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Diffstat (limited to 'methods/connect.cc')
| -rw-r--r-- | methods/connect.cc | 342 |
1 files changed, 342 insertions, 0 deletions
diff --git a/methods/connect.cc b/methods/connect.cc new file mode 100644 index 000000000..f6fb14769 --- /dev/null +++ b/methods/connect.cc @@ -0,0 +1,342 @@ +// -*- mode: cpp; mode: fold -*- +// Description /*{{{*/ +// $Id: connect.cc,v 1.10.2.1 2004/01/16 18:58:50 mdz Exp $ +/* ###################################################################### + + Connect - Replacement connect call + + This was originally authored by Jason Gunthorpe <jgg@debian.org> + and is placed in the Public Domain, do with it what you will. + + ##################################################################### */ + /*}}}*/ +// Include Files /*{{{*/ +#include <config.h> + +#include <apt-pkg/error.h> +#include <apt-pkg/fileutl.h> +#include <apt-pkg/strutl.h> +#include <apt-pkg/acquire-method.h> +#include <apt-pkg/configuration.h> +#include <apt-pkg/srvrec.h> + +#include <stdio.h> +#include <errno.h> +#include <unistd.h> +#include <sstream> +#include <string.h> +#include<set> +#include<string> + +// Internet stuff +#include <netinet/in.h> +#include <sys/socket.h> +#include <arpa/inet.h> +#include <netdb.h> + +#include "connect.h" +#include "rfc2553emu.h" +#include <apti18n.h> + /*}}}*/ + +static std::string LastHost; +static int LastPort = 0; +static struct addrinfo *LastHostAddr = 0; +static struct addrinfo *LastUsed = 0; + +static std::vector<SrvRec> SrvRecords; + +// Set of IP/hostnames that we timed out before or couldn't resolve +static std::set<std::string> bad_addr; + +// RotateDNS - Select a new server from a DNS rotation /*{{{*/ +// --------------------------------------------------------------------- +/* This is called during certain errors in order to recover by selecting a + new server */ +void RotateDNS() +{ + if (LastUsed != 0 && LastUsed->ai_next != 0) + LastUsed = LastUsed->ai_next; + else + LastUsed = LastHostAddr; +} + /*}}}*/ +static bool ConnectionAllowed(char const * const Service, std::string const &Host)/*{{{*/ +{ + if (unlikely(Host.empty())) // the only legal empty host (RFC2782 '.' target) is detected by caller + return false; + if (APT::String::Endswith(Host, ".onion") && _config->FindB("Acquire::BlockDotOnion", true)) + { + // TRANSLATOR: %s is e.g. Tor's ".onion" which would likely fail or leak info (RFC7686) + _error->Error(_("Direct connection to %s domains is blocked by default."), ".onion"); + if (strcmp(Service, "http") == 0) + _error->Error(_("If you meant to use Tor remember to use %s instead of %s."), "tor+http", "http"); + return false; + } + return true; +} + /*}}}*/ +// DoConnect - Attempt a connect operation /*{{{*/ +// --------------------------------------------------------------------- +/* This helper function attempts a connection to a single address. */ +static bool DoConnect(struct addrinfo *Addr,std::string const &Host, + unsigned long TimeOut,int &Fd,pkgAcqMethod *Owner) +{ + // Show a status indicator + char Name[NI_MAXHOST]; + char Service[NI_MAXSERV]; + + Name[0] = 0; + Service[0] = 0; + getnameinfo(Addr->ai_addr,Addr->ai_addrlen, + Name,sizeof(Name),Service,sizeof(Service), + NI_NUMERICHOST|NI_NUMERICSERV); + Owner->Status(_("Connecting to %s (%s)"),Host.c_str(),Name); + + // if that addr did timeout before, we do not try it again + if(bad_addr.find(std::string(Name)) != bad_addr.end()) + return false; + + /* If this is an IP rotation store the IP we are using.. If something goes + wrong this will get tacked onto the end of the error message */ + if (LastHostAddr->ai_next != 0) + { + std::stringstream ss; + ioprintf(ss, _("[IP: %s %s]"),Name,Service); + Owner->SetIP(ss.str()); + } + + // Get a socket + if ((Fd = socket(Addr->ai_family,Addr->ai_socktype, + Addr->ai_protocol)) < 0) + return _error->Errno("socket",_("Could not create a socket for %s (f=%u t=%u p=%u)"), + Name,Addr->ai_family,Addr->ai_socktype,Addr->ai_protocol); + + SetNonBlock(Fd,true); + if (connect(Fd,Addr->ai_addr,Addr->ai_addrlen) < 0 && + errno != EINPROGRESS) + return _error->Errno("connect",_("Cannot initiate the connection " + "to %s:%s (%s)."),Host.c_str(),Service,Name); + + /* This implements a timeout for connect by opening the connection + nonblocking */ + if (WaitFd(Fd,true,TimeOut) == false) { + bad_addr.insert(bad_addr.begin(), std::string(Name)); + Owner->SetFailReason("Timeout"); + return _error->Error(_("Could not connect to %s:%s (%s), " + "connection timed out"),Host.c_str(),Service,Name); + } + + // Check the socket for an error condition + unsigned int Err; + unsigned int Len = sizeof(Err); + if (getsockopt(Fd,SOL_SOCKET,SO_ERROR,&Err,&Len) != 0) + return _error->Errno("getsockopt",_("Failed")); + + if (Err != 0) + { + errno = Err; + if(errno == ECONNREFUSED) + Owner->SetFailReason("ConnectionRefused"); + else if (errno == ETIMEDOUT) + Owner->SetFailReason("ConnectionTimedOut"); + bad_addr.insert(bad_addr.begin(), std::string(Name)); + return _error->Errno("connect",_("Could not connect to %s:%s (%s)."),Host.c_str(), + Service,Name); + } + + return true; +} + /*}}}*/ +// Connect to a given Hostname /*{{{*/ +static bool ConnectToHostname(std::string const &Host, int const Port, + const char * const Service, int DefPort, int &Fd, + unsigned long const TimeOut, pkgAcqMethod * const Owner) +{ + if (ConnectionAllowed(Service, Host) == false) + return false; + // Convert the port name/number + char ServStr[300]; + if (Port != 0) + snprintf(ServStr,sizeof(ServStr),"%i", Port); + else + snprintf(ServStr,sizeof(ServStr),"%s", Service); + + /* We used a cached address record.. Yes this is against the spec but + the way we have setup our rotating dns suggests that this is more + sensible */ + if (LastHost != Host || LastPort != Port) + { + Owner->Status(_("Connecting to %s"),Host.c_str()); + + // Free the old address structure + if (LastHostAddr != 0) + { + freeaddrinfo(LastHostAddr); + LastHostAddr = 0; + LastUsed = 0; + } + + // We only understand SOCK_STREAM sockets. + struct addrinfo Hints; + memset(&Hints,0,sizeof(Hints)); + Hints.ai_socktype = SOCK_STREAM; + Hints.ai_flags = 0; +#ifdef AI_IDN + if (_config->FindB("Acquire::Connect::IDN", true) == true) + Hints.ai_flags |= AI_IDN; +#endif + // see getaddrinfo(3): only return address if system has such a address configured + // useful if system is ipv4 only, to not get ipv6, but that fails if the system has + // no address configured: e.g. offline and trying to connect to localhost. + if (_config->FindB("Acquire::Connect::AddrConfig", true) == true) + Hints.ai_flags |= AI_ADDRCONFIG; + Hints.ai_protocol = 0; + + if(_config->FindB("Acquire::ForceIPv4", false) == true) + Hints.ai_family = AF_INET; + else if(_config->FindB("Acquire::ForceIPv6", false) == true) + Hints.ai_family = AF_INET6; + else + Hints.ai_family = AF_UNSPEC; + + // if we couldn't resolve the host before, we don't try now + if(bad_addr.find(Host) != bad_addr.end()) + return _error->Error(_("Could not resolve '%s'"),Host.c_str()); + + // Resolve both the host and service simultaneously + while (1) + { + int Res; + if ((Res = getaddrinfo(Host.c_str(),ServStr,&Hints,&LastHostAddr)) != 0 || + LastHostAddr == 0) + { + if (Res == EAI_NONAME || Res == EAI_SERVICE) + { + if (DefPort != 0) + { + snprintf(ServStr, sizeof(ServStr), "%i", DefPort); + DefPort = 0; + continue; + } + bad_addr.insert(bad_addr.begin(), Host); + Owner->SetFailReason("ResolveFailure"); + return _error->Error(_("Could not resolve '%s'"),Host.c_str()); + } + + if (Res == EAI_AGAIN) + { + Owner->SetFailReason("TmpResolveFailure"); + return _error->Error(_("Temporary failure resolving '%s'"), + Host.c_str()); + } + if (Res == EAI_SYSTEM) + return _error->Errno("getaddrinfo", _("System error resolving '%s:%s'"), + Host.c_str(),ServStr); + return _error->Error(_("Something wicked happened resolving '%s:%s' (%i - %s)"), + Host.c_str(),ServStr,Res,gai_strerror(Res)); + } + break; + } + + LastHost = Host; + LastPort = Port; + } + + // When we have an IP rotation stay with the last IP. + struct addrinfo *CurHost = LastHostAddr; + if (LastUsed != 0) + CurHost = LastUsed; + + while (CurHost != 0) + { + if (DoConnect(CurHost,Host,TimeOut,Fd,Owner) == true) + { + LastUsed = CurHost; + return true; + } + close(Fd); + Fd = -1; + + // Ignore UNIX domain sockets + do + { + CurHost = CurHost->ai_next; + } + while (CurHost != 0 && CurHost->ai_family == AF_UNIX); + + /* If we reached the end of the search list then wrap around to the + start */ + if (CurHost == 0 && LastUsed != 0) + CurHost = LastHostAddr; + + // Reached the end of the search cycle + if (CurHost == LastUsed) + break; + + if (CurHost != 0) + _error->Discard(); + } + + if (_error->PendingError() == true) + return false; + return _error->Error(_("Unable to connect to %s:%s:"),Host.c_str(),ServStr); +} + /*}}}*/ +// Connect - Connect to a server /*{{{*/ +// --------------------------------------------------------------------- +/* Performs a connection to the server (including SRV record lookup) */ +bool Connect(std::string Host,int Port,const char *Service, + int DefPort,int &Fd, + unsigned long TimeOut,pkgAcqMethod *Owner) +{ + if (_error->PendingError() == true) + return false; + + if (ConnectionAllowed(Service, Host) == false) + return false; + + if(LastHost != Host || LastPort != Port) + { + SrvRecords.clear(); + if (_config->FindB("Acquire::EnableSrvRecords", true) == true) + { + GetSrvRecords(Host, DefPort, SrvRecords); + // RFC2782 defines that a lonely '.' target is an abort reason + if (SrvRecords.size() == 1 && SrvRecords[0].target.empty()) + return _error->Error("SRV records for %s indicate that " + "%s service is not available at this domain", Host.c_str(), Service); + } + } + + size_t stackSize = 0; + // try to connect in the priority order of the srv records + std::string initialHost{std::move(Host)}; + while(SrvRecords.empty() == false) + { + _error->PushToStack(); + ++stackSize; + // PopFromSrvRecs will also remove the server + Host = PopFromSrvRecs(SrvRecords).target; + auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd, TimeOut, Owner); + if (ret) + { + while(stackSize--) + _error->RevertToStack(); + return true; + } + } + Host = std::move(initialHost); + + // we have no (good) SrvRecords for this host, connect right away + _error->PushToStack(); + ++stackSize; + auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd, + TimeOut, Owner); + while(stackSize--) + if (ret) + _error->RevertToStack(); + else + _error->MergeWithStack(); + return ret; +} |