tidy up, make less awful

1 files changed, 253 insertions, 0 deletions

diff --git a/sia.c b/sia.c
new file mode 100644
index 0000000..3c47c8b
--- /dev/null
+++ b/sia.c
@@ -0,0 +1,253 @@
+#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;
+}
+
+