tracker.cpp

来自「最经典的bittorrent协议的实现的源码」· C++ 代码 · 共 615 行 · 第 1/2 页

#include "tracker.h"

#ifndef WINDOWS
#include <unistd.h>
#include <netdb.h>
#endif

#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "peerlist.h"
#include "peer.h"
#include "httpencode.h"
#include "bencode.h"
#include "setnonblock.h"
#include "connect_nonb.h"
#include "btcontent.h"
#include "iplist.h"

#include "btconfig.h"
#include "ctcs.h"
#include "console.h"
#include "bttime.h"

#ifndef HAVE_SNPRINTF
#include "compat.h"
#endif

btTracker Tracker;

btTracker::btTracker()
{
  memset(m_host,0,MAXHOSTNAMELEN);
  memset(m_path,0,MAXPATHLEN);
  memset(m_trackerid,0,PEER_ID_LEN+1);

  m_sock = INVALID_SOCKET;
  m_port = 80;
  m_status = T_FREE;
  m_f_started = m_f_stoped = m_f_completed = m_f_restart = 0;

  m_interval = 15;
  m_peers_count = m_seeds_count = 0;

  m_connect_refuse_click = 0;
  m_last_timestamp = (time_t) 0;
  m_prevpeers = 0;
}

btTracker::~btTracker()
{
  if( m_sock != INVALID_SOCKET) CLOSE_SOCKET(m_sock);
}

void btTracker::Reset(time_t new_interval)
{
  if(new_interval) m_interval = new_interval;

  if( INVALID_SOCKET != m_sock ){
    CLOSE_SOCKET(m_sock);
    m_sock = INVALID_SOCKET;
  }

  m_reponse_buffer.Reset();
  time(&m_last_timestamp);
  if( m_f_stoped ){
    m_status = T_FINISHED;
    if( m_f_restart ) Restart();
  }
  else m_status = T_FREE;
}

int btTracker:: _IPsin(char *h, int p, struct sockaddr_in *psin)
{
  psin->sin_family = AF_INET;
  psin->sin_port = htons(p);
  psin->sin_addr.s_addr = inet_addr(h);
  return ( psin->sin_addr.s_addr == INADDR_NONE ) ? -1 : 0;
}

int btTracker:: _s2sin(char *h,int p,struct sockaddr_in *psin)
{
  psin->sin_family = AF_INET;
  psin->sin_port = htons(p);
  if( h ){
    psin->sin_addr.s_addr = inet_addr(h);
    if(psin->sin_addr.s_addr == INADDR_NONE){
      struct hostent *ph = gethostbyname(h);
      if( !ph  || ph->h_addrtype != AF_INET){
        memset(psin,0,sizeof(struct sockaddr_in));
        return -1;
      }
      memcpy(&psin->sin_addr,ph->h_addr_list[0],sizeof(struct in_addr));
    }
  }else 
    psin->sin_addr.s_addr = htonl(INADDR_ANY);
  return 0;
}

int btTracker::_UpdatePeerList(char *buf,size_t bufsiz)
{
  char tmphost[MAXHOSTNAMELEN];
  const char *ps;
  size_t i,pos,tmpport;
  size_t cnt = 0;

  struct sockaddr_in addr;

  if( decode_query(buf,bufsiz,"failure reason",&ps,&i,(int64_t*)0,QUERY_STR) ){
    char failreason[1024];
    if( i < 1024 ){
      memcpy(failreason, ps, i);
      failreason[i] = '\0';
    }else{
      memcpy(failreason, ps, 1000);
      failreason[1000] = '\0';
      strcat(failreason,"...");
    }
    CONSOLE.Warning(1, "TRACKER FAILURE REASON: %s", failreason);
    return -1;
  }
  if( decode_query(buf,bufsiz,"warning message",&ps,&i,(int64_t*)0,QUERY_STR) ){
    char warnmsg[1024];
    if( i < 1024 ){
      memcpy(warnmsg, ps, i);
      warnmsg[i] = '\0';
    }else{
      memcpy(warnmsg, ps, 1000);
      warnmsg[1000] = '\0';
      strcat(warnmsg,"...");
    }
    CONSOLE.Warning(2, "TRACKER WARNING: %s", warnmsg);
  }

  m_peers_count = m_seeds_count = 0;

  if( decode_query(buf,bufsiz,"tracker id",&ps,&i,(int64_t*)0,QUERY_STR) ){
    if( i <= PEER_ID_LEN ){
      memcpy(m_trackerid, ps, i);
      m_trackerid[i] = '\0';
    }else{
      memcpy(m_trackerid, ps, PEER_ID_LEN);
      m_trackerid[PEER_ID_LEN] = '\0';
    }
  }

  if( !decode_query(buf, bufsiz, "interval", (const char**)0, &i,
      (int64_t*)0, QUERY_INT) )
    return -1;

  if(m_interval != (time_t)i) m_interval = (time_t)i;
  if(m_default_interval != (time_t)i) m_default_interval = (time_t)i;

  if( decode_query(buf, bufsiz, "complete", (const char**)0, &i,
      (int64_t*)0, QUERY_INT) )
    m_seeds_count = i;
  if( decode_query(buf, bufsiz, "incomplete", (const char**)0, &i,
      (int64_t*)0, QUERY_INT) )
    m_peers_count = m_seeds_count + i;
  else m_peers_count = m_seeds_count;

  pos = decode_query(buf, bufsiz, "peers", (const char**)0, (size_t *)0,
    (int64_t*)0, QUERY_POS);

  if( !pos ){
    return -1;
  }

  if(4 > bufsiz - pos){return -1; } // peers list ̫С

  buf += (pos + 1); bufsiz -= (pos + 1);

  ps = buf-1;
  if (*ps != 'l') {		// binary peers section if not 'l'
    addr.sin_family = AF_INET;
    i = 0;
    while (*ps != ':' ) i = i * 10 + (*ps++ - '0');
    i /= 6;
    ps++;
    while (i-- > 0) {
      // if peer is not us
      if( !Self.IpEquiv(*(struct sockaddr_in *)ps) ){
        memcpy(&addr.sin_addr,ps,sizeof(struct in_addr));
        memcpy(&addr.sin_port,ps+sizeof(struct in_addr),sizeof(unsigned short));
        cnt++;
        IPQUEUE.Add(&addr);
      }
    ps += 6;
    }
  }
  else
  for( ; bufsiz && *buf!='e'; buf += pos, bufsiz -= pos ){
    pos = decode_dict(buf,bufsiz,(char*)0);
    if(!pos) break;
    if( !decode_query(buf,pos,"ip",&ps,&i,(int64_t*)0,QUERY_STR) ||
        MAXHOSTNAMELEN < i ) continue;
    memcpy(tmphost,ps,i); tmphost[i] = '\0';

    if( !decode_query(buf,pos,"port",(const char**)0,&tmpport,(int64_t*)0,
                      QUERY_INT) ) continue;

    if( !decode_query(buf,pos,"peer id",&ps,&i,(int64_t*)0,QUERY_STR) &&
        i != 20 ) continue;

    if(_IPsin(tmphost,tmpport,&addr) < 0){
      CONSOLE.Warning(3, "warn, detected invalid ip address %s.",tmphost);
      continue;
    }

    if( !Self.IpEquiv(addr) ){
      cnt++;
      IPQUEUE.Add(&addr);
    }
  }

  if(arg_verbose) CONSOLE.Debug("new peers=%d; next check in %d sec",
    (int)cnt, (int)m_interval);
  return 0;
}

int btTracker::CheckReponse()
{
  char *pdata, *format;
  ssize_t r;
  size_t q, hlen, dlen;

  r = m_reponse_buffer.FeedIn(m_sock);

  if( r > 0 ) return 0;

  q = m_reponse_buffer.Count();

  if( !q ){
    int error = 0;
    socklen_t n = sizeof(error);
    if(getsockopt(m_sock, SOL_SOCKET,SO_ERROR,&error,&n) < 0)
      error = errno;
    if( error != 0 ) CONSOLE.Warning(2,
      "warn, received nothing from tracker:  %s", strerror(error));
    else CONSOLE.Warning(2, "warn, received nothing from tracker!");
    Reset( (-1 == r) ? 15 : 0 );
    return -1;
  }

  Reset( (-1 == r) ? 15 : 0 );  // can't reset socket before error check

  hlen = Http_split(m_reponse_buffer.BasePointer(), q, &pdata,&dlen);

  if( !hlen ){
    CONSOLE.Warning(2, "warn, tracker reponse invalid. No html header found.");
    return -1;
  }

  r = Http_reponse_code(m_reponse_buffer.BasePointer(),hlen);
  if ( r != 200 ){
    if( r == 301 || r == 302 ){
      char redirect[MAXPATHLEN], ih_buf[20 * 3 + 1], pi_buf[20 * 3 + 1],
           tmppath[MAXPATHLEN];

      if( Http_get_header(m_reponse_buffer.BasePointer(), hlen, "Location",
          redirect) < 0 )
        return -1;

      if( Http_url_analyse(redirect,m_host,&m_port,m_path) < 0 ){
        CONSOLE.Warning(1,
          "warn, tracker redirected to an invalid url %s", redirect);
        return -1;
      }else{
        char *c = strstr(m_path, "?info_hash=");
        if( !c ) c = strstr(m_path, "&info_hash=");
        if( c ) *c = '\0';
        if(arg_verbose) CONSOLE.Debug("tracker redirect to %s", redirect);
        if( BuildBaseRequest() < 0 ) return -1;
      }

      if( Connect() < 0 ){
        Reset(15);
        return -1;
      }else return 0;
    }else if( r >= 400 ){
      CONSOLE.Warning(2, "Tracker reponse code >= 400 !!!");
      CONSOLE.Warning(2,
        "The file is not registered on this tracker or may have been removed.");
      CONSOLE.Warning(2,
        "IF YOU CONTINUE TO GET THIS MESSAGE AND DOWNLOAD DOES NOT BEGIN, PLEASE STOP CTORRENT!");
      if( pdata && dlen ){  // write(STDERR_FILENO, pdata, dlen);
        CONSOLE.Warning(0, "Tracker reponse data DUMP:");
        CONSOLE.Warning(0, "%s", pdata);
        CONSOLE.Warning(0, "== DUMP OVER==");
      }
      return -1;
    }else
      return 0;
  }

  if( !m_f_started ) m_f_started = 1;
  m_connect_refuse_click = 0;
  m_ok_click++;

  if ( !pdata ){
    CONSOLE.Warning(2, "warn, peers list received from tracker is empty.");
    return 0;
  }
  return _UpdatePeerList(pdata,dlen);
}