src/connection.cpp

   1 #include <connection.h>
   2 #include <unistd.h>
   3 #include <fcntl.h>
   4 #include <sys/errno.h>
   5 #include <sys/ioctl.h>
   6 #include <sys/utsname.h>
   7 #include <errno.h>
   8 #include <vector>
   9 #include "inspircd.h"
  10 #include "modules.h"
  11
  12 extern std::vector<Module*> modules;
  13 extern std::vector<ircd_module*> factory;
  14
  15 extern int MODCOUNT;
  16
  17 #define STATE_CLEAR 1
  18 #define STATE_WAIT_FOR_ACK 2
  19
  20 packet::packet()
  21 {
  22         srand(time(NULL));
  23         id = random();
  24 }
  25
  26 packet::~packet()
  27 {
  28 }
  29
  30 connection::connection()
  31 {
  32         key = GenKey();
  33         fd = 0;
  34         state = STATE_CLEAR;
  35         buffer.clear();
  36 }
  37
  38
  39 bool connection::CreateListener(char* host, int p)
  40 {
  41         sockaddr_in host_address;
  42         int flags;
  43         in_addr addy;
  44         int on = 0;
  45         struct linger linger = { 0 };
  46
  47         fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  48         if (fd <= 0)
  49         {
  50                 return false;
  51         }
  52
  53         memset((void*)&host_address, 0, sizeof(host_address));
  54
  55         host_address.sin_family = AF_INET;
  56
  57         if (!strcmp(host,""))
  58         {
  59                 host_address.sin_addr.s_addr = htonl(INADDR_ANY);
  60         }
  61         else
  62         {
  63                 inet_aton(host,&addy);
  64                 host_address.sin_addr = addy;
  65         }
  66
  67         host_address.sin_port = htons(p);
  68
  69         if (bind(fd,(sockaddr*)&host_address,sizeof(host_address))<0)
  70         {
  71                 return false;
  72         }
  73
  74         // make the socket non-blocking
  75         flags = fcntl(fd, F_GETFL, 0);
  76         fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  77
  78         this->port = p;
  79
  80     setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,(const char*)&on,sizeof(on));
  81     linger.l_onoff = 1;
  82     linger.l_linger = 0;
  83     setsockopt(fd,SOL_SOCKET,SO_LINGER,(const char*)&linger,sizeof(linger));
  84
  85         return true;
  86 }
  87
  88 bool connection::BeginLink(char* targethost, int port, char* password)
  89 {
  90         char connect[MAXBUF];
  91
  92         if (this->fd)
  93         {
  94                 sprintf(connect,"S %s %s :%s",getservername().c_str(),password,getserverdesc().c_str());
  95                 this->haspassed = false;
  96                 return this->SendPacket(connect, targethost, port, 0);
  97         }
  98         return false;
  99 }
 100
 101 // targethost: in dot notation a.b.c.d
 102 void connection::TerminateLink(char* targethost)
 103 {
 104 }
 105
 106 // host: in dot notation a.b.c.d
 107 // port: host byte order
 108 bool connection::SendPacket(char *message, char* host, int port, long ourkey)
 109 {
 110         sockaddr_in host_address;
 111         in_addr addy;
 112         packet p;
 113
 114         memset((void*)&host_address, 0, sizeof(host_address));
 115
 116         host_address.sin_family = AF_INET;
 117         inet_aton(host,&addy);
 118         host_address.sin_addr = addy;
 119
 120         host_address.sin_port = htons(port);
 121
 122         strcpy(p.data,message);
 123         p.type = PT_SYN_WITH_DATA;
 124         p.key = ourkey;
 125
 126
 127         FOREACH_MOD OnPacketTransmit(p.data);
 128
 129         log(DEBUG,"main: Connection::SendPacket() sent '%s' to %s:%d",p.data,host,port);
 130
 131         // returns false if the packet could not be sent (e.g. target host down)
 132         if (sendto(this->fd,&p,sizeof(p),0,(sockaddr*)&host_address,sizeof(host_address))<0)
 133         {
 134                 log(DEBUG,"sendto() failed for Connection::SendPacket() with a packet of size %d: %s",sizeof(p),strerror(errno));
 135                 return false;
 136         }
 137         this->state = STATE_WAIT_FOR_ACK;
 138
 139
 140         // host_address remains unchanged. we only want to receive from where we just sent the packet to.
 141
 142         // retry the packet up to 5 times
 143         for (int retries = 0; retries < 5; retries++)
 144         {
 145                 socklen_t host_address_size;
 146                 host_address.sin_family=AF_INET;
 147                 host_address_size=sizeof(host_address);
 148
 149                 // wait for ack, or timeout.
 150                 // if reached a timeout, send again.
 151                 // the packet id in the ack must match that in the original packet
 152                 // this MUST operate in lock/step fashion!!!
 153                 int cycles = 0;
 154                 packet p2;
 155                 do
 156                 {
 157                         fd_set sfd;
 158                         timeval tval;
 159                         tval.tv_usec = 100;
 160                         tval.tv_sec = 0;
 161                         FD_ZERO(&sfd);
 162                         FD_SET(fd,&sfd);
 163                         int res = select(65535, &sfd, NULL, NULL, &tval);
 164                         cycles++;
 165                 }
 166                 while ((recvfrom(fd,&p2,sizeof(p2),0,(sockaddr*)&host_address,&host_address_size)<0) && (cycles < 10));
 167
 168                 if (cycles >= 10)
 169                 {
 170                         log(DEFAULT,"ERROR! connection::SendPacket() waited >10000 nanosecs for an ACK. Will resend up to 5 times");
 171                 }
 172                 else
 173                 {
 174                         if (p2.type != PT_ACK_ONLY)
 175                         {
 176                                 packet_buf pb;
 177                                 pb.p.id = p.id;
 178                                 pb.p.key = p.key;
 179                                 pb.p.type = p.type;
 180                                 strcpy(pb.host,inet_ntoa(host_address.sin_addr));
 181                                 pb.port = ntohs(host_address.sin_port);
 182                                 this->buffer.push_back(pb);
 183
 184                                 log(DEFAULT,"ERROR! connection::SendPacket() received a data response and was expecting an ACK!!!");
 185                                 this->state = STATE_CLEAR;
 186                                 return true;
 187                         }
 188
 189                         if (p2.id != p.id)
 190                         {
 191                                 log(DEFAULT,"ERROR! connection::SendPacket() received an ack for a packet it didnt send!");
 192                                 this->state = STATE_CLEAR;
 193                                 return false;
 194                         }
 195                         else
 196                         {
 197                                 log(DEFAULT,"Successfully received ACK");
 198                                 this->state = STATE_CLEAR;
 199                                 return true;
 200                                 break;
 201                         }
 202                 }
 203         }
 204         log(DEFAULT,"We never received an ack. Something fishy going on, host is dead.");
 205         this->state = STATE_CLEAR;
 206         return false;
 207
 208 }
 209
 210 bool connection::SendSYN(char* host, int port)
 211 {
 212         sockaddr_in host_address;
 213         in_addr addy;
 214         packet p;
 215
 216         memset((void*)&host_address, 0, sizeof(host_address));
 217
 218         host_address.sin_family = AF_INET;
 219         inet_aton(host,&addy);
 220         host_address.sin_addr = addy;
 221
 222         host_address.sin_port = htons(port);
 223
 224         p.type = PT_SYN_ONLY;
 225         p.key = key;
 226         strcpy(p.data,"");
 227
 228         if (sendto(fd,&p,sizeof(p),0,(sockaddr*)&host_address,sizeof(host_address))<0)
 229         {
 230                 return false;
 231         }
 232         return true;
 233
 234 }
 235
 236 bool connection::SendACK(char* host, int port, int reply_id)
 237 {
 238         sockaddr_in host_address;
 239         in_addr addy;
 240         packet p;
 241
 242         memset((void*)&host_address, 0, sizeof(host_address));
 243
 244         host_address.sin_family = AF_INET;
 245         inet_aton(host,&addy);
 246         host_address.sin_addr = addy;
 247
 248         host_address.sin_port = htons(port);
 249
 250         p.type = PT_ACK_ONLY;
 251         p.key = key;
 252         p.id = reply_id;
 253         strcpy(p.data,"");
 254
 255         if (sendto(fd,&p,sizeof(p),0,(sockaddr*)&host_address,sizeof(host_address))<0)
 256         {
 257                 return false;
 258         }
 259
 260 }
 261
 262
 263 // Generates a server key. This is pseudo-random.
 264 // the server always uses the same server-key in all communications
 265 // across the network. All other servers must remember the server key
 266 // of servers in the network, e.g.:
 267 //
 268 // ServerA:  key=5555555555
 269 // ServerB:  key=6666666666
 270 // I am ServerC: key=77777777777
 271 //
 272 // If ServerC sees a packet from ServerA, and the key stored for ServerA
 273 // is 0, then cache the key as the servers key.
 274 // after this point, any packet from ServerA which does not contain its key,
 275 // 555555555, will be silently dropped.
 276 // This should prevent blind spoofing, as to fake a server you must know its
 277 // assigned key, and to do that you must receive messages that are origintated
 278 // from it or hack the running executable.
 279 //
 280 // During the AUTH phase (when server passwords are checked, the key in any
 281 // packet MUST be 0). Only the initial SERVER/PASS packets may have a key
 282 // of 0 (and any ACK responses to them).
 283 //
 284
 285 long connection::GenKey()
 286 {
 287         srand(time(NULL));
 288         return (random()*time(NULL));
 289 }
 290
 291 // host: in dot notation a.b.c.d
 292 // port: host byte order
 293 bool connection::RecvPacket(char *message, char* host, int &prt, long &theirkey)
 294 {
 295         // returns false if no packet waiting for receive, e.g. EAGAIN or ECONNRESET
 296         sockaddr_in host_address;
 297         socklen_t host_address_size;
 298         packet p;
 299
 300         memset((void*)&host_address, 0, sizeof(host_address));
 301
 302         host_address.sin_family=AF_INET;
 303         host_address_size=sizeof(host_address);
 304
 305         //int recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlen);
 306         if (recvfrom(fd,&p,sizeof(p),0,(sockaddr*)&host_address,&host_address_size)<0)
 307         {
 308                 if (buffer.size())
 309                 {
 310                         log(DEBUG,"Fetching a buffered packet size %d",buffer.size());
 311                         strcpy(message,buffer[0].p.data);
 312                         theirkey = buffer[0].p.key;
 313                         strcpy(host,buffer[0].host);
 314                         prt = buffer[0].port;
 315
 316                         buffer.erase(0);
 317
 318                         return true;
 319                 }
 320                 return false;
 321         }
 322
 323         log(DEBUG,"connection::RecvPacket(): received packet type %d '%s' from '%s'",p.type,p.data,inet_ntoa(host_address.sin_addr));
 324
 325         if (p.type == PT_SYN_ONLY)
 326         {
 327                 strcpy(message,p.data);
 328                 strcpy(host,inet_ntoa(host_address.sin_addr));
 329                 prt = ntohs(host_address.sin_port);
 330                 SendACK(host,this->port,p.id);
 331                 return false;
 332         }
 333
 334         if (p.type == PT_ACK_ONLY)
 335         {
 336                 strcpy(message,p.data);
 337                 strcpy(host,inet_ntoa(host_address.sin_addr));
 338                 prt = ntohs(host_address.sin_port);
 339                 this->state = STATE_CLEAR;
 340                 return false;
 341         }
 342
 343         if (p.type == PT_SYN_WITH_DATA)
 344         {
 345                 strcpy(message,p.data);
 346                 strcpy(host,inet_ntoa(host_address.sin_addr));
 347                 theirkey = p.key;
 348                 prt = ntohs(host_address.sin_port); // the port we received it on
 349                 SendACK(host,prt,p.id);
 350
 351                 if (buffer.size())
 352                 {
 353                         log(DEBUG,"Fetching a buffered packet size %d",buffer.size());
 354                         packet_buf pb;
 355                         pb.p.id = p.id;
 356                         pb.p.key = p.key;
 357                         pb.p.type = p.type;
 358                         strcpy(pb.host,inet_ntoa(host_address.sin_addr));
 359                         pb.port = ntohs(host_address.sin_port);
 360                         this->buffer.push_back(pb);
 361
 362                         strcpy(message,buffer[0].p.data);
 363                         theirkey = buffer[0].p.key;
 364                         strcpy(host,buffer[0].host);
 365                         prt = buffer[0].port;
 366
 367                         buffer.erase(0);
 368                 }
 369
 370                 return true;
 371         }
 372
 373         log(DEBUG,"connection::RecvPacket(): Invalid packet type %d (protocol error)",p.type);
 374         return true;
 375 }
 376