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