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comparison efrtest/dlcap-sync.c @ 468:4104b0390fab

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efrtest: new program gsmefr-dlcap-sync
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 13 May 2024 07:21:09 +0000
parents
children d80ccb3c3970
comparison
equal deleted inserted replaced
467:ad032051166a 468:4104b0390fab
1 /*
2 * This program reads a TCH/EFS downlink capture file from a FreeCalypso GSM MS
3 * that was produced in a session in which seqsync PCMA or PCMU input was fed
4 * into the test call from IP-PSTN side. It looks for EFR DHF followed by
5 * specific frame patterns indicating how the seqsync input was transcoded
6 * by the alien GSM network, and reports its findings.
7 */
8
9 #include <ctype.h>
10 #include <stdio.h>
11 #include <stdint.h>
12 #include <stdlib.h>
13 #include <string.h>
14 #include <strings.h>
15
16 static const uint8_t efr_dhf[31] = {
17 0xC0,0x85,0xEB,0x49,0x0F,0xAA,0xD6,0x03,0xE3,0xA1,0x86,0x07,0xB0,0xC4,0x2C,0x08,
18 0x04,0x80,0x55,0x80,0x00,0x00,0x00,0x00,0x03,0x6B,0x00,0x00,0x00,0x00,0x00,
19 };
20
21 static const uint8_t mr122_dhf[31] = {
22 0xC0,0x85,0x4D,0xB9,0x6A,0xAA,0xD6,0x00,0x00,0x00,0x00,0x01,0xB5,0x87,0xF6,0x68,
23 0x37,0x94,0x09,0x00,0x41,0x58,0x54,0xF1,0x0F,0x6B,0x02,0x40,0x3C,0x7E,0xA0,
24 };
25
26 extern const uint8_t sync_from_pcma[320*31];
27 extern const uint8_t sync_from_pcmu[320*31];
28
29 static int
30 check_for_match(input, table)
31 const uint8_t *input, *table;
32 {
33 unsigned n;
34
35 for (n = 0; n < 320; n++) {
36 if (!bcmp(input, table + n * 31, 31))
37 return n;
38 }
39 return -1;
40 }
41
42 main(argc, argv)
43 char **argv;
44 {
45 FILE *inf;
46 char linebuf[128];
47 int lineno, rc;
48 uint16_t status_words[3];
49 uint8_t tidsp_bytes[33], efr_bytes[31];
50 const uint8_t *match_table;
51 int dhf_state;
52 char *dhf_name;
53
54 if (argc != 3) {
55 usage: fprintf(stderr, "usage: %s dlcap-file alaw|ulaw\n", argv[0]);
56 exit(1);
57 }
58 inf = fopen(argv[1], "r");
59 if (!inf) {
60 perror(argv[1]);
61 exit(1);
62 }
63 if (!strcmp(argv[2], "alaw"))
64 match_table = sync_from_pcma;
65 else if (!strcmp(argv[2], "ulaw"))
66 match_table = sync_from_pcmu;
67 else
68 goto usage;
69 dhf_state = 0;
70 for (lineno = 1; fgets(linebuf, sizeof linebuf, inf); lineno++) {
71 /* support both old and new formats */
72 if (isxdigit(linebuf[0]) && isxdigit(linebuf[1]) &&
73 isxdigit(linebuf[2]) && isxdigit(linebuf[3])) {
74 rc = parse_dlcap_common(linebuf, status_words,
75 tidsp_bytes);
76 if (rc < 0) {
77 invalid: fprintf(stderr,
78 "error: %s is not in the expected format\n",
79 argv[1]);
80 exit(1);
81 }
82 } else if (!strncmp(linebuf, "EFR ", 4)) {
83 rc = parse_dlcap_common(linebuf + 4, status_words,
84 tidsp_bytes);
85 if (rc < 0)
86 goto invalid;
87 if (linebuf[85] != ' ')
88 goto invalid;
89 if (!isdigit(linebuf[86]))
90 goto invalid;
91 } else
92 goto invalid;
93 if ((status_words[0] & 0xC204) != 0xC000) {
94 dhf_state = 0;
95 continue;
96 }
97 efr_tidsp_to_std(tidsp_bytes, efr_bytes);
98 if (!bcmp(efr_bytes, efr_dhf, 31)) {
99 dhf_state = 1;
100 continue;
101 }
102 if (!bcmp(efr_bytes, mr122_dhf, 31)) {
103 dhf_state = 2;
104 continue;
105 }
106 if (!dhf_state)
107 continue;
108 rc = check_for_match(efr_bytes, match_table);
109 if (rc >= 0 && rc <= 159) {
110 printf(
111 "line %d: match to standard EFR with offset %d\n",
112 lineno, rc);
113 if (dhf_state == 2)
114 printf("... but preceded by MR122 DHF!\n");
115 } else if (rc >= 160 && rc <= 279) {
116 printf("line %d: match to AMR-EFR with offset %d\n",
117 lineno, rc - 160);
118 if (dhf_state == 2)
119 printf("... but preceded by MR122 DHF!\n");
120 } else if (rc >= 280 && rc <= 319) {
121 printf("line %d: match to AMR-EFR with offset %d\n",
122 lineno, rc - 160);
123 switch (dhf_state) {
124 case 1:
125 dhf_name = "EFR";
126 break;
127 case 2:
128 dhf_name = "MR122";
129 break;
130 default:
131 dhf_name = "???";
132 }
133 printf("previous frame was %s DHF\n", dhf_name);
134 }
135 dhf_state = 0;
136 }
137 exit(0);
138 }