/* connect:
* Set the target address and send the first connection request. This
* might not get through of course; later we can just repeat the send
* statement because the target address is already set. No need to store
* it anywhere.
*/
static int connect (NET_CONN *conn, const char *target)
{
int id;
static int next_id = 0;
struct conn_data_t *data = conn->data;
/* The id is a compound of the current time (with 1 second
* granularity), and an increasing counter. The time is needed
* because the counter resets when you restart the program, and
* the counter is needed because of the granularity of the time. */
/* Strictly, this line needs a mutex, but there's nowhere around
* here we can call `MUTEX_CREATE'. */
id = (next_id++ << 16) + (time(NULL) & 0xffff);
strcpy (data->connect_string, "connect");
data->connect_string[8] = (id >> 24) & 0xff;
data->connect_string[9] = (id >> 16) & 0xff;
data->connect_string[10] = (id >> 8) & 0xff;
data->connect_string[11] = id & 0xff;
if (net_assigntarget (data->chan, target)) return 1;
if (net_send (data->chan, data->connect_string, 12)) return 2;
data->connect_timestamp = __libnet_timer_func();
return 0;
}
/* net_init:
* Initialises the libnet library.
*/
int net_init (void) {
if (!initialised) {
initialised = 1;
if (!__libnet_internal__mutex_create)
net_set_mutex_funcs (NULL, NULL, NULL, NULL);
if (!__libnet_timer_func)
net_set_timer_func (NULL);
__libnet_timer_func();
detected_drivers = net_driverlist_create();
initialised_drivers = net_driverlist_create();
temp_detected_list = net_driverlist_create();
net_drivers_all = net_driverlist_create();
__libnet_internal__classes_init();
__libnet_internal__drivers_init();
__libnet_internal__channels_init();
__libnet_internal__conns_init();
if (!done_atexit) {
if (atexit(exitfunc)) {
exitfunc();
return 1;
}
done_atexit = 1;
}
}
return 0;
}
/* get_channel:
* Scans the list of connections for one matching this connector, and
* fills it in if found, returning positive. Otherwise, adds a new entry
* to the list, fills it in, and returns negative. On error, returns zero.
*/
static int get_channel (struct conns_list *conns, const char *addr, int conn_id, int type, const char *bind, NET_CHANNEL **chan, struct conn_data_t *condat)
{
#if 0
/* Before we do anything else, time out entries which have been here
* too long */
struct conns_list *ptr = conns;
while (ptr->next) {
if ((unsigned)(__libnet_timer_func() - ptr->last_access_time) > 10000) {
struct conns_list *ptr2 = ptr->next;
ptr->next = ptr2->next;
free (ptr2->addr);
free (ptr2);
}
}
#endif
while (conns->next) {
conns = conns->next;
if ((conn_id == conns->client_conn_id) && !strcmp (addr, conns->addr)) {
*chan = conns->chan;
conns->last_access_time = __libnet_timer_func();
return 1;
}
}
conns->next = malloc (sizeof *conns->next);
if (conns->next) {
conns->next->next = NULL;
conns->next->addr = strdup (addr);
conns->next->client_conn_id = conn_id;
conns->next->ref = condat;
conns->next->last_access_time = __libnet_timer_func();
if (conns->next->addr) {
conns->next->chan = net_openchannel (type, bind);
if (conns->next->chan) {
*chan = conns->next->chan;
return -1;
}
free (conns->next->addr);
}
free (conns->next);
conns->next = NULL;
}
return 0;
}
/* poll_connect:
* This function does two things. Firstly it checks for a response from
* the server. If there's no response, it then resends the connection
* request.
*
* The possible problem here is that the server's response might just be
* delayed. The best way I can see around this problem is for the server
* to keep an eye on the return addresses of the connection attempts, and
* not open a fresh channel each time a duplicate of an old packet arrives.
* This actually kills two birds with one stone, since if either the
* client's request packet or the server's response packet are dropped, the
* client will eventually resend, causing the server to send an identical
* response.
*
* Later note: In fact we needed to introduce an almost-unique identifier
* to pass as well, since the channel's address may be reused later on.
*/
static int poll_connect (NET_CONN *conn)
{
struct conn_data_t *data = conn->data;
char buffer[8+NET_MAX_ADDRESS_LENGTH];
char addr[NET_MAX_ADDRESS_LENGTH];
if ((net_receive (data->chan, buffer, 8+NET_MAX_ADDRESS_LENGTH, addr) == 8+NET_MAX_ADDRESS_LENGTH) && (!memcmp (buffer, "\0\0\0\0\0\0\0", 8))) {
net_fixupaddress_channel(data->chan, &buffer[8], addr);
net_assigntarget (data->chan, addr);
strcpy (conn->peer_addr, addr);
return 1;
}
/* No response */
{
unsigned long clock_value = __libnet_timer_func();
if ((unsigned)(clock_value - data->connect_timestamp) > RESEND_RATE) {
net_send (data->chan, data->connect_string, 8);
data->connect_timestamp = clock_value;
}
}
return 0;
}
/* poll:
* This function handles all the true I/O for the RDMs.
*/
static void poll (NET_CONN *conn)
{
struct conn_data_t *data = conn->data;
/* First check whether anything in the outgoing queue needs sending */
{
struct out_packet_t *outp;
int clock_value = __libnet_timer_func(), i;
for (i = 0; i < MAX_OUTGOING_PACKETS; i++) {
outp = data->out.packets + i;
if ((outp->data) && (!outp->ack) && ((unsigned)(clock_value - outp->last_send_time) > RESEND_RATE)) {
net_send (data->chan, outp->data, outp->size + 4);
outp->last_send_time = clock_value;
}
}
}
/* Then receive any incoming data */
{
int count = 10; /* max num of packets [we're not meant to block] */
unsigned char receive_buffer[16384];
while (count--) {
int x;
unsigned id;
x = net_receive (data->chan, receive_buffer, sizeof receive_buffer, 0);
if ((x == 0) || (x == -1)) break; /* quit if no more data or error */
if (x < 4) continue; /* badly formed packet -- no ID */
id = 0;
id = (id << 8) + receive_buffer[3];
id = (id << 8) + receive_buffer[2];
id = (id << 8) + receive_buffer[1];
id = (id << 8) + receive_buffer[0];
if (id == 0) { /* it's an acknowledgement */
if (x != 8) continue; /* badly formed */
id = (id << 8) + receive_buffer[7];
id = (id << 8) + receive_buffer[6];
id = (id << 8) + receive_buffer[5];
id = (id << 8) + receive_buffer[4];
if (id >= data->out.base_index)
data->out.packets[id % MAX_OUTGOING_PACKETS].ack = 1;
if (id == data->out.base_index) {
int i, j = id % MAX_OUTGOING_PACKETS;
for (i = 0; i < MAX_OUTGOING_PACKETS; i++) {
if (!data->out.packets[j].ack || !data->out.packets[j].data) break;
data->out.base_index++;
free (data->out.packets[j].data);
data->out.packets[j].data = NULL;
j = (j + 1) % MAX_OUTGOING_PACKETS;
}
}
continue;
}
if (x == 4) continue; /* zero length */
if (id >= data->in.base_index + MAX_INCOMING_PACKETS)
continue;
if (id >= data->in.base_index) {
struct in_packet_t *ptr = data->in.packets + id % MAX_INCOMING_PACKETS;
if (!ptr->data) { /* haven't got this one yet */
ptr->data = malloc (x - 4);
if (!ptr->data) continue;
memcpy (ptr->data, receive_buffer + 4, x - 4);
ptr->size = x - 4;
}
}
/* Acknowledge */
{
char buf[8] = { 0 };
memcpy (buf + 4, receive_buffer, 4);
net_send (data->chan, buf, 8);
}
}
}
}
/* safe_sleep:
* This routine acts roughly like `sleep', waiting a certain
* number of seconds. It's used because in Linux at least,
* normal `sleep' uses SIGALRM in Linux, which we'd rather
* not touch (Allegro likes it to be left alone).
*/
static void safe_sleep (int seconds)
{
unsigned x = __libnet_timer_func();
int y = 0;
while (y < seconds * 1000) y = (unsigned)(__libnet_timer_func() - x);
}
