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#include "udp.h"
#include "inet.h"
#include "net_sys.h"
#include "ntp.h"
//http://ptspts.blogspot.com/2009/11/how-to-convert-unix-timestamp-to-civil.html
// Convert a Unix timestamp to a civil date ([year, month, day, hour, minute,
// second]) in GMT.
void timestamp_to_gmt_civil(uint32_t ts)
{
uint32_t s = ts%86400;
ts /= 86400;
uint32_t h = s/3600;
uint32_t m = s/60%60;
s = s%60;
uint32_t x = (ts*4+102032)/146097+15;
uint32_t b = ts+2442113+x-(x/4);
uint32_t c = (b*20-2442)/7305;
uint32_t d = b-365*c-c/4;
uint32_t e = d*1000/30601;
uint32_t f = d-e*30-e*601/1000;
if(e < 14){c-=4716;e-=1;}
else {c-=4715;e-=13;}
// final result is in: c / e / f / h / m / s
klog ("%d.%d.%d %d:%d:%d UTC",f,e,c,h,m,s);
}
uint32_t ntp_generic(struct netdev *dev, uint32_t ip, uint16_t src, uint16_t dst, uint8_t* pos,uint8_t *end)
{
pos-=48; // we need 48 bytes
struct udp_v4_ntp *ntp=pos;
ntp->li_vn_mode=0x1b; // Eight bits. li, vn, and mode.
// li. Two bits. Leap indicator.
// vn. Three bits. Version number of the protocol.
// mode. Three bits. Client will pick mode 3 for client.
ntp->stratum=0; // Eight bits. Stratum level of the local clock.
ntp->poll=0; // Eight bits. Maximum interval between successive messages.
ntp->precision=0; // Eight bits. Precision of the local clock.
ntp->rootDelay=0; // 32 bits. Total round trip delay time.
ntp->rootDispersion=0; // 32 bits. Max error aloud from primary clock source.
ntp->refId=0; // 32 bits. Reference clock identifier.
ntp->refTm_s=0; // 32 bits. Reference time-stamp seconds.
ntp->refTm_f=0; // 32 bits. Reference time-stamp fraction of a second.
ntp->origTm_s=0; // 32 bits. Originate time-stamp seconds.
ntp->origTm_f=0; // 32 bits. Originate time-stamp fraction of a second.
ntp->rxTm_s=0; // 32 bits. Received time-stamp seconds.
ntp->rxTm_f=0; // 32 bits. Received time-stamp fraction of a second.
ntp->txTm_s=0; // 32 bits and the most important field the client cares about. Transmit time-stamp seconds.
ntp->txTm_f=0; // 32 bits. Transmit time-stamp fraction of a second.
return udp_generic(dev, ip, src, dst, pos,end);
}
uint32_t ntp_incoming(uint8_t* start, uint8_t *pos)
{
struct udp_v4_ntp *ntp=pos;
uint32_t ntp_time=ntohl(ntp->txTm_s);
uint32_t unix_time=ntp_time-2208988800; // subtract offset to get unixtime
timestamp_to_gmt_civil(unix_time);
return 0; // all ok
}
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