/* Called when we receive a packet */
static void
my_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p,
struct ip_addr *addr, u16_t port)
{
xid_t xid;
struct rpc_queue *q_item;
xid = extract_xid(p->payload);
q_item = get_from_queue(xid);
debug("Recieved a reply for xid: %u (%d) %p\n",
xid, p->len, q_item);
if (q_item == NULL)
return;
if (q_item->func != NULL) {
p->arg[0] = p->payload;
q_item->func(q_item->callback, q_item->arg, p);
}
/* Free our memory */
pbuf_free(p);
pbuf_free(q_item->pbuf);
free(q_item);
}
static void
add_to_queue(struct pbuf *pbuf, int port,
void (*func)(void *, uintptr_t, struct pbuf *),
void *callback, uintptr_t arg)
{
/* Need a lock here */
struct rpc_queue *q_item;
struct rpc_queue *tmp;
q_item = malloc(sizeof(struct rpc_queue));
assert(q_item != NULL);
q_item->next = NULL;
q_item->pbuf = pbuf;
q_item->xid = extract_xid(pbuf->payload);
q_item->timeout = 0;
q_item->port = port;
q_item->func = func;
q_item->arg = arg;
q_item->callback = callback;
if (queue == NULL) {
/* Add at start of the linked list */
queue = q_item;
} else {
/* Add to end of the linked list */
for(tmp = queue; tmp->next != NULL; tmp = tmp->next)
;
tmp->next = q_item;
}
}
enum rpc_stat
rpc_call(struct pbuf *pbuf, int len, struct udp_pcb *pcb,
void (*func)(void *, uintptr_t, struct pbuf *),
void *callback, uintptr_t token)
{
struct rpc_call_arg call_arg;
struct rpc_queue *q_item;
int time_out;
enum rpc_stat stat;
xid_t xid;
/* If we give up early, we must ensure that the argument remains in memory
* just in case the packet comes in later */
assert(pcb);
assert(pbuf);
/* GeneratrSend the thing with the unlock frunction as a callback */
call_arg.func = func;
call_arg.callback = callback;
call_arg.token = token;
call_arg.complete = 0;
/* Make the call */
xid = extract_xid(pbuf);
stat = rpc_send(pbuf, pbuf->tot_len, pcb, &rpc_call_cb, NULL,
(uintptr_t)&call_arg);
if(stat){
return stat;
}
/* Wait for the response */
time_out = RETRANSMIT_DELAY_MS * (CALL_RETRIES + 1);
while(time_out >= 0){
_usleep(CALL_TIMEOUT_MS * 1000);
if(call_arg.complete) {
/* Success */
return 0;
}
rpc_timeout(CALL_TIMEOUT_MS);
time_out -= CALL_TIMEOUT_MS;
}
/* If we get here, we have failed. Data is on the stack so make sure
* we remove references from the queue */
q_item = get_from_queue(xid);
assert(q_item);
pbuf_free(q_item->pbuf);
free(q_item);
return RPCERR_COMM;
}
static void
my_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p,
struct ip_addr *addr, u16_t port)
{
xid_t xid;
struct rpc_queue *q_item;
(void)port;
xid = extract_xid(p);
q_item = get_from_queue(xid);
debug("Recieved a reply for xid: %u (%d) %p\n", xid, p->len, q_item);
if (q_item != NULL){
assert(q_item->func);
q_item->func(q_item->callback, q_item->arg, p);
/* Clean up the queue item */
pbuf_free(q_item->pbuf);
free(q_item);
}
/* Done with the incoming packet so free it */
pbuf_free(p);
}
