static int t1_resynchronize(ifd_protocol_t * p, int nad)
{
t1_state_t *t1 = (t1_state_t *) p;
unsigned char block[4];
unsigned int retries = 3;
if (p->reader && p->reader->device)
ifd_device_flush(p->reader->device);
while (retries--) {
t1->ns = 0;
t1->nr = 0;
block[0] = nad;
block[1] = T1_S_BLOCK | T1_S_RESYNC;
block[2] = 0;
t1_compute_checksum(t1, block, 3);
if (t1_xcv(t1, block, 4, sizeof(block)) != 4) {
ifd_debug(1, "fatal: transmit/receive failed");
break;
}
if (!t1_verify_checksum(t1, block, 4)) {
ifd_debug(1, "checksum failed");
continue;
}
if (block[1] == (T1_S_BLOCK | T1_S_RESPONSE | T1_S_RESYNC))
return 0;
}
t1->state = DEAD;
return -1;
}
static unsigned int t1_build(t1_state_t * t1, unsigned char *block,
unsigned char dad, unsigned char pcb,
ct_buf_t * bp, size_t * lenp)
{
unsigned int len;
len = bp ? ct_buf_avail(bp) : 0;
if (len > t1->ifsc) {
pcb |= T1_MORE_BLOCKS;
len = t1->ifsc;
}
/* Add the sequence number */
switch (t1_block_type(pcb)) {
case T1_R_BLOCK:
pcb |= t1->nr << T1_R_SEQ_SHIFT;
break;
case T1_I_BLOCK:
pcb |= t1->ns << T1_I_SEQ_SHIFT;
break;
}
block[0] = dad;
block[1] = pcb;
block[2] = len;
if (len)
memcpy(block + 3, ct_buf_head(bp), len);
if (lenp)
*lenp = len;
return t1_compute_checksum(t1, block, len + 3);
}
unsigned int t1_build(t1_state_t * t1, unsigned char *block,
unsigned char dad, unsigned char pcb,
ct_buf_t *bp, size_t *lenp)
{
unsigned int len;
char more = FALSE;
len = bp ? ct_buf_avail(bp) : 0;
if (len > t1->ifsc) {
pcb |= T1_MORE_BLOCKS;
len = t1->ifsc;
more = TRUE;
}
/* Add the sequence number */
switch (t1_block_type(pcb)) {
case T1_R_BLOCK:
pcb |= t1->nr << T1_R_SEQ_SHIFT;
break;
case T1_I_BLOCK:
pcb |= t1->ns << T1_I_SEQ_SHIFT;
t1->more = more;
DEBUG_COMM2("more bit: %d", more);
break;
}
block[0] = dad;
block[1] = pcb;
block[2] = len;
if (len)
memcpy(block + 3, ct_buf_head(bp), len);
if (lenp)
*lenp = len;
len = t1_compute_checksum(t1, block, len + 3);
/* memorize the last sent block */
/* only 4 bytes since we are only interesed in R-blocks */
memcpy(t1->previous_block, block, 4);
return len;
}