pdns/rec_channel.cc

   1 #ifdef HAVE_CONFIG_H
   2 #include "config.h"
   3 #endif
   4 #include "rec_channel.hh"
   5 #include "utility.hh"
   6 #include <sys/socket.h>
   7 #include <cerrno>
   8 #include "misc.hh"
   9 #include <string.h>
  10 #include <cstdlib>
  11 #include <unistd.h>
  12 #include <sys/types.h>
  13 #include <sys/stat.h>
  14 #include <iostream>
  15
  16 #include "pdnsexception.hh"
  17
  18 #include "namespaces.hh"
  19
  20 RecursorControlChannel::RecursorControlChannel()
  21 {
  22   d_fd=-1;
  23   *d_local.sun_path=0;
  24   d_local.sun_family=0;
  25 }
  26
  27 RecursorControlChannel::~RecursorControlChannel()
  28 {
  29   if(d_fd > 0)
  30     close(d_fd);
  31   if(*d_local.sun_path)
  32     unlink(d_local.sun_path);
  33 }
  34
  35 int RecursorControlChannel::listen(const string& fname)
  36 {
  37   d_fd=socket(AF_UNIX,SOCK_DGRAM,0);
  38   setCloseOnExec(d_fd);
  39
  40   if(d_fd < 0)
  41     throw PDNSException("Creating UNIX domain socket: "+stringerror());
  42
  43   int tmp=1;
  44   if(setsockopt(d_fd, SOL_SOCKET, SO_REUSEADDR,(char*)&tmp,sizeof tmp)<0)
  45     throw PDNSException("Setsockopt failed: "+stringerror());
  46
  47   int err=unlink(fname.c_str());
  48   if(err < 0 && errno!=ENOENT)
  49     throw PDNSException("Can't remove (previous) controlsocket '"+fname+"': "+stringerror() + " (try --socket-dir)");
  50
  51   if(makeUNsockaddr(fname, &d_local))
  52     throw PDNSException("Unable to bind to controlsocket, path '"+fname+"' is not a valid UNIX socket path.");
  53
  54   if(bind(d_fd, (sockaddr*)&d_local,sizeof(d_local))<0)
  55     throw PDNSException("Unable to bind to controlsocket '"+fname+"': "+stringerror());
  56
  57   return d_fd;
  58 }
  59
  60 void RecursorControlChannel::connect(const string& path, const string& fname)
  61 {
  62   struct sockaddr_un remote;
  63
  64   d_fd=socket(AF_UNIX,SOCK_DGRAM,0);
  65   setCloseOnExec(d_fd);
  66
  67   if(d_fd < 0)
  68     throw PDNSException("Creating UNIX domain socket: "+string(strerror(errno)));
  69
  70   try {
  71     int tmp=1;
  72     if(setsockopt(d_fd, SOL_SOCKET, SO_REUSEADDR,(char*)&tmp,sizeof tmp)<0)
  73       throw PDNSException("Setsockopt failed: "+stringerror());
  74
  75     string localname=path+"/lsockXXXXXX";
  76     *d_local.sun_path=0;
  77     if (makeUNsockaddr(localname, &d_local))
  78       throw PDNSException("Unable to bind to local temporary file, path '"+localname+"' is not a valid UNIX socket path.");
  79
  80     if(mkstemp(d_local.sun_path) < 0)
  81       throw PDNSException("Unable to generate local temporary file in directory '"+path+"': "+stringerror());
  82
  83     int err=unlink(d_local.sun_path);
  84     if(err < 0 && errno!=ENOENT)
  85       throw PDNSException("Unable to remove local controlsocket: "+stringerror());
  86
  87     if(bind(d_fd, (sockaddr*)&d_local,sizeof(d_local))<0)
  88       throw PDNSException("Unable to bind to local temporary file: "+stringerror());
  89
  90     if(chmod(d_local.sun_path,0666)<0) // make sure that pdns can reply!
  91       throw PDNSException("Unable to chmod local temporary socket: "+stringerror());
  92
  93     string remotename=path+"/"+fname;
  94     if (makeUNsockaddr(remotename, &remote))
  95       throw PDNSException("Unable to connect to controlsocket, path '"+remotename+"' is not a valid UNIX socket path.");
  96
  97     if(::connect(d_fd, (sockaddr*)&remote, sizeof(remote)) < 0) {
  98       if(*d_local.sun_path)
  99         unlink(d_local.sun_path);
 100       throw PDNSException("Unable to connect to remote '"+string(remote.sun_path)+"': "+stringerror());
 101     }
 102
 103   } catch (...) {
 104     close(d_fd);
 105     d_fd=-1;
 106     d_local.sun_path[0]=0;
 107     throw;
 108   }
 109 }
 110
 111 void RecursorControlChannel::send(const std::string& msg, const std::string* remote)
 112 {
 113   if(remote) {
 114     struct sockaddr_un remoteaddr;
 115     memset(&remoteaddr, 0, sizeof(remoteaddr));
 116
 117     remoteaddr.sun_family=AF_UNIX;
 118     strncpy(remoteaddr.sun_path, remote->c_str(), sizeof(remoteaddr.sun_path));
 119     remoteaddr.sun_path[sizeof(remoteaddr.sun_path)-1] = '\0';
 120
 121     if(::sendto(d_fd, msg.c_str(), msg.length(), 0, (struct sockaddr*) &remoteaddr, sizeof(remoteaddr) ) < 0)
 122       throw PDNSException("Unable to send message over control channel '"+string(remoteaddr.sun_path)+"': "+string(strerror(errno)));
 123   }
 124   else if(::send(d_fd, msg.c_str(), msg.length(), 0) < 0)
 125     throw PDNSException("Unable to send message over control channel: "+string(strerror(errno)));
 126 }
 127
 128 string RecursorControlChannel::recv(std::string* remote, unsigned int timeout)
 129 {
 130   char buffer[16384];
 131   ssize_t len;
 132   struct sockaddr_un remoteaddr;
 133   socklen_t addrlen=sizeof(remoteaddr);
 134
 135   int ret=waitForData(d_fd, timeout, 0);
 136   if(ret==0)
 137     throw PDNSException("Timeout waiting for answer from control channel");
 138
 139   if( ret < 0 || (len=::recvfrom(d_fd, buffer, sizeof(buffer), 0, (struct sockaddr*)&remoteaddr, &addrlen)) < 0)
 140     throw PDNSException("Unable to receive message over control channel: "+string(strerror(errno)));
 141
 142   if(remote)
 143     *remote=remoteaddr.sun_path;
 144
 145   return string(buffer, buffer+len);
 146 }
 147