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         buffer.clear();
  86
  87         return true;
  88 }
  89
  90 bool connection::BeginLink(char* targethost, int port, char* password)
  91 {
  92         char connect[MAXBUF];
  93
  94         if (this->fd)
  95         {
  96                 sprintf(connect,"S %s %s :%s",getservername().c_str(),password,getserverdesc().c_str());
  97                 this->haspassed = false;
  98                 return this->SendPacket(connect, targethost, port, 0);
  99         }
 100         return false;
 101 }
 102
 103 // targethost: in dot notation a.b.c.d
 104 void connection::TerminateLink(char* targethost)
 105 {
 106 }
 107
 108 // host: in dot notation a.b.c.d
 109 // port: host byte order
 110 bool connection::SendPacket(char *message, char* host, int port, long ourkey)
 111 {
 112         sockaddr_in host_address;
 113         in_addr addy;
 114         packet p;
 115
 116         memset((void*)&host_address, 0, sizeof(host_address));
 117
 118         host_address.sin_family = AF_INET;
 119         inet_aton(host,&addy);
 120         host_address.sin_addr = addy;
 121
 122         host_address.sin_port = htons(port);
 123
 124         strcpy(p.data,message);
 125         p.type = PT_SYN_WITH_DATA;
 126         p.key = ourkey;
 127
 128
 129         FOREACH_MOD OnPacketTransmit(p.data);
 130
 131         log(DEBUG,"main: Connection::SendPacket() sent '%s' to %s:%d",p.data,host,port);
 132
 133         // returns false if the packet could not be sent (e.g. target host down)
 134         if (sendto(this->fd,&p,sizeof(p),0,(sockaddr*)&host_address,sizeof(host_address))<0)
 135         {
 136                 log(DEBUG,"sendto() failed for Connection::SendPacket() with a packet of size %d: %s",sizeof(p),strerror(errno));
 137                 return false;
 138         }
 139         this->state = STATE_WAIT_FOR_ACK;
 140
 141
 142         // host_address remains unchanged. we only want to receive from where we just sent the packet to.
 143
 144         // retry the packet up to 5 times
 145         for (int retries = 0; retries < 5; retries++)
 146         {
 147                 socklen_t host_address_size;
 148                 host_address.sin_family=AF_INET;
 149                 host_address_size=sizeof(host_address);
 150
 151                 // wait for ack, or timeout.
 152                 // if reached a timeout, send again.
 153                 // the packet id in the ack must match that in the original packet
 154                 // this MUST operate in lock/step fashion!!!
 155                 int cycles = 0;
 156                 packet p2;
 157                 do
 158                 {
 159                         fd_set sfd;
 160                         timeval tval;
 161                         tval.tv_usec = 100;
 162                         tval.tv_sec = 0;
 163                         FD_ZERO(&sfd);
 164                         FD_SET(fd,&sfd);
 165                         int res = select(65535, &sfd, NULL, NULL, &tval);
 166                         cycles++;
 167                 }
 168                 while ((recvfrom(fd,&p2,sizeof(p2),0,(sockaddr*)&host_address,&host_address_size)<0) && (cycles < 10));
 169
 170                 if (cycles >= 10)
 171                 {
 172                         log(DEFAULT,"ERROR! connection::SendPacket() waited >10000 nanosecs for an ACK. Will resend up to 5 times");
 173                 }
 174                 else
 175                 {
 176                         if (p2.type != PT_ACK_ONLY)
 177                         {
 178                                 packet_buf pb;
 179                                 pb.p.id = p.id;
 180                                 pb.p.key = p.key;
 181                                 pb.p.type = p.type;
 182                                 strcpy(pb.p.data,p.data);
 183                                 strcpy(pb.host,inet_ntoa(host_address.sin_addr));
 184                                 pb.port = ntohs(host_address.sin_port);
 185                                 this->buffer.push_back(pb);
 186
 187                                 log(DEFAULT,"ERROR! connection::SendPacket() received a data response and was expecting an ACK!!!");
 188                                 this->state = STATE_CLEAR;
 189                                 return true;
 190                         }
 191
 192                         if (p2.id != p.id)
 193                         {
 194                                 log(DEFAULT,"ERROR! connection::SendPacket() received an ack for a packet it didnt send!");
 195                                 this->state = STATE_CLEAR;
 196                                 return false;
 197                         }
 198                         else
 199                         {
 200                                 log(DEFAULT,"Successfully received ACK");
 201                                 this->state = STATE_CLEAR;
 202                                 return true;
 203                                 break;
 204                         }
 205                 }
 206         }
 207         log(DEFAULT,"We never received an ack. Something fishy going on, host is dead.");
 208         this->state = STATE_CLEAR;
 209         return false;
 210
 211 }
 212
 213 bool connection::SendSYN(char* host, int port)
 214 {
 215         sockaddr_in host_address;
 216         in_addr addy;
 217         packet p;
 218
 219         memset((void*)&host_address, 0, sizeof(host_address));
 220
 221         host_address.sin_family = AF_INET;
 222         inet_aton(host,&addy);
 223         host_address.sin_addr = addy;
 224
 225         host_address.sin_port = htons(port);
 226
 227         p.type = PT_SYN_ONLY;
 228         p.key = key;
 229         strcpy(p.data,"");
 230
 231         if (sendto(fd,&p,sizeof(p),0,(sockaddr*)&host_address,sizeof(host_address))<0)
 232         {
 233                 return false;
 234         }
 235         return true;
 236
 237 }
 238
 239 bool connection::SendACK(char* host, int port, int reply_id)
 240 {
 241         sockaddr_in host_address;
 242         in_addr addy;
 243         packet p;
 244
 245         memset((void*)&host_address, 0, sizeof(host_address));
 246
 247         host_address.sin_family = AF_INET;
 248         inet_aton(host,&addy);
 249         host_address.sin_addr = addy;
 250
 251         host_address.sin_port = htons(port);
 252
 253         p.type = PT_ACK_ONLY;
 254         p.key = key;
 255         p.id = reply_id;
 256         strcpy(p.data,"");
 257
 258         if (sendto(fd,&p,sizeof(p),0,(sockaddr*)&host_address,sizeof(host_address))<0)
 259         {
 260                 return false;
 261         }
 262
 263 }
 264
 265
 266 // Generates a server key. This is pseudo-random.
 267 // the server always uses the same server-key in all communications
 268 // across the network. All other servers must remember the server key
 269 // of servers in the network, e.g.:
 270 //
 271 // ServerA:  key=5555555555
 272 // ServerB:  key=6666666666
 273 // I am ServerC: key=77777777777
 274 //
 275 // If ServerC sees a packet from ServerA, and the key stored for ServerA
 276 // is 0, then cache the key as the servers key.
 277 // after this point, any packet from ServerA which does not contain its key,
 278 // 555555555, will be silently dropped.
 279 // This should prevent blind spoofing, as to fake a server you must know its
 280 // assigned key, and to do that you must receive messages that are origintated
 281 // from it or hack the running executable.
 282 //
 283 // During the AUTH phase (when server passwords are checked, the key in any
 284 // packet MUST be 0). Only the initial SERVER/PASS packets may have a key
 285 // of 0 (and any ACK responses to them).
 286 //
 287
 288 long connection::GenKey()
 289 {
 290         srand(time(NULL));
 291         return (random()*time(NULL));
 292 }
 293
 294 // host: in dot notation a.b.c.d
 295 // port: host byte order
 296 bool connection::RecvPacket(char *message, char* host, int &prt, long &theirkey)
 297 {
 298         // returns false if no packet waiting for receive, e.g. EAGAIN or ECONNRESET
 299         sockaddr_in host_address;
 300         socklen_t host_address_size;
 301         packet p;
 302
 303         memset((void*)&host_address, 0, sizeof(host_address));
 304
 305         host_address.sin_family=AF_INET;
 306         host_address_size=sizeof(host_address);
 307
 308         //int recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlen);
 309         if (recvfrom(fd,&p,sizeof(p),0,(sockaddr*)&host_address,&host_address_size)<0)
 310         {
 311                 if (buffer.size()>0)
 312                 {
 313                         log(DEBUG,"Fetching a buffered packet size %d",buffer.size());
 314                         strcpy(message,buffer[0].p.data);
 315                         theirkey = buffer[0].p.key;
 316                         strcpy(host,buffer[0].host);
 317                         prt = buffer[0].port;
 318
 319                         buffer.erase(buffer.begin());
 320
 321                         return true;
 322                 }
 323                 return false;
 324         }
 325
 326         log(DEBUG,"connection::RecvPacket(): received packet type %d '%s' from '%s'",p.type,p.data,inet_ntoa(host_address.sin_addr));
 327
 328         if (p.type == PT_SYN_ONLY)
 329         {
 330                 strcpy(message,p.data);
 331                 strcpy(host,inet_ntoa(host_address.sin_addr));
 332                 prt = ntohs(host_address.sin_port);
 333                 SendACK(host,this->port,p.id);
 334                 return false;
 335         }
 336
 337         if (p.type == PT_ACK_ONLY)
 338         {
 339                 strcpy(message,p.data);
 340                 strcpy(host,inet_ntoa(host_address.sin_addr));
 341                 prt = ntohs(host_address.sin_port);
 342                 this->state = STATE_CLEAR;
 343                 return false;
 344         }
 345
 346         if (p.type == PT_SYN_WITH_DATA)
 347         {
 348                 strcpy(message,p.data);
 349                 strcpy(host,inet_ntoa(host_address.sin_addr));
 350                 theirkey = p.key;
 351                 prt = ntohs(host_address.sin_port); // the port we received it on
 352                 SendACK(host,prt,p.id);
 353
 354                 if (buffer.size()>0)
 355                 {
 356                         log(DEBUG,"Fetching a buffered packet size %d",buffer.size());
 357                         packet_buf pb;
 358                         pb.p.id = p.id;
 359                         pb.p.key = p.key;
 360                         pb.p.type = p.type;
 361                         strcpy(pb.p.data,p.data);
 362                         strcpy(pb.host,inet_ntoa(host_address.sin_addr));
 363                         pb.port = ntohs(host_address.sin_port);
 364                         this->buffer.push_back(pb);
 365
 366                         strcpy(message,buffer[0].p.data);
 367                         theirkey = buffer[0].p.key;
 368                         strcpy(host,buffer[0].host);
 369                         prt = buffer[0].port;
 370
 371                         buffer.erase(buffer.begin());
 372                 }
 373
 374                 return true;
 375         }
 376
 377         log(DEBUG,"connection::RecvPacket(): Invalid packet type %d (protocol error)",p.type);
 378         return true;
 379 }
 380