methods/connect.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: connect.cc,v 1.9 2002/09/14 05:28:38 jgg 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 "connect.h"
  15 #include <apt-pkg/error.h>
  16 #include <apt-pkg/fileutl.h>
  17
  18 #include <stdio.h>
  19 #include <errno.h>
  20 #include <unistd.h>
  21
  22 // Internet stuff
  23 #include <netinet/in.h>
  24 #include <sys/socket.h>
  25 #include <arpa/inet.h>
  26 #include <netdb.h>
  27
  28 #include "rfc2553emu.h"
  29                                                                         /*}}}*/
  30
  31 static string LastHost;
  32 static int LastPort = 0;
  33 static struct addrinfo *LastHostAddr = 0;
  34 static struct addrinfo *LastUsed = 0;
  35
  36 // RotateDNS - Select a new server from a DNS rotation                  /*{{{*/
  37 // ---------------------------------------------------------------------
  38 /* This is called during certain errors in order to recover by selecting a
  39    new server */
  40 void RotateDNS()
  41 {
  42    if (LastUsed != 0 && LastUsed->ai_next != 0)
  43       LastUsed = LastUsed->ai_next;
  44    else
  45       LastUsed = LastHostAddr;
  46 }
  47                                                                         /*}}}*/
  48 // DoConnect - Attempt a connect operation                              /*{{{*/
  49 // ---------------------------------------------------------------------
  50 /* This helper function attempts a connection to a single address. */
  51 static bool DoConnect(struct addrinfo *Addr,string Host,
  52                       unsigned long TimeOut,int &Fd,pkgAcqMethod *Owner)
  53 {
  54    // Show a status indicator
  55    char Name[NI_MAXHOST];
  56    char Service[NI_MAXSERV];
  57
  58    Name[0] = 0;
  59    Service[0] = 0;
  60    getnameinfo(Addr->ai_addr,Addr->ai_addrlen,
  61                Name,sizeof(Name),Service,sizeof(Service),
  62                NI_NUMERICHOST|NI_NUMERICSERV);
  63    Owner->Status("Connecting to %s (%s)",Host.c_str(),Name);
  64
  65    /* If this is an IP rotation store the IP we are using.. If something goes
  66       wrong this will get tacked onto the end of the error message */
  67    if (LastHostAddr->ai_next != 0)
  68    {
  69       char Name2[NI_MAXHOST + NI_MAXSERV + 10];
  70       snprintf(Name2,sizeof(Name2),"[IP: %s %s]",Name,Service);
  71       Owner->SetFailExtraMsg(string(Name2));
  72    }
  73    else
  74       Owner->SetFailExtraMsg("");
  75
  76    // Get a socket
  77    if ((Fd = socket(Addr->ai_family,Addr->ai_socktype,
  78                     Addr->ai_protocol)) < 0)
  79       return _error->Errno("socket","Could not create a socket for %s (f=%u t=%u p=%u)",
  80                            Name,Addr->ai_family,Addr->ai_socktype,Addr->ai_protocol);
  81
  82    SetNonBlock(Fd,true);
  83    if (connect(Fd,Addr->ai_addr,Addr->ai_addrlen) < 0 &&
  84        errno != EINPROGRESS)
  85       return _error->Errno("connect","Cannot initiate the connection "
  86                            "to %s:%s (%s).",Host.c_str(),Service,Name);
  87
  88    /* This implements a timeout for connect by opening the connection
  89       nonblocking */
  90    if (WaitFd(Fd,true,TimeOut) == false)
  91       return _error->Error("Could not connect to %s:%s (%s), "
  92                            "connection timed out",Host.c_str(),Service,Name);
  93
  94    // Check the socket for an error condition
  95    unsigned int Err;
  96    unsigned int Len = sizeof(Err);
  97    if (getsockopt(Fd,SOL_SOCKET,SO_ERROR,&Err,&Len) != 0)
  98       return _error->Errno("getsockopt","Failed");
  99
 100    if (Err != 0)
 101    {
 102       errno = Err;
 103       return _error->Errno("connect","Could not connect to %s:%s (%s).",Host.c_str(),
 104                            Service,Name);
 105    }
 106
 107    return true;
 108 }
 109                                                                         /*}}}*/
 110 // Connect - Connect to a server                                        /*{{{*/
 111 // ---------------------------------------------------------------------
 112 /* Performs a connection to the server */
 113 bool Connect(string Host,int Port,const char *Service,int DefPort,int &Fd,
 114              unsigned long TimeOut,pkgAcqMethod *Owner)
 115 {
 116    if (_error->PendingError() == true)
 117       return false;
 118
 119    // Convert the port name/number
 120    char ServStr[300];
 121    if (Port != 0)
 122       snprintf(ServStr,sizeof(ServStr),"%u",Port);
 123    else
 124       snprintf(ServStr,sizeof(ServStr),"%s",Service);
 125
 126    /* We used a cached address record.. Yes this is against the spec but
 127       the way we have setup our rotating dns suggests that this is more
 128       sensible */
 129    if (LastHost != Host || LastPort != Port)
 130    {
 131       Owner->Status("Connecting to %s",Host.c_str());
 132
 133       // Free the old address structure
 134       if (LastHostAddr != 0)
 135       {
 136          freeaddrinfo(LastHostAddr);
 137          LastHostAddr = 0;
 138          LastUsed = 0;
 139       }
 140
 141       // We only understand SOCK_STREAM sockets.
 142       struct addrinfo Hints;
 143       memset(&Hints,0,sizeof(Hints));
 144       Hints.ai_socktype = SOCK_STREAM;
 145       Hints.ai_protocol = 0;
 146
 147       // Resolve both the host and service simultaneously
 148       while (1)
 149       {
 150          int Res;
 151          if ((Res = getaddrinfo(Host.c_str(),ServStr,&Hints,&LastHostAddr)) != 0 ||
 152              LastHostAddr == 0)
 153          {
 154             if (Res == EAI_NONAME || Res == EAI_SERVICE)
 155             {
 156                if (DefPort != 0)
 157                {
 158                   snprintf(ServStr,sizeof(ServStr),"%u",DefPort);
 159                   DefPort = 0;
 160                   continue;
 161                }
 162                return _error->Error("Could not resolve '%s'",Host.c_str());
 163             }
 164
 165             if (Res == EAI_AGAIN)
 166                return _error->Error("Temporary failure resolving '%s'",
 167                                     Host.c_str());
 168             return _error->Error("Something wicked happened resolving '%s:%s' (%i)",
 169                                  Host.c_str(),ServStr,Res);
 170          }
 171          break;
 172       }
 173
 174       LastHost = Host;
 175       LastPort = Port;
 176    }
 177
 178    // When we have an IP rotation stay with the last IP.
 179    struct addrinfo *CurHost = LastHostAddr;
 180    if (LastUsed != 0)
 181        CurHost = LastUsed;
 182
 183    while (CurHost != 0)
 184    {
 185       if (DoConnect(CurHost,Host,TimeOut,Fd,Owner) == true)
 186       {
 187          LastUsed = CurHost;
 188          return true;
 189       }
 190       close(Fd);
 191       Fd = -1;
 192
 193       // Ignore UNIX domain sockets
 194       do
 195       {
 196          CurHost = CurHost->ai_next;
 197       }
 198       while (CurHost != 0 && CurHost->ai_family == AF_UNIX);
 199
 200       /* If we reached the end of the search list then wrap around to the
 201          start */
 202       if (CurHost == 0 && LastUsed != 0)
 203          CurHost = LastHostAddr;
 204
 205       // Reached the end of the search cycle
 206       if (CurHost == LastUsed)
 207          break;
 208
 209       if (CurHost != 0)
 210          _error->Discard();
 211    }
 212
 213    if (_error->PendingError() == true)
 214       return false;
 215    return _error->Error("Unable to connect to %s %s:",Host.c_str(),ServStr);
 216 }
 217                                                                         /*}}}*/