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/**
* @file
* SNTP client module
*/
/*
* Copyright (c) 2007-2009 Frédéric 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: Frédéric 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:
* - 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 */
#ifndef SNTP_SUPPRESS_DELAY_CHECK
#if SNTP_UPDATE_DELAY < 15000
#error "SNTPv4 RFC 4330 enforces a minimum update time of 15 seconds (define SNTP_SUPPRESS_DELAY_CHECK to disable this error)!"
#endif
#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 << 6)
#define SNTP_LI_LAST_MINUTE_61_SEC (0x01 << 6)
#define SNTP_LI_LAST_MINUTE_59_SEC (0x02 << 6)
#define SNTP_LI_ALARM_CONDITION (0x03 << 6) /* (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 1970 and Feb 7, 2036 06:28:16 UTC (epoch 1) */
#define DIFF_SEC_1970_2036 ((s32_t)2085978496L)
/** Convert NTP timestamp fraction to microseconds.
*/
#ifndef SNTP_FRAC_TO_US
# if LWIP_HAVE_INT64
# define SNTP_FRAC_TO_US(f) ((u32_t)(((u64_t)(f) * 1000000UL) >> 32))
# else
# define SNTP_FRAC_TO_US(f) ((u32_t)(f) / 4295)
# endif
#endif /* !SNTP_FRAC_TO_US */
/* Configure behaviour depending on native, microsecond or second precision.
* Treat NTP timestamps as signed two's-complement integers. This way,
* timestamps that have the MSB set simply become negative offsets from
* the epoch (Feb 7, 2036 06:28:16 UTC). Representable dates range from
* 1968 to 2104.
*/
#ifndef SNTP_SET_SYSTEM_TIME_NTP
# ifdef SNTP_SET_SYSTEM_TIME_US
# define SNTP_SET_SYSTEM_TIME_NTP(s, f) \
SNTP_SET_SYSTEM_TIME_US((u32_t)((s) + DIFF_SEC_1970_2036), SNTP_FRAC_TO_US(f))
# else
# define SNTP_SET_SYSTEM_TIME_NTP(s, f) \
SNTP_SET_SYSTEM_TIME((u32_t)((s) + DIFF_SEC_1970_2036))
# endif
#endif /* !SNTP_SET_SYSTEM_TIME_NTP */
/* Get the system time either natively as NTP timestamp or convert from
* Unix time in seconds and microseconds. Take care to avoid overflow if the
* microsecond value is at the maximum of 999999. Also add 0.5 us fudge to
* avoid special values like 0, and to mask round-off errors that would
* otherwise break round-trip conversion identity.
*/
#ifndef SNTP_GET_SYSTEM_TIME_NTP
# define SNTP_GET_SYSTEM_TIME_NTP(s, f) do { \
u32_t sec_, usec_; \
SNTP_GET_SYSTEM_TIME(sec_, usec_); \
(s) = (s32_t)(sec_ - DIFF_SEC_1970_2036); \
(f) = usec_ * 4295 - ((usec_ * 2143) >> 16) + 2147; \
} while (0)
#endif /* !SNTP_GET_SYSTEM_TIME_NTP */
/* Start offset of the timestamps to extract from the SNTP packet */
#define SNTP_OFFSET_TIMESTAMPS \
(SNTP_OFFSET_TRANSMIT_TIME + 8 - sizeof(struct sntp_timestamps))
/* Round-trip delay arithmetic helpers */
#if SNTP_COMP_ROUNDTRIP
# if !LWIP_HAVE_INT64
# error "SNTP round-trip delay compensation requires 64-bit arithmetic"
# endif
# define SNTP_SEC_FRAC_TO_S64(s, f) \
((s64_t)(((u64_t)(s) << 32) | (u32_t)(f)))
# define SNTP_TIMESTAMP_TO_S64(t) \
SNTP_SEC_FRAC_TO_S64(lwip_ntohl((t).sec), lwip_ntohl((t).frac))
#endif /* SNTP_COMP_ROUNDTRIP */
/**
* 64-bit NTP timestamp, in network byte order.
*/
struct sntp_time {
u32_t sec;
u32_t frac;
};
/**
* Timestamps to be extracted from the NTP header.
*/
struct sntp_timestamps {
#if SNTP_COMP_ROUNDTRIP || SNTP_CHECK_RESPONSE >= 2
struct sntp_time orig;
struct sntp_time recv;
#endif
struct sntp_time xmit;
};
/**
* SNTP packet format (without optional fields)
* Timestamps are coded as 64 bits:
* - signed 32 bits seconds since Feb 07, 2036, 06:28:16 UTC (epoch 1)
* - unsigned 32 bits seconds fraction (2^32 = 1 second)
*/
#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. Stored in network byte order. */
static struct sntp_time sntp_last_timestamp_sent;
#endif /* SNTP_CHECK_RESPONSE >= 2 */
#if defined(LWIP_DEBUG) && !defined(sntp_format_time)
/* Debug print helper. */
static const char *
sntp_format_time(s32_t sec)
{
time_t ut;
ut = (time_t)((time_t)sec + (time_t)DIFF_SEC_1970_2036);
return ctime(&ut);
}
#endif /* LWIP_DEBUG && !sntp_format_time */
/**
* SNTP processing of received timestamp
*/
static void
sntp_process(const struct sntp_timestamps *timestamps)
{
s32_t sec;
u32_t frac;
sec = (s32_t)lwip_ntohl(timestamps->xmit.sec);
frac = lwip_ntohl(timestamps->xmit.frac);
#if SNTP_COMP_ROUNDTRIP
# if SNTP_CHECK_RESPONSE >= 2
if (timestamps->recv.sec != 0 || timestamps->recv.frac != 0)
# endif
{
s32_t dest_sec;
u32_t dest_frac;
u32_t step_sec;
/* Get the destination time stamp, i.e. the current system time */
SNTP_GET_SYSTEM_TIME_NTP(dest_sec, dest_frac);
step_sec = (dest_sec < sec) ? ((u32_t)sec - (u32_t)dest_sec)
: ((u32_t)dest_sec - (u32_t)sec);
/* In order to avoid overflows, skip the compensation if the clock step
* is larger than about 34 years. */
if ((step_sec >> 30) == 0) {
s64_t t1, t2, t3, t4;
t4 = SNTP_SEC_FRAC_TO_S64(dest_sec, dest_frac);
t3 = SNTP_SEC_FRAC_TO_S64(sec, frac);
t1 = SNTP_TIMESTAMP_TO_S64(timestamps->orig);
t2 = SNTP_TIMESTAMP_TO_S64(timestamps->recv);
/* Clock offset calculation according to RFC 4330 */
t4 += ((t2 - t1) + (t3 - t4)) / 2;
sec = (s32_t)((u64_t)t4 >> 32);
frac = (u32_t)((u64_t)t4);
}
}
#endif /* SNTP_COMP_ROUNDTRIP */
SNTP_SET_SYSTEM_TIME_NTP(sec, frac);
LWIP_UNUSED_ARG(frac); /* might be unused if only seconds are set */
LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_process: %s, %" U32_F " us\n",
sntp_format_time(sec), SNTP_FRAC_TO_US(frac)));
}
/**
* 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 || SNTP_COMP_ROUNDTRIP
{
s32_t secs;
u32_t sec, frac;
/* Get the transmit timestamp */
SNTP_GET_SYSTEM_TIME_NTP(secs, frac);
sec = lwip_htonl((u32_t)secs);
frac = lwip_htonl(frac);
# if SNTP_CHECK_RESPONSE >= 2
sntp_last_timestamp_sent.sec = sec;
sntp_last_timestamp_sent.frac = frac;
# endif
req->transmit_timestamp[0] = sec;
req->transmit_timestamp[1] = frac;
}
#endif /* SNTP_CHECK_RESPONSE >= 2 || SNTP_COMP_ROUNDTRIP */
}
/**
* 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)
{
struct sntp_timestamps timestamps;
u8_t mode;
u8_t stratum;
err_t err;
LWIP_UNUSED_ARG(arg);
LWIP_UNUSED_ARG(pcb);
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) {
mode = pbuf_get_at(p, SNTP_OFFSET_LI_VN_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))) {
stratum = pbuf_get_at(p, 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 {
pbuf_copy_partial(p, ×tamps, sizeof(timestamps), SNTP_OFFSET_TIMESTAMPS);
#if SNTP_CHECK_RESPONSE >= 2
/* check originate_timetamp against sntp_last_timestamp_sent */
if (timestamps.orig.sec != sntp_last_timestamp_sent.sec ||
timestamps.orig.frac != sntp_last_timestamp_sent.frac) {
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;
}
}
} 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) {
/* correct packet received: process it it */
sntp_process(×tamps);
/* Set up timeout for next request (only if poll response was received)*/
if (sntp_opmode == SNTP_OPMODE_POLL) {
u32_t sntp_update_delay;
sys_untimeout(sntp_try_next_server, NULL);
sys_untimeout(sntp_request, NULL);
/* Correct response, reset retry timeout */
SNTP_RESET_RETRY_TIMEOUT();
sntp_update_delay = (u32_t)SNTP_UPDATE_DELAY;
sys_timeout(sntp_update_delay, sntp_request, NULL);
LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_recv: Scheduled next time request: %"U32_F" ms\n",
sntp_update_delay));
}
} else if (err == SNTP_ERR_KOD) {
/* KOD errors are only processed in case of an explicit poll response */
if (sntp_opmode == SNTP_OPMODE_POLL) {
/* Kiss-of-death packet. Use another server or increase UPDATE_DELAY. */
sntp_try_next_server(NULL);
}
} else {
/* ignore any broken packet, poll mode: retry after timeout to avoid flooding */
}
}
/** 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);
sys_untimeout(sntp_try_next_server, 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 */