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serval-dna/fakeradio.c
Jeremy Lakeman 8d80cf55f2 Fix printf formats
2013-12-16 15:19:15 +10:30

537 lines
14 KiB
C
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/*
Serval DNA radio serial modem simulator
Copyright (C) 2013 Serval Project Inc.
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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <stdint.h>
#include <fcntl.h>
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#include <errno.h>
#include <time.h>
#include <sys/time.h>
#include <strings.h>
#include <string.h>
#include <unistd.h>
#define PACKET_SIZE 255
int chars_per_ms=1;
long ber=0;
struct radio_state {
int fd;
int state;
const char *name;
char commandbuffer[128];
unsigned cb_len;
unsigned char txbuffer[1280];
unsigned txb_len;
unsigned tx_count;
unsigned wait_count;
unsigned char rxbuffer[512];
unsigned rxb_len;
int64_t last_char_ms;
int64_t next_rssi_time_ms;
int rssi_output;
unsigned char seqnum;
};
#define STATE_ONLINE 0
#define STATE_PLUS 1
#define STATE_PLUSPLUS 2
#define STATE_PLUSPLUSPLUS 3
#define STATE_COMMAND 4
int64_t gettime_ms()
{
struct timeval nowtv;
// If gettimeofday() fails or returns an invalid value, all else is lost!
if (gettimeofday(&nowtv, NULL) == -1)
perror("gettimeofday");
return nowtv.tv_sec * 1000LL + nowtv.tv_usec / 1000;
}
void log_time(){
struct timeval tv;
struct tm tm;
gettimeofday(&tv, NULL);
localtime_r(&tv.tv_sec, &tm);
char buf[50];
if (strftime(buf, sizeof buf, "%T", &tm) == 0)
fprintf(stderr, "EMPTYTIME___ ");
else
fprintf(stderr, "%s.%03u ", buf, (unsigned int)tv.tv_usec / 1000);
}
int append_bytes(struct radio_state *s, const char *bytes, int len)
{
if (len==-1)
len = strlen(bytes);
if (len + s->rxb_len > sizeof(s->rxbuffer))
return -1;
bcopy(bytes, &s->rxbuffer[s->rxb_len], len);
s->rxb_len+=len;
return len;
}
int processCommand(struct radio_state *s)
{
if (!s->cb_len) return 0;
s->commandbuffer[s->cb_len]=0;
char *cmd=s->commandbuffer;
log_time();
fprintf(stderr, "Processing command from %s \"%s\"\n", s->name, cmd);
if (!strcasecmp(cmd,"AT")) {
// Noop
append_bytes(s, "OK\r", -1);
return 0;
}
if (!strcasecmp(cmd,"ATO")) {
append_bytes(s, "OK\r", -1);
s->state=STATE_ONLINE;
return 0;
}
if (!strcasecmp(cmd,"AT&T")) {
append_bytes(s, "OK\r", -1);
s->rssi_output=0;
return 0;
}
if (!strcasecmp(cmd,"AT&T=RSSI")) {
append_bytes(s, "OK\r", -1);
s->rssi_output=1;
return 0;
}
if (!strcasecmp(cmd,"ATI")) {
append_bytes(s, "RFD900a SIMULATOR 1.6\rOK\r", -1);
return 0;
}
append_bytes(s, "ERROR\r", -1);
return 1;
}
int dump(char *name, unsigned char *addr, size_t len)
{
unsigned i,j;
if (name)
fprintf(stderr,"Dump of %s\n",name);
for(i=0;i<len;i+=16){
fprintf(stderr," %04x :",i);
for(j=0;j<16&&(i+j)<len;j++)
fprintf(stderr," %02x",addr[i+j]);
for(;j<16;j++)
fprintf(stderr," ");
fprintf(stderr," ");
for(j=0;j<16&&(i+j)<len;j++)
fprintf(stderr,"%c",addr[i+j]>=' '&&addr[i+j]<0x7f?addr[i+j]:'.');
fprintf(stderr,"\n");
}
return 0;
}
static void store_char(struct radio_state *s, unsigned char c)
{
if(s->txb_len<sizeof(s->txbuffer)){
s->txbuffer[s->txb_len++]=c;
}else{
log_time();
fprintf(stderr, "*** Dropped char %02x\n", c);
}
}
int read_bytes(struct radio_state *s)
{
unsigned char buff[8];
int i;
int bytes=read(s->fd,buff,sizeof(buff));
if (bytes<=0)
return bytes;
log_time();
fprintf(stderr, "Read from %s\n", s->name);
dump(NULL,buff,bytes);
s->last_char_ms = gettime_ms();
// process incoming bytes
for (i=0;i<bytes;i++){
// either append to a command buffer
if (s->state==STATE_COMMAND){
if (buff[i]=='\r'){
// and process the commend on EOL
processCommand(s);
s->cb_len=0;
// backspace characters
}else if (buff[i]=='\b'||buff[i]=='\x7f'){
if (s->cb_len>0)
s->cb_len--;
// append to command buffer
}else if (s->cb_len<127)
s->commandbuffer[s->cb_len++]=buff[i];
continue;
}
// or watch for "+++"
if (buff[i]=='+'){
if (s->state < STATE_PLUSPLUSPLUS)
s->state++;
}else
s->state=STATE_ONLINE;
// or append to the transmit buffer if there's room
store_char(s,buff[i]);
}
return bytes;
}
void write_bytes(struct radio_state *s)
{
ssize_t wrote = s->rxb_len;
if (wrote>8)
wrote=8;
if (s->last_char_ms)
wrote = write(s->fd, s->rxbuffer, wrote);
if (wrote != -1){
log_time();
fprintf(stderr, "Wrote to %s\n", s->name);
dump(NULL, s->rxbuffer, (size_t)wrote);
if ((size_t)wrote < s->rxb_len)
bcopy(&s->rxbuffer[(size_t)wrote], s->rxbuffer, s->rxb_len - (size_t)wrote);
s->rxb_len -= (size_t)wrote;
}
}
int transmitter=0;
int64_t next_transmit_time=0;
#define MAVLINK10_STX 254
#define RADIO_SOURCE_SYSTEM '3'
#define RADIO_SOURCE_COMPONENT 'D'
#define MAVLINK_MSG_ID_RADIO 166
#define MAVLINK_HDR 8
int MAVLINK_MESSAGE_CRCS[]={72, 39, 190, 92, 191, 217, 104, 119, 0, 219, 60, 186, 10, 0, 0, 0, 0, 0, 0, 0, 89, 159, 162, 121, 0, 149, 222, 110, 179, 136, 66, 126, 185, 147, 112, 252, 162, 215, 229, 128, 9, 106, 101, 213, 4, 229, 21, 214, 215, 14, 206, 50, 157, 126, 108, 213, 95, 5, 127, 0, 0, 0, 57, 126, 130, 119, 193, 191, 236, 158, 143, 0, 0, 104, 123, 131, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 174, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 155, 0, 0, 0, 0, 0, 0, 0, 0, 0, 143, 29, 208, 188, 118, 242, 19, 97, 233, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 178, 224, 60, 106, 7};
uint16_t mavlink_crc(unsigned char *buf,int length)
{
uint16_t sum = 0xFFFF;
uint8_t i, stoplen;
stoplen = length + 6;
// MAVLink 1.0 has an extra CRC seed
buf[length+6] = MAVLINK_MESSAGE_CRCS[buf[5]];
stoplen++;
i = 1;
while (i<stoplen) {
uint8_t tmp;
tmp = buf[i] ^ (uint8_t)(sum&0xff);
tmp ^= (tmp<<4);
sum = (sum>>8) ^ (tmp<<8) ^ (tmp<<3) ^ (tmp>>4);
i++;
}
return sum;
}
int build_heartbeat(struct radio_state *s){
if (s->rxb_len + MAVLINK_HDR + 9 > sizeof(s->rxbuffer))
return -1;
log_time();
fprintf(stderr,"Building heartbeat for %s\n", s->name);
unsigned char *b=&s->rxbuffer[s->rxb_len];
b[0] = MAVLINK10_STX;
b[1] = 9;
b[2] = s->seqnum++;
b[3] = RADIO_SOURCE_SYSTEM;
b[4] = RADIO_SOURCE_COMPONENT;
b[5] = MAVLINK_MSG_ID_RADIO;
b[6] = 0; //rxerrors
b[7] = 0; //rxerrors
b[8] = 0; //fixed
b[9] = 0; //fixed
b[10] = 43; //average RSSI
b[11] = 35; //remote average RSSI
int space = sizeof(s->txbuffer) - s->txb_len;
b[12] = ((space/8)*100) / (sizeof(s->txbuffer)/8); //txbuf space
b[13] = 20; //noise
b[14] = 20; //remote noise
uint16_t crc = mavlink_crc(b, 9);
b[15]=crc&0xFF;
b[16]=(crc>>8)&0xFF;
s->rxb_len += MAVLINK_HDR+9;
return 0;
}
void transfer_bytes(struct radio_state *radios)
{
// if there's data to transmit, copy a radio packet from one device to the other
int receiver = transmitter^1;
struct radio_state *r = &radios[receiver];
struct radio_state *t = &radios[transmitter];
size_t bytes = t->txb_len;
if (bytes > PACKET_SIZE)
bytes = PACKET_SIZE;
// try to send some number of whole mavlink frames from our buffer
{
size_t p=0, send=0;
while (p < bytes){
if (t->txbuffer[p]==MAVLINK10_STX){
// a mavlink header
// we can send everything before this header
if (p>0)
send = p-1;
// wait for more bytes or for the next transmit slot
// TODO add time limit
if (p+1 >= bytes)
break;
// how big is this mavlink frame?
size_t size = t->txbuffer[p+1];
// if the size is valid, try to send the whole packet at once
if (size <= PACKET_SIZE - MAVLINK_HDR){
// wait for more bytes or for the next transmit slot
// TODO add time limit
if (p+size+MAVLINK_HDR > bytes)
break;
// detect when we are about to transmit a heartbeat frame
if (size==9 && t->txbuffer[p+5]==0){
// reply to the host with a heartbeat
build_heartbeat(t);
}
p+=size+MAVLINK_HDR;
send=p;
continue;
}
}
// no valid mavlink frames? just send as much as we can
send=p;
p++;
}
if (send<bytes && !send){
if (bytes < PACKET_SIZE && t->wait_count++ <5){
log_time();
fprintf(stderr,"Waiting for more bytes for %s\n", t->name);
dump(NULL, t->txbuffer, bytes);
}else
send = bytes;
}
if (send)
t->wait_count=0;
bytes=send;
}
if (bytes>0){
log_time();
fprintf(stderr, "Transferring %zd byte packet from %s to %s\n", bytes, t->name, r->name);
}
unsigned i, j;
int dropped=0;
// preamble length in bits that must arrive intact
#define PREAMBLE_LENGTH (20+8)
// simulate the probability of a bit error in the packet pre-amble and drop the whole packet
for (i=0;i<PREAMBLE_LENGTH;i++){
if (random()<ber)
dropped=1;
}
if (dropped){
fprintf(stderr,"Dropped the whole radio packet due to bit flip in the pre-amble\n");
}else{
for (i=0;i<bytes && r->rxb_len<sizeof(r->rxbuffer);i++){
char byte = t->txbuffer[i];
// introduce bit errors
for(j=0;j<8;j++) {
if (random()<ber) {
byte^=(1<<j);
fprintf(stderr,"Flipped a bit\n");
}
}
r->rxbuffer[r->rxb_len++]=byte;
}
}
if (bytes>0 && bytes < t->txb_len)
bcopy(&t->txbuffer[bytes], t->txbuffer, t->txb_len - bytes);
t->txb_len-=bytes;
// set the wait time for the next transmission
next_transmit_time = gettime_ms() + 5 + bytes/chars_per_ms;
if (bytes==0 || t->tx_count == 0 || --t->tx_count == 0){
// swap who's turn it is to transmit after sending 3 packets or running out of data.
transmitter = receiver;
r->tx_count=3;
// add Tx->Rx change time (it's about 40ms between receiving empty packets)
next_transmit_time+=15;
}
}
int calc_ber(double target_packet_fraction)
{
int byte_count=220+32;
int max_error_bytes=16;
int ber;
int p;
int byte;
int bit;
// 9,000,000 gives a packet delivery rate of ~99%
// so no point starting smaller than that.
// Only ~30,000,000 reduces packet delivery rate to
// ~1%, so the search range is fairly narrow.
ber=0;
if (target_packet_fraction<=0.9) ber=6900000;
if (target_packet_fraction<=0.5) ber=16900000;
if (target_packet_fraction<=0.25) ber=20600000;
if (target_packet_fraction<=0.1) ber=23400000;
if (target_packet_fraction<=0.05) ber=28600000;
for(;ber<0x70ffffff;ber+=100000)
{
int packet_errors=0;
for(p=0;p<1000;p++) {
int byte_errors=0;
int dropped = 0;
for (byte=0;byte<PREAMBLE_LENGTH;byte++){
if (random()<ber){
dropped = 1;
break;
}
}
if (!dropped){
for(byte=0;byte<byte_count;byte++) {
for(bit=0;bit<8;bit++) if (random()<ber) { byte_errors++; break; }
if (byte_errors>max_error_bytes) { dropped=1; break; }
}
}
if (dropped)
packet_errors++;
}
if (packet_errors>=((1.0-target_packet_fraction)*1000)) break;
}
fprintf(stderr,"ber magic value=%d\n",ber);
return ber;
}
int main(int argc,char **argv)
{
if (argc>=1) {
chars_per_ms=atol(argv[1]);
if (argc>=2)
ber=calc_ber(atof(argv[2]));
}
struct pollfd fds[2];
struct radio_state radios[2];
bzero(&radios,sizeof radios);
int i;
radios[0].name="left";
radios[1].name="right";
for (i=0;i<2;i++){
radios[i].fd=posix_openpt(O_RDWR|O_NOCTTY);
grantpt(radios[i].fd);
unlockpt(radios[i].fd);
fcntl(radios[i].fd,F_SETFL,fcntl(radios[i].fd, F_GETFL, NULL)|O_NONBLOCK);
fprintf(stdout,"%s:%s\n", radios[i].name, ptsname(radios[i].fd));
fds[i].fd = radios[i].fd;
}
fflush(stdout);
fprintf(stderr, "Sending %d bytes per ms\n", chars_per_ms);
fprintf(stderr, "Introducing %f%% bit errors\n", (ber * 100.0) / 0xFFFFFFFF);
while(1) {
// what events do we need to poll for? how long can we block?
int64_t now = gettime_ms();
int64_t next_event = now+10000;
for (i=0;i<2;i++){
// always watch for incoming data, though we will throw it away if we run out of buffer space
fds[i].events = POLLIN;
// if we have data to write data, watch for POLLOUT too.
if (radios[i].rxb_len)
fds[i].events |= POLLOUT;
if (radios[i].rssi_output && next_event > radios[i].next_rssi_time_ms)
next_event = radios[i].next_rssi_time_ms;
if (radios[i].state==STATE_PLUSPLUSPLUS && next_event > radios[i].last_char_ms+1000)
next_event = radios[i].last_char_ms+1000;
if (radios[i].txb_len && next_event > next_transmit_time)
next_event = next_transmit_time;
}
int delay = next_event - now;
if (delay<0)
delay=0;
poll(fds,2,delay);
for (i=0;i<2;i++){
if (fds[i].revents & POLLIN)
read_bytes(&radios[i]);
if (fds[i].revents & POLLOUT)
write_bytes(&radios[i]);
now = gettime_ms();
if (radios[i].rssi_output && now >= radios[i].next_rssi_time_ms){
if (append_bytes(&radios[i], "L/R RSSI: 200/190 L/R noise: 80/70 pkts: 10 txe=0 rxe=0 stx=0 srx=0 ecc=0/0 temp=42 dco=0\r\n", -1)>0)
radios[i].next_rssi_time_ms=now+1000;
}
if (radios[i].state==STATE_PLUSPLUSPLUS && now >= radios[i].last_char_ms+1000){
fprintf(stderr, "Detected +++ from %s\n",radios[i].name);
if (append_bytes(&radios[i], "OK\r\n", -1)>0)
radios[i].state=STATE_COMMAND;
}
}
if (now >= next_transmit_time)
transfer_bytes(radios);
}
return 0;
}
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