/********************************************************************
*
* get_loop_output - get outgoing packets from the ppp device,
* and detect when we want to bring the real link up.
* Return value is 1 if we need to bring up the link, 0 otherwise.
*/
int
get_loop_output(void)
{
int rv = 0;
int n;
if (new_style_driver) {
while ((n = read_packet(inpacket_buf)) > 0)
if (loop_frame(inpacket_buf, n))
rv = 1;
return rv;
}
while ((n = read(master_fd, inbuf, sizeof(inbuf))) > 0)
if (loop_chars(inbuf, n))
rv = 1;
if (n == 0)
fatal("eof on loopback");
if (errno != EWOULDBLOCK)
fatal("read from loopback: %m(%d)", errno);
return rv;
}
/*
* loop_chars - process characters received from the loopback.
* Calls loop_frame when a complete frame has been accumulated.
* Return value is 1 if we need to bring up the link, 0 otherwise.
*/
int
loop_chars(
unsigned char *p,
int n)
{
int c, rv;
rv = 0;
for (; n > 0; --n) {
c = *p++;
if (c == PPP_FLAG) {
if (!escape_flag && !flush_flag
&& framelen > 2 && fcs == PPP_GOODFCS) {
framelen -= 2;
if (loop_frame(frame, framelen))
rv = 1;
}
framelen = 0;
flush_flag = 0;
escape_flag = 0;
fcs = PPP_INITFCS;
continue;
}
if (flush_flag)
continue;
if (escape_flag) {
c ^= PPP_TRANS;
escape_flag = 0;
} else if (c == PPP_ESCAPE) {
escape_flag = 1;
continue;
}
if (framelen >= framemax) {
flush_flag = 1;
continue;
}
frame[framelen++] = c;
fcs = PPP_FCS(fcs, c);
}
return rv;
}
