Commit d965598e authored by Paul Sokolovsky's avatar Paul Sokolovsky Committed by Jukka Rissanen
Browse files

net: dns: Allow to initialize DNS servers from struct sockaddr[] 



In some cases, we need to initialize DNS servers from a binary
addresses, e.g. in case of DHCP processing. With existing API,
such addresses would need to be converted to strings, just to
be converted back to struct sockaddr in dns_resolve_init().
This is not efficient, and with a number of addresses quite
cumbersome. So instead, allow to pass DNS server either as
strings, or as struct sockaddr's (or both).

Signed-off-by: default avatarPaul Sokolovsky <paul.sokolovsky@linaro.org>
parent a3231798

include/net/dns_resolve.h

+9 −4
Original line number Diff line number Diff line
@@ -176,7 +176,8 @@ struct dns_resolve_context { 
 * @brief Init DNS resolving context.

 *

 * @details This function sets the DNS server address and initializes the

 * DNS context that is used by the actual resolver.

 * DNS context that is used by the actual resolver. DNS server addresses

 * can be specified either in textual form, or as struct sockaddr (or both).

 * Note that the recommended way to resolve DNS names is to use

 * the dns_get_addr_info() API. In that case user does not need to

 * call dns_resolve_init() as the DNS servers are already setup by the system.
@@ -185,18 +186,22 @@ struct dns_resolve_context { 
 * the stack, then the variable needs to be valid for the whole duration of

 * the resolving. Caller does not need to fill the variable beforehand or

 * edit the context afterwards.

 * @param dns_servers DNS server addresses. The array is null terminated.

 * The port number can be given in the string.

 * @param dns_servers_str DNS server addresses using textual strings. The

 * array is NULL terminated. The port number can be given in the string.

 * Syntax for the server addresses with or without port numbers:

 *    IPv4        : 10.0.9.1

 *    IPv4 + port : 10.0.9.1:5353

 *    IPv6        : 2001:db8::22:42

 *    IPv6 + port : [2001:db8::22:42]:5353

 * @param dns_servers_sa DNS server addresses as struct sockaddr. The array

 * is NULL terminated. Port numbers are optional in struct sockaddr, the

 * default will be used if set to 0.

 *

 * @return 0 if ok, <0 if error.

 */

int dns_resolve_init(struct dns_resolve_context *ctx,

		     const char *dns_servers[]);

		     const char *dns_servers_str[],

		     const struct sockaddr *dns_servers_sa[]);



/**

 * @brief Close DNS resolving context.

subsys/net/lib/dns/resolve.c

+65 −49
Original line number Diff line number Diff line
@@ -77,49 +77,10 @@ NET_BUF_POOL_DEFINE(dns_qname_pool, DNS_RESOLVER_BUF_CTR, DNS_MAX_NAME_LEN, 


static struct dns_resolve_context dns_default_ctx;



int dns_resolve_init(struct dns_resolve_context *ctx, const char *servers[])

static void dns_postprocess_server(struct dns_resolve_context *ctx, int idx)

{

#if defined(CONFIG_NET_IPV6)

	struct sockaddr_in6 local_addr6 = {

		.sin6_family = AF_INET6,

		.sin6_port = 0,

	};

#endif

#if defined(CONFIG_NET_IPV4)

	struct sockaddr_in local_addr4 = {

		.sin_family = AF_INET,

		.sin_port = 0,

	};

#endif

	struct sockaddr *local_addr = NULL;

	socklen_t addr_len = 0;

	int i = 0, idx = 0;

	int ret, count;



	if (!ctx) {

		return -ENOENT;

	}



	if (!servers || !*servers) {

		return -ENOENT;

	}



	if (ctx->is_used) {

		return -ENOTEMPTY;

	}



	memset(ctx, 0, sizeof(*ctx));



	for (i = 0; i < SERVER_COUNT && servers[i]; i++) {

	struct sockaddr *addr = &ctx->servers[idx].dns_server;



		memset(addr, 0, sizeof(*addr));



		ret = net_ipaddr_parse(servers[i], strlen(servers[i]), addr);

		if (!ret) {

			continue;

		}



	if (addr->sa_family == AF_INET) {

		if (net_is_ipv4_addr_mcast(&net_sin(addr)->sin_addr)) {

			ctx->servers[idx].is_mdns = true;
@@ -156,11 +117,66 @@ int dns_resolve_init(struct dns_resolve_context *ctx, const char *servers[]) 
			}

		}

	}

}



int dns_resolve_init(struct dns_resolve_context *ctx, const char *servers[],

		     const struct sockaddr *servers_sa[])

{

#if defined(CONFIG_NET_IPV6)

	struct sockaddr_in6 local_addr6 = {

		.sin6_family = AF_INET6,

		.sin6_port = 0,

	};

#endif

#if defined(CONFIG_NET_IPV4)

	struct sockaddr_in local_addr4 = {

		.sin_family = AF_INET,

		.sin_port = 0,

	};

#endif

	struct sockaddr *local_addr = NULL;

	socklen_t addr_len = 0;

	int i = 0, idx = 0;

	int ret, count;



	if (!ctx) {

		return -ENOENT;

	}



	if (ctx->is_used) {

		return -ENOTEMPTY;

	}



	memset(ctx, 0, sizeof(*ctx));



	if (servers) {

		for (i = 0; idx < SERVER_COUNT && servers[i]; i++) {

			struct sockaddr *addr = &ctx->servers[idx].dns_server;



			memset(addr, 0, sizeof(*addr));



			ret = net_ipaddr_parse(servers[i], strlen(servers[i]),

					       addr);

			if (!ret) {

				continue;

			}



			dns_postprocess_server(ctx, idx);



			NET_DBG("[%d] %s", i, servers[i]);



			idx++;

		}

	}



	if (servers_sa) {

		for (i = 0; idx < SERVER_COUNT && servers_sa[i]; i++) {

			memcpy(&ctx->servers[idx].dns_server, servers_sa[i],

			       sizeof(ctx->servers[idx].dns_server));

			dns_postprocess_server(ctx, idx);

			idx++;

		}

	}



	for (i = 0, count = 0;

	     i < SERVER_COUNT && ctx->servers[i].dns_server.sa_family; i++) {
@@ -904,7 +920,7 @@ void dns_init_resolver(void) 


	dns_servers[SERVER_COUNT] = NULL;



	ret = dns_resolve_init(dns_resolve_get_default(), dns_servers);

	ret = dns_resolve_init(dns_resolve_get_default(), dns_servers, NULL);

	if (ret < 0) {

		NET_WARN("Cannot initialize DNS resolver (%d)", ret);

	}

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