diff options
author | hm <hm@FreeBSD.org> | 2001-05-25 13:04:58 +0000 |
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committer | hm <hm@FreeBSD.org> | 2001-05-25 13:04:58 +0000 |
commit | e478212afdc19df583f5c90737b556e1ee9191b7 (patch) | |
tree | 6773d87b250ed5052a60802fa4a8e1fa93b03d4a /share/examples | |
parent | 8dcea40c52b0d3421319a5844c2877a5552ee990 (diff) | |
download | FreeBSD-src-e478212afdc19df583f5c90737b556e1ee9191b7.zip FreeBSD-src-e478212afdc19df583f5c90737b556e1ee9191b7.tar.gz |
Submitted by: phk
Add the V.21 modem emulator code written by phk from the old i4b tarball.
Diffstat (limited to 'share/examples')
-rw-r--r-- | share/examples/isdn/v21/Makefile | 12 | ||||
-rw-r--r-- | share/examples/isdn/v21/README | 50 | ||||
-rw-r--r-- | share/examples/isdn/v21/v21modem.c | 393 |
3 files changed, 455 insertions, 0 deletions
diff --git a/share/examples/isdn/v21/Makefile b/share/examples/isdn/v21/Makefile new file mode 100644 index 0000000..3c49996 --- /dev/null +++ b/share/examples/isdn/v21/Makefile @@ -0,0 +1,12 @@ +# $FreeBSD$ + +PROG= v21modem +NOMAN= 1 +LDADD= -lutil -lm +CFLAGS+= -g -Wall + +.if !defined(BSDTYPE) +BSDTYPE!=uname +.endif + +.include <bsd.prog.mk> diff --git a/share/examples/isdn/v21/README b/share/examples/isdn/v21/README new file mode 100644 index 0000000..52f553c --- /dev/null +++ b/share/examples/isdn/v21/README @@ -0,0 +1,50 @@ + + V.21 Modem for ISDN4BSD. + +INTRODUCTION: + +The modem is implemented in software and is rather simple minded. + +It works with my Telebit TB2500 and Zyxel 2864I modems. + +There are plenty of knobs and handles which can be adjusted and I have +no real idea what to set them to for best all-round performance. + +The carrier detect timer may be a bit short tempered, and this is +probably why the dialing modem needs to be told to talk V.21 up +front. If this code were mode tolerant of loss of carrier auto +negotiation might work. + +When you get carrier ("CONNECT 300"), you must press a key before the +login banner gets printed. See the comments in "input_byte" why this +is. + +THE KERNEL PART: + +Implementes a crude "send these tones" facility, but it is enough to +take most of the real-time worries out of doing FSK modulation in +software. If suitably extended, the code could also be used to +send DTMF tones and other similar signals. + +INSTALLATION: + +The program is started from /etc/isdn/isdnd.rc: + +entry + name = I4BTEL + usrdevicename = tel + usrdeviceunit = 0 + isdncontroller = 0 + isdnchannel = -1 + local-phone-incoming = 2934812934 + remote-phone-incoming = * + dialin-reaction = answer + answerprog = v21modem + b1protocol = raw + idletime-incoming = 5 + + +Poul-Henning (phk@freebsd.org) +19991212 + +$FreeBSD$ diff --git a/share/examples/isdn/v21/v21modem.c b/share/examples/isdn/v21/v21modem.c new file mode 100644 index 0000000..0906f35 --- /dev/null +++ b/share/examples/isdn/v21/v21modem.c @@ -0,0 +1,393 @@ +/* + * ---------------------------------------------------------------------------- + * "THE BEER-WARE LICENSE" (Revision 42): + * <phk@FreeBSD.org> wrote this file. As long as you retain this notice you + * can do whatever you want with this stuff. If we meet some day, and you think + * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp + * ---------------------------------------------------------------------------- + * + * This is a V.21 modem for ISDN4BSD. + * + * $FreeBSD$ + */ + +#include <string.h> +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <fcntl.h> +#include <err.h> +#include <sys/ioccom.h> +#include <errno.h> +#include <syslog.h> +#include <sys/types.h> +#include <sys/ioctl.h> +#include <termios.h> +#include <libutil.h> + +#include <machine/i4b_tel_ioctl.h> + +static void create_session(void); +static void input_byte(int byte, int stopbit); +static void sample(int vol, int* tones); +static void tonedetect(unsigned char *ptr, int count); +static void uart(int bit); + +static int dcd; /* Carrier on ? */ +static int ptyfd = -1; /* PTY filedescriptor */ +static int telfd = -1; /* I4BTEL filedescriptor */ + +/* + * Alaw to Linear [-32767..32767] conversion + */ + +static int a2l[256] = { -5504, -5248, -6016, -5760, -4480, -4224, +-4992, -4736, -7552, -7296, -8064, -7808, -6528, -6272, -7040, +-6784, -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368, +-3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392, -22016, +-20992, -24064, -23040, -17920, -16896, -19968, -18944, -30208, +-29184, -32256, -31232, -26112, -25088, -28160, -27136, -11008, +-10496, -12032, -11520, -8960, -8448, -9984, -9472, -15104, -14592, +-16128, -15616, -13056, -12544, -14080, -13568, -344, -328, -376, +-360, -280, -264, -312, -296, -472, -456, -504, -488, -408, -392, +-440, -424, -88, -72, -120, -104, -24, -8, -56, -40, -216, -200, +-248, -232, -152, -136, -184, -168, -1376, -1312, -1504, -1440, +-1120, -1056, -1248, -1184, -1888, -1824, -2016, -1952, -1632, +-1568, -1760, -1696, -688, -656, -752, -720, -560, -528, -624, +-592, -944, -912, -1008, -976, -816, -784, -880, -848, 5504, 5248, +6016, 5760, 4480, 4224, 4992, 4736, 7552, 7296, 8064, 7808, 6528, +6272, 7040, 6784, 2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368, +3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392, 22016, 20992, 24064, +23040, 17920, 16896, 19968, 18944, 30208, 29184, 32256, 31232, +26112, 25088, 28160, 27136, 11008, 10496, 12032, 11520, 8960, 8448, +9984, 9472, 15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568, +344, 328, 376, 360, 280, 264, 312, 296, 472, 456, 504, 488, 408, +392, 440, 424, 88, 72, 120, 104, 24, 8, 56, 40, 216, 200, 248, 232, +152, 136, 184, 168, 1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184, +1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696, 688, 656, 752, 720, +560, 528, 624, 592, 944, 912, 1008, 976, 816, 784, 880, 848 }; + +/* + * A High Q Tone detector + */ + +#define NTONES 2 /* Number of tones to detect */ +#define SCALE 4096 /* Scaling factor */ +#define EXPAVG 14 /* Exponential Average factor */ +#define POLERAD 3885 /* pole_radius ^ 2 * SCALE */ + +/* Table of "-cos(2 * PI * frequency / sample_rate) * SCALE" */ +static int p[NTONES] = { + -2941, /* 980 Hz */ + -2460 /* 1180 Hz */ +}; + +static void +tonedetect(unsigned char *ptr, int count) +{ + int i, j; + int y; + int c, d, f, n; + static int k[NTONES], h[NTONES]; + static int tones[NTONES]; + static int amplitude; + + + for (i = 0; i < count; i++) { + y = a2l[*ptr++]; + if (y > 0) + amplitude += (y - amplitude) / EXPAVG; + else + amplitude += (-y - amplitude) / EXPAVG; + + for(j = 0; j < NTONES; j++) { + c = (POLERAD * (y - k[j])) / SCALE; + d = y + c; + f = (p[j] * (d - h[j])) / SCALE; + n = y - k[j] - c; + if (n < 0) + n = -n; + k[j] = h[j] + f; + h[j] = f + d; + tones[j] += (n - tones[j]) / EXPAVG; + } + sample(amplitude, tones); + } +} + +/* + * Taste each sample, detect (loss off) carrier, and feed uart + */ + +#define NCARRIER 1000 /* Samples of carrier for detection */ + +static void +sample(int vol, int* tones) +{ + static int carrier; + + if ((tones[0] + tones[1]) > vol * 3/2) { /* XXX */ + if (carrier < NCARRIER) + carrier ++; + } else { + if (carrier > 0) + carrier --; + } + + if (!dcd && carrier > NCARRIER / 2) { + syslog(LOG_ERR, "CARRIER ON"); + dcd = 1; + } else if (dcd && carrier < NCARRIER / 2) { + syslog(LOG_ERR, "CARRIER OFF"); + dcd = 0; + } + + if (!dcd) + return; + + if (tones[0] > tones[1]) { + uart(1); + } else { + uart(0); + } +} + +/* + * A UART in software + */ + +#define BITCENTER 13 /* Middle of a bit: 8000/300/2 */ +static int bitsample[] = { /* table of sampling points */ + BITCENTER, + BITCENTER + 27, + BITCENTER + 54, + BITCENTER + 80, + BITCENTER + 107, + BITCENTER + 134, + BITCENTER + 160, + BITCENTER + 187, + BITCENTER + 214, + BITCENTER + 240 +}; + +static void +uart(int bit) +{ + static int n, v, j; + + if (n == 0 && bit == 1) + return; /* Waiting for start bit */ + if (n == 0) { + j = 0; /* Begin start bit */ + v = 0; + n++; + } else if (j == 0 && bit && n > bitsample[j]) { + n = 0; /* Gone by middle of start bit */ + } else if (n > bitsample[j]) { + j++; /* Sample point */ + if (j == 10) { + n = 0; + input_byte(v, bit); + } else { + v = v / 2 + 128 * bit; + n++; + } + } else { + n++; + } +} + +/* + * Send a byte using kenrnel tone generation support + */ + +static void +output_byte(int val) +{ + struct i4b_tel_tones tt; + int i; + + i = 0; + tt.frequency[i] = 1850; tt.duration[i++] = 27; + + tt.frequency[i] = val & 1 ? 1650 : 1850; tt.duration[i++] = 27; + tt.frequency[i] = val & 2 ? 1650 : 1850; tt.duration[i++] = 26; + tt.frequency[i] = val & 4 ? 1650 : 1850; tt.duration[i++] = 27; + tt.frequency[i] = val & 8 ? 1650 : 1850; tt.duration[i++] = 27; + tt.frequency[i] = val & 16 ? 1650 : 1850; tt.duration[i++] = 26; + tt.frequency[i] = val & 32 ? 1650 : 1850; tt.duration[i++] = 27; + tt.frequency[i] = val & 64 ? 1650 : 1850; tt.duration[i++] = 27; + tt.frequency[i] = val & 128 ? 1650 : 1850; tt.duration[i++] = 26; + + tt.frequency[i] = 1650; tt.duration[i++] = 27; + tt.frequency[i] = 1650; tt.duration[i++] = 0; + + i = ioctl(telfd, I4B_TEL_TONES, &tt); + if (i != 0 && errno != EAGAIN) { + syslog(LOG_ERR, "%d: *** %d/%d ***", __LINE__, i, errno); + exit(0); + } +} + +/* + * Create Session + */ + +static void +create_session(void) +{ + int i; + char buf[100]; + + i = forkpty(&ptyfd, buf, 0, 0); + if (i == 0) { + execl("/usr/libexec/getty", "getty", "std.300", "-", NULL); + syslog(LOG_ERR, "exec getty %d", errno); + exit(2); + } else if (i < 0) { + syslog(LOG_ERR, "forkpty failed %d", errno); + exit(2); + } + syslog(LOG_ERR, "pty %s", buf); +} + +static void +input_byte(int byte, int stopbit) +{ + u_char c; + int i; + static int first; + static u_char buf[80]; + + if (!stopbit) + return; + c = byte; + /* + * I have no idea why, but my TB2500 modem sends a sequence of + * 28 bytes after carrier is established at the link level, but + * before it is acceptted at the logical level. + * + * [16100214010201060100000000ff0201020301080402400010034510] + * + * Unfortunately this contains a ^D which kills getty. + * The following code swallows this sequence, assuming that it + * is always the same length and always start with 0x16. + * + */ + if (first == 0 && c == 0x16) { + sprintf(buf, "%02x", c); + first = 27; + return; + } else if (first == 0) { + first = -1; + dcd = 2; + return; + } + if (first > 0) { + sprintf(buf + strlen(buf), "%02x", c); + first--; + if (!first) { + syslog(LOG_NOTICE, "Got magic [%s]", buf); + *buf = 0; + } + return; + } + if (ptyfd != -1 && dcd) { + i = write(ptyfd, &c, 1); + if (i != 1 && errno != EAGAIN) { + syslog(LOG_ERR, "%d: *** %d/%d ***", __LINE__, i, errno); + exit(0); + } + } +} + +int +main(int argc, char **argv) +{ + char *device = "/dev/tel0"; + u_char ibuf[2048]; + int ii, io; + int i, maxfd; + struct i4b_tel_tones tt; + fd_set rfd, wfd, efd; + + openlog("v21modem", LOG_PID, LOG_DAEMON); + /* Find our device name */ + for (i = 0; i < argc; i++) + if (!strcmp(argv[i], "-D")) + device = argv[i + 1]; + telfd = open(device, O_RDWR, 0); + if (telfd < 0) { + syslog(LOG_ERR, "open %s: %m", device); + exit (0); + } + syslog(LOG_NOTICE, "Running on %s", device); + + /* Output V.25 tone and carrier */ + i = 0; + tt.frequency[i] = 0; tt.duration[i++] = 1000; + tt.frequency[i] = 2100; tt.duration[i++] = 2*8000; + tt.frequency[i] = 0; tt.duration[i++] = 400; + tt.frequency[i] = 1650; tt.duration[i++] = 1; + tt.frequency[i] = 1650; tt.duration[i++] = 0; + tt.frequency[i] = 0; tt.duration[i++] = 0; + i = ioctl(telfd, I4B_TEL_TONES, &tt); + if (i < 0) { + syslog(LOG_ERR, "hangup"); + exit(0); + } + + create_session(); + + /* Wait for carrier */ + do { + ii = read(telfd, ibuf, sizeof ibuf); + tonedetect(ibuf, ii); + } while (ii > 0 && dcd != 2); + if (ii < 0) { + syslog(LOG_ERR, "hangup"); + exit(0); + } + + maxfd = ptyfd; + if (telfd > maxfd) + maxfd = telfd; + maxfd += 1; + do { + FD_ZERO(&rfd); + FD_SET(telfd, &rfd); + FD_SET(ptyfd, &rfd); + FD_ZERO(&wfd); + FD_ZERO(&efd); + FD_SET(telfd, &efd); + FD_SET(ptyfd, &efd); + i = select(maxfd, &rfd, &wfd, &efd, NULL); + if (FD_ISSET(telfd, &rfd)) { + ii = read(telfd, ibuf, sizeof ibuf); + if (ii > 0) + tonedetect(ibuf, ii); + else + syslog(LOG_ERR, "hangup"); + } + if (FD_ISSET(ptyfd, &rfd)) { + io = read(ptyfd, ibuf, 1); + if (io == 1) + output_byte(*ibuf); + else if (io == 0) { + syslog(LOG_ERR, "Session EOF"); + exit(0); + } + + } + if (FD_ISSET(telfd, &efd)) { + syslog(LOG_ERR, "Exception TELFD"); + exit (0); + } + if (FD_ISSET(ptyfd, &efd)) { + syslog(LOG_ERR, "Exception PTYFD"); + exit (0); + } + } while (dcd); + syslog(LOG_ERR, "Carrier Lost"); + exit(0); +} |