methods/connect.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: connect.cc,v 1.10.2.1 2004/01/16 18:58:50 mdz Exp $
   4 /* ######################################################################
   5
   6    Connect - Replacement connect call
   7
   8    This was originally authored by Jason Gunthorpe <jgg@debian.org>
   9    and is placed in the Public Domain, do with it what you will.
  10
  11    ##################################################################### */
  12                                                                         /*}}}*/
  13 // Include Files                                                        /*{{{*/
  14 #include <config.h>
  15
  16 #include <apt-pkg/error.h>
  17 #include <apt-pkg/fileutl.h>
  18 #include <apt-pkg/strutl.h>
  19 #include <apt-pkg/acquire-method.h>
  20 #include <apt-pkg/configuration.h>
  21 #include <apt-pkg/srvrec.h>
  22
  23 #include <stdio.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <sstream>
  27 #include <string.h>
  28 #include<set>
  29 #include<string>
  30
  31 // Internet stuff
  32 #include <netinet/in.h>
  33 #include <sys/socket.h>
  34 #include <arpa/inet.h>
  35 #include <netdb.h>
  36
  37 #include "connect.h"
  38 #include "rfc2553emu.h"
  39 #include <apti18n.h>
  40                                                                         /*}}}*/
  41
  42 static std::string LastHost;
  43 static int LastPort = 0;
  44 static struct addrinfo *LastHostAddr = 0;
  45 static struct addrinfo *LastUsed = 0;
  46
  47 static std::vector<SrvRec> SrvRecords;
  48
  49 // Set of IP/hostnames that we timed out before or couldn't resolve
  50 static std::set<std::string> bad_addr;
  51
  52 // RotateDNS - Select a new server from a DNS rotation                  /*{{{*/
  53 // ---------------------------------------------------------------------
  54 /* This is called during certain errors in order to recover by selecting a
  55    new server */
  56 void RotateDNS()
  57 {
  58    if (LastUsed != 0 && LastUsed->ai_next != 0)
  59       LastUsed = LastUsed->ai_next;
  60    else
  61       LastUsed = LastHostAddr;
  62 }
  63                                                                         /*}}}*/
  64 // DoConnect - Attempt a connect operation                              /*{{{*/
  65 // ---------------------------------------------------------------------
  66 /* This helper function attempts a connection to a single address. */
  67 static bool DoConnect(struct addrinfo *Addr,std::string Host,
  68                       unsigned long TimeOut,int &Fd,pkgAcqMethod *Owner)
  69 {
  70    // Show a status indicator
  71    char Name[NI_MAXHOST];
  72    char Service[NI_MAXSERV];
  73
  74    Name[0] = 0;
  75    Service[0] = 0;
  76    getnameinfo(Addr->ai_addr,Addr->ai_addrlen,
  77                Name,sizeof(Name),Service,sizeof(Service),
  78                NI_NUMERICHOST|NI_NUMERICSERV);
  79    Owner->Status(_("Connecting to %s (%s)"),Host.c_str(),Name);
  80
  81    // if that addr did timeout before, we do not try it again
  82    if(bad_addr.find(std::string(Name)) != bad_addr.end())
  83       return false;
  84
  85    /* If this is an IP rotation store the IP we are using.. If something goes
  86       wrong this will get tacked onto the end of the error message */
  87    if (LastHostAddr->ai_next != 0)
  88    {
  89       std::stringstream ss;
  90       ioprintf(ss, _("[IP: %s %s]"),Name,Service);
  91       Owner->SetIP(ss.str());
  92    }
  93
  94    // Get a socket
  95    if ((Fd = socket(Addr->ai_family,Addr->ai_socktype,
  96                     Addr->ai_protocol)) < 0)
  97       return _error->Errno("socket",_("Could not create a socket for %s (f=%u t=%u p=%u)"),
  98                            Name,Addr->ai_family,Addr->ai_socktype,Addr->ai_protocol);
  99
 100    SetNonBlock(Fd,true);
 101    if (connect(Fd,Addr->ai_addr,Addr->ai_addrlen) < 0 &&
 102        errno != EINPROGRESS)
 103       return _error->Errno("connect",_("Cannot initiate the connection "
 104                            "to %s:%s (%s)."),Host.c_str(),Service,Name);
 105
 106    /* This implements a timeout for connect by opening the connection
 107       nonblocking */
 108    if (WaitFd(Fd,true,TimeOut) == false) {
 109       bad_addr.insert(bad_addr.begin(), std::string(Name));
 110       Owner->SetFailReason("Timeout");
 111       return _error->Error(_("Could not connect to %s:%s (%s), "
 112                            "connection timed out"),Host.c_str(),Service,Name);
 113    }
 114
 115    // Check the socket for an error condition
 116    unsigned int Err;
 117    unsigned int Len = sizeof(Err);
 118    if (getsockopt(Fd,SOL_SOCKET,SO_ERROR,&Err,&Len) != 0)
 119       return _error->Errno("getsockopt",_("Failed"));
 120
 121    if (Err != 0)
 122    {
 123       errno = Err;
 124       if(errno == ECONNREFUSED)
 125          Owner->SetFailReason("ConnectionRefused");
 126       else if (errno == ETIMEDOUT)
 127          Owner->SetFailReason("ConnectionTimedOut");
 128       bad_addr.insert(bad_addr.begin(), std::string(Name));
 129       return _error->Errno("connect",_("Could not connect to %s:%s (%s)."),Host.c_str(),
 130                            Service,Name);
 131    }
 132
 133    return true;
 134 }
 135                                                                         /*}}}*/
 136 // Connect to a given Hostname                                          /*{{{*/
 137 static bool ConnectToHostname(std::string const &Host, int const Port,
 138       const char * const Service, int DefPort, int &Fd,
 139       unsigned long const TimeOut, pkgAcqMethod * const Owner)
 140 {
 141    // Convert the port name/number
 142    char ServStr[300];
 143    if (Port != 0)
 144       snprintf(ServStr,sizeof(ServStr),"%i", Port);
 145    else
 146       snprintf(ServStr,sizeof(ServStr),"%s", Service);
 147
 148    /* We used a cached address record.. Yes this is against the spec but
 149       the way we have setup our rotating dns suggests that this is more
 150       sensible */
 151    if (LastHost != Host || LastPort != Port)
 152    {
 153       Owner->Status(_("Connecting to %s"),Host.c_str());
 154
 155       // Free the old address structure
 156       if (LastHostAddr != 0)
 157       {
 158          freeaddrinfo(LastHostAddr);
 159          LastHostAddr = 0;
 160          LastUsed = 0;
 161       }
 162
 163       // We only understand SOCK_STREAM sockets.
 164       struct addrinfo Hints;
 165       memset(&Hints,0,sizeof(Hints));
 166       Hints.ai_socktype = SOCK_STREAM;
 167       Hints.ai_flags = 0;
 168       if (_config->FindB("Acquire::Connect::IDN", true) == true)
 169          Hints.ai_flags |= AI_IDN;
 170       // see getaddrinfo(3): only return address if system has such a address configured
 171       // useful if system is ipv4 only, to not get ipv6, but that fails if the system has
 172       // no address configured: e.g. offline and trying to connect to localhost.
 173       if (_config->FindB("Acquire::Connect::AddrConfig", true) == true)
 174          Hints.ai_flags |= AI_ADDRCONFIG;
 175       Hints.ai_protocol = 0;
 176
 177       if(_config->FindB("Acquire::ForceIPv4", false) == true)
 178          Hints.ai_family = AF_INET;
 179       else if(_config->FindB("Acquire::ForceIPv6", false) == true)
 180          Hints.ai_family = AF_INET6;
 181       else
 182          Hints.ai_family = AF_UNSPEC;
 183
 184       // if we couldn't resolve the host before, we don't try now
 185       if(bad_addr.find(Host) != bad_addr.end())
 186          return _error->Error(_("Could not resolve '%s'"),Host.c_str());
 187
 188       // Resolve both the host and service simultaneously
 189       while (1)
 190       {
 191          int Res;
 192          if ((Res = getaddrinfo(Host.c_str(),ServStr,&Hints,&LastHostAddr)) != 0 ||
 193              LastHostAddr == 0)
 194          {
 195             if (Res == EAI_NONAME || Res == EAI_SERVICE)
 196             {
 197                if (DefPort != 0)
 198                {
 199                   snprintf(ServStr, sizeof(ServStr), "%i", DefPort);
 200                   DefPort = 0;
 201                   continue;
 202                }
 203                bad_addr.insert(bad_addr.begin(), Host);
 204                Owner->SetFailReason("ResolveFailure");
 205                return _error->Error(_("Could not resolve '%s'"),Host.c_str());
 206             }
 207
 208             if (Res == EAI_AGAIN)
 209             {
 210                Owner->SetFailReason("TmpResolveFailure");
 211                return _error->Error(_("Temporary failure resolving '%s'"),
 212                                     Host.c_str());
 213             }
 214             if (Res == EAI_SYSTEM)
 215                return _error->Errno("getaddrinfo", _("System error resolving '%s:%s'"),
 216                                       Host.c_str(),ServStr);
 217             return _error->Error(_("Something wicked happened resolving '%s:%s' (%i - %s)"),
 218                                  Host.c_str(),ServStr,Res,gai_strerror(Res));
 219          }
 220          break;
 221       }
 222
 223       LastHost = Host;
 224       LastPort = Port;
 225    }
 226
 227    // When we have an IP rotation stay with the last IP.
 228    struct addrinfo *CurHost = LastHostAddr;
 229    if (LastUsed != 0)
 230        CurHost = LastUsed;
 231
 232    while (CurHost != 0)
 233    {
 234       if (DoConnect(CurHost,Host,TimeOut,Fd,Owner) == true)
 235       {
 236          LastUsed = CurHost;
 237          return true;
 238       }
 239       close(Fd);
 240       Fd = -1;
 241
 242       // Ignore UNIX domain sockets
 243       do
 244       {
 245          CurHost = CurHost->ai_next;
 246       }
 247       while (CurHost != 0 && CurHost->ai_family == AF_UNIX);
 248
 249       /* If we reached the end of the search list then wrap around to the
 250          start */
 251       if (CurHost == 0 && LastUsed != 0)
 252          CurHost = LastHostAddr;
 253
 254       // Reached the end of the search cycle
 255       if (CurHost == LastUsed)
 256          break;
 257
 258       if (CurHost != 0)
 259          _error->Discard();
 260    }
 261
 262    if (_error->PendingError() == true)
 263       return false;
 264    return _error->Error(_("Unable to connect to %s:%s:"),Host.c_str(),ServStr);
 265 }
 266                                                                         /*}}}*/
 267 // Connect - Connect to a server                                        /*{{{*/
 268 // ---------------------------------------------------------------------
 269 /* Performs a connection to the server (including SRV record lookup) */
 270 bool Connect(std::string Host,int Port,const char *Service,
 271                             int DefPort,int &Fd,
 272                             unsigned long TimeOut,pkgAcqMethod *Owner)
 273 {
 274    if (_error->PendingError() == true)
 275       return false;
 276
 277    if(LastHost != Host || LastPort != Port)
 278    {
 279       SrvRecords.clear();
 280       if (_config->FindB("Acquire::EnableSrvRecords", true) == true)
 281          GetSrvRecords(Host, DefPort, SrvRecords);
 282    }
 283
 284    size_t stackSize = 0;
 285    // try to connect in the priority order of the srv records
 286    std::string initialHost{std::move(Host)};
 287    while(SrvRecords.empty() == false)
 288    {
 289       _error->PushToStack();
 290       ++stackSize;
 291       // PopFromSrvRecs will also remove the server
 292       Host = PopFromSrvRecs(SrvRecords).target;
 293       auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd, TimeOut, Owner);
 294       if (ret)
 295       {
 296          while(stackSize--)
 297             _error->RevertToStack();
 298          return true;
 299       }
 300    }
 301    Host = std::move(initialHost);
 302
 303    // we have no (good) SrvRecords for this host, connect right away
 304    _error->PushToStack();
 305    ++stackSize;
 306    auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd,
 307          TimeOut, Owner);
 308    while(stackSize--)
 309       if (ret)
 310          _error->RevertToStack();
 311       else
 312          _error->MergeWithStack();
 313    return ret;
 314 }