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 static void setSocketBuffer(int fd, int optname, uint32_t size)
  36 {
  37   uint32_t psize=0;
  38   socklen_t len=sizeof(psize);
  39
  40   if (getsockopt(fd, SOL_SOCKET, optname, (void*)&psize, &len))
  41     throw PDNSException("Unable to getsocket buffer size: "+stringerror());
  42
  43   if (psize > size)
  44     return;
  45
  46   // failure to raise is not fatal
  47   setsockopt(fd, SOL_SOCKET, optname, (const void*)&size, sizeof(size));
  48 }
  49
  50
  51 static void setSocketReceiveBuffer(int fd, uint32_t size)
  52 {
  53   setSocketBuffer(fd, SO_RCVBUF, size);
  54 }
  55
  56 static void setSocketSendBuffer(int fd, uint32_t size)
  57 {
  58   setSocketBuffer(fd, SO_SNDBUF, size);
  59 }
  60
  61 int RecursorControlChannel::listen(const string& fname)
  62 {
  63   d_fd=socket(AF_UNIX,SOCK_DGRAM,0);
  64   setCloseOnExec(d_fd);
  65
  66   if(d_fd < 0)
  67     throw PDNSException("Creating UNIX domain socket: "+stringerror());
  68
  69   int tmp=1;
  70   if(setsockopt(d_fd, SOL_SOCKET, SO_REUSEADDR,(char*)&tmp,sizeof tmp)<0)
  71     throw PDNSException("Setsockopt failed: "+stringerror());
  72
  73   int err=unlink(fname.c_str());
  74   if(err < 0 && errno!=ENOENT)
  75     throw PDNSException("Can't remove (previous) controlsocket '"+fname+"': "+stringerror() + " (try --socket-dir)");
  76
  77   if(makeUNsockaddr(fname, &d_local))
  78     throw PDNSException("Unable to bind to controlsocket, path '"+fname+"' is not a valid UNIX socket path.");
  79
  80   if(bind(d_fd, (sockaddr*)&d_local,sizeof(d_local))<0)
  81     throw PDNSException("Unable to bind to controlsocket '"+fname+"': "+stringerror());
  82
  83   // receive buf should be size of max datagram plus address size
  84   setSocketReceiveBuffer(d_fd, 60 * 1024);
  85   setSocketSendBuffer(d_fd, 64 * 1024);
  86
  87   return d_fd;
  88 }
  89
  90 void RecursorControlChannel::connect(const string& path, const string& fname)
  91 {
  92   struct sockaddr_un remote;
  93
  94   d_fd=socket(AF_UNIX,SOCK_DGRAM,0);
  95   setCloseOnExec(d_fd);
  96
  97   if(d_fd < 0)
  98     throw PDNSException("Creating UNIX domain socket: "+string(strerror(errno)));
  99
 100   try {
 101     int tmp=1;
 102     if(setsockopt(d_fd, SOL_SOCKET, SO_REUSEADDR,(char*)&tmp,sizeof tmp)<0)
 103       throw PDNSException("Setsockopt failed: "+stringerror());
 104
 105     string localname=path+"/lsockXXXXXX";
 106     *d_local.sun_path=0;
 107     if (makeUNsockaddr(localname, &d_local))
 108       throw PDNSException("Unable to bind to local temporary file, path '"+localname+"' is not a valid UNIX socket path.");
 109
 110     if(mkstemp(d_local.sun_path) < 0)
 111       throw PDNSException("Unable to generate local temporary file in directory '"+path+"': "+stringerror());
 112
 113     int err=unlink(d_local.sun_path);
 114     if(err < 0 && errno!=ENOENT)
 115       throw PDNSException("Unable to remove local controlsocket: "+stringerror());
 116
 117     if(bind(d_fd, (sockaddr*)&d_local,sizeof(d_local))<0)
 118       throw PDNSException("Unable to bind to local temporary file: "+stringerror());
 119
 120     if(chmod(d_local.sun_path,0666)<0) // make sure that pdns can reply!
 121       throw PDNSException("Unable to chmod local temporary socket: "+stringerror());
 122
 123     string remotename=path+"/"+fname;
 124     if (makeUNsockaddr(remotename, &remote))
 125       throw PDNSException("Unable to connect to controlsocket, path '"+remotename+"' is not a valid UNIX socket path.");
 126
 127     if(::connect(d_fd, (sockaddr*)&remote, sizeof(remote)) < 0) {
 128       if(*d_local.sun_path)
 129         unlink(d_local.sun_path);
 130       throw PDNSException("Unable to connect to remote '"+string(remote.sun_path)+"': "+stringerror());
 131     }
 132
 133     // receive buf should be size of max datagram plus address size
 134     setSocketReceiveBuffer(d_fd, 60 * 1024);
 135     setSocketSendBuffer(d_fd, 64 * 1024);
 136
 137   } catch (...) {
 138     close(d_fd);
 139     d_fd=-1;
 140     d_local.sun_path[0]=0;
 141     throw;
 142   }
 143 }
 144
 145 void RecursorControlChannel::send(const std::string& msg, const std::string* remote, unsigned int timeout)
 146 {
 147   int ret = waitForRWData(d_fd, false, timeout, 0);
 148   if(ret == 0) {
 149     throw PDNSException("Timeout sending message over control channel");
 150   }
 151   else if(ret < 0) {
 152     throw PDNSException("Error sending message over control channel:" + string(strerror(errno)));
 153   }
 154
 155   if(remote) {
 156     struct sockaddr_un remoteaddr;
 157     memset(&remoteaddr, 0, sizeof(remoteaddr));
 158
 159     remoteaddr.sun_family=AF_UNIX;
 160     strncpy(remoteaddr.sun_path, remote->c_str(), sizeof(remoteaddr.sun_path)-1);
 161     remoteaddr.sun_path[sizeof(remoteaddr.sun_path)-1] = '\0';
 162
 163     if(::sendto(d_fd, msg.c_str(), msg.length(), 0, (struct sockaddr*) &remoteaddr, sizeof(remoteaddr) ) < 0)
 164       throw PDNSException("Unable to send message over control channel '"+string(remoteaddr.sun_path)+"': "+string(strerror(errno)));
 165   }
 166   else if(::send(d_fd, msg.c_str(), msg.length(), 0) < 0)
 167     throw PDNSException("Unable to send message over control channel: "+string(strerror(errno)));
 168 }
 169
 170 string RecursorControlChannel::recv(std::string* remote, unsigned int timeout)
 171 {
 172   char buffer[16384];
 173   ssize_t len;
 174   struct sockaddr_un remoteaddr;
 175   socklen_t addrlen=sizeof(remoteaddr);
 176
 177   int ret=waitForData(d_fd, timeout, 0);
 178   if(ret==0)
 179     throw PDNSException("Timeout waiting for answer from control channel");
 180
 181   if( ret < 0 || (len=::recvfrom(d_fd, buffer, sizeof(buffer), 0, (struct sockaddr*)&remoteaddr, &addrlen)) < 0)
 182     throw PDNSException("Unable to receive message over control channel: "+string(strerror(errno)));
 183
 184   if(remote)
 185     *remote=remoteaddr.sun_path;
 186
 187   return string(buffer, buffer+len);
 188 }
 189