) { this_p->frame_data[n*7+6] = (this_p->frame_data[n*7+6] & ~ SSID_SSID_MASK) | ((ssid << SSID_SSID_SHIFT) & SSID_SSID_MASK) ; } else { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error: ax25_set_ssid(%d,%d), num_addr=%d\n", n, ssid, this_p->num_addr); } } /*------------------------------------------------------------------------------ * * Name: ax25_get_h * * Purpose: Return "has been repeated" flag of specified address in current packet. * * Inputs: n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * Bugs: No bounds checking is performed. Be careful. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: True or false. * *------------------------------------------------------------------------------*/ int ax25_get_h (packet_t this_p, int n) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); assert (n >= 0 && n < this_p->num_addr); if (n >= 0 && n < this_p->num_addr) { return ((this_p->frame_data[n*7+6] & SSID_H_MASK) >> SSID_H_SHIFT); } else { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error: ax25_get_h(%d), num_addr=%d\n", n, this_p->num_addr); return (0); } } /*------------------------------------------------------------------------------ * * Name: ax25_set_h * * Purpose: Set the "has been repeated" flag of specified address in current packet. * * Inputs: n - Index of address. Use the symbols * Should be in range of AX25_REPEATER_1 .. AX25_REPEATER_8. * * Bugs: No bounds checking is performed. Be careful. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: None * *------------------------------------------------------------------------------*/ void ax25_set_h (packet_t this_p, int n) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (n >= 0 && n < this_p->num_addr) { this_p->frame_data[n*7+6] |= SSID_H_MASK; } else { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error: ax25_set_hd(%d), num_addr=%d\n", n, this_p->num_addr); } } /*------------------------------------------------------------------------------ * * Name: ax25_get_heard * * Purpose: Return index of the station that we heard. * * Inputs: none * * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: If any of the digipeaters have the has-been-repeated bit set, * return the index of the last one. Otherwise return index for source. * *------------------------------------------------------------------------------*/ int ax25_get_heard(packet_t this_p) { int i; int result; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); result = AX25_SOURCE; for (i = AX25_REPEATER_1; i < ax25_get_num_addr(this_p); i++) { if (ax25_get_h(this_p,i)) { result = i; } } return (result); } /*------------------------------------------------------------------------------ * * Name: ax25_get_first_not_repeated * * Purpose: Return index of the first repeater that does NOT have the * "has been repeated" flag set or -1 if none. * * Inputs: none * * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: In range of X25_REPEATER_1 .. X25_REPEATER_8 or -1 if none. * *------------------------------------------------------------------------------*/ int ax25_get_first_not_repeated(packet_t this_p) { int i; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); for (i = AX25_REPEATER_1; i < ax25_get_num_addr(this_p); i++) { if ( ! ax25_get_h(this_p,i)) { return (i); } } return (-1); } /*------------------------------------------------------------------------------ * * Name: ax25_get_rr * * Purpose: Return the two reserved "RR" bits in the specified address field. * * Inputs: pp - Packet object. * * n - Index of address. Use the symbols * AX25_DESTINATION, AX25_SOURCE, AX25_REPEATER1, etc. * * Returns: 0, 1, 2, or 3. * *------------------------------------------------------------------------------*/ int ax25_get_rr (packet_t this_p, int n) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); assert (n >= 0 && n < this_p->num_addr); if (n >= 0 && n < this_p->num_addr) { return ((this_p->frame_data[n*7+6] & SSID_RR_MASK) >> SSID_RR_SHIFT); } else { text_color_set(DW_COLOR_ERROR); dw_printf ("Internal error: ax25_get_rr(%d), num_addr=%d\n", n, this_p->num_addr); return (0); } } /*------------------------------------------------------------------------------ * * Name: ax25_get_info * * Purpose: Obtain Information part of current packet. * * Inputs: this_p - Packet object pointer. * * Outputs: paddr - Starting address of information part is returned here. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: Number of octets in the Information part. * Should be in the range of AX25_MIN_INFO_LEN .. AX25_MAX_INFO_LEN. * *------------------------------------------------------------------------------*/ int ax25_get_info (packet_t this_p, unsigned char **paddr) { unsigned char *info_ptr; int info_len; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (this_p->num_addr >= 2) { /* AX.25 */ info_ptr = this_p->frame_data + ax25_get_info_offset(this_p); info_len = ax25_get_num_info(this_p); } else { /* Not AX.25. Treat Whole packet as info. */ info_ptr = this_p->frame_data; info_len = this_p->frame_len; } /* Add nul character in case caller treats as printable string. */ assert (info_len >= 0); info_ptr[info_len] = '\0'; *paddr = info_ptr; return (info_len); } /* end ax25_get_info */ /*------------------------------------------------------------------------------ * * Name: ax25_cut_at_crlf * * Purpose: Truncate the information part at the first CR or LF. * This is used for the RF>IS IGate function. * CR/LF is used as record separator so we must remove it * before packaging up packet to sending to server. * * Inputs: this_p - Packet object pointer. * * Outputs: Packet is modified in place. * * Returns: Number of characters removed from the end. * 0 if not changed. * * Assumption: ax25_from_text or ax25_from_frame was called first. * *------------------------------------------------------------------------------*/ int ax25_cut_at_crlf (packet_t this_p) { unsigned char *info_ptr; int info_len; int j; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); info_len = ax25_get_info (this_p, &info_ptr); // Can't use strchr because there is potential of nul character. for (j = 0; j < info_len; j++) { if (info_ptr[j] == '\r' || info_ptr[j] == '\n') { int chop = info_len - j; this_p->frame_len -= chop; return (chop); } } return (0); } /*------------------------------------------------------------------------------ * * Name: ax25_get_dti * * Purpose: Get Data Type Identifier from Information part. * * Inputs: None. * * Assumption: ax25_from_text or ax25_from_frame was called first. * * Returns: First byte from the information part. * *------------------------------------------------------------------------------*/ int ax25_get_dti (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (this_p->num_addr >= 2) { return (this_p->frame_data[ax25_get_info_offset(this_p)]); } return (' '); } /*------------------------------------------------------------------------------ * * Name: ax25_set_nextp * * Purpose: Set next packet object in queue. * * Inputs: this_p - Current packet object. * * next_p - pointer to next one * * Description: This is used to build a linked list for a queue. * *------------------------------------------------------------------------------*/ void ax25_set_nextp (packet_t this_p, packet_t next_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); this_p->nextp = next_p; } /*------------------------------------------------------------------------------ * * Name: ax25_get_nextp * * Purpose: Obtain next packet object in queue. * * Inputs: Packet object. * * Returns: Following object in queue or NULL. * *------------------------------------------------------------------------------*/ packet_t ax25_get_nextp (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); return (this_p->nextp); } /*------------------------------------------------------------------------------ * * Name: ax25_set_release_time * * Purpose: Set release time * * Inputs: this_p - Current packet object. * * release_time - Time as returned by dtime_now(). * *------------------------------------------------------------------------------*/ void ax25_set_release_time (packet_t this_p, double release_time) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); this_p->release_time = release_time; } /*------------------------------------------------------------------------------ * * Name: ax25_get_release_time * * Purpose: Get release time. * *------------------------------------------------------------------------------*/ double ax25_get_release_time (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); return (this_p->release_time); } /*------------------------------------------------------------------------------ * * Name: ax25_set_modulo * * Purpose: Set modulo value for I and S frame sequence numbers. * *------------------------------------------------------------------------------*/ void ax25_set_modulo (packet_t this_p, int modulo) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); this_p->modulo = modulo; } /*------------------------------------------------------------------ * * Function: ax25_format_addrs * * Purpose: Format all the addresses suitable for printing. * * The AX.25 spec refers to this as "Source Path Header" - "TNC-2" Format * * Inputs: Current packet. * * Outputs: result - All addresses combined into a single string of the form: * * "Source > Destination [ , repeater ... ] :" * * An asterisk is displayed after the last digipeater * with the "H" bit set. e.g. If we hear RPT2, * * SRC>DST,RPT1,RPT2*,RPT3: * * No asterisk means the source is being heard directly. * Needs to be 101 characters to avoid overflowing. * (Up to 100 characters + \0) * * Errors: No error checking so caller needs to be careful. * * *------------------------------------------------------------------*/ // TODO: max len for result. buffer overflow? void ax25_format_addrs (packet_t this_p, char *result) { int i; int heard; char stemp[AX25_MAX_ADDR_LEN]; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); *result = '\0'; /* New in 0.9. */ /* Don't get upset if no addresses. */ /* This will allow packets that do not comply to AX.25 format. */ if (this_p->num_addr == 0) { return; } ax25_get_addr_with_ssid (this_p, AX25_SOURCE, stemp); strcat (result, stemp); strcat (result, ">"); ax25_get_addr_with_ssid (this_p, AX25_DESTINATION, stemp); strcat (result, stemp); heard = ax25_get_heard(this_p); for (i=(int)AX25_REPEATER_1; inum_addr; i++) { ax25_get_addr_with_ssid (this_p, i, stemp); strcat (result, ","); strcat (result, stemp); if (i == heard) { strcat (result, "*"); } } strcat (result, ":"); } /*------------------------------------------------------------------ * * Function: ax25_format_via_path * * Purpose: Format via path addresses suitable for printing. * * Inputs: Current packet. * * result_size - Number of bytes available for result. * We can have up to 8 addresses x 9 characters * plus 7 commas, possible *, and nul = 81 minimum. * * Outputs: result - Digipeater field addresses combined into a single string of the form: * * "repeater, repeater ..." * * An asterisk is displayed after the last digipeater * with the "H" bit set. e.g. If we hear RPT2, * * RPT1,RPT2*,RPT3 * * No asterisk means the source is being heard directly. * *------------------------------------------------------------------*/ void ax25_format_via_path (packet_t this_p, char *result, size_t result_size) { int i; int heard; char stemp[AX25_MAX_ADDR_LEN]; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); *result = '\0'; /* Don't get upset if no addresses. */ /* This will allow packets that do not comply to AX.25 format. */ if (this_p->num_addr == 0) { return; } heard = ax25_get_heard(this_p); for (i=(int)AX25_REPEATER_1; inum_addr; i++) { if (i > (int)AX25_REPEATER_1) { strlcat (result, ",", result_size); } ax25_get_addr_with_ssid (this_p, i, stemp); strlcat (result, stemp, result_size); if (i == heard) { strlcat (result, "*", result_size); } } } /* end ax25_format_via_path */ /*------------------------------------------------------------------ * * Function: ax25_pack * * Purpose: Put all the pieces into format ready for transmission. * * Inputs: this_p - pointer to packet object. * * Outputs: result - Frame buffer, AX25_MAX_PACKET_LEN bytes. * Should also have two extra for FCS to be * added later. * * Returns: Number of octets in the frame buffer. * Does NOT include the extra 2 for FCS. * * Errors: Returns -1. * *------------------------------------------------------------------*/ int ax25_pack (packet_t this_p, unsigned char result[AX25_MAX_PACKET_LEN]) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); assert (this_p->frame_len >= 0 && this_p->frame_len <= AX25_MAX_PACKET_LEN); memcpy (result, this_p->frame_data, this_p->frame_len); return (this_p->frame_len); } /*------------------------------------------------------------------ * * Function: ax25_frame_type * * Purpose: Extract the type of frame. * This is derived from the control byte(s) but * is an enumerated type for easier handling. * * Inputs: this_p - pointer to packet object. * * Outputs: desc - Text description such as "I frame" or * "U frame SABME". * Supply 40 bytes to be safe. * * cr - Command or response? * * pf - P/F - Poll/Final or -1 if not applicable * * nr - N(R) - receive sequence or -1 if not applicable. * * ns - N(S) - send sequence or -1 if not applicable. * * Returns: Frame type from enum ax25_frame_type_e. * *------------------------------------------------------------------*/ // TODO: need someway to ensure caller allocated enough space. // Should pass in as parameter. #define DESC_SIZ 40 ax25_frame_type_t ax25_frame_type (packet_t this_p, cmdres_t *cr, char *desc, int *pf, int *nr, int *ns) { int c; // U frames are always one control byte. int c2 = 0; // I & S frames can have second Control byte. assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); strlcpy (desc, "????", DESC_SIZ); *cr = cr_11; *pf = -1; *nr = -1; *ns = -1; c = ax25_get_control(this_p); if (c < 0) { strlcpy (desc, "Not AX.25", DESC_SIZ); return (frame_not_AX25); } /* * TERRIBLE HACK :-( for display purposes. * * I and S frames can have 1 or 2 control bytes but there is * no good way to determine this without dipping into the data * link state machine. Can we guess? * * S frames have no protocol id or information so if there is one * more byte beyond the control field, we could assume there are * two control bytes. * * For I frames, the protocol id will usually be 0xf0. If we find * that as the first byte of the information field, it is probably * the pid and not part of the information. Ditto for segments 0x08. * Not fool proof but good enough for troubleshooting text out. * * If we have a link to the peer station, this will be set properly * before it needs to be used for other reasons. * * Setting one of the RR bits (find reference!) is sounding better and better. * It's in common usage so I should lobby to get that in the official protocol spec. */ if (this_p->modulo == 0 && (c & 3) == 1 && ax25_get_c2(this_p) != -1) { this_p->modulo = modulo_128; } else if (this_p->modulo == 0 && (c & 1) == 0 && this_p->frame_data[ax25_get_info_offset(this_p)] == 0xF0) { this_p->modulo = modulo_128; } else if (this_p->modulo == 0 && (c & 1) == 0 && this_p->frame_data[ax25_get_info_offset(this_p)] == 0x08) { // same for segments this_p->modulo = modulo_128; } if (this_p->modulo == modulo_128) { c2 = ax25_get_c2 (this_p); } int dst_c = this_p->frame_data[AX25_DESTINATION * 7 + 6] & SSID_H_MASK; int src_c = this_p->frame_data[AX25_SOURCE * 7 + 6] & SSID_H_MASK; char cr_text[8]; char pf_text[8]; if (dst_c) { if (src_c) { *cr = cr_11; strcpy(cr_text,"cc=11"); strcpy(pf_text,"p/f"); } else { *cr = cr_cmd; strcpy(cr_text,"cmd"); strcpy(pf_text,"p"); } } else { if (src_c) { *cr = cr_res; strcpy(cr_text,"res"); strcpy(pf_text,"f"); } else { *cr = cr_00; strcpy(cr_text,"cc=00"); strcpy(pf_text,"p/f"); } } if ((c & 1) == 0) { // Information rrr p sss 0 or sssssss 0 rrrrrrr p if (this_p->modulo == modulo_128) { *ns = (c >> 1) & 0x7f; *pf = c2 & 1; *nr = (c2 >> 1) & 0x7f; } else { *ns = (c >> 1) & 7; *pf = (c >> 4) & 1; *nr = (c >> 5) & 7; } //snprintf (desc, DESC_SIZ, "I %s, n(s)=%d, n(r)=%d, %s=%d", cr_text, *ns, *nr, pf_text, *pf); snprintf (desc, DESC_SIZ, "I %s, n(s)=%d, n(r)=%d, %s=%d, pid=0x%02x", cr_text, *ns, *nr, pf_text, *pf, ax25_get_pid(this_p)); return (frame_type_I); } else if ((c & 2) == 0) { // Supervisory rrr p/f ss 0 1 or 0000 ss 0 1 rrrrrrr p/f if (this_p->modulo == modulo_128) { *pf = c2 & 1; *nr = (c2 >> 1) & 0x7f; } else { *pf = (c >> 4) & 1; *nr = (c >> 5) & 7; } switch ((c >> 2) & 3) { case 0: snprintf (desc, DESC_SIZ, "RR %s, n(r)=%d, %s=%d", cr_text, *nr, pf_text, *pf); return (frame_type_S_RR); break; case 1: snprintf (desc, DESC_SIZ, "RNR %s, n(r)=%d, %s=%d", cr_text, *nr, pf_text, *pf); return (frame_type_S_RNR); break; case 2: snprintf (desc, DESC_SIZ, "REJ %s, n(r)=%d, %s=%d", cr_text, *nr, pf_text, *pf); return (frame_type_S_REJ); break; case 3: snprintf (desc, DESC_SIZ, "SREJ %s, n(r)=%d, %s=%d", cr_text, *nr, pf_text, *pf); return (frame_type_S_SREJ); break; } } else { // Unnumbered mmm p/f mm 1 1 *pf = (c >> 4) & 1; switch (c & 0xef) { case 0x6f: snprintf (desc, DESC_SIZ, "SABME %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_SABME); break; case 0x2f: snprintf (desc, DESC_SIZ, "SABM %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_SABM); break; case 0x43: snprintf (desc, DESC_SIZ, "DISC %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_DISC); break; case 0x0f: snprintf (desc, DESC_SIZ, "DM %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_DM); break; case 0x63: snprintf (desc, DESC_SIZ, "UA %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_UA); break; case 0x87: snprintf (desc, DESC_SIZ, "FRMR %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_FRMR); break; case 0x03: snprintf (desc, DESC_SIZ, "UI %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_UI); break; case 0xaf: snprintf (desc, DESC_SIZ, "XID %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_XID); break; case 0xe3: snprintf (desc, DESC_SIZ, "TEST %s, %s=%d", cr_text, pf_text, *pf); return (frame_type_U_TEST); break; default: snprintf (desc, DESC_SIZ, "U other???"); return (frame_type_U); break; } } // Should be unreachable but compiler doesn't realize that. // Here only to suppress "warning: control reaches end of non-void function" return (frame_not_AX25); } /* end ax25_frame_type */ /*------------------------------------------------------------------ * * Function: ax25_hex_dump * * Purpose: Print out packet in hexadecimal for debugging. * * Inputs: fptr - Pointer to frame data. * * flen - Frame length, bytes. Does not include CRC. * *------------------------------------------------------------------*/ static void hex_dump (unsigned char *p, int len) { int n, i, offset; offset = 0; while (len > 0) { n = len < 16 ? len : 16; dw_printf (" %03x: ", offset); for (i=0; i>5)&7, (c>>4)&1, (c>>1)&7); } else if ((c & 0xf) == 0x01) { snprintf (out, outsiz, "S frame RR: n(r)=%d, p/f=%d", (c>>5)&7, (c>>4)&1); } else if ((c & 0xf) == 0x05) { snprintf (out, outsiz, "S frame RNR: n(r)=%d, p/f=%d", (c>>5)&7, (c>>4)&1); } else if ((c & 0xf) == 0x09) { snprintf (out, outsiz, "S frame REJ: n(r)=%d, p/f=%d", (c>>5)&7, (c>>4)&1); } else if ((c & 0xf) == 0x0D) { snprintf (out, outsiz, "S frame sREJ: n(r)=%d, p/f=%d", (c>>5)&7, (c>>4)&1); } else if ((c & 0xef) == 0x6f) { snprintf (out, outsiz, "U frame SABME: p=%d", (c>>4)&1); } else if ((c & 0xef) == 0x2f) { snprintf (out, outsiz, "U frame SABM: p=%d", (c>>4)&1); } else if ((c & 0xef) == 0x43) { snprintf (out, outsiz, "U frame DISC: p=%d", (c>>4)&1); } else if ((c & 0xef) == 0x0f) { snprintf (out, outsiz, "U frame DM: f=%d", (c>>4)&1); } else if ((c & 0xef) == 0x63) { snprintf (out, outsiz, "U frame UA: f=%d", (c>>4)&1); } else if ((c & 0xef) == 0x87) { snprintf (out, outsiz, "U frame FRMR: f=%d", (c>>4)&1); } else if ((c & 0xef) == 0x03) { snprintf (out, outsiz, "U frame UI: p/f=%d", (c>>4)&1); } else if ((c & 0xef) == 0xAF) { snprintf (out, outsiz, "U frame XID: p/f=%d", (c>>4)&1); } else if ((c & 0xef) == 0xe3) { snprintf (out, outsiz, "U frame TEST: p/f=%d", (c>>4)&1); } else { snprintf (out, outsiz, "Unknown frame type for control = 0x%02x", c); } } /* Text description of protocol id octet. */ #define PID_TEXT_SIZE 80 static void pid_to_text (int p, char out[PID_TEXT_SIZE]) { if ((p & 0x30) == 0x10) { snprintf (out, PID_TEXT_SIZE, "AX.25 layer 3 implemented."); } else if ((p & 0x30) == 0x20) { snprintf (out, PID_TEXT_SIZE, "AX.25 layer 3 implemented."); } else if (p == 0x01) { snprintf (out, PID_TEXT_SIZE, "ISO 8208/CCITT X.25 PLP"); } else if (p == 0x06) { snprintf (out, PID_TEXT_SIZE, "Compressed TCP/IP packet. Van Jacobson (RFC 1144)"); } else if (p == 0x07) { snprintf (out, PID_TEXT_SIZE, "Uncompressed TCP/IP packet. Van Jacobson (RFC 1144)"); } else if (p == 0x08) { snprintf (out, PID_TEXT_SIZE, "Segmentation fragment"); } else if (p == 0xC3) { snprintf (out, PID_TEXT_SIZE, "TEXNET datagram protocol"); } else if (p == 0xC4) { snprintf (out, PID_TEXT_SIZE, "Link Quality Protocol"); } else if (p == 0xCA) { snprintf (out, PID_TEXT_SIZE, "Appletalk"); } else if (p == 0xCB) { snprintf (out, PID_TEXT_SIZE, "Appletalk ARP"); } else if (p == 0xCC) { snprintf (out, PID_TEXT_SIZE, "ARPA Internet Protocol"); } else if (p == 0xCD) { snprintf (out, PID_TEXT_SIZE, "ARPA Address resolution"); } else if (p == 0xCE) { snprintf (out, PID_TEXT_SIZE, "FlexNet"); } else if (p == 0xCF) { snprintf (out, PID_TEXT_SIZE, "NET/ROM"); } else if (p == 0xF0) { snprintf (out, PID_TEXT_SIZE, "No layer 3 protocol implemented."); } else if (p == 0xFF) { snprintf (out, PID_TEXT_SIZE, "Escape character. Next octet contains more Level 3 protocol information."); } else { snprintf (out, PID_TEXT_SIZE, "Unknown protocol id = 0x%02x", p); } } void ax25_hex_dump (packet_t this_p) { int n; unsigned char *fptr = this_p->frame_data; int flen = this_p->frame_len; if (this_p->num_addr >= AX25_MIN_ADDRS && this_p->num_addr <= AX25_MAX_ADDRS) { int c, p; char cp_text[120]; char l_text[20]; c = fptr[this_p->num_addr*7]; p = fptr[this_p->num_addr*7+1]; ctrl_to_text (c, cp_text, sizeof(cp_text)); // TODO: use ax25_frame_type() instead. if ( (c & 0x01) == 0 || /* I xxxx xxx0 */ c == 0x03 || c == 0x13) { /* UI 000x 0011 */ char pid_text[PID_TEXT_SIZE]; pid_to_text (p, pid_text); strlcat (cp_text, ", ", sizeof(cp_text)); strlcat (cp_text, pid_text, sizeof(cp_text)); } snprintf (l_text, sizeof(l_text), ", length = %d", flen); strlcat (cp_text, l_text, sizeof(cp_text)); dw_printf ("%s\n", cp_text); } // Address fields must be only upper case letters and digits. // If less than 6 characters, trailing positions are filled with ASCII space. // Using all zero bits in one of these 6 positions is wrong. // Any non printable characters will be printed as "." here. dw_printf (" dest %c%c%c%c%c%c %2d c/r=%d res=%d last=%d\n", isprint(fptr[0]>>1) ? fptr[0]>>1 : '.', isprint(fptr[1]>>1) ? fptr[1]>>1 : '.', isprint(fptr[2]>>1) ? fptr[2]>>1 : '.', isprint(fptr[3]>>1) ? fptr[3]>>1 : '.', isprint(fptr[4]>>1) ? fptr[4]>>1 : '.', isprint(fptr[5]>>1) ? fptr[5]>>1 : '.', (fptr[6]&SSID_SSID_MASK)>>SSID_SSID_SHIFT, (fptr[6]&SSID_H_MASK)>>SSID_H_SHIFT, (fptr[6]&SSID_RR_MASK)>>SSID_RR_SHIFT, fptr[6]&SSID_LAST_MASK); dw_printf (" source %c%c%c%c%c%c %2d c/r=%d res=%d last=%d\n", isprint(fptr[7]>>1) ? fptr[7]>>1 : '.', isprint(fptr[8]>>1) ? fptr[8]>>1 : '.', isprint(fptr[9]>>1) ? fptr[9]>>1 : '.', isprint(fptr[10]>>1) ? fptr[10]>>1 : '.', isprint(fptr[11]>>1) ? fptr[11]>>1 : '.', isprint(fptr[12]>>1) ? fptr[12]>>1 : '.', (fptr[13]&SSID_SSID_MASK)>>SSID_SSID_SHIFT, (fptr[13]&SSID_H_MASK)>>SSID_H_SHIFT, (fptr[13]&SSID_RR_MASK)>>SSID_RR_SHIFT, fptr[13]&SSID_LAST_MASK); for (n=2; nnum_addr; n++) { dw_printf (" digi %d %c%c%c%c%c%c %2d h=%d res=%d last=%d\n", n - 1, isprint(fptr[n*7+0]>>1) ? fptr[n*7+0]>>1 : '.', isprint(fptr[n*7+1]>>1) ? fptr[n*7+1]>>1 : '.', isprint(fptr[n*7+2]>>1) ? fptr[n*7+2]>>1 : '.', isprint(fptr[n*7+3]>>1) ? fptr[n*7+3]>>1 : '.', isprint(fptr[n*7+4]>>1) ? fptr[n*7+4]>>1 : '.', isprint(fptr[n*7+5]>>1) ? fptr[n*7+5]>>1 : '.', (fptr[n*7+6]&SSID_SSID_MASK)>>SSID_SSID_SHIFT, (fptr[n*7+6]&SSID_H_MASK)>>SSID_H_SHIFT, (fptr[n*7+6]&SSID_RR_MASK)>>SSID_RR_SHIFT, fptr[n*7+6]&SSID_LAST_MASK); } hex_dump (fptr, flen); } /* end ax25_hex_dump */ /*------------------------------------------------------------------ * * Function: ax25_is_aprs * * Purpose: Is this packet APRS format? * * Inputs: this_p - pointer to packet object. * * Returns: True if this frame has the proper control * octets for an APRS packet. * control 3 for UI frame * protocol id 0xf0 for no layer 3 * * * Description: Dire Wolf should be able to act as a KISS TNC for * any type of AX.25 activity. However, there are other * places where we want to process only APRS. * (e.g. digipeating and IGate.) * *------------------------------------------------------------------*/ int ax25_is_aprs (packet_t this_p) { int ctrl, pid, is_aprs; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (this_p->frame_len == 0) return(0); ctrl = ax25_get_control(this_p); pid = ax25_get_pid(this_p); is_aprs = this_p->num_addr >= 2 && ctrl == AX25_UI_FRAME && pid == AX25_PID_NO_LAYER_3; #if 0 text_color_set(DW_COLOR_ERROR); dw_printf ("ax25_is_aprs(): ctrl=%02x, pid=%02x, is_aprs=%d\n", ctrl, pid, is_aprs); #endif return (is_aprs); } /*------------------------------------------------------------------ * * Function: ax25_is_null_frame * * Purpose: Is this packet structure empty? * * Inputs: this_p - pointer to packet object. * * Returns: True if frame data length is 0. * * Description: This is used when we want to wake up the * transmit queue processing thread but don't * want to transmit a frame. * *------------------------------------------------------------------*/ int ax25_is_null_frame (packet_t this_p) { int is_null; assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); is_null = this_p->frame_len == 0; #if 0 text_color_set(DW_COLOR_ERROR); dw_printf ("ax25_is_null_frame(): is_null=%d\n", is_null); #endif return (is_null); } /*------------------------------------------------------------------ * * Function: ax25_get_control ax25_get_c2 * * Purpose: Get Control field from packet. * * Inputs: this_p - pointer to packet object. * * Returns: APRS uses AX25_UI_FRAME. * This could also be used in other situations. * *------------------------------------------------------------------*/ int ax25_get_control (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (this_p->frame_len == 0) return(-1); if (this_p->num_addr >= 2) { return (this_p->frame_data[ax25_get_control_offset(this_p)]); } return (-1); } int ax25_get_c2 (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); if (this_p->frame_len == 0) return(-1); if (this_p->num_addr >= 2) { int offset2 = ax25_get_control_offset(this_p)+1; if (offset2 < this_p->frame_len) { return (this_p->frame_data[offset2]); } else { return (-1); /* attempt to go beyond the end of frame. */ } } return (-1); /* not AX.25 */ } /*------------------------------------------------------------------ * * Function: ax25_get_pid * * Purpose: Get protocol ID from packet. * * Inputs: this_p - pointer to packet object. * * Returns: APRS uses 0xf0 for no layer 3. * This could also be used in other situations. * * AX.25: "The Protocol Identifier (PID) field appears in information * frames (I and UI) only. It identifies which kind of * Layer 3 protocol, if any, is in use." * *------------------------------------------------------------------*/ int ax25_get_pid (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); // TODO: handle 2 control byte case. // TODO: sanity check: is it I or UI frame? if (this_p->frame_len == 0) return(-1); if (this_p->num_addr >= 2) { return (this_p->frame_data[ax25_get_pid_offset(this_p)]); } return (-1); } /*------------------------------------------------------------------ * * Function: ax25_get_frame_len * * Purpose: Get length of frame. * * Inputs: this_p - pointer to packet object. * * Returns: Number of octets in the frame buffer. * Does NOT include the extra 2 for FCS. * *------------------------------------------------------------------*/ int ax25_get_frame_len (packet_t this_p) { assert (this_p->magic1 == MAGIC); assert (this_p->magic2 == MAGIC); assert (this_p->frame_len >= 0 && this_p->frame_len <= AX25_MAX_PACKET_LEN); return (this_p->frame_len); } /* end ax25_get_frame_len */ /*------------------------------------------------------------------------------ * * Name: ax25_dedupe_crc * * Purpose: Calculate a checksum for the packet source, destination, and * information but NOT the digipeaters. * This is used for duplicate detection in the digipeater * and IGate algorithms. * * Input: pp - Pointer to packet object. * * Returns: Value which will be the same for a duplicate but very unlikely * to match a non-duplicate packet. * * Description: For detecting duplicates, we need to look * + source station * + destination * + information field * but NOT the changing list of digipeaters. * * Typically, only a checksum is kept to reduce memory * requirements and amount of compution for comparisons. * There is a very very small probability that two unrelated * packets will result in the same checksum, and the * undesired dropping of the packet. * * There is a 1 / 65536 chance of getting a false positive match * which is good enough for this application. * We could reduce that with a 32 bit CRC instead of reusing * code from the AX.25 frame CRC calculation. * * Version 1.3: We exclude any trailing CR/LF at the end of the info part * so we can detect duplicates that are received only over the * air and those which have gone thru an IGate where the process * removes any trailing CR/LF. Example: * * Original via RF only: * W1TG-1>APU25N,N3LEE-10*,WIDE2-1: * * When we get the same thing via APRS-IS: * W1TG-1>APU25N,K1FFK,WIDE2*,qAR,WB2ZII-15:= 1 && (pinfo[info_len-1] == '\r' || pinfo[info_len-1] == '\n' || pinfo[info_len-1] == ' ')) { // Temporary for debugging! // if (pinfo[info_len-1] == ' ') { // text_color_set(DW_COLOR_ERROR); // dw_printf ("DEBUG: ax25_dedupe_crc ignoring trailing space.\n"); // } info_len--; } crc = 0xffff; crc = crc16((unsigned char *)src, strlen(src), crc); crc = crc16((unsigned char *)dest, strlen(dest), crc); crc = crc16(pinfo, info_len, crc); return (crc); } /*------------------------------------------------------------------------------ * * Name: ax25_m_m_crc * * Purpose: Calculate a checksum for the packet. * This is used for the multimodem duplicate detection. * * Input: pp - Pointer to packet object. * * Returns: Value which will be the same for a duplicate but very unlikely * to match a non-duplicate packet. * * Description: For detecting duplicates, we need to look the entire packet. * * Typically, only a checksum is kept to reduce memory * requirements and amount of compution for comparisons. * There is a very very small probability that two unrelated * packets will result in the same checksum, and the * undesired dropping of the packet. *------------------------------------------------------------------------------*/ unsigned short ax25_m_m_crc (packet_t pp) { unsigned short crc; unsigned char fbuf[AX25_MAX_PACKET_LEN]; int flen; flen = ax25_pack (pp, fbuf); crc = 0xffff; crc = crc16(fbuf, flen, crc); return (crc); } /*------------------------------------------------------------------ * * Function: ax25_safe_print * * Purpose: Print given string, changing non printable characters to * hexadecimal notation. Note that character values * , 28, 29, 30, and 31 can appear in MIC-E message. * * Inputs: pstr - Pointer to string. * * len - Number of bytes. If < 0 we use strlen(). * * ascii_only - Restrict output to only ASCII. * Normally we allow UTF-8. * * Stops after non-zero len characters or at nul. * * Returns: none * * Description: Print a string in a "safe" manner. * Anything that is not a printable character * will be converted to a hexadecimal representation. * For example, a Line Feed character will appear as <0x0a> * rather than dropping down to the next line on the screen. * * ax25_from_text can accept this format. * * * Example: W1MED-1>T2QP0S,N1OHZ,N8VIM*,WIDE1-1:'cQBl <0x1c>-/]<0x0d> * ------ ------ * * Questions: What should we do about UTF-8? Should that be displayed * as hexadecimal for troubleshooting? Maybe an option so the * packet raw data is in hexadecimal but an extracted * comment displays UTF-8? Or a command line option for only ASCII? * * Trailing space: * I recently noticed a case where a packet has space character * at the end. If the last character of the line is a space, * this will be displayed in hexadecimal to make it obvious. * *------------------------------------------------------------------*/ #define MAXSAFE 500 void ax25_safe_print (char *pstr, int len, int ascii_only) { int ch; char safe_str[MAXSAFE*6+1]; int safe_len; safe_len = 0; safe_str[safe_len] = '\0'; if (len < 0) len = strlen(pstr); if (len > MAXSAFE) len = MAXSAFE; while (len > 0) { ch = *((unsigned char *)pstr); if (ch == ' ' && (len == 1 || pstr[1] == '\0')) { snprintf (safe_str + safe_len, sizeof(safe_str)-safe_len, "<0x%02x>", ch); safe_len += 6; } else if (ch < ' ' || ch == 0x7f || ch == 0xfe || ch == 0xff || (ascii_only && ch >= 0x80) ) { /* Control codes and delete. */ /* UTF-8 does not use fe and ff except in a possible */ /* "Byte Order Mark" (BOM) at the beginning. */ snprintf (safe_str + safe_len, sizeof(safe_str)-safe_len, "<0x%02x>", ch); safe_len += 6; } else { /* Let everything else thru so we can handle UTF-8 */ /* Maybe we should have an option to display 0x80 */ /* and above as hexadecimal. */ safe_str[safe_len++] = ch; safe_str[safe_len] = '\0'; } pstr++; len--; } // TODO1.2: should return string rather printing to remove a race condition. dw_printf ("%s", safe_str); } /* end ax25_safe_print */ /*------------------------------------------------------------------ * * Function: ax25_alevel_to_text * * Purpose: Convert audio level to text representation. * * Inputs: alevel - Audio levels collected from demodulator. * * Outputs: text - Text representation for presentation to user. * Currently it will look something like this: * * r(m/s) * * With n,m,s corresponding to received, mark, and space. * Comma is to be avoided because one place this * ends up is in a CSV format file. * * size should be AX25_ALEVEL_TO_TEXT_SIZE. * * Returns: True if something to print. (currently if alevel.original >= 0) * False if not. * * Description: Audio level used to be simple; it was a single number. * In version 1.2, we start collecting more details. * At the moment, it includes: * * - Received level from new method. * - Levels from mark & space filters to examine the ratio. * * We print this in multiple places so put it into a function. * *------------------------------------------------------------------*/ int ax25_alevel_to_text (alevel_t alevel, char text[AX25_ALEVEL_TO_TEXT_SIZE]) { if (alevel.rec < 0) { strlcpy (text, "", AX25_ALEVEL_TO_TEXT_SIZE); return (0); } // TODO1.2: haven't thought much about non-AFSK cases yet. // What should we do for 9600 baud? // For DTMF omit the two extra numbers. if (alevel.mark >= 0 && alevel.space < 0) { /* baseband */ snprintf (text, AX25_ALEVEL_TO_TEXT_SIZE, "%d(%+d/%+d)", alevel.rec, alevel.mark, alevel.space); } else if (alevel.mark == -1 && alevel.space == -1) { /* PSK - single number. */ snprintf (text, AX25_ALEVEL_TO_TEXT_SIZE, "%d", alevel.rec); } else if (alevel.mark == -2 && alevel.space == -2) { /* DTMF - single number. */ snprintf (text, AX25_ALEVEL_TO_TEXT_SIZE, "%d", alevel.rec); } else { /* AFSK */ //snprintf (text, AX25_ALEVEL_TO_TEXT_SIZE, "%d:%d(%d/%d=%05.3f=)", alevel.original, alevel.rec, alevel.mark, alevel.space, alevel.ms_ratio); snprintf (text, AX25_ALEVEL_TO_TEXT_SIZE, "%d(%d/%d)", alevel.rec, alevel.mark, alevel.space); } return (1); } /* end ax25_alevel_to_text */ /* end ax25_pad.c */