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[nsapi] Add support for implementation-provided DNS servers 

Support intended for DNS servers provided by DHCP requests.
pull/2497/head
Christopher Haster 2016-08-15 17:54:57 -05:00
parent dc9ddd42ef
commit f9552ddbbe
1 changed files with 28 additions and 4 deletions
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32
features/net/network-socket/nsapi_dns.cpp
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@ -20,11 +20,12 @@
#include <stdlib.h>
// DNS options
#define DNS_BUFFER_SIZE 256
#define DNS_TIMEOUT 5000
#define DNS_SERVERS_SIZE 5
#define DNS_SERVERS_LENGTH (sizeof DNS_SERVERS / sizeof DNS_SERVERS[0])
const nsapi_addr_t DNS_SERVERS[] = {
nsapi_addr_t dns_servers[DNS_SERVERS_SIZE] = {
{NSAPI_IPv4, {8, 8, 8, 8}},
{NSAPI_IPv4, {209, 244, 0, 3}},
{NSAPI_IPv4, {84, 200, 69, 80}},
@ -33,6 +34,29 @@ const nsapi_addr_t DNS_SERVERS[] = {
};
// DNS server configuration
NSAPI_C_LINKAGE
int nsapi_dns_add_server(nsapi_addr_t addr)
{
memmove(&dns_servers[1], &dns_servers[0],
(DNS_SERVERS_SIZE-1)*sizeof(nsapi_addr_t));
dns_servers[0] = addr;
return 0;
}
int nsapi_dns_add_server(const SocketAddress &address)
{
return nsapi_dns_add_server(address.get_addr());
}
int nsapi_dns_add_server(const char *address)
{
return nsapi_dns_add_server(SocketAddress(address));
}
// DNS packet parsing
static void dns_append_byte(uint8_t **p, uint8_t byte)
{
*(*p)++ = byte;
@ -204,12 +228,12 @@ static int nsapi_dns_query_multiple(NetworkStack *stack,
int result = NSAPI_ERROR_DNS_FAILURE;
// check against each dns server
for (unsigned i = 0; i < DNS_SERVERS_LENGTH; i++) {
for (unsigned i = 0; i < DNS_SERVERS_SIZE; i++) {
// send the question
uint8_t *p = packet;
dns_append_question(&p, host, version);
err = socket.sendto(SocketAddress(DNS_SERVERS[i], 53), packet, DNS_BUFFER_SIZE);
err = socket.sendto(SocketAddress(dns_servers[i], 53), packet, DNS_BUFFER_SIZE);
if (err == NSAPI_ERROR_WOULD_BLOCK) {
continue;
} else if (err < 0) {