12a0f71711
DHCPv4, MQTT, DNS client, ... Change-Id: I5c5d7437bb53610678eba38d307c86694ac01da9 Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
109 lines
2.7 KiB
C
109 lines
2.7 KiB
C
/*
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* Copyright (c) 2016 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef _DNS_CLIENT_H_
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#define _DNS_CLIENT_H_
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#include <net/net_context.h>
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#include <net/net_ip.h>
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/**
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* @brief DNS Client library
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* @defgroup dns_client DNS Client Library
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* @{
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*/
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enum dns_query_type {
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DNS_QUERY_TYPE_A = 1, /* IPv4 */
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DNS_QUERY_TYPE_AAAA = 28 /* IPv6 */
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};
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struct dns_context {
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/* rx_sem and rx buffer, for internal use only */
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struct k_sem rx_sem;
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struct net_buf *rx_buf;
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/** Previously initialized network context */
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struct net_context *net_ctx;
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/** An array of IPv4 or IPv6 address */
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union {
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struct in_addr *ipv4;
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struct in6_addr *ipv6;
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} address;
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/** IP address and port number of the DNS server. */
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struct sockaddr *dns_server;
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/** RX/TX timeout.
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* This timeout is also used when a buffer is
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* required from the dns data internal pool.
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*/
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int32_t timeout;
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/** C-string containing the Domain Name to resolve,
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* i.e. 'example.com'.
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*/
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const char *name;
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/** Query type: IPv4 or IPv6 */
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uint16_t query_type;
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/** Available positions in the 'address' array. */
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uint8_t elements;
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/** Number of IPv4 addresses stored in 'address'. */
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uint8_t items;
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};
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/**
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* @brief dns_init DNS resolver initialization routine
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* @details This routine must be called before any other
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* dns routine.
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* @param ctx DNS Client structure
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* @return 0, always.
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* Note: new versions may return error codes.
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*/
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int dns_init(struct dns_context *ctx);
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/**
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* @brief dns_resolve Retrieves the IP addresses associated to the
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* domain name 'client->name'.
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* @details This routine obtains the IP addresses
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* associated to the domain name 'client->name'.
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* The DNS server is specified by the sockaddr
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* structure inside 'client'.
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* Depending on the DNS server used, one or more
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* IP addresses may be recovered by this routine.
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*
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* NOTE: You can use an IPv6 DNS server to look-up
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* for IPv4 addresses or an IPv4 server to look-up
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* for IPv6 address. Domain name services are not
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* tied to any specific routing or transport
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* technology.
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*
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* @param ctx DNS Client structure
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* @return 0 on success
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* The number of returned addresses (client->items)
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* may be less than the one reported by the DNS
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* server. However, this situation is considered a
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* success because we are 'resolving' the 'name'.
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* Workaround: increase 'client->elements'.
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* @return -EIO on network error.
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* @return -EINVAL if an invalid parameter was passed as
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* an argument to this routine. This value is also
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* returned if the application received a malformed
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* packet from the DNS server.
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* @return -ENOMEM if there are no buffers available.
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*/
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int dns_resolve(struct dns_context *ctx);
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/**
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* @}
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*/
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#endif
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