/*
 * filter.cpp: A plugin for the Video Disk Recorder
 *
 * See the README file for copyright information and how to reach the author.
 *
 * $Id$
 */

#include <netinet/if_ether.h>
#include <unistd.h>

#include "filter.h"

#undef WRITE_RAW

cFilterInfosatepg::cFilterInfosatepg(cGlobalInfosatepg *Global)
{
  global = Global;
  Set(global->Pid,0,0);
}

u_long cFilterInfosatepg::do_sum(u_long sum, u_char *buf, int nBytes)
{
  int nleft=nBytes;
  u_short *w = (u_short*)buf;

  while (nleft > 1)
  {
    sum += *w++;
    nleft -= 2;
  }

  if (nleft == 1)
  {
    u_short answer = 0;
    *(u_char*)(&answer) = *(u_char*)w;
    sum += answer;
  }
  return sum;
}

u_short cFilterInfosatepg::foldsum(u_long sum)
{
  while (sum>>16)
    sum = (sum >> 16) + (sum & 0xFFFF);

  return ((u_short) ~sum);
}

u_short cFilterInfosatepg::IPChecksum(iphdr *ipHeader)
{
  return foldsum(do_sum(0, (u_char*) ipHeader, sizeof(iphdr)));

}   /* IpChecksum() */


u_short cFilterInfosatepg::UDPChecksum(iphdr *ipHeader, udphdr *udpHeader)
{
  u_long sum = 0;

  // Ip-Pseudo-Header
  sum = do_sum(sum, (u_char*)(&ipHeader->saddr), sizeof(ipHeader->saddr));
  sum = do_sum(sum, (u_char*)(&ipHeader->daddr), sizeof(ipHeader->daddr));
  sum += udpHeader->len;
  sum += ipHeader->protocol<<8;

  sum = do_sum(sum, (u_char*)udpHeader, ntohs(udpHeader->len));

  return foldsum(sum);
}


void cFilterInfosatepg::Process(u_short Pid, u_char Tid, const u_char *Data, int Length)
{
#define SECT_IP_HDR_START  12
#define SECT_UDP_HDR_START 32
#define SECT_IS_HDR_START  40
#define SECT_IS_DATA_START 52

  if (Data[0]!=0x3E) return;

  struct ethhdr eth_hdr;
  memset(&eth_hdr,0,sizeof(struct ethhdr));

  eth_hdr.h_dest[0]=Data[11];
  eth_hdr.h_dest[1]=Data[10];
  eth_hdr.h_dest[2]=Data[9];
  eth_hdr.h_dest[3]=Data[8];
  eth_hdr.h_dest[4]=Data[4];
  eth_hdr.h_dest[5]=Data[3];

  if (!global->CheckMAC(&eth_hdr)) return;

  int mac = eth_hdr.h_dest[5];

  struct iphdr *ip_hdr = (iphdr *) &Data[SECT_IP_HDR_START];
  struct udphdr *udp_hdr = (udphdr *) &Data[SECT_UDP_HDR_START];

  // Only IPv4
  if (ip_hdr->version!=4) return;

  // Check IP checksum
  if (IPChecksum(ip_hdr)!=0)
  {
    dsyslog("infosatepg: ip checksum error");
    return;
  }

  // Only UDP
  if (ip_hdr->protocol!=17) return;

  // Check UDP checksum
  if (UDPChecksum(ip_hdr,udp_hdr)!=0)
  {
    dsyslog("infosatepg: udp checksum error");
    return;
  }

  struct infosathdr *ishdr = (struct infosathdr*) &Data[SECT_IS_HDR_START];

  if (ntohs(ishdr->technisatId)!=0x0001) return;

  const u_char *infosatdata = &Data[SECT_IS_DATA_START];
  int len = Length - SECT_IS_DATA_START-4;

  char file[1024];
  snprintf(file,sizeof(file),"%s/infosatepg%02i%02i_%03i.dat",global->Directory(),ishdr->day,ishdr->month,
           ntohs(ishdr->pktcnt));

  if (global->Infosatdata[mac].NeverSeen(ishdr->day,ishdr->month,ntohs(ishdr->pktcnt)))
  {
    // never seen such a packet -> init structure
    global->Infosatdata[mac].Init(file,ishdr->day,ishdr->month,ntohs(ishdr->pktcnt));
  }

  // Check if we already have this packet
  if (global->Infosatdata[mac].GetBit(ntohs(ishdr->pktnr))) return;

  // set bit in Infosatdata bitfield
  global->Infosatdata[mac].SetBit(ntohs(ishdr->pktnr),true);

#ifdef VDRDEBUG
  dsyslog("infosatepg: mac=%02x-%02x-%02x-%02x-%02x-%02x",eth_hdr.h_dest[0],eth_hdr.h_dest[1],
          eth_hdr.h_dest[2],eth_hdr.h_dest[3],eth_hdr.h_dest[4],eth_hdr.h_dest[5] );

  dsyslog("infosatepg: tid=%04i tbl=%04i stbl=%04i day=%02i month=%02i pktnr=%03i pktcnt=%03i len=%i",
          ntohs(ishdr->technisatId),ishdr->tableId,ishdr->tablesubId,ishdr->day,
          ishdr->month, ntohs(ishdr->pktnr), ntohs(ishdr->pktcnt), len);

  dsyslog("infosatepg: save to %s", file);
#endif

  int f=open(file,O_RDWR|O_CREAT,0664);
  if (f==-1)
  {
    if (errno!=ENOSPC)
    {
      esyslog("infosatepg: unable to create file '%s'", file);
    }
    return;
  }
  off_t offset = (off_t) (ntohs(ishdr->pktnr)*1400);
  if (lseek(f,offset,SEEK_SET)!=(off_t) -1)
  {
#ifdef VDRDEBUG
    dsyslog("infosatepg: writing to %li",offset);
#endif
    write(f,infosatdata,len);
  }
  close(f);

#ifdef WRITE_RAW
  sprintf(file,"%s/%03i.dat",dir,ntohs(ishdr->pktnr));
  f=open(file,O_RDWR|O_CREAT,0664);
  if (f==-1) return;
  write(f,Data,Length);
  close(f);
#endif

  // check if we have all packets
  if (global->Infosatdata[mac].ReceivedAll())
  {
    // we have all packets
    isyslog("infosatepg: day=%02i month=%02i fully received", ishdr->day,ishdr->month);
  }

}