static void pico_dns_client_retransmission(unsigned long now, void *arg)
{
struct pico_dns_key *key = (struct pico_dns_key *)arg;
struct pico_dns_ns *q_ns = NULL;
if (!key->retrans) {
dns_dbg("DNS: no retransmission!\n");
pico_free(key->q_hdr);
if(pico_tree_delete(&DNSTable,key))
pico_free(key);
}
else if (key->retrans <= PICO_DNS_CLIENT_MAX_RETRANS) {
key->retrans++;
dns_dbg("DNS: retransmission! (%u attempts)\n", key->retrans);
// ugly hack
q_ns = pico_tree_next(pico_tree_findNode(&NSTable,&key->q_ns))->keyValue;
if (q_ns)
key->q_ns = *q_ns;
else
key->q_ns = *((struct pico_dns_ns *)pico_tree_first(&NSTable));
pico_dns_client_send(key);
pico_timer_add(PICO_DNS_CLIENT_RETRANS, pico_dns_client_retransmission, key);
} else {
dns_dbg("DNS ERROR: no reply from nameservers! (%u attempts)\n", key->retrans);
pico_socket_close(key->s);
pico_err = PICO_ERR_EIO;
key->callback(NULL, key->arg);
pico_free(key->q_hdr);
/* RB_REMOVE returns pointer to removed element, NULL to indicate error */
if(pico_tree_delete(&DNSTable,key))
pico_free(key);
}
}
static struct pico_dns_query *pico_dns_client_add_query(struct pico_dns_prefix *hdr, uint16_t len, struct pico_dns_query_suffix *suffix,
void (*callback)(char *, void *), void *arg)
{
struct pico_dns_query *q = NULL, *found = NULL;
q = pico_zalloc(sizeof(struct pico_dns_query));
if (!q)
return NULL;
q->query = (char *)hdr;
q->len = len;
q->id = short_be(hdr->id);
q->qtype = short_be(suffix->qtype);
q->qclass = short_be(suffix->qclass);
q->retrans = 1;
q->q_ns = *((struct pico_dns_ns *)pico_tree_first(&NSTable));
q->callback = callback;
q->arg = arg;
q->s = pico_socket_open(PICO_PROTO_IPV4, PICO_PROTO_UDP, &pico_dns_client_callback);
if (!q->s) {
pico_free(q);
return NULL;
}
found = pico_tree_insert(&DNSTable, q);
if (found) {
pico_err = PICO_ERR_EAGAIN;
pico_socket_close(q->s);
pico_free(q);
return NULL;
}
return q;
}
static struct pico_dns_ns pico_dns_client_next_ns(struct pico_ip4 *ns_addr)
{
struct pico_dns_ns dns = {{0}}, *nxtdns = NULL;
struct pico_tree_node *node = NULL, *nxtnode = NULL;
dns.ns = *ns_addr;
node = pico_tree_findNode(&NSTable, &dns);
if (!node)
return dns; /* keep using current NS */
nxtnode = pico_tree_next(node);
nxtdns = nxtnode->keyValue;
if (!nxtdns)
nxtdns = (struct pico_dns_ns *)pico_tree_first(&NSTable);
return *nxtdns;
}
int pico_dns_client_nameserver(struct pico_ip4 *ns, uint8_t flag)
{
struct pico_dns_ns test, *key = NULL;
if (!ns) {
pico_err = PICO_ERR_EINVAL;
return -1;
}
switch (flag)
{
case PICO_DNS_NS_ADD:
key = pico_zalloc(sizeof(struct pico_dns_ns));
if (!key) {
pico_err = PICO_ERR_ENOMEM;
return -1;
}
key->ns = *ns;
if(pico_tree_insert(&NSTable,key)){
dns_dbg("DNS WARNING: nameserver %08X already added\n",ns->addr);
pico_err = PICO_ERR_EINVAL;
pico_free(key);
return -1; /* Element key already exists */
}
dns_dbg("DNS: nameserver %08X added\n", ns->addr);
/* If default NS found, remove it */
pico_string_to_ipv4(PICO_DNS_NS_GOOGLE, &test.ns.addr);
if (ns->addr != test.ns.addr) {
key = pico_tree_findKey(&NSTable,&test);
if (key) {
if(pico_tree_delete(&NSTable,key)) {
dns_dbg("DNS: default nameserver %08X removed\n", test.ns.addr);
pico_free(key);
} else {
pico_err = PICO_ERR_EAGAIN;
return -1;
}
}
}
break;
case PICO_DNS_NS_DEL:
test.ns = *ns;
key = pico_tree_findKey(&NSTable,&test);
if (!key) {
dns_dbg("DNS WARNING: nameserver %08X not found\n", ns->addr);
pico_err = PICO_ERR_EINVAL;
return -1;
}
/* RB_REMOVE returns pointer to removed element, NULL to indicate error */
if(pico_tree_delete(&NSTable,key)) {
dns_dbg("DNS: nameserver %08X removed\n",key->ns.addr);
pico_free(key);
} else {
pico_err = PICO_ERR_EAGAIN;
return -1;
}
/* If no NS left, add default NS */
if(pico_tree_first(&NSTable) == NULL){
dns_dbg("DNS: add default nameserver\n");
return pico_dns_client_init();
}
break;
default:
pico_err = PICO_ERR_EINVAL;
return -1;
}
return 0;
}
