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#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include "util.h"
#include "sia.h"
int sia_fn_valid (SIA_Block *s)
{
switch (s->function) {
case SIA_FN_ACCOUNT_ID:
case SIA_FN_ORIGIN_ID:
case SIA_FN_END_OF_DATA:
case SIA_FN_WAIT:
case SIA_FN_ABORT:
case SIA_FN_RES_3:
case SIA_FN_RES_4:
case SIA_FN_RES_5:
case SIA_FN_ACK_AND_STANDBY:
case SIA_FN_ACK_AND_DISCONNECT:
case SIA_FN_ACKNOLEDGE:
case SIA_FN_ALT_ACKNOLEDGE:
case SIA_FN_REJECT:
case SIA_FN_ALT_REJECT:
case SIA_FN_REMOTE_LOGIN:
case SIA_FN_CONFIGURATION:
case SIA_FN_ASCII:
case SIA_FN_CONTROL:
case SIA_FN_ENVIRONMENTAL:
case SIA_FN_VIDEO:
case SIA_FN_LISTEN_IN:
case SIA_FN_NEW_EVENT:
case SIA_FN_OLD_EVENT:
case SIA_FN_PROGRAM:
case SIA_FN_VCHN_REQUEST:
case SIA_FN_EXTENDED:
case SIA_FN_VCHN_FRAME:
return 1;
}
return 0;
}
int sia_fn_permits_ack (unsigned char fn)
{
switch (fn) {
case SIA_FN_ALT_REJECT:
case SIA_FN_REJECT:
case SIA_FN_ALT_ACKNOLEDGE:
case SIA_FN_ACKNOLEDGE:
case SIA_FN_CONFIGURATION:
case SIA_FN_CONTROL:
case SIA_FN_EXTENDED:
return 0;
}
return 1;
}
unsigned int sia_data_length (SIA_Block *s)
{
return s->length;
}
unsigned int sia_length (SIA_Block *s)
{
return sia_data_length (s) + 3;
}
int sia_parity_valid (SIA_Block *s)
{
unsigned char parity = 0xff;
unsigned i, l = sia_length (s);
for (i = 0; i < l; ++i)
parity ^= s->block[i];
return !parity;
}
void sia_set_parity (SIA_Block *s)
{
unsigned char parity = 0xff;
unsigned i, l = sia_length (s) - 1;
for (i = 0; i < l; ++i)
parity ^= s->block[i];
s->block[l] = parity;
}
ssize_t sia_write (int fd, SIA_Block *s)
{
ssize_t rc, l = sia_length (s);
sia_set_parity (s);
rc = write (fd, s->block, l);
if (rc == l) return 1;
if (rc > 0) rc = 0;
return rc;
}
ssize_t sia_acknoledge (int fd)
{
SIA_Block b;
b.length = 0;
b.request_ack = 0;
b.reverse_channel = 0;
b.function = SIA_FN_ACKNOLEDGE;
return sia_write (fd, &b);
}
/* Zero on success, 1 on error */
int sia_ack_if_needed (int fd, SIA_Block *s)
{
if (!s->request_ack) return 0;
if (!sia_fn_permits_ack (s->function))
return 0;
return ! (sia_acknoledge (fd) == 1);
}
/* Returns 0 for need more data, number of bytes consumed for success, -1 for parse error */
/* On tcp/ip the form appears to be to drop the connexion on parse error*/
/* On serial drain the buffer as comms is bursty */
int sia_parse (unsigned char *buf, unsigned len, SIA_Block *b)
{
unsigned calc_len;
if (len < 2) return 0;
if (len > SIA_MAX_BLOCK_LENGTH) len = SIA_MAX_BLOCK_LENGTH;
memcpy (b->block, buf, len);
if (!sia_fn_valid (b)) return -1;
calc_len = sia_length (b);
if (len < calc_len) return 0;
if (!sia_parity_valid (b)) return -1;
return calc_len;
}
/*Returns 0 for success, -1 for error */
int sia_rx_with_timeout (int fd, SIA_Block *b, int timeout)
{
unsigned char buf[SIA_MAX_BLOCK_LENGTH];
unsigned ptr = 0;
int rc;
struct timeval tv = {0};
tv.tv_sec = timeout;
while (tv.tv_sec || tv.tv_usec) {
fd_set rfds;
FD_ZERO (&rfds);
FD_SET (fd, &rfds);
rc = select (fd + 1, &rfds, NULL, NULL, &tv);
if (rc <= 0) return -1;
rc = read (fd, &buf[ptr], 1);
if (rc <= 0)
return -1;
ptr++;
switch (sia_parse (buf, ptr, b)) {
case -1:
return -1;
case 0:
break;
default:
return 0;
}
}
return 0;
}
int sia_rx_with_timeout_ignore_log (int fd, SIA_Block *b, int timeout)
{
int ret;
do {
ret = sia_rx_with_timeout (fd, b, timeout);
if (ret < 0) return ret;
} while ((b->function == SIA_FN_ACCOUNT_ID) || (b->function == SIA_FN_NEW_EVENT) || (b->function == SIA_FN_OLD_EVENT) || (b->function == SIA_FN_ASCII));
return ret;
}
int sia_login (int fd, SIA_Block *b)
{
const char *pin = "543210"; //JMM: Oh yes! and there's no way to change it from the panel, you need the £3k bit of software to do that
b->reverse_channel = 0;
b->request_ack = 1;
b->function = SIA_FN_REMOTE_LOGIN;
b->length = strlen (pin);
memcpy (b->data, pin, b->length);
if (fd_drain (fd))
return -1;
if (sia_write (fd, b) != 1)
return -1;
if (sia_rx_with_timeout_ignore_log (fd, b, SIA_TIMEOUT))
return -1;
if (b->function != SIA_FN_CONFIGURATION)
return -1;
return 0;
}
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