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Posted to commits@mynewt.apache.org by ma...@apache.org on 2016/09/30 00:31:06 UTC
[23/51] [abbrv] [partial] incubator-mynewt-core git commit:
net/ip/lwip_base; LwIP.
http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/blob/f5a0f2a0/net/ip/lwip_base/src/apps/sntp/sntp.c
----------------------------------------------------------------------
diff --git a/net/ip/lwip_base/src/apps/sntp/sntp.c b/net/ip/lwip_base/src/apps/sntp/sntp.c
new file mode 100644
index 0000000..8d43eb0
--- /dev/null
+++ b/net/ip/lwip_base/src/apps/sntp/sntp.c
@@ -0,0 +1,726 @@
+/**
+ * @file
+ * SNTP client module
+ */
+
+/*
+ * Copyright (c) 2007-2009 Fr�d�ric Bernon, Simon Goldschmidt
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Fr�d�ric Bernon, Simon Goldschmidt
+ */
+
+
+/**
+ * @defgroup sntp SNTP
+ * @ingroup apps
+ *
+ * This is simple "SNTP" client for the lwIP raw API.
+ * It is a minimal implementation of SNTPv4 as specified in RFC 4330.
+ *
+ * For a list of some public NTP servers, see this link :
+ * http://support.ntp.org/bin/view/Servers/NTPPoolServers
+ *
+ * @todo:
+ * - set/change servers at runtime
+ * - complete SNTP_CHECK_RESPONSE checks 3 and 4
+ */
+
+#include "lwip/apps/sntp.h"
+
+#include "lwip/opt.h"
+#include "lwip/timeouts.h"
+#include "lwip/udp.h"
+#include "lwip/dns.h"
+#include "lwip/ip_addr.h"
+#include "lwip/pbuf.h"
+#include "lwip/dhcp.h"
+
+#include <string.h>
+#include <time.h>
+
+#if LWIP_UDP
+
+/* Handle support for more than one server via SNTP_MAX_SERVERS */
+#if SNTP_MAX_SERVERS > 1
+#define SNTP_SUPPORT_MULTIPLE_SERVERS 1
+#else /* NTP_MAX_SERVERS > 1 */
+#define SNTP_SUPPORT_MULTIPLE_SERVERS 0
+#endif /* NTP_MAX_SERVERS > 1 */
+
+#if (SNTP_UPDATE_DELAY < 15000) && !defined(SNTP_SUPPRESS_DELAY_CHECK)
+#error "SNTPv4 RFC 4330 enforces a minimum update time of 15 seconds (define SNTP_SUPPRESS_DELAY_CHECK to disable this error)!"
+#endif
+
+/* Configure behaviour depending on microsecond or second precision */
+#ifdef SNTP_SET_SYSTEM_TIME_US
+#define SNTP_CALC_TIME_US 1
+#define SNTP_RECEIVE_TIME_SIZE 2
+#else
+#define SNTP_SET_SYSTEM_TIME_US(sec, us)
+#define SNTP_CALC_TIME_US 0
+#define SNTP_RECEIVE_TIME_SIZE 1
+#endif
+
+
+/* the various debug levels for this file */
+#define SNTP_DEBUG_TRACE (SNTP_DEBUG | LWIP_DBG_TRACE)
+#define SNTP_DEBUG_STATE (SNTP_DEBUG | LWIP_DBG_STATE)
+#define SNTP_DEBUG_WARN (SNTP_DEBUG | LWIP_DBG_LEVEL_WARNING)
+#define SNTP_DEBUG_WARN_STATE (SNTP_DEBUG | LWIP_DBG_LEVEL_WARNING | LWIP_DBG_STATE)
+#define SNTP_DEBUG_SERIOUS (SNTP_DEBUG | LWIP_DBG_LEVEL_SERIOUS)
+
+#define SNTP_ERR_KOD 1
+
+/* SNTP protocol defines */
+#define SNTP_MSG_LEN 48
+
+#define SNTP_OFFSET_LI_VN_MODE 0
+#define SNTP_LI_MASK 0xC0
+#define SNTP_LI_NO_WARNING 0x00
+#define SNTP_LI_LAST_MINUTE_61_SEC 0x01
+#define SNTP_LI_LAST_MINUTE_59_SEC 0x02
+#define SNTP_LI_ALARM_CONDITION 0x03 /* (clock not synchronized) */
+
+#define SNTP_VERSION_MASK 0x38
+#define SNTP_VERSION (4/* NTP Version 4*/<<3)
+
+#define SNTP_MODE_MASK 0x07
+#define SNTP_MODE_CLIENT 0x03
+#define SNTP_MODE_SERVER 0x04
+#define SNTP_MODE_BROADCAST 0x05
+
+#define SNTP_OFFSET_STRATUM 1
+#define SNTP_STRATUM_KOD 0x00
+
+#define SNTP_OFFSET_ORIGINATE_TIME 24
+#define SNTP_OFFSET_RECEIVE_TIME 32
+#define SNTP_OFFSET_TRANSMIT_TIME 40
+
+/* number of seconds between 1900 and 1970 (MSB=1)*/
+#define DIFF_SEC_1900_1970 (2208988800UL)
+/* number of seconds between 1970 and Feb 7, 2036 (6:28:16 UTC) (MSB=0) */
+#define DIFF_SEC_1970_2036 (2085978496UL)
+
+/**
+ * SNTP packet format (without optional fields)
+ * Timestamps are coded as 64 bits:
+ * - 32 bits seconds since Jan 01, 1970, 00:00
+ * - 32 bits seconds fraction (0-padded)
+ * For future use, if the MSB in the seconds part is set, seconds are based
+ * on Feb 07, 2036, 06:28:16.
+ */
+#ifdef PACK_STRUCT_USE_INCLUDES
+# include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct sntp_msg {
+ PACK_STRUCT_FLD_8(u8_t li_vn_mode);
+ PACK_STRUCT_FLD_8(u8_t stratum);
+ PACK_STRUCT_FLD_8(u8_t poll);
+ PACK_STRUCT_FLD_8(u8_t precision);
+ PACK_STRUCT_FIELD(u32_t root_delay);
+ PACK_STRUCT_FIELD(u32_t root_dispersion);
+ PACK_STRUCT_FIELD(u32_t reference_identifier);
+ PACK_STRUCT_FIELD(u32_t reference_timestamp[2]);
+ PACK_STRUCT_FIELD(u32_t originate_timestamp[2]);
+ PACK_STRUCT_FIELD(u32_t receive_timestamp[2]);
+ PACK_STRUCT_FIELD(u32_t transmit_timestamp[2]);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+# include "arch/epstruct.h"
+#endif
+
+/* function prototypes */
+static void sntp_request(void *arg);
+
+/** The operating mode */
+static u8_t sntp_opmode;
+
+/** The UDP pcb used by the SNTP client */
+static struct udp_pcb* sntp_pcb;
+/** Names/Addresses of servers */
+struct sntp_server {
+#if SNTP_SERVER_DNS
+ char* name;
+#endif /* SNTP_SERVER_DNS */
+ ip_addr_t addr;
+};
+static struct sntp_server sntp_servers[SNTP_MAX_SERVERS];
+
+#if SNTP_GET_SERVERS_FROM_DHCP
+static u8_t sntp_set_servers_from_dhcp;
+#endif /* SNTP_GET_SERVERS_FROM_DHCP */
+#if SNTP_SUPPORT_MULTIPLE_SERVERS
+/** The currently used server (initialized to 0) */
+static u8_t sntp_current_server;
+#else /* SNTP_SUPPORT_MULTIPLE_SERVERS */
+#define sntp_current_server 0
+#endif /* SNTP_SUPPORT_MULTIPLE_SERVERS */
+
+#if SNTP_RETRY_TIMEOUT_EXP
+#define SNTP_RESET_RETRY_TIMEOUT() sntp_retry_timeout = SNTP_RETRY_TIMEOUT
+/** Retry time, initialized with SNTP_RETRY_TIMEOUT and doubled with each retry. */
+static u32_t sntp_retry_timeout;
+#else /* SNTP_RETRY_TIMEOUT_EXP */
+#define SNTP_RESET_RETRY_TIMEOUT()
+#define sntp_retry_timeout SNTP_RETRY_TIMEOUT
+#endif /* SNTP_RETRY_TIMEOUT_EXP */
+
+#if SNTP_CHECK_RESPONSE >= 1
+/** Saves the last server address to compare with response */
+static ip_addr_t sntp_last_server_address;
+#endif /* SNTP_CHECK_RESPONSE >= 1 */
+
+#if SNTP_CHECK_RESPONSE >= 2
+/** Saves the last timestamp sent (which is sent back by the server)
+ * to compare against in response */
+static u32_t sntp_last_timestamp_sent[2];
+#endif /* SNTP_CHECK_RESPONSE >= 2 */
+
+/**
+ * SNTP processing of received timestamp
+ */
+static void
+sntp_process(u32_t *receive_timestamp)
+{
+ /* convert SNTP time (1900-based) to unix GMT time (1970-based)
+ * if MSB is 0, SNTP time is 2036-based!
+ */
+ u32_t rx_secs = ntohl(receive_timestamp[0]);
+ int is_1900_based = ((rx_secs & 0x80000000) != 0);
+ u32_t t = is_1900_based ? (rx_secs - DIFF_SEC_1900_1970) : (rx_secs + DIFF_SEC_1970_2036);
+ time_t tim = t;
+
+#if SNTP_CALC_TIME_US
+ u32_t us = ntohl(receive_timestamp[1]) / 4295;
+ SNTP_SET_SYSTEM_TIME_US(t, us);
+ /* display local time from GMT time */
+ LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_process: %s, %"U32_F" us", ctime(&tim), us));
+
+#else /* SNTP_CALC_TIME_US */
+
+ /* change system time and/or the update the RTC clock */
+ SNTP_SET_SYSTEM_TIME(t);
+ /* display local time from GMT time */
+ LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_process: %s", ctime(&tim)));
+#endif /* SNTP_CALC_TIME_US */
+ LWIP_UNUSED_ARG(tim);
+}
+
+/**
+ * Initialize request struct to be sent to server.
+ */
+static void
+sntp_initialize_request(struct sntp_msg *req)
+{
+ memset(req, 0, SNTP_MSG_LEN);
+ req->li_vn_mode = SNTP_LI_NO_WARNING | SNTP_VERSION | SNTP_MODE_CLIENT;
+
+#if SNTP_CHECK_RESPONSE >= 2
+ {
+ u32_t sntp_time_sec, sntp_time_us;
+ /* fill in transmit timestamp and save it in 'sntp_last_timestamp_sent' */
+ SNTP_GET_SYSTEM_TIME(sntp_time_sec, sntp_time_us);
+ sntp_last_timestamp_sent[0] = htonl(sntp_time_sec + DIFF_SEC_1900_1970);
+ req->transmit_timestamp[0] = sntp_last_timestamp_sent[0];
+ /* we send/save us instead of fraction to be faster... */
+ sntp_last_timestamp_sent[1] = htonl(sntp_time_us);
+ req->transmit_timestamp[1] = sntp_last_timestamp_sent[1];
+ }
+#endif /* SNTP_CHECK_RESPONSE >= 2 */
+}
+
+/**
+ * Retry: send a new request (and increase retry timeout).
+ *
+ * @param arg is unused (only necessary to conform to sys_timeout)
+ */
+static void
+sntp_retry(void* arg)
+{
+ LWIP_UNUSED_ARG(arg);
+
+ LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_retry: Next request will be sent in %"U32_F" ms\n",
+ sntp_retry_timeout));
+
+ /* set up a timer to send a retry and increase the retry delay */
+ sys_timeout(sntp_retry_timeout, sntp_request, NULL);
+
+#if SNTP_RETRY_TIMEOUT_EXP
+ {
+ u32_t new_retry_timeout;
+ /* increase the timeout for next retry */
+ new_retry_timeout = sntp_retry_timeout << 1;
+ /* limit to maximum timeout and prevent overflow */
+ if ((new_retry_timeout <= SNTP_RETRY_TIMEOUT_MAX) &&
+ (new_retry_timeout > sntp_retry_timeout)) {
+ sntp_retry_timeout = new_retry_timeout;
+ }
+ }
+#endif /* SNTP_RETRY_TIMEOUT_EXP */
+}
+
+#if SNTP_SUPPORT_MULTIPLE_SERVERS
+/**
+ * If Kiss-of-Death is received (or another packet parsing error),
+ * try the next server or retry the current server and increase the retry
+ * timeout if only one server is available.
+ * (implicitly, SNTP_MAX_SERVERS > 1)
+ *
+ * @param arg is unused (only necessary to conform to sys_timeout)
+ */
+static void
+sntp_try_next_server(void* arg)
+{
+ u8_t old_server, i;
+ LWIP_UNUSED_ARG(arg);
+
+ old_server = sntp_current_server;
+ for (i = 0; i < SNTP_MAX_SERVERS - 1; i++) {
+ sntp_current_server++;
+ if (sntp_current_server >= SNTP_MAX_SERVERS) {
+ sntp_current_server = 0;
+ }
+ if (!ip_addr_isany(&sntp_servers[sntp_current_server].addr)
+#if SNTP_SERVER_DNS
+ || (sntp_servers[sntp_current_server].name != NULL)
+#endif
+ ) {
+ LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_try_next_server: Sending request to server %"U16_F"\n",
+ (u16_t)sntp_current_server));
+ /* new server: reset retry timeout */
+ SNTP_RESET_RETRY_TIMEOUT();
+ /* instantly send a request to the next server */
+ sntp_request(NULL);
+ return;
+ }
+ }
+ /* no other valid server found */
+ sntp_current_server = old_server;
+ sntp_retry(NULL);
+}
+#else /* SNTP_SUPPORT_MULTIPLE_SERVERS */
+/* Always retry on error if only one server is supported */
+#define sntp_try_next_server sntp_retry
+#endif /* SNTP_SUPPORT_MULTIPLE_SERVERS */
+
+/** UDP recv callback for the sntp pcb */
+static void
+sntp_recv(void *arg, struct udp_pcb* pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
+{
+ u8_t mode;
+ u8_t stratum;
+ u32_t receive_timestamp[SNTP_RECEIVE_TIME_SIZE];
+ err_t err;
+
+ LWIP_UNUSED_ARG(arg);
+ LWIP_UNUSED_ARG(pcb);
+
+ /* packet received: stop retry timeout */
+ sys_untimeout(sntp_try_next_server, NULL);
+ sys_untimeout(sntp_request, NULL);
+
+ err = ERR_ARG;
+#if SNTP_CHECK_RESPONSE >= 1
+ /* check server address and port */
+ if (((sntp_opmode != SNTP_OPMODE_POLL) || ip_addr_cmp(addr, &sntp_last_server_address)) &&
+ (port == SNTP_PORT))
+#else /* SNTP_CHECK_RESPONSE >= 1 */
+ LWIP_UNUSED_ARG(addr);
+ LWIP_UNUSED_ARG(port);
+#endif /* SNTP_CHECK_RESPONSE >= 1 */
+ {
+ /* process the response */
+ if (p->tot_len == SNTP_MSG_LEN) {
+ pbuf_copy_partial(p, &mode, 1, SNTP_OFFSET_LI_VN_MODE);
+ mode &= SNTP_MODE_MASK;
+ /* if this is a SNTP response... */
+ if (((sntp_opmode == SNTP_OPMODE_POLL) && (mode == SNTP_MODE_SERVER)) ||
+ ((sntp_opmode == SNTP_OPMODE_LISTENONLY) && (mode == SNTP_MODE_BROADCAST))) {
+ pbuf_copy_partial(p, &stratum, 1, SNTP_OFFSET_STRATUM);
+ if (stratum == SNTP_STRATUM_KOD) {
+ /* Kiss-of-death packet. Use another server or increase UPDATE_DELAY. */
+ err = SNTP_ERR_KOD;
+ LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_recv: Received Kiss-of-Death\n"));
+ } else {
+#if SNTP_CHECK_RESPONSE >= 2
+ /* check originate_timetamp against sntp_last_timestamp_sent */
+ u32_t originate_timestamp[2];
+ pbuf_copy_partial(p, &originate_timestamp, 8, SNTP_OFFSET_ORIGINATE_TIME);
+ if ((originate_timestamp[0] != sntp_last_timestamp_sent[0]) ||
+ (originate_timestamp[1] != sntp_last_timestamp_sent[1]))
+ {
+ LWIP_DEBUGF(SNTP_DEBUG_WARN, ("sntp_recv: Invalid originate timestamp in response\n"));
+ } else
+#endif /* SNTP_CHECK_RESPONSE >= 2 */
+ /* @todo: add code for SNTP_CHECK_RESPONSE >= 3 and >= 4 here */
+ {
+ /* correct answer */
+ err = ERR_OK;
+ pbuf_copy_partial(p, &receive_timestamp, SNTP_RECEIVE_TIME_SIZE * 4, SNTP_OFFSET_TRANSMIT_TIME);
+ }
+ }
+ } else {
+ LWIP_DEBUGF(SNTP_DEBUG_WARN, ("sntp_recv: Invalid mode in response: %"U16_F"\n", (u16_t)mode));
+ /* wait for correct response */
+ err = ERR_TIMEOUT;
+ }
+ } else {
+ LWIP_DEBUGF(SNTP_DEBUG_WARN, ("sntp_recv: Invalid packet length: %"U16_F"\n", p->tot_len));
+ }
+ }
+#if SNTP_CHECK_RESPONSE >= 1
+ else {
+ /* packet from wrong remote address or port, wait for correct response */
+ err = ERR_TIMEOUT;
+ }
+#endif /* SNTP_CHECK_RESPONSE >= 1 */
+ pbuf_free(p);
+ if (err == ERR_OK) {
+ sntp_process(receive_timestamp);
+
+ /* Set up timeout for next request (only if poll response was received)*/
+ if (sntp_opmode == SNTP_OPMODE_POLL) {
+ /* Correct response, reset retry timeout */
+ SNTP_RESET_RETRY_TIMEOUT();
+
+ sys_timeout((u32_t)SNTP_UPDATE_DELAY, sntp_request, NULL);
+ LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_recv: Scheduled next time request: %"U32_F" ms\n",
+ (u32_t)SNTP_UPDATE_DELAY));
+ }
+ } else if (err != ERR_TIMEOUT) {
+ /* Errors are only processed in case of an explicit poll response */
+ if (sntp_opmode == SNTP_OPMODE_POLL) {
+ if (err == SNTP_ERR_KOD) {
+ /* Kiss-of-death packet. Use another server or increase UPDATE_DELAY. */
+ sntp_try_next_server(NULL);
+ } else {
+ /* another error, try the same server again */
+ sntp_retry(NULL);
+ }
+ }
+ }
+}
+
+/** Actually send an sntp request to a server.
+ *
+ * @param server_addr resolved IP address of the SNTP server
+ */
+static void
+sntp_send_request(const ip_addr_t *server_addr)
+{
+ struct pbuf* p;
+ p = pbuf_alloc(PBUF_TRANSPORT, SNTP_MSG_LEN, PBUF_RAM);
+ if (p != NULL) {
+ struct sntp_msg *sntpmsg = (struct sntp_msg *)p->payload;
+ LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_send_request: Sending request to server\n"));
+ /* initialize request message */
+ sntp_initialize_request(sntpmsg);
+ /* send request */
+ udp_sendto(sntp_pcb, p, server_addr, SNTP_PORT);
+ /* free the pbuf after sending it */
+ pbuf_free(p);
+ /* set up receive timeout: try next server or retry on timeout */
+ sys_timeout((u32_t)SNTP_RECV_TIMEOUT, sntp_try_next_server, NULL);
+#if SNTP_CHECK_RESPONSE >= 1
+ /* save server address to verify it in sntp_recv */
+ ip_addr_set(&sntp_last_server_address, server_addr);
+#endif /* SNTP_CHECK_RESPONSE >= 1 */
+ } else {
+ LWIP_DEBUGF(SNTP_DEBUG_SERIOUS, ("sntp_send_request: Out of memory, trying again in %"U32_F" ms\n",
+ (u32_t)SNTP_RETRY_TIMEOUT));
+ /* out of memory: set up a timer to send a retry */
+ sys_timeout((u32_t)SNTP_RETRY_TIMEOUT, sntp_request, NULL);
+ }
+}
+
+#if SNTP_SERVER_DNS
+/**
+ * DNS found callback when using DNS names as server address.
+ */
+static void
+sntp_dns_found(const char* hostname, const ip_addr_t *ipaddr, void *arg)
+{
+ LWIP_UNUSED_ARG(hostname);
+ LWIP_UNUSED_ARG(arg);
+
+ if (ipaddr != NULL) {
+ /* Address resolved, send request */
+ LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_dns_found: Server address resolved, sending request\n"));
+ sntp_send_request(ipaddr);
+ } else {
+ /* DNS resolving failed -> try another server */
+ LWIP_DEBUGF(SNTP_DEBUG_WARN_STATE, ("sntp_dns_found: Failed to resolve server address resolved, trying next server\n"));
+ sntp_try_next_server(NULL);
+ }
+}
+#endif /* SNTP_SERVER_DNS */
+
+/**
+ * Send out an sntp request.
+ *
+ * @param arg is unused (only necessary to conform to sys_timeout)
+ */
+static void
+sntp_request(void *arg)
+{
+ ip_addr_t sntp_server_address;
+ err_t err;
+
+ LWIP_UNUSED_ARG(arg);
+
+ /* initialize SNTP server address */
+#if SNTP_SERVER_DNS
+ if (sntp_servers[sntp_current_server].name) {
+ /* always resolve the name and rely on dns-internal caching & timeout */
+ ip_addr_set_zero(&sntp_servers[sntp_current_server].addr);
+ err = dns_gethostbyname(sntp_servers[sntp_current_server].name, &sntp_server_address,
+ sntp_dns_found, NULL);
+ if (err == ERR_INPROGRESS) {
+ /* DNS request sent, wait for sntp_dns_found being called */
+ LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_request: Waiting for server address to be resolved.\n"));
+ return;
+ } else if (err == ERR_OK) {
+ sntp_servers[sntp_current_server].addr = sntp_server_address;
+ }
+ } else
+#endif /* SNTP_SERVER_DNS */
+ {
+ sntp_server_address = sntp_servers[sntp_current_server].addr;
+ err = (ip_addr_isany_val(sntp_server_address)) ? ERR_ARG : ERR_OK;
+ }
+
+ if (err == ERR_OK) {
+ LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_request: current server address is %s\n",
+ ipaddr_ntoa(&sntp_server_address)));
+ sntp_send_request(&sntp_server_address);
+ } else {
+ /* address conversion failed, try another server */
+ LWIP_DEBUGF(SNTP_DEBUG_WARN_STATE, ("sntp_request: Invalid server address, trying next server.\n"));
+ sys_timeout((u32_t)SNTP_RETRY_TIMEOUT, sntp_try_next_server, NULL);
+ }
+}
+
+/**
+ * @ingroup sntp
+ * Initialize this module.
+ * Send out request instantly or after SNTP_STARTUP_DELAY(_FUNC).
+ */
+void
+sntp_init(void)
+{
+#ifdef SNTP_SERVER_ADDRESS
+#if SNTP_SERVER_DNS
+ sntp_setservername(0, SNTP_SERVER_ADDRESS);
+#else
+#error SNTP_SERVER_ADDRESS string not supported SNTP_SERVER_DNS==0
+#endif
+#endif /* SNTP_SERVER_ADDRESS */
+
+ if (sntp_pcb == NULL) {
+ sntp_pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
+ LWIP_ASSERT("Failed to allocate udp pcb for sntp client", sntp_pcb != NULL);
+ if (sntp_pcb != NULL) {
+ udp_recv(sntp_pcb, sntp_recv, NULL);
+
+ if (sntp_opmode == SNTP_OPMODE_POLL) {
+ SNTP_RESET_RETRY_TIMEOUT();
+#if SNTP_STARTUP_DELAY
+ sys_timeout((u32_t)SNTP_STARTUP_DELAY_FUNC, sntp_request, NULL);
+#else
+ sntp_request(NULL);
+#endif
+ } else if (sntp_opmode == SNTP_OPMODE_LISTENONLY) {
+ ip_set_option(sntp_pcb, SOF_BROADCAST);
+ udp_bind(sntp_pcb, IP_ANY_TYPE, SNTP_PORT);
+ }
+ }
+ }
+}
+
+/**
+ * @ingroup sntp
+ * Stop this module.
+ */
+void
+sntp_stop(void)
+{
+ if (sntp_pcb != NULL) {
+ sys_untimeout(sntp_request, NULL);
+ udp_remove(sntp_pcb);
+ sntp_pcb = NULL;
+ }
+}
+
+/**
+ * @ingroup sntp
+ * Get enabled state.
+ */
+u8_t sntp_enabled(void)
+{
+ return (sntp_pcb != NULL)? 1 : 0;
+}
+
+/**
+ * @ingroup sntp
+ * Sets the operating mode.
+ * @param operating_mode one of the available operating modes
+ */
+void
+sntp_setoperatingmode(u8_t operating_mode)
+{
+ LWIP_ASSERT("Invalid operating mode", operating_mode <= SNTP_OPMODE_LISTENONLY);
+ LWIP_ASSERT("Operating mode must not be set while SNTP client is running", sntp_pcb == NULL);
+ sntp_opmode = operating_mode;
+}
+
+/**
+ * @ingroup sntp
+ * Gets the operating mode.
+ */
+u8_t
+sntp_getoperatingmode(void)
+{
+ return sntp_opmode;
+}
+
+#if SNTP_GET_SERVERS_FROM_DHCP
+/**
+ * Config SNTP server handling by IP address, name, or DHCP; clear table
+ * @param set_servers_from_dhcp enable or disable getting server addresses from dhcp
+ */
+void
+sntp_servermode_dhcp(int set_servers_from_dhcp)
+{
+ u8_t new_mode = set_servers_from_dhcp ? 1 : 0;
+ if (sntp_set_servers_from_dhcp != new_mode) {
+ sntp_set_servers_from_dhcp = new_mode;
+ }
+}
+#endif /* SNTP_GET_SERVERS_FROM_DHCP */
+
+/**
+ * @ingroup sntp
+ * Initialize one of the NTP servers by IP address
+ *
+ * @param idx the index of the NTP server to set must be < SNTP_MAX_SERVERS
+ * @param server IP address of the NTP server to set
+ */
+void
+sntp_setserver(u8_t idx, const ip_addr_t *server)
+{
+ if (idx < SNTP_MAX_SERVERS) {
+ if (server != NULL) {
+ sntp_servers[idx].addr = (*server);
+ } else {
+ ip_addr_set_zero(&sntp_servers[idx].addr);
+ }
+#if SNTP_SERVER_DNS
+ sntp_servers[idx].name = NULL;
+#endif
+ }
+}
+
+#if LWIP_DHCP && SNTP_GET_SERVERS_FROM_DHCP
+/**
+ * Initialize one of the NTP servers by IP address, required by DHCP
+ *
+ * @param numdns the index of the NTP server to set must be < SNTP_MAX_SERVERS
+ * @param dnsserver IP address of the NTP server to set
+ */
+void
+dhcp_set_ntp_servers(u8_t num, const ip4_addr_t *server)
+{
+ LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp: %s %u.%u.%u.%u as NTP server #%u via DHCP\n",
+ (sntp_set_servers_from_dhcp ? "Got" : "Rejected"),
+ ip4_addr1(server), ip4_addr2(server), ip4_addr3(server), ip4_addr4(server), num));
+ if (sntp_set_servers_from_dhcp && num) {
+ u8_t i;
+ for (i = 0; (i < num) && (i < SNTP_MAX_SERVERS); i++) {
+ ip_addr_t addr;
+ ip_addr_copy_from_ip4(addr, server[i]);
+ sntp_setserver(i, &addr);
+ }
+ for (i = num; i < SNTP_MAX_SERVERS; i++) {
+ sntp_setserver(i, NULL);
+ }
+ }
+}
+#endif /* LWIP_DHCP && SNTP_GET_SERVERS_FROM_DHCP */
+
+/**
+ * @ingroup sntp
+ * Obtain one of the currently configured by IP address (or DHCP) NTP servers
+ *
+ * @param idx the index of the NTP server
+ * @return IP address of the indexed NTP server or "ip_addr_any" if the NTP
+ * server has not been configured by address (or at all).
+ */
+const ip_addr_t*
+sntp_getserver(u8_t idx)
+{
+ if (idx < SNTP_MAX_SERVERS) {
+ return &sntp_servers[idx].addr;
+ }
+ return IP_ADDR_ANY;
+}
+
+#if SNTP_SERVER_DNS
+/**
+ * Initialize one of the NTP servers by name
+ *
+ * @param numdns the index of the NTP server to set must be < SNTP_MAX_SERVERS
+ * @param dnsserver DNS name of the NTP server to set, to be resolved at contact time
+ */
+void
+sntp_setservername(u8_t idx, char *server)
+{
+ if (idx < SNTP_MAX_SERVERS) {
+ sntp_servers[idx].name = server;
+ }
+}
+
+/**
+ * Obtain one of the currently configured by name NTP servers.
+ *
+ * @param numdns the index of the NTP server
+ * @return IP address of the indexed NTP server or NULL if the NTP
+ * server has not been configured by name (or at all)
+ */
+char *
+sntp_getservername(u8_t idx)
+{
+ if (idx < SNTP_MAX_SERVERS) {
+ return sntp_servers[idx].name;
+ }
+ return NULL;
+}
+#endif /* SNTP_SERVER_DNS */
+
+#endif /* LWIP_UDP */
http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/blob/f5a0f2a0/net/ip/lwip_base/src/core/def.c
----------------------------------------------------------------------
diff --git a/net/ip/lwip_base/src/core/def.c b/net/ip/lwip_base/src/core/def.c
new file mode 100644
index 0000000..7d3c93f
--- /dev/null
+++ b/net/ip/lwip_base/src/core/def.c
@@ -0,0 +1,105 @@
+/**
+ * @file
+ * Common functions used throughout the stack.
+ *
+ * These are reference implementations of the byte swapping functions.
+ * Again with the aim of being simple, correct and fully portable.
+ * Byte swapping is the second thing you would want to optimize. You will
+ * need to port it to your architecture and in your cc.h:
+ *
+ * \#define LWIP_PLATFORM_BYTESWAP 1
+ * \#define LWIP_PLATFORM_HTONS(x) your_htons
+ * \#define LWIP_PLATFORM_HTONL(x) your_htonl
+ *
+ * Note ntohs() and ntohl() are merely references to the htonx counterparts.
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Simon Goldschmidt
+ *
+ */
+
+#include "lwip/opt.h"
+#include "lwip/def.h"
+
+#if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
+
+/**
+ * Convert an u16_t from host- to network byte order.
+ *
+ * @param n u16_t in host byte order
+ * @return n in network byte order
+ */
+u16_t
+lwip_htons(u16_t n)
+{
+ return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
+}
+
+/**
+ * Convert an u16_t from network- to host byte order.
+ *
+ * @param n u16_t in network byte order
+ * @return n in host byte order
+ */
+u16_t
+lwip_ntohs(u16_t n)
+{
+ return lwip_htons(n);
+}
+
+/**
+ * Convert an u32_t from host- to network byte order.
+ *
+ * @param n u32_t in host byte order
+ * @return n in network byte order
+ */
+u32_t
+lwip_htonl(u32_t n)
+{
+ return ((n & 0xff) << 24) |
+ ((n & 0xff00) << 8) |
+ ((n & 0xff0000UL) >> 8) |
+ ((n & 0xff000000UL) >> 24);
+}
+
+/**
+ * Convert an u32_t from network- to host byte order.
+ *
+ * @param n u32_t in network byte order
+ * @return n in host byte order
+ */
+u32_t
+lwip_ntohl(u32_t n)
+{
+ return lwip_htonl(n);
+}
+
+#endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */
http://git-wip-us.apache.org/repos/asf/incubator-mynewt-core/blob/f5a0f2a0/net/ip/lwip_base/src/core/dns.c
----------------------------------------------------------------------
diff --git a/net/ip/lwip_base/src/core/dns.c b/net/ip/lwip_base/src/core/dns.c
new file mode 100644
index 0000000..b19f9b0
--- /dev/null
+++ b/net/ip/lwip_base/src/core/dns.c
@@ -0,0 +1,1468 @@
+/**
+ * @file
+ * DNS - host name to IP address resolver.
+ *
+ * @defgroup dns DNS
+ * @ingroup callbackstyle_api
+ *
+ * Implements a DNS host name to IP address resolver.
+ *
+ * The lwIP DNS resolver functions are used to lookup a host name and
+ * map it to a numerical IP address. It maintains a list of resolved
+ * hostnames that can be queried with the dns_lookup() function.
+ * New hostnames can be resolved using the dns_query() function.
+ *
+ * The lwIP version of the resolver also adds a non-blocking version of
+ * gethostbyname() that will work with a raw API application. This function
+ * checks for an IP address string first and converts it if it is valid.
+ * gethostbyname() then does a dns_lookup() to see if the name is
+ * already in the table. If so, the IP is returned. If not, a query is
+ * issued and the function returns with a ERR_INPROGRESS status. The app
+ * using the dns client must then go into a waiting state.
+ *
+ * Once a hostname has been resolved (or found to be non-existent),
+ * the resolver code calls a specified callback function (which
+ * must be implemented by the module that uses the resolver).
+ *
+ * All functions must be called from TCPIP thread.
+ *
+ * @see @ref netconn_common for thread-safe access.
+ */
+
+/*
+ * Port to lwIP from uIP
+ * by Jim Pettinato April 2007
+ *
+ * security fixes and more by Simon Goldschmidt
+ *
+ * uIP version Copyright (c) 2002-2003, Adam Dunkels.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ * products derived from this software without specific prior
+ * written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+ * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*-----------------------------------------------------------------------------
+ * RFC 1035 - Domain names - implementation and specification
+ * RFC 2181 - Clarifications to the DNS Specification
+ *----------------------------------------------------------------------------*/
+
+/** @todo: define good default values (rfc compliance) */
+/** @todo: improve answer parsing, more checkings... */
+/** @todo: check RFC1035 - 7.3. Processing responses */
+
+/*-----------------------------------------------------------------------------
+ * Includes
+ *----------------------------------------------------------------------------*/
+
+#include "lwip/opt.h"
+
+#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/udp.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/dns.h"
+#include "lwip/prot/dns.h"
+
+#include <string.h>
+
+/** Random generator function to create random TXIDs and source ports for queries */
+#ifndef DNS_RAND_TXID
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_XID) != 0)
+#define DNS_RAND_TXID LWIP_RAND
+#else
+static u16_t dns_txid;
+#define DNS_RAND_TXID() (++dns_txid)
+#endif
+#endif
+
+/** Limits the source port to be >= 1024 by default */
+#ifndef DNS_PORT_ALLOWED
+#define DNS_PORT_ALLOWED(port) ((port) >= 1024)
+#endif
+
+/** DNS maximum number of retries when asking for a name, before "timeout". */
+#ifndef DNS_MAX_RETRIES
+#define DNS_MAX_RETRIES 4
+#endif
+
+/** DNS resource record max. TTL (one week as default) */
+#ifndef DNS_MAX_TTL
+#define DNS_MAX_TTL 604800
+#elif DNS_MAX_TTL > 0x7FFFFFFF
+#error DNS_MAX_TTL must be a positive 32-bit value
+#endif
+
+/* The number of parallel requests (i.e. calls to dns_gethostbyname
+ * that cannot be answered from the DNS table.
+ * This is set to the table size by default.
+ */
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
+#ifndef DNS_MAX_REQUESTS
+#define DNS_MAX_REQUESTS DNS_TABLE_SIZE
+#endif
+#else
+/* In this configuration, both arrays have to have the same size and are used
+ * like one entry (used/free) */
+#define DNS_MAX_REQUESTS DNS_TABLE_SIZE
+#endif
+
+/* The number of UDP source ports used in parallel */
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
+#ifndef DNS_MAX_SOURCE_PORTS
+#define DNS_MAX_SOURCE_PORTS DNS_MAX_REQUESTS
+#endif
+#else
+#ifdef DNS_MAX_SOURCE_PORTS
+#undef DNS_MAX_SOURCE_PORTS
+#endif
+#define DNS_MAX_SOURCE_PORTS 1
+#endif
+
+#if LWIP_IPV4 && LWIP_IPV6
+#define LWIP_DNS_ADDRTYPE_IS_IPV6(t) (((t) == LWIP_DNS_ADDRTYPE_IPV6_IPV4) || ((t) == LWIP_DNS_ADDRTYPE_IPV6))
+#define LWIP_DNS_ADDRTYPE_MATCH_IP(t, ip) (IP_IS_V6_VAL(ip) ? LWIP_DNS_ADDRTYPE_IS_IPV6(t) : (!LWIP_DNS_ADDRTYPE_IS_IPV6(t)))
+#define LWIP_DNS_ADDRTYPE_ARG(x) , x
+#define LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(x) x
+#define LWIP_DNS_SET_ADDRTYPE(x, y) do { x = y; } while(0)
+#else
+#if LWIP_IPV6
+#define LWIP_DNS_ADDRTYPE_IS_IPV6(t) 1
+#else
+#define LWIP_DNS_ADDRTYPE_IS_IPV6(t) 0
+#endif
+#define LWIP_DNS_ADDRTYPE_MATCH_IP(t, ip) 1
+#define LWIP_DNS_ADDRTYPE_ARG(x)
+#define LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(x) 0
+#define LWIP_DNS_SET_ADDRTYPE(x, y)
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
+/** DNS query message structure.
+ No packing needed: only used locally on the stack. */
+struct dns_query {
+ /* DNS query record starts with either a domain name or a pointer
+ to a name already present somewhere in the packet. */
+ u16_t type;
+ u16_t cls;
+};
+#define SIZEOF_DNS_QUERY 4
+
+/** DNS answer message structure.
+ No packing needed: only used locally on the stack. */
+struct dns_answer {
+ /* DNS answer record starts with either a domain name or a pointer
+ to a name already present somewhere in the packet. */
+ u16_t type;
+ u16_t cls;
+ u32_t ttl;
+ u16_t len;
+};
+#define SIZEOF_DNS_ANSWER 10
+/* maximum allowed size for the struct due to non-packed */
+#define SIZEOF_DNS_ANSWER_ASSERT 12
+
+/* DNS table entry states */
+typedef enum {
+ DNS_STATE_UNUSED = 0,
+ DNS_STATE_NEW = 1,
+ DNS_STATE_ASKING = 2,
+ DNS_STATE_DONE = 3
+} dns_state_enum_t;
+
+/** DNS table entry */
+struct dns_table_entry {
+ u32_t ttl;
+ ip_addr_t ipaddr;
+ u16_t txid;
+ u8_t state;
+ u8_t server_idx;
+ u8_t tmr;
+ u8_t retries;
+ u8_t seqno;
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
+ u8_t pcb_idx;
+#endif
+ char name[DNS_MAX_NAME_LENGTH];
+#if LWIP_IPV4 && LWIP_IPV6
+ u8_t reqaddrtype;
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+};
+
+/** DNS request table entry: used when dns_gehostbyname cannot answer the
+ * request from the DNS table */
+struct dns_req_entry {
+ /* pointer to callback on DNS query done */
+ dns_found_callback found;
+ /* argument passed to the callback function */
+ void *arg;
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
+ u8_t dns_table_idx;
+#endif
+#if LWIP_IPV4 && LWIP_IPV6
+ u8_t reqaddrtype;
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+};
+
+#if DNS_LOCAL_HOSTLIST
+
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+/** Local host-list. For hostnames in this list, no
+ * external name resolution is performed */
+static struct local_hostlist_entry *local_hostlist_dynamic;
+#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+
+/** Defining this allows the local_hostlist_static to be placed in a different
+ * linker section (e.g. FLASH) */
+#ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
+#define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
+#endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
+/** Defining this allows the local_hostlist_static to be placed in a different
+ * linker section (e.g. FLASH) */
+#ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
+#define DNS_LOCAL_HOSTLIST_STORAGE_POST
+#endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
+DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
+ DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
+
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+
+static void dns_init_local(void);
+#endif /* DNS_LOCAL_HOSTLIST */
+
+
+/* forward declarations */
+static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port);
+static void dns_check_entries(void);
+static void dns_call_found(u8_t idx, ip_addr_t* addr);
+
+/*-----------------------------------------------------------------------------
+ * Globals
+ *----------------------------------------------------------------------------*/
+
+/* DNS variables */
+static struct udp_pcb *dns_pcbs[DNS_MAX_SOURCE_PORTS];
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
+static u8_t dns_last_pcb_idx;
+#endif
+static u8_t dns_seqno;
+static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
+static struct dns_req_entry dns_requests[DNS_MAX_REQUESTS];
+static ip_addr_t dns_servers[DNS_MAX_SERVERS];
+
+#ifndef LWIP_DNS_STRICMP
+#define LWIP_DNS_STRICMP(str1, str2) dns_stricmp(str1, str2)
+/**
+ * A small but sufficient implementation for case insensitive strcmp.
+ * This can be defined to e.g. stricmp for windows or strcasecmp for linux. */
+static int
+dns_stricmp(const char* str1, const char* str2)
+{
+ char c1, c2;
+
+ do {
+ c1 = *str1++;
+ c2 = *str2++;
+ if (c1 != c2) {
+ char c1_upc = c1 | 0x20;
+ if ((c1_upc >= 'a') && (c1_upc <= 'z')) {
+ /* characters are not equal an one is in the alphabet range:
+ downcase both chars and check again */
+ char c2_upc = c2 | 0x20;
+ if (c1_upc != c2_upc) {
+ /* still not equal */
+ /* don't care for < or > */
+ return 1;
+ }
+ } else {
+ /* characters are not equal but none is in the alphabet range */
+ return 1;
+ }
+ }
+ } while (c1 != 0);
+ return 0;
+}
+#endif /* LWIP_DNS_STRICMP */
+
+/**
+ * Initialize the resolver: set up the UDP pcb and configure the default server
+ * (if DNS_SERVER_ADDRESS is set).
+ */
+void
+dns_init(void)
+{
+#ifdef DNS_SERVER_ADDRESS
+ /* initialize default DNS server address */
+ ip_addr_t dnsserver;
+ DNS_SERVER_ADDRESS(&dnsserver);
+ dns_setserver(0, &dnsserver);
+#endif /* DNS_SERVER_ADDRESS */
+
+ LWIP_ASSERT("sanity check SIZEOF_DNS_QUERY",
+ sizeof(struct dns_query) == SIZEOF_DNS_QUERY);
+ LWIP_ASSERT("sanity check SIZEOF_DNS_ANSWER",
+ sizeof(struct dns_answer) <= SIZEOF_DNS_ANSWER_ASSERT);
+
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
+
+ /* if dns client not yet initialized... */
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) == 0)
+ if (dns_pcbs[0] == NULL) {
+ dns_pcbs[0] = udp_new_ip_type(IPADDR_TYPE_ANY);
+ LWIP_ASSERT("dns_pcbs[0] != NULL", dns_pcbs[0] != NULL);
+
+ /* initialize DNS table not needed (initialized to zero since it is a
+ * global variable) */
+ LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
+ DNS_STATE_UNUSED == 0);
+
+ /* initialize DNS client */
+ udp_bind(dns_pcbs[0], IP_ANY_TYPE, 0);
+ udp_recv(dns_pcbs[0], dns_recv, NULL);
+ }
+#endif
+
+#if DNS_LOCAL_HOSTLIST
+ dns_init_local();
+#endif
+}
+
+/**
+ * @ingroup dns
+ * Initialize one of the DNS servers.
+ *
+ * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
+ * @param dnsserver IP address of the DNS server to set
+ */
+void
+dns_setserver(u8_t numdns, const ip_addr_t *dnsserver)
+{
+ if (numdns < DNS_MAX_SERVERS) {
+ if (dnsserver != NULL) {
+ dns_servers[numdns] = (*dnsserver);
+ } else {
+ dns_servers[numdns] = *IP_ADDR_ANY;
+ }
+ }
+}
+
+/**
+ * @ingroup dns
+ * Obtain one of the currently configured DNS server.
+ *
+ * @param numdns the index of the DNS server
+ * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
+ * server has not been configured.
+ */
+const ip_addr_t*
+dns_getserver(u8_t numdns)
+{
+ if (numdns < DNS_MAX_SERVERS) {
+ return &dns_servers[numdns];
+ } else {
+ return IP_ADDR_ANY;
+ }
+}
+
+/**
+ * The DNS resolver client timer - handle retries and timeouts and should
+ * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
+ */
+void
+dns_tmr(void)
+{
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
+ dns_check_entries();
+}
+
+#if DNS_LOCAL_HOSTLIST
+static void
+dns_init_local(void)
+{
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
+ size_t i;
+ struct local_hostlist_entry *entry;
+ /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
+ struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
+ size_t namelen;
+ for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_init); i++) {
+ struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
+ LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
+ namelen = strlen(init_entry->name);
+ LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
+ entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
+ LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
+ if (entry != NULL) {
+ char* entry_name = (char*)entry + sizeof(struct local_hostlist_entry);
+ MEMCPY(entry_name, init_entry->name, namelen);
+ entry_name[namelen] = 0;
+ entry->name = entry_name;
+ entry->addr = init_entry->addr;
+ entry->next = local_hostlist_dynamic;
+ local_hostlist_dynamic = entry;
+ }
+ }
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
+}
+
+/**
+ * @ingroup dns
+ * Scans the local host-list for a hostname.
+ *
+ * @param hostname Hostname to look for in the local host-list
+ * @param addr the first IP address for the hostname in the local host-list or
+ * IPADDR_NONE if not found.
+ * @return ERR_OK if found, ERR_ARG if not found
+ */
+static err_t
+dns_lookup_local(const char *hostname, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype))
+{
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+ struct local_hostlist_entry *entry = local_hostlist_dynamic;
+ while (entry != NULL) {
+ if ((LWIP_DNS_STRICMP(entry->name, hostname) == 0) &&
+ LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, entry->addr)) {
+ if (addr) {
+ ip_addr_copy(*addr, entry->addr);
+ }
+ return ERR_OK;
+ }
+ entry = entry->next;
+ }
+#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+ size_t i;
+ for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_static); i++) {
+ if ((LWIP_DNS_STRICMP(local_hostlist_static[i].name, hostname) == 0) &&
+ LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, local_hostlist_static[i].addr)) {
+ if (addr) {
+ ip_addr_copy(*addr, local_hostlist_static[i].addr);
+ }
+ return ERR_OK;
+ }
+ }
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+ return ERR_ARG;
+}
+
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+/**
+ * @ingroup dns
+ * Remove all entries from the local host-list for a specific hostname
+ * and/or IP address
+ *
+ * @param hostname hostname for which entries shall be removed from the local
+ * host-list
+ * @param addr address for which entries shall be removed from the local host-list
+ * @return the number of removed entries
+ */
+int
+dns_local_removehost(const char *hostname, const ip_addr_t *addr)
+{
+ int removed = 0;
+ struct local_hostlist_entry *entry = local_hostlist_dynamic;
+ struct local_hostlist_entry *last_entry = NULL;
+ while (entry != NULL) {
+ if (((hostname == NULL) || !LWIP_DNS_STRICMP(entry->name, hostname)) &&
+ ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
+ struct local_hostlist_entry *free_entry;
+ if (last_entry != NULL) {
+ last_entry->next = entry->next;
+ } else {
+ local_hostlist_dynamic = entry->next;
+ }
+ free_entry = entry;
+ entry = entry->next;
+ memp_free(MEMP_LOCALHOSTLIST, free_entry);
+ removed++;
+ } else {
+ last_entry = entry;
+ entry = entry->next;
+ }
+ }
+ return removed;
+}
+
+/**
+ * @ingroup dns
+ * Add a hostname/IP address pair to the local host-list.
+ * Duplicates are not checked.
+ *
+ * @param hostname hostname of the new entry
+ * @param addr IP address of the new entry
+ * @return ERR_OK if succeeded or ERR_MEM on memory error
+ */
+err_t
+dns_local_addhost(const char *hostname, const ip_addr_t *addr)
+{
+ struct local_hostlist_entry *entry;
+ size_t namelen;
+ char* entry_name;
+ LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
+ namelen = strlen(hostname);
+ LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
+ entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
+ if (entry == NULL) {
+ return ERR_MEM;
+ }
+ entry_name = (char*)entry + sizeof(struct local_hostlist_entry);
+ MEMCPY(entry_name, hostname, namelen);
+ entry_name[namelen] = 0;
+ entry->name = entry_name;
+ ip_addr_copy(entry->addr, *addr);
+ entry->next = local_hostlist_dynamic;
+ local_hostlist_dynamic = entry;
+ return ERR_OK;
+}
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
+#endif /* DNS_LOCAL_HOSTLIST */
+
+/**
+ * @ingroup dns
+ * Look up a hostname in the array of known hostnames.
+ *
+ * @note This function only looks in the internal array of known
+ * hostnames, it does not send out a query for the hostname if none
+ * was found. The function dns_enqueue() can be used to send a query
+ * for a hostname.
+ *
+ * @param name the hostname to look up
+ * @param addr the hostname's IP address, as u32_t (instead of ip_addr_t to
+ * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
+ * was not found in the cached dns_table.
+ * @return ERR_OK if found, ERR_ARG if not found
+ */
+static err_t
+dns_lookup(const char *name, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype))
+{
+ u8_t i;
+#if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
+#endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
+#if DNS_LOCAL_HOSTLIST
+ if (dns_lookup_local(name, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)) == ERR_OK) {
+ return ERR_OK;
+ }
+#endif /* DNS_LOCAL_HOSTLIST */
+#ifdef DNS_LOOKUP_LOCAL_EXTERN
+ if (DNS_LOOKUP_LOCAL_EXTERN(name, addr, LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(dns_addrtype)) == ERR_OK) {
+ return ERR_OK;
+ }
+#endif /* DNS_LOOKUP_LOCAL_EXTERN */
+
+ /* Walk through name list, return entry if found. If not, return NULL. */
+ for (i = 0; i < DNS_TABLE_SIZE; ++i) {
+ if ((dns_table[i].state == DNS_STATE_DONE) &&
+ (LWIP_DNS_STRICMP(name, dns_table[i].name) == 0) &&
+ LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, dns_table[i].ipaddr)) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
+ ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
+ LWIP_DEBUGF(DNS_DEBUG, ("\n"));
+ if (addr) {
+ ip_addr_copy(*addr, dns_table[i].ipaddr);
+ }
+ return ERR_OK;
+ }
+ }
+
+ return ERR_ARG;
+}
+
+/**
+ * Compare the "dotted" name "query" with the encoded name "response"
+ * to make sure an answer from the DNS server matches the current dns_table
+ * entry (otherwise, answers might arrive late for hostname not on the list
+ * any more).
+ *
+ * @param query hostname (not encoded) from the dns_table
+ * @param p pbuf containing the encoded hostname in the DNS response
+ * @param start_offset offset into p where the name starts
+ * @return 0xFFFF: names differ, other: names equal -> offset behind name
+ */
+static u16_t
+dns_compare_name(const char *query, struct pbuf* p, u16_t start_offset)
+{
+ int n;
+ u16_t response_offset = start_offset;
+
+ do {
+ n = pbuf_try_get_at(p, response_offset++);
+ if (n < 0) {
+ return 0xFFFF;
+ }
+ /** @see RFC 1035 - 4.1.4. Message compression */
+ if ((n & 0xc0) == 0xc0) {
+ /* Compressed name: cannot be equal since we don't send them */
+ return 0xFFFF;
+ } else {
+ /* Not compressed name */
+ while (n > 0) {
+ int c = pbuf_try_get_at(p, response_offset);
+ if (c < 0) {
+ return 0xFFFF;
+ }
+ if ((*query) != (u8_t)c) {
+ return 0xFFFF;
+ }
+ ++response_offset;
+ ++query;
+ --n;
+ }
+ ++query;
+ }
+ n = pbuf_try_get_at(p, response_offset);
+ if (n < 0) {
+ return 0xFFFF;
+ }
+ } while (n != 0);
+
+ return response_offset + 1;
+}
+
+/**
+ * Walk through a compact encoded DNS name and return the end of the name.
+ *
+ * @param p pbuf containing the name
+ * @param query_idx start index into p pointing to encoded DNS name in the DNS server response
+ * @return index to end of the name
+ */
+static u16_t
+dns_skip_name(struct pbuf* p, u16_t query_idx)
+{
+ int n;
+ u16_t offset = query_idx;
+
+ do {
+ n = pbuf_try_get_at(p, offset++);
+ if (n < 0) {
+ return 0xFFFF;
+ }
+ /** @see RFC 1035 - 4.1.4. Message compression */
+ if ((n & 0xc0) == 0xc0) {
+ /* Compressed name: since we only want to skip it (not check it), stop here */
+ break;
+ } else {
+ /* Not compressed name */
+ if (offset + n >= p->tot_len) {
+ return 0xFFFF;
+ }
+ offset = (u16_t)(offset + n);
+ }
+ n = pbuf_try_get_at(p, offset);
+ if (n < 0) {
+ return 0xFFFF;
+ }
+ } while (n != 0);
+
+ return offset + 1;
+}
+
+/**
+ * Send a DNS query packet.
+ *
+ * @param idx the DNS table entry index for which to send a request
+ * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
+ */
+static err_t
+dns_send(u8_t idx)
+{
+ err_t err;
+ struct dns_hdr hdr;
+ struct dns_query qry;
+ struct pbuf *p;
+ u16_t query_idx, copy_len;
+ const char *hostname, *hostname_part;
+ u8_t n;
+ u8_t pcb_idx;
+ struct dns_table_entry* entry = &dns_table[idx];
+
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
+ (u16_t)(entry->server_idx), entry->name));
+ LWIP_ASSERT("dns server out of array", entry->server_idx < DNS_MAX_SERVERS);
+ if (ip_addr_isany_val(dns_servers[entry->server_idx])) {
+ /* DNS server not valid anymore, e.g. PPP netif has been shut down */
+ /* call specified callback function if provided */
+ dns_call_found(idx, NULL);
+ /* flush this entry */
+ entry->state = DNS_STATE_UNUSED;
+ return ERR_OK;
+ }
+
+ /* if here, we have either a new query or a retry on a previous query to process */
+ p = pbuf_alloc(PBUF_TRANSPORT, (u16_t)(SIZEOF_DNS_HDR + strlen(entry->name) + 2 +
+ SIZEOF_DNS_QUERY), PBUF_RAM);
+ if (p != NULL) {
+ /* fill dns header */
+ memset(&hdr, 0, SIZEOF_DNS_HDR);
+ hdr.id = htons(entry->txid);
+ hdr.flags1 = DNS_FLAG1_RD;
+ hdr.numquestions = PP_HTONS(1);
+ pbuf_take(p, &hdr, SIZEOF_DNS_HDR);
+ hostname = entry->name;
+ --hostname;
+
+ /* convert hostname into suitable query format. */
+ query_idx = SIZEOF_DNS_HDR;
+ do {
+ ++hostname;
+ hostname_part = hostname;
+ for (n = 0; *hostname != '.' && *hostname != 0; ++hostname) {
+ ++n;
+ }
+ copy_len = (u16_t)(hostname - hostname_part);
+ pbuf_put_at(p, query_idx, n);
+ pbuf_take_at(p, hostname_part, copy_len, query_idx + 1);
+ query_idx += n + 1;
+ } while (*hostname != 0);
+ pbuf_put_at(p, query_idx, 0);
+ query_idx++;
+
+ /* fill dns query */
+ if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype)) {
+ qry.type = PP_HTONS(DNS_RRTYPE_AAAA);
+ } else {
+ qry.type = PP_HTONS(DNS_RRTYPE_A);
+ }
+ qry.cls = PP_HTONS(DNS_RRCLASS_IN);
+ pbuf_take_at(p, &qry, SIZEOF_DNS_QUERY, query_idx);
+
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
+ pcb_idx = entry->pcb_idx;
+#else
+ pcb_idx = 0;
+#endif
+ /* send dns packet */
+ LWIP_DEBUGF(DNS_DEBUG, ("sending DNS request ID %d for name \"%s\" to server %d\r\n",
+ entry->txid, entry->name, entry->server_idx));
+ err = udp_sendto(dns_pcbs[pcb_idx], p, &dns_servers[entry->server_idx], DNS_SERVER_PORT);
+
+ /* free pbuf */
+ pbuf_free(p);
+ } else {
+ err = ERR_MEM;
+ }
+
+ return err;
+}
+
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
+static struct udp_pcb*
+dns_alloc_random_port(void)
+{
+ err_t err;
+ struct udp_pcb* ret;
+
+ ret = udp_new_ip_type(IPADDR_TYPE_ANY);
+ if (ret == NULL) {
+ /* out of memory, have to reuse an existing pcb */
+ return NULL;
+ }
+ do {
+ u16_t port = (u16_t)DNS_RAND_TXID();
+ if (!DNS_PORT_ALLOWED(port)) {
+ /* this port is not allowed, try again */
+ err = ERR_USE;
+ continue;
+ }
+ err = udp_bind(ret, IP_ANY_TYPE, port);
+ } while (err == ERR_USE);
+ if (err != ERR_OK) {
+ udp_remove(ret);
+ return NULL;
+ }
+ udp_recv(ret, dns_recv, NULL);
+ return ret;
+}
+
+/**
+ * dns_alloc_pcb() - allocates a new pcb (or reuses an existing one) to be used
+ * for sending a request
+ *
+ * @return an index into dns_pcbs
+ */
+static u8_t
+dns_alloc_pcb(void)
+{
+ u8_t i;
+ u8_t idx;
+
+ for (i = 0; i < DNS_MAX_SOURCE_PORTS; i++) {
+ if (dns_pcbs[i] == NULL) {
+ break;
+ }
+ }
+ if (i < DNS_MAX_SOURCE_PORTS) {
+ dns_pcbs[i] = dns_alloc_random_port();
+ if (dns_pcbs[i] != NULL) {
+ /* succeeded */
+ dns_last_pcb_idx = i;
+ return i;
+ }
+ }
+ /* if we come here, creating a new UDP pcb failed, so we have to use
+ an already existing one */
+ for (i = 0, idx = dns_last_pcb_idx + 1; i < DNS_MAX_SOURCE_PORTS; i++, idx++) {
+ if (idx >= DNS_MAX_SOURCE_PORTS) {
+ idx = 0;
+ }
+ if (dns_pcbs[idx] != NULL) {
+ dns_last_pcb_idx = idx;
+ return idx;
+ }
+ }
+ return DNS_MAX_SOURCE_PORTS;
+}
+#endif /* ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) */
+
+/**
+ * dns_call_found() - call the found callback and check if there are duplicate
+ * entries for the given hostname. If there are any, their found callback will
+ * be called and they will be removed.
+ *
+ * @param idx dns table index of the entry that is resolved or removed
+ * @param addr IP address for the hostname (or NULL on error or memory shortage)
+ */
+static void
+dns_call_found(u8_t idx, ip_addr_t* addr)
+{
+#if ((LWIP_DNS_SECURE & (LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING | LWIP_DNS_SECURE_RAND_SRC_PORT)) != 0)
+ u8_t i;
+#endif
+
+#if LWIP_IPV4 && LWIP_IPV6
+ if (addr != NULL) {
+ /* check that address type matches the request and adapt the table entry */
+ if (IP_IS_V6_VAL(*addr)) {
+ LWIP_ASSERT("invalid response", LWIP_DNS_ADDRTYPE_IS_IPV6(dns_table[idx].reqaddrtype));
+ dns_table[idx].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV6;
+ } else {
+ LWIP_ASSERT("invalid response", !LWIP_DNS_ADDRTYPE_IS_IPV6(dns_table[idx].reqaddrtype));
+ dns_table[idx].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV4;
+ }
+ }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
+ for (i = 0; i < DNS_MAX_REQUESTS; i++) {
+ if (dns_requests[i].found && (dns_requests[i].dns_table_idx == idx)) {
+ (*dns_requests[i].found)(dns_table[idx].name, addr, dns_requests[i].arg);
+ /* flush this entry */
+ dns_requests[i].found = NULL;
+ }
+ }
+#else
+ if (dns_requests[idx].found) {
+ (*dns_requests[idx].found)(dns_table[idx].name, addr, dns_requests[idx].arg);
+ }
+ dns_requests[idx].found = NULL;
+#endif
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
+ /* close the pcb used unless other request are using it */
+ for (i = 0; i < DNS_MAX_REQUESTS; i++) {
+ if (i == idx) {
+ continue; /* only check other requests */
+ }
+ if (dns_table[i].state == DNS_STATE_ASKING) {
+ if (dns_table[i].pcb_idx == dns_table[idx].pcb_idx) {
+ /* another request is still using the same pcb */
+ dns_table[idx].pcb_idx = DNS_MAX_SOURCE_PORTS;
+ break;
+ }
+ }
+ }
+ if (dns_table[idx].pcb_idx < DNS_MAX_SOURCE_PORTS) {
+ /* if we come here, the pcb is not used any more and can be removed */
+ udp_remove(dns_pcbs[dns_table[idx].pcb_idx]);
+ dns_pcbs[dns_table[idx].pcb_idx] = NULL;
+ dns_table[idx].pcb_idx = DNS_MAX_SOURCE_PORTS;
+ }
+#endif
+}
+
+/* Create a query transmission ID that is unique for all outstanding queries */
+static u16_t
+dns_create_txid(void)
+{
+ u16_t txid;
+ u8_t i;
+
+again:
+ txid = (u16_t)DNS_RAND_TXID();
+
+ /* check whether the ID is unique */
+ for (i = 0; i < DNS_TABLE_SIZE; i++) {
+ if ((dns_table[i].state == DNS_STATE_ASKING) &&
+ (dns_table[i].txid == txid)) {
+ /* ID already used by another pending query */
+ goto again;
+ }
+ }
+
+ return txid;
+}
+
+/**
+ * dns_check_entry() - see if entry has not yet been queried and, if so, sends out a query.
+ * Check an entry in the dns_table:
+ * - send out query for new entries
+ * - retry old pending entries on timeout (also with different servers)
+ * - remove completed entries from the table if their TTL has expired
+ *
+ * @param i index of the dns_table entry to check
+ */
+static void
+dns_check_entry(u8_t i)
+{
+ err_t err;
+ struct dns_table_entry *entry = &dns_table[i];
+
+ LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
+
+ switch (entry->state) {
+ case DNS_STATE_NEW:
+ /* initialize new entry */
+ entry->txid = dns_create_txid();
+ entry->state = DNS_STATE_ASKING;
+ entry->server_idx = 0;
+ entry->tmr = 1;
+ entry->retries = 0;
+
+ /* send DNS packet for this entry */
+ err = dns_send(i);
+ if (err != ERR_OK) {
+ LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
+ ("dns_send returned error: %s\n", lwip_strerr(err)));
+ }
+ break;
+ case DNS_STATE_ASKING:
+ if (--entry->tmr == 0) {
+ if (++entry->retries == DNS_MAX_RETRIES) {
+ if ((entry->server_idx + 1 < DNS_MAX_SERVERS) && !ip_addr_isany_val(dns_servers[entry->server_idx + 1])) {
+ /* change of server */
+ entry->server_idx++;
+ entry->tmr = 1;
+ entry->retries = 0;
+ } else {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", entry->name));
+ /* call specified callback function if provided */
+ dns_call_found(i, NULL);
+ /* flush this entry */
+ entry->state = DNS_STATE_UNUSED;
+ break;
+ }
+ } else {
+ /* wait longer for the next retry */
+ entry->tmr = entry->retries;
+ }
+
+ /* send DNS packet for this entry */
+ err = dns_send(i);
+ if (err != ERR_OK) {
+ LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
+ ("dns_send returned error: %s\n", lwip_strerr(err)));
+ }
+ }
+ break;
+ case DNS_STATE_DONE:
+ /* if the time to live is nul */
+ if ((entry->ttl == 0) || (--entry->ttl == 0)) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", entry->name));
+ /* flush this entry, there cannot be any related pending entries in this state */
+ entry->state = DNS_STATE_UNUSED;
+ }
+ break;
+ case DNS_STATE_UNUSED:
+ /* nothing to do */
+ break;
+ default:
+ LWIP_ASSERT("unknown dns_table entry state:", 0);
+ break;
+ }
+}
+
+/**
+ * Call dns_check_entry for each entry in dns_table - check all entries.
+ */
+static void
+dns_check_entries(void)
+{
+ u8_t i;
+
+ for (i = 0; i < DNS_TABLE_SIZE; ++i) {
+ dns_check_entry(i);
+ }
+}
+
+/**
+ * Save TTL and call dns_call_found for correct response.
+ */
+static void
+dns_correct_response(u8_t idx, u32_t ttl)
+{
+ struct dns_table_entry *entry = &dns_table[idx];
+
+ entry->state = DNS_STATE_DONE;
+
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", entry->name));
+ ip_addr_debug_print(DNS_DEBUG, (&(entry->ipaddr)));
+ LWIP_DEBUGF(DNS_DEBUG, ("\n"));
+
+ /* read the answer resource record's TTL, and maximize it if needed */
+ entry->ttl = ttl;
+ if (entry->ttl > DNS_MAX_TTL) {
+ entry->ttl = DNS_MAX_TTL;
+ }
+ dns_call_found(idx, &entry->ipaddr);
+
+ if (entry->ttl == 0) {
+ /* RFC 883, page 29: "Zero values are
+ interpreted to mean that the RR can only be used for the
+ transaction in progress, and should not be cached."
+ -> flush this entry now */
+ /* entry reused during callback? */
+ if (entry->state == DNS_STATE_DONE) {
+ entry->state = DNS_STATE_UNUSED;
+ }
+ }
+}
+/**
+ * Receive input function for DNS response packets arriving for the dns UDP pcb.
+ *
+ * @params see udp.h
+ */
+static void
+dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
+{
+ u8_t i;
+ u16_t txid;
+ u16_t res_idx;
+ struct dns_hdr hdr;
+ struct dns_answer ans;
+ struct dns_query qry;
+ u16_t nquestions, nanswers;
+
+ LWIP_UNUSED_ARG(arg);
+ LWIP_UNUSED_ARG(pcb);
+ LWIP_UNUSED_ARG(port);
+
+ /* is the dns message big enough ? */
+ if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY)) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
+ /* free pbuf and return */
+ goto memerr;
+ }
+
+ /* copy dns payload inside static buffer for processing */
+ if (pbuf_copy_partial(p, &hdr, SIZEOF_DNS_HDR, 0) == SIZEOF_DNS_HDR) {
+ /* Match the ID in the DNS header with the name table. */
+ txid = htons(hdr.id);
+ for (i = 0; i < DNS_TABLE_SIZE; i++) {
+ const struct dns_table_entry *entry = &dns_table[i];
+ if ((entry->state == DNS_STATE_ASKING) &&
+ (entry->txid == txid)) {
+
+ /* We only care about the question(s) and the answers. The authrr
+ and the extrarr are simply discarded. */
+ nquestions = htons(hdr.numquestions);
+ nanswers = htons(hdr.numanswers);
+
+ /* Check for correct response. */
+ if ((hdr.flags1 & DNS_FLAG1_RESPONSE) == 0) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": not a response\n", entry->name));
+ goto memerr; /* ignore this packet */
+ }
+ if (nquestions != 1) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name));
+ goto memerr; /* ignore this packet */
+ }
+
+ /* Check whether response comes from the same network address to which the
+ question was sent. (RFC 5452) */
+ if (!ip_addr_cmp(addr, &dns_servers[entry->server_idx])) {
+ goto memerr; /* ignore this packet */
+ }
+
+ /* Check if the name in the "question" part match with the name in the entry and
+ skip it if equal. */
+ res_idx = dns_compare_name(entry->name, p, SIZEOF_DNS_HDR);
+ if (res_idx == 0xFFFF) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name));
+ goto memerr; /* ignore this packet */
+ }
+
+ /* check if "question" part matches the request */
+ if (pbuf_copy_partial(p, &qry, SIZEOF_DNS_QUERY, res_idx) != SIZEOF_DNS_QUERY) {
+ goto memerr; /* ignore this packet */
+ }
+ if ((qry.cls != PP_HTONS(DNS_RRCLASS_IN)) ||
+ (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype) && (qry.type != PP_HTONS(DNS_RRTYPE_AAAA))) ||
+ (!LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype) && (qry.type != PP_HTONS(DNS_RRTYPE_A)))) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name));
+ goto memerr; /* ignore this packet */
+ }
+ /* skip the rest of the "question" part */
+ res_idx += SIZEOF_DNS_QUERY;
+
+ /* Check for error. If so, call callback to inform. */
+ if (hdr.flags2 & DNS_FLAG2_ERR_MASK) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", entry->name));
+ } else {
+ while ((nanswers > 0) && (res_idx < p->tot_len)) {
+ /* skip answer resource record's host name */
+ res_idx = dns_skip_name(p, res_idx);
+ if (res_idx == 0xFFFF) {
+ goto memerr; /* ignore this packet */
+ }
+
+ /* Check for IP address type and Internet class. Others are discarded. */
+ if (pbuf_copy_partial(p, &ans, SIZEOF_DNS_ANSWER, res_idx) != SIZEOF_DNS_ANSWER) {
+ goto memerr; /* ignore this packet */
+ }
+ res_idx += SIZEOF_DNS_ANSWER;
+
+ if (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) {
+#if LWIP_IPV4
+ if ((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.len == PP_HTONS(sizeof(ip4_addr_t)))) {
+#if LWIP_IPV4 && LWIP_IPV6
+ if (!LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype))
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+ {
+ ip4_addr_t ip4addr;
+ /* read the IP address after answer resource record's header */
+ if (pbuf_copy_partial(p, &ip4addr, sizeof(ip4_addr_t), res_idx) != sizeof(ip4_addr_t)) {
+ goto memerr; /* ignore this packet */
+ }
+ ip_addr_copy_from_ip4(dns_table[i].ipaddr, ip4addr);
+ pbuf_free(p);
+ /* handle correct response */
+ dns_correct_response(i, ntohl(ans.ttl));
+ return;
+ }
+ }
+#endif /* LWIP_IPV4 */
+#if LWIP_IPV6
+ if ((ans.type == PP_HTONS(DNS_RRTYPE_AAAA)) && (ans.len == PP_HTONS(sizeof(ip6_addr_t)))) {
+#if LWIP_IPV4 && LWIP_IPV6
+ if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype))
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+ {
+ ip6_addr_t ip6addr;
+ /* read the IP address after answer resource record's header */
+ if (pbuf_copy_partial(p, &ip6addr, sizeof(ip6_addr_t), res_idx) != sizeof(ip6_addr_t)) {
+ goto memerr; /* ignore this packet */
+ }
+ ip_addr_copy_from_ip6(dns_table[i].ipaddr, ip6addr);
+ pbuf_free(p);
+ /* handle correct response */
+ dns_correct_response(i, ntohl(ans.ttl));
+ return;
+ }
+ }
+#endif /* LWIP_IPV6 */
+ }
+ /* skip this answer */
+ if ((int)(res_idx + htons(ans.len)) > 0xFFFF) {
+ goto memerr; /* ignore this packet */
+ }
+ res_idx += htons(ans.len);
+ --nanswers;
+ }
+#if LWIP_IPV4 && LWIP_IPV6
+ if ((entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) ||
+ (entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV6_IPV4)) {
+ if (entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) {
+ /* IPv4 failed, try IPv6 */
+ dns_table[i].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV6;
+ } else {
+ /* IPv6 failed, try IPv4 */
+ dns_table[i].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV4;
+ }
+ pbuf_free(p);
+ dns_table[i].state = DNS_STATE_NEW;
+ dns_check_entry(i);
+ return;
+ }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", entry->name));
+ }
+ /* call callback to indicate error, clean up memory and return */
+ pbuf_free(p);
+ dns_call_found(i, NULL);
+ dns_table[i].state = DNS_STATE_UNUSED;
+ return;
+ }
+ }
+ }
+
+memerr:
+ /* deallocate memory and return */
+ pbuf_free(p);
+ return;
+}
+
+/**
+ * Queues a new hostname to resolve and sends out a DNS query for that hostname
+ *
+ * @param name the hostname that is to be queried
+ * @param hostnamelen length of the hostname
+ * @param found a callback function to be called on success, failure or timeout
+ * @param callback_arg argument to pass to the callback function
+ * @return @return a err_t return code.
+ */
+static err_t
+dns_enqueue(const char *name, size_t hostnamelen, dns_found_callback found,
+ void *callback_arg LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype))
+{
+ u8_t i;
+ u8_t lseq, lseqi;
+ struct dns_table_entry *entry = NULL;
+ size_t namelen;
+ struct dns_req_entry* req;
+
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
+ u8_t r;
+ /* check for duplicate entries */
+ for (i = 0; i < DNS_TABLE_SIZE; i++) {
+ if ((dns_table[i].state == DNS_STATE_ASKING) &&
+ (LWIP_DNS_STRICMP(name, dns_table[i].name) == 0)) {
+#if LWIP_IPV4 && LWIP_IPV6
+ if (dns_table[i].reqaddrtype != dns_addrtype) {
+ /* requested address types don't match
+ this can lead to 2 concurrent requests, but mixing the address types
+ for the same host should not be that common */
+ continue;
+ }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+ /* this is a duplicate entry, find a free request entry */
+ for (r = 0; r < DNS_MAX_REQUESTS; r++) {
+ if (dns_requests[r].found == 0) {
+ dns_requests[r].found = found;
+ dns_requests[r].arg = callback_arg;
+ dns_requests[r].dns_table_idx = i;
+ LWIP_DNS_SET_ADDRTYPE(dns_requests[r].reqaddrtype, dns_addrtype);
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": duplicate request\n", name));
+ return ERR_INPROGRESS;
+ }
+ }
+ }
+ }
+ /* no duplicate entries found */
+#endif
+
+ /* search an unused entry, or the oldest one */
+ lseq = 0;
+ lseqi = DNS_TABLE_SIZE;
+ for (i = 0; i < DNS_TABLE_SIZE; ++i) {
+ entry = &dns_table[i];
+ /* is it an unused entry ? */
+ if (entry->state == DNS_STATE_UNUSED) {
+ break;
+ }
+ /* check if this is the oldest completed entry */
+ if (entry->state == DNS_STATE_DONE) {
+ if ((u8_t)(dns_seqno - entry->seqno) > lseq) {
+ lseq = dns_seqno - entry->seqno;
+ lseqi = i;
+ }
+ }
+ }
+
+ /* if we don't have found an unused entry, use the oldest completed one */
+ if (i == DNS_TABLE_SIZE) {
+ if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
+ /* no entry can be used now, table is full */
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
+ return ERR_MEM;
+ } else {
+ /* use the oldest completed one */
+ i = lseqi;
+ entry = &dns_table[i];
+ }
+ }
+
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
+ /* find a free request entry */
+ req = NULL;
+ for (r = 0; r < DNS_MAX_REQUESTS; r++) {
+ if (dns_requests[r].found == NULL) {
+ req = &dns_requests[r];
+ break;
+ }
+ }
+ if (req == NULL) {
+ /* no request entry can be used now, table is full */
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS request entries table is full\n", name));
+ return ERR_MEM;
+ }
+ req->dns_table_idx = i;
+#else
+ /* in this configuration, the entry index is the same as the request index */
+ req = &dns_requests[i];
+#endif
+
+ /* use this entry */
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
+
+ /* fill the entry */
+ entry->state = DNS_STATE_NEW;
+ entry->seqno = dns_seqno;
+ LWIP_DNS_SET_ADDRTYPE(entry->reqaddrtype, dns_addrtype);
+ LWIP_DNS_SET_ADDRTYPE(req->reqaddrtype, dns_addrtype);
+ req->found = found;
+ req->arg = callback_arg;
+ namelen = LWIP_MIN(hostnamelen, DNS_MAX_NAME_LENGTH-1);
+ MEMCPY(entry->name, name, namelen);
+ entry->name[namelen] = 0;
+
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
+ entry->pcb_idx = dns_alloc_pcb();
+ if (entry->pcb_idx >= DNS_MAX_SOURCE_PORTS) {
+ /* failed to get a UDP pcb */
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": failed to allocate a pcb\n", name));
+ entry->state = DNS_STATE_UNUSED;
+ req->found = NULL;
+ return ERR_MEM;
+ }
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS pcb %"U16_F"\n", name, (u16_t)(entry->pcb_idx)));
+#endif
+
+ dns_seqno++;
+
+ /* force to send query without waiting timer */
+ dns_check_entry(i);
+
+ /* dns query is enqueued */
+ return ERR_INPROGRESS;
+}
+
+/**
+ * @ingroup dns
+ * Resolve a hostname (string) into an IP address.
+ * NON-BLOCKING callback version for use with raw API!!!
+ *
+ * Returns immediately with one of err_t return codes:
+ * - ERR_OK if hostname is a valid IP address string or the host
+ * name is already in the local names table.
+ * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
+ * for resolution if no errors are present.
+ * - ERR_ARG: dns client not initialized or invalid hostname
+ *
+ * @param hostname the hostname that is to be queried
+ * @param addr pointer to a ip_addr_t where to store the address if it is already
+ * cached in the dns_table (only valid if ERR_OK is returned!)
+ * @param found a callback function to be called on success, failure or timeout (only if
+ * ERR_INPROGRESS is returned!)
+ * @param callback_arg argument to pass to the callback function
+ * @return a err_t return code.
+ */
+err_t
+dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
+ void *callback_arg)
+{
+ return dns_gethostbyname_addrtype(hostname, addr, found, callback_arg, LWIP_DNS_ADDRTYPE_DEFAULT);
+}
+
+/**
+ * @ingroup dns
+ * Like dns_gethostbyname, but returned address type can be controlled:
+ * @param hostname the hostname that is to be queried
+ * @param addr pointer to a ip_addr_t where to store the address if it is already
+ * cached in the dns_table (only valid if ERR_OK is returned!)
+ * @param found a callback function to be called on success, failure or timeout (only if
+ * ERR_INPROGRESS is returned!)
+ * @param callback_arg argument to pass to the callback function
+ * @param dns_addrtype: - LWIP_DNS_ADDRTYPE_IPV4_IPV6: try to resolve IPv4 first, try IPv6 if IPv4 fails only
+ * - LWIP_DNS_ADDRTYPE_IPV6_IPV4: try to resolve IPv6 first, try IPv4 if IPv6 fails only
+ * - LWIP_DNS_ADDRTYPE_IPV4: try to resolve IPv4 only
+ * - LWIP_DNS_ADDRTYPE_IPV6: try to resolve IPv6 only
+ */
+err_t
+dns_gethostbyname_addrtype(const char *hostname, ip_addr_t *addr, dns_found_callback found,
+ void *callback_arg, u8_t dns_addrtype)
+{
+ size_t hostnamelen;
+ /* not initialized or no valid server yet, or invalid addr pointer
+ * or invalid hostname or invalid hostname length */
+ if ((addr == NULL) ||
+ (!hostname) || (!hostname[0])) {
+ return ERR_ARG;
+ }
+#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) == 0)
+ if (dns_pcbs[0] == NULL) {
+ return ERR_ARG;
+ }
+#endif
+ hostnamelen = strlen(hostname);
+ if (hostnamelen >= DNS_MAX_NAME_LENGTH) {
+ LWIP_DEBUGF(DNS_DEBUG, ("dns_gethostbyname: name too long to resolve"));
+ return ERR_ARG;
+ }
+
+
+#if LWIP_HAVE_LOOPIF
+ if (strcmp(hostname, "localhost") == 0) {
+ ip_addr_set_loopback(LWIP_DNS_ADDRTYPE_IS_IPV6(dns_addrtype), addr);
+ return ERR_OK;
+ }
+#endif /* LWIP_HAVE_LOOPIF */
+
+ /* host name already in octet notation? set ip addr and return ERR_OK */
+ if (ipaddr_aton(hostname, addr)) {
+#if LWIP_IPV4 && LWIP_IPV6
+ if ((IP_IS_V6(addr) && (dns_addrtype != LWIP_DNS_ADDRTYPE_IPV4)) ||
+ (IP_IS_V4(addr) && (dns_addrtype != LWIP_DNS_ADDRTYPE_IPV6)))
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+ {
+ return ERR_OK;
+ }
+ }
+ /* already have this address cached? */
+ if (dns_lookup(hostname, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)) == ERR_OK) {
+ return ERR_OK;
+ }
+#if LWIP_IPV4 && LWIP_IPV6
+ if ((dns_addrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) || (dns_addrtype == LWIP_DNS_ADDRTYPE_IPV6_IPV4)) {
+ /* fallback to 2nd IP type and try again to lookup */
+ u8_t fallback;
+ if (dns_addrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) {
+ fallback = LWIP_DNS_ADDRTYPE_IPV6;
+ } else {
+ fallback = LWIP_DNS_ADDRTYPE_IPV4;
+ }
+ if (dns_lookup(hostname, addr LWIP_DNS_ADDRTYPE_ARG(fallback)) == ERR_OK) {
+ return ERR_OK;
+ }
+ }
+#else /* LWIP_IPV4 && LWIP_IPV6 */
+ LWIP_UNUSED_ARG(dns_addrtype);
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
+ /* prevent calling found callback if no server is set, return error instead */
+ if (ip_addr_isany_val(dns_servers[0])) {
+ return ERR_VAL;
+ }
+
+ /* queue query with specified callback */
+ return dns_enqueue(hostname, hostnamelen, found, callback_arg LWIP_DNS_ADDRTYPE_ARG(dns_addrtype));
+}
+
+#endif /* LWIP_DNS */