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WIP: simcom2rtp bridge, interfacing SIMcom audio over USB to RTP

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Change-Id: Id3f8633fae8881c2168d61732371e65eaff140ad
This commit is contained in:
Harald Welte
2020-08-06 22:39:30 +02:00
parent 172f5acfce
commit c7d15fb70d
6 changed files with 685 additions and 0 deletions
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11
contrib/simcom2rtp/Makefile Normal file
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CFLAGS:= -O2 -g -Wall $(shell pkg-config --cflags libosmocore libosmotrau)
LIBS:= $(shell pkg-config --libs libosmocore libosmotrau)
all: osmo-simcom2rtp
osmo-simcom2rtp: g711.o g711_table.o simcom2rtp.o
$(CC) $(LDFLAGS) -o $@ $^ $(LIBS)
%.o: %.c
$(CC) $(CFLAGS) -o $@ -c $^

313
contrib/simcom2rtp/g711.c Normal file
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/*
* This source code is a product of Sun Microsystems, Inc. and is provided
* for unrestricted use. Users may copy or modify this source code without
* charge.
*
* SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
* THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
*
* Sun source code is provided with no support and without any obligation on
* the part of Sun Microsystems, Inc. to assist in its use, correction,
* modification or enhancement.
*
* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
* OR ANY PART THEREOF.
*
* In no event will Sun Microsystems, Inc. be liable for any lost revenue
* or profits or other special, indirect and consequential damages, even if
* Sun has been advised of the possibility of such damages.
*
* Sun Microsystems, Inc.
* 2550 Garcia Avenue
* Mountain View, California 94043
*/
/*
* December 30, 1994:
* Functions linear2alaw, linear2ulaw have been updated to correctly
* convert unquantized 16 bit values.
* Tables for direct u- to A-law and A- to u-law conversions have been
* corrected.
* Borge Lindberg, Center for PersonKommunikation, Aalborg University.
* bli@cpk.auc.dk
*
*/
/*
* Downloaded from comp.speech site in Cambridge.
*
*/
#include "g711.h"
/*
* g711.c
*
* u-law, A-law and linear PCM conversions.
* Source: http://www.speech.kth.se/cost250/refsys/latest/src/g711.c
*/
#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
#define QUANT_MASK (0xf) /* Quantization field mask. */
#define NSEGS (8) /* Number of A-law segments. */
#define SEG_SHIFT (4) /* Left shift for segment number. */
#define SEG_MASK (0x70) /* Segment field mask. */
static short seg_aend[8] = {0x1F, 0x3F, 0x7F, 0xFF,
0x1FF, 0x3FF, 0x7FF, 0xFFF};
static short seg_uend[8] = {0x3F, 0x7F, 0xFF, 0x1FF,
0x3FF, 0x7FF, 0xFFF, 0x1FFF};
/* copy from CCITT G.711 specifications */
unsigned char _u2a[128] = { /* u- to A-law conversions */
1, 1, 2, 2, 3, 3, 4, 4,
5, 5, 6, 6, 7, 7, 8, 8,
9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 29, 31, 33, 34, 35, 36,
37, 38, 39, 40, 41, 42, 43, 44,
46, 48, 49, 50, 51, 52, 53, 54,
55, 56, 57, 58, 59, 60, 61, 62,
64, 65, 66, 67, 68, 69, 70, 71,
72, 73, 74, 75, 76, 77, 78, 79,
/* corrected:
81, 82, 83, 84, 85, 86, 87, 88,
should be: */
80, 82, 83, 84, 85, 86, 87, 88,
89, 90, 91, 92, 93, 94, 95, 96,
97, 98, 99, 100, 101, 102, 103, 104,
105, 106, 107, 108, 109, 110, 111, 112,
113, 114, 115, 116, 117, 118, 119, 120,
121, 122, 123, 124, 125, 126, 127, 128};
unsigned char _a2u[128] = { /* A- to u-law conversions */
1, 3, 5, 7, 9, 11, 13, 15,
16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31,
32, 32, 33, 33, 34, 34, 35, 35,
36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 48, 49, 49,
50, 51, 52, 53, 54, 55, 56, 57,
58, 59, 60, 61, 62, 63, 64, 64,
65, 66, 67, 68, 69, 70, 71, 72,
/* corrected:
73, 74, 75, 76, 77, 78, 79, 79,
should be: */
73, 74, 75, 76, 77, 78, 79, 80,
80, 81, 82, 83, 84, 85, 86, 87,
88, 89, 90, 91, 92, 93, 94, 95,
96, 97, 98, 99, 100, 101, 102, 103,
104, 105, 106, 107, 108, 109, 110, 111,
112, 113, 114, 115, 116, 117, 118, 119,
120, 121, 122, 123, 124, 125, 126, 127};
static short search(
short val,
short *table,
short size)
{
short i;
for (i = 0; i < size; i++) {
if (val <= *table++)
return (i);
}
return (size);
}
/*
* linear2alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
*
* linear2alaw() accepts an 16-bit integer and encodes it as A-law data.
*
* Linear Input Code Compressed Code
* ------------------------ ---------------
* 0000000wxyza 000wxyz
* 0000001wxyza 001wxyz
* 000001wxyzab 010wxyz
* 00001wxyzabc 011wxyz
* 0001wxyzabcd 100wxyz
* 001wxyzabcde 101wxyz
* 01wxyzabcdef 110wxyz
* 1wxyzabcdefg 111wxyz
*
* For further information see John C. Bellamy's Digital Telephony, 1982,
* John Wiley & Sons, pps 98-111 and 472-476.
*/
unsigned char
linear2alaw(short pcm_val) /* 2's complement (16-bit range) */
{
short mask;
short seg;
unsigned char aval;
pcm_val = pcm_val >> 3;
if (pcm_val >= 0) {
mask = 0xD5; /* sign (7th) bit = 1 */
} else {
mask = 0x55; /* sign bit = 0 */
pcm_val = -pcm_val - 1;
}
/* Convert the scaled magnitude to segment number. */
seg = search(pcm_val, seg_aend, 8);
/* Combine the sign, segment, and quantization bits. */
if (seg >= 8) /* out of range, return maximum value. */
return (unsigned char) (0x7F ^ mask);
else {
aval = (unsigned char) seg << SEG_SHIFT;
if (seg < 2)
aval |= (pcm_val >> 1) & QUANT_MASK;
else
aval |= (pcm_val >> seg) & QUANT_MASK;
return (aval ^ mask);
}
}
/*
* alaw2linear() - Convert an A-law value to 16-bit linear PCM
*
*/
short
alaw2linear(
unsigned char a_val)
{
short t;
short seg;
a_val ^= 0x55;
t = (a_val & QUANT_MASK) << 4;
seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
switch (seg) {
case 0:
t += 8;
break;
case 1:
t += 0x108;
break;
default:
t += 0x108;
t <<= seg - 1;
}
return ((a_val & SIGN_BIT) ? t : -t);
}
#define BIAS (0x84) /* Bias for linear code. */
#define CLIP 8159
/*
* linear2ulaw() - Convert a linear PCM value to u-law
*
* In order to simplify the encoding process, the original linear magnitude
* is biased by adding 33 which shifts the encoding range from (0 - 8158) to
* (33 - 8191). The result can be seen in the following encoding table:
*
* Biased Linear Input Code Compressed Code
* ------------------------ ---------------
* 00000001wxyza 000wxyz
* 0000001wxyzab 001wxyz
* 000001wxyzabc 010wxyz
* 00001wxyzabcd 011wxyz
* 0001wxyzabcde 100wxyz
* 001wxyzabcdef 101wxyz
* 01wxyzabcdefg 110wxyz
* 1wxyzabcdefgh 111wxyz
*
* Each biased linear code has a leading 1 which identifies the segment
* number. The value of the segment number is equal to 7 minus the number
* of leading 0's. The quantization interval is directly available as the
* four bits wxyz. * The trailing bits (a - h) are ignored.
*
* Ordinarily the complement of the resulting code word is used for
* transmission, and so the code word is complemented before it is returned.
*
* For further information see John C. Bellamy's Digital Telephony, 1982,
* John Wiley & Sons, pps 98-111 and 472-476.
*/
unsigned char
linear2ulaw(
short pcm_val) /* 2's complement (16-bit range) */
{
short mask;
short seg;
unsigned char uval;
/* Get the sign and the magnitude of the value. */
pcm_val = pcm_val >> 2;
if (pcm_val < 0) {
pcm_val = -pcm_val;
mask = 0x7F;
} else {
mask = 0xFF;
}
if ( pcm_val > CLIP ) pcm_val = CLIP; /* clip the magnitude */
pcm_val += (BIAS >> 2);
/* Convert the scaled magnitude to segment number. */
seg = search(pcm_val, seg_uend, 8);
/*
* Combine the sign, segment, quantization bits;
* and complement the code word.
*/
if (seg >= 8) /* out of range, return maximum value. */
return (unsigned char) (0x7F ^ mask);
else {
uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF);
return (uval ^ mask);
}
}
/*
* ulaw2linear() - Convert a u-law value to 16-bit linear PCM
*
* First, a biased linear code is derived from the code word. An unbiased
* output can then be obtained by subtracting 33 from the biased code.
*
* Note that this function expects to be passed the complement of the
* original code word. This is in keeping with ISDN conventions.
*/
short
ulaw2linear(
unsigned char u_val)
{
short t;
/* Complement to obtain normal u-law value. */
u_val = ~u_val;
/*
* Extract and bias the quantization bits. Then
* shift up by the segment number and subtract out the bias.
*/
t = ((u_val & QUANT_MASK) << 3) + BIAS;
t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
}
/* A-law to u-law conversion */
unsigned char
alaw2ulaw(
unsigned char aval)
{
aval &= 0xff;
return (unsigned char) ((aval & 0x80) ? (0xFF ^ _a2u[aval ^ 0xD5]) :
(0x7F ^ _a2u[aval ^ 0x55]));
}
/* u-law to A-law conversion */
unsigned char
ulaw2alaw(
unsigned char uval)
{
uval &= 0xff;
return (unsigned char) ((uval & 0x80) ? (0xD5 ^ (_u2a[0xFF ^ uval] - 1)) :
(0x55 ^ (_u2a[0x7F ^ uval] - 1)));
}
/* ---------- end of g711.c ----------------------------------------------------- */

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/*
* g711.h
*
* u-law, A-law and linear PCM conversions.
* Source: http://www.speech.kth.se/cost250/refsys/latest/src/g711.h
*/
#ifndef _G711_H_
#define _G711_H_
#ifdef __cplusplus
extern "C" {
#endif
unsigned char linear2alaw(short pcm_val);
short alaw2linear(unsigned char a_val);
unsigned char linear2ulaw(short pcm_val);
short ulaw2linear(unsigned char u_val);
unsigned char alaw2ulaw(unsigned char aval);
unsigned char ulaw2alaw(unsigned char uval);
#ifdef __cplusplus
}
#endif
#endif /* _G711_H_ */

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contrib/simcom2rtp/g711_table.c Normal file
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#ifndef G711_TABLE_H
#define G711_TABLE_H
#include "g711.h"
/* 16384 entries per table (16 bit) */
unsigned char linear_to_alaw[65536];
unsigned char linear_to_ulaw[65536];
/* 16384 entries per table (8 bit) */
unsigned short alaw_to_linear[256];
unsigned short ulaw_to_linear[256];
static void build_linear_to_xlaw_table(unsigned char *linear_to_xlaw,
unsigned char (*linear2xlaw)(short))
{
int i;
for (i=0; i<65536;i++){
linear_to_xlaw[i] = linear2xlaw((short) i);
}
}
static void build_xlaw_to_linear_table(unsigned short *xlaw_to_linear,
short (*xlaw2linear)(unsigned char))
{
int i;
for (i=0; i<256;i++){
xlaw_to_linear[i] = (unsigned short) xlaw2linear(i);
}
}
static void pcm16_to_xlaw(unsigned char *linear_to_xlaw, int src_length, const char *src_samples, char *dst_samples)
{
int i;
const unsigned short *s_samples;
s_samples = (const unsigned short *)src_samples;
for (i=0; i < src_length / 2; i++)
{
dst_samples[i] = linear_to_xlaw[s_samples[i]];
}
}
static void xlaw_to_pcm16(unsigned short *xlaw_to_linear, int src_length, const char *src_samples, char *dst_samples)
{
int i;
unsigned char *s_samples;
unsigned short *d_samples;
s_samples = (unsigned char *) src_samples;
d_samples = (unsigned short *)dst_samples;
for (i=0; i < src_length; i++)
{
d_samples[i] = xlaw_to_linear[s_samples[i]];
}
}
void pcm16_to_alaw(int src_length, const char *src_samples, char *dst_samples)
{
pcm16_to_xlaw(linear_to_alaw, src_length, src_samples, dst_samples);
}
void pcm16_to_ulaw(int src_length, const char *src_samples, char *dst_samples)
{
pcm16_to_xlaw(linear_to_ulaw, src_length, src_samples, dst_samples);
}
void alaw_to_pcm16(int src_length, const char *src_samples, char *dst_samples)
{
xlaw_to_pcm16(alaw_to_linear, src_length, src_samples, dst_samples);
}
void ulaw_to_pcm16(int src_length, const char *src_samples, char *dst_samples)
{
xlaw_to_pcm16(ulaw_to_linear, src_length, src_samples, dst_samples);
}
void pcm16_alaw_tableinit()
{
build_linear_to_xlaw_table(linear_to_alaw, linear2alaw);
}
void pcm16_ulaw_tableinit()
{
build_linear_to_xlaw_table(linear_to_ulaw, linear2ulaw);
}
void alaw_pcm16_tableinit()
{
build_xlaw_to_linear_table(alaw_to_linear, alaw2linear);
}
void ulaw_pcm16_tableinit()
{
build_xlaw_to_linear_table(ulaw_to_linear, ulaw2linear);
}
#endif // G711_TABLE_H

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contrib/simcom2rtp/g711_table.h Normal file
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#ifndef G711_TABLE_H
#define G711_TABLE_H
void pcm16_to_alaw(int length, const char *src_samples, char *dst_samples);
void pcm16_to_ulaw(int length, const char *src_samples, char *dst_samples);
void alaw_to_pcm16(int length, const char *src_samples, char *dst_samples);
void ulaw_to_pcm16(int length, const char *src_samples, char *dst_samples);
void pcm16_alaw_tableinit();
void pcm16_ulaw_tableinit();
void alaw_pcm16_tableinit();
void ulaw_pcm16_tableinit();
#endif // G711_TABLE_H

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contrib/simcom2rtp/simcom2rtp.c Normal file
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#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <osmocom/core/select.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/fsm.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/application.h>
#include <osmocom/core/serial.h>
#include <osmocom/trau/osmo_ortp.h>
#include "g711.h"
#define RTP_PT_PCMU 0
#define RTP_PT_PCMA 8
struct modem_state {
struct osmo_fd data_fd;
struct osmo_rtp_socket *rtp;
/* queue of linear PCM audio in RTP -> modem direction */
struct llist_head rtp2modem;
/* message buffer used if samples insufficient for next RTP frame were received */
struct msgb *modem2rtp;
};
static void *g_tall_ctx;
/* call-back on received RTP data */
static void ortp_rx_cb(struct osmo_rtp_socket *rs, const uint8_t *payload,
unsigned int payload_len, uint16_t seq_nr, uint32_t timestamp, bool marker)
{
/* we received a RTP frame */
struct modem_state *ms = rs->priv;
struct msgb *msg = msgb_alloc(payload_len*2, "RTP Rx");
unsigned int i;
int16_t *out;
OSMO_ASSERT(msg);
out = (int16_t *) msgb_put(msg, payload_len*2);
if (payload_len != 160) {
fprintf(stderr, "RTP payload length %d != 160, dropping\n", payload_len);
msgb_free(msg);
return;
}
/* convert from Alaw to linear PCM (160 -> 320 bytes) */
for (i = 0; i < payload_len; i++)
out[i] = alaw2linear(payload[i]);
/* append to the write queue */
msgb_enqueue(&ms->rtp2modem, msg);
ms->data_fd.when |= OSMO_FD_WRITE;
}
static void modem2rtp(struct modem_state *ms, const uint8_t *data, unsigned int len)
{
const int16_t *data16 = (const int16_t *)data;
unsigned int samples = len / 2;
unsigned int offset = 0;
unsigned int i;
/* samples are always 16bit, we cannot read half a sample */
OSMO_ASSERT((len & 1) == 0);
/* first complete any pending incomplete RTP frame */
if (ms->modem2rtp) {
struct msgb *msg = ms->modem2rtp;
unsigned int missing_samples = 160 - msgb_length(msg);
for (i = 0; i < missing_samples; i++) {
if (i >= samples)
break;
msgb_put_u8(msg, linear2alaw(data16[i]));
}
offset = i;
if (msgb_length(msg) == 160) {
osmo_rtp_send_frame_ext(ms->rtp, msgb_data(msg), msgb_length(msg), 160, false);
msgb_free(msg);
}
}
/* then send as many RTP frames as we have samples */
for (offset = offset; offset + 160 <= samples; offset += 160) {
uint8_t buf[160];
for (i = 0; i < sizeof(buf); i++)
buf[i] = linear2alaw(data16[offset + i]);
osmo_rtp_send_frame_ext(ms->rtp, buf, sizeof(buf), 160, false);
}
/* store remainder in msgb */
if (offset < samples) {
struct msgb *msg = msgb_alloc_c(ms, 160, "modem2rtp");
OSMO_ASSERT(msg);
OSMO_ASSERT(len - offset < 160);
for (i = 0; i < len - offset; i++)
msgb_put_u8(msg, linear2alaw(data16[offset + i]));
ms->modem2rtp = msg;
}
}
/* call back on file descriptor events of the modem DATA ttyUSB device */
static int modem_data_fd_cb(struct osmo_fd *ofd, unsigned int what)
{
struct modem_state *ms = ofd->data;
int rc;
if (what & OSMO_FD_READ) {
/* SIM5360 USB AUDIO Application Note v1.01 states 1600 bytes every 100ms */
uint8_t rx_buf[1600];
rc = read(ofd->fd, rx_buf, sizeof(rx_buf));
OSMO_ASSERT(rc > 0);
modem2rtp(ms, rx_buf, rc);
}
if (what & OSMO_FD_WRITE) {
struct msgb *msg = msgb_dequeue(&ms->rtp2modem);
if (!msg)
ofd->when &= ~OSMO_FD_WRITE;
else {
/* SIM5300 USB AUDIO Application Note v1.01 states 640 bytes every 40ms;
* we simply write every RTP frame individually (320 bytes every 20ms) */
rc = write(ofd->fd, msgb_data(msg), msgb_length(msg));
if (rc != msgb_length(msg))
fprintf(stderr, "Short write: %d < %u\n", rc, msgb_length(msg));
msgb_free(msg);
}
}
return 0;
}
static int modem_data_open(struct modem_state *ms, const char *basepath)
{
char fname[PATH_MAX+1];
int fd;
/* the assumption is that the caller provides something like
* "/dev/serial/by-path/pci-0000:00:14.0-usb-0:2:1" */
snprintf(fname, sizeof(fname), "%s.0-port0", basepath);
fd = osmo_serial_init(fname, 921600);
if (fd < 0) {
fprintf(stderr, "failed to open device '%s': %s\n", fname, strerror(errno));
return -1;
}
osmo_fd_setup(&ms->data_fd, fd, OSMO_FD_READ, modem_data_fd_cb, ms, 0);
osmo_fd_register(&ms->data_fd);
return 0;
}
static struct modem_state *modem_create(void *ctx)
{
struct modem_state *ms = talloc_zero(ctx, struct modem_state);
int rc;
INIT_LLIST_HEAD(&ms->rtp2modem);
ms->rtp = osmo_rtp_socket_create(ms, 0);
OSMO_ASSERT(ms->rtp);
osmo_rtp_socket_set_pt(ms->rtp, RTP_PT_PCMA);
ms->rtp->priv = ms;
ms->rtp->rx_cb = ortp_rx_cb;
rc = osmo_rtp_socket_bind(ms->rtp, "0.0.0.0", 1111);
OSMO_ASSERT(rc == 0);
rc = osmo_rtp_socket_connect(ms->rtp, "127.0.0.1", 2222);
//rc = osmo_rtp_socket_autoconnect(ms->rtp);
OSMO_ASSERT(rc == 0);
osmo_rtp_set_source_desc(ms->rtp, "cname", "simcom2rtp", NULL, NULL, NULL,
"osmo-simcom2rtp", NULL);
return ms;
}
int main(int argc, char **argv)
{
talloc_enable_null_tracking();
g_tall_ctx = talloc_named_const(NULL, 1, "simcom2rtp");
msgb_talloc_ctx_init(g_tall_ctx, 0);
osmo_init_logging2(g_tall_ctx, NULL);
osmo_fsm_log_timeouts(true);
osmo_fsm_log_addr(true);
//osmo_stats_init(g_tall_ctx);
osmo_rtp_init(g_tall_ctx);
struct modem_state *ms = modem_create(g_tall_ctx);
int rc;
OSMO_ASSERT(ms);
rc = modem_data_open(ms, "/dev/serial/by-path/pci-0000:00:14.0-usb-0:2:1");
OSMO_ASSERT(rc == 0);
while (1) {
osmo_select_main(0);
}
}