| 1 | /*************************************************************************** |
| 2 | * Copyright (C) 2006 by Gerd v. Egidy * |
| 3 | * gve@intra2net.com * |
| 4 | * * |
| 5 | * This library is free software; you can redistribute it and/or modify * |
| 6 | * it under the terms of the GNU Lesser General Public License version * |
| 7 | * 2.1 as published by the Free Software Foundation. * |
| 8 | * * |
| 9 | * This library is distributed in the hope that it will be useful, * |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
| 12 | * GNU Lesser General Public License for more details. * |
| 13 | * * |
| 14 | * You should have received a copy of the GNU Lesser General Public * |
| 15 | * License along with this program; if not, write to the * |
| 16 | * Free Software Foundation, Inc., * |
| 17 | * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * |
| 18 | ***************************************************************************/ |
| 19 | |
| 20 | #include <stdio.h> |
| 21 | #include <errno.h> |
| 22 | #include <stdlib.h> |
| 23 | #include <unistd.h> |
| 24 | #include <sys/types.h> |
| 25 | #include <sys/socket.h> |
| 26 | #include <sys/un.h> |
| 27 | #include <sys/time.h> |
| 28 | #include <arpa/inet.h> |
| 29 | #include <netinet/in.h> |
| 30 | #include <netdb.h> |
| 31 | #include <fcntl.h> |
| 32 | #include <time.h> |
| 33 | #include <pwd.h> |
| 34 | #include <grp.h> |
| 35 | |
| 36 | #include <sstream> |
| 37 | #include <iostream> |
| 38 | #include <algorithm> |
| 39 | |
| 40 | #include "socket_handler.hxx" |
| 41 | #include "t2n_exception.hxx" |
| 42 | #include "log.hxx" |
| 43 | |
| 44 | using namespace std; |
| 45 | |
| 46 | namespace libt2n |
| 47 | { |
| 48 | |
| 49 | socket_handler::socket_handler(int _sock, socket_type_value _socket_type) |
| 50 | : sock(_sock) |
| 51 | , recv_buffer_size( default_recv_buffer_size ) |
| 52 | , write_block_size( default_write_block_size ) |
| 53 | , write_timeout( default_write_timeout ) |
| 54 | , socket_type(_socket_type) |
| 55 | { |
| 56 | } |
| 57 | |
| 58 | |
| 59 | /// set options like fast reuse and keepalive every socket should have |
| 60 | void socket_handler::set_socket_options(int sock) |
| 61 | { |
| 62 | int i=1; |
| 63 | |
| 64 | /* fast reuse enable */ |
| 65 | if (setsockopt(sock,SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i)) < 0) |
| 66 | EXCEPTIONSTREAM(error,t2n_communication_error,"error setting socket option: " << strerror(errno)); |
| 67 | |
| 68 | /* keepalive enable */ |
| 69 | if (setsockopt(sock,SOL_SOCKET, SO_KEEPALIVE, &i, sizeof(i)) < 0) |
| 70 | EXCEPTIONSTREAM(error,t2n_communication_error,"error setting socket option: " << strerror(errno)); |
| 71 | |
| 72 | /* close on exec */ |
| 73 | int fdflags; |
| 74 | fdflags=fcntl(sock,F_GETFD, 0); |
| 75 | if (fdflags < 0) |
| 76 | EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno)); |
| 77 | |
| 78 | fdflags |= FD_CLOEXEC; |
| 79 | if (fcntl(sock,F_SETFD,fdflags) < 0) |
| 80 | EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno)); |
| 81 | |
| 82 | /* non-blocking mode */ |
| 83 | int flflags; |
| 84 | flflags=fcntl(sock,F_GETFL,0); |
| 85 | if (flflags < 0) |
| 86 | EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno)); |
| 87 | |
| 88 | flflags |= O_NONBLOCK; |
| 89 | if (fcntl(sock,F_SETFL,flflags) < 0) |
| 90 | EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno)); |
| 91 | } |
| 92 | |
| 93 | /// close the underlying socket connection. Don't call directly, use the version provided |
| 94 | /// by the connection class you are using. |
| 95 | void socket_handler::close() |
| 96 | { |
| 97 | LOGSTREAM(debug,"close connection"); |
| 98 | // graceful shutdown |
| 99 | shutdown(sock,SHUT_RDWR); |
| 100 | ::close(sock); |
| 101 | } |
| 102 | |
| 103 | /// is the underlying socket connection still open? |
| 104 | bool socket_handler::is_closed() |
| 105 | { |
| 106 | int r=fcntl(sock,F_GETFL); |
| 107 | |
| 108 | return !(r & O_ACCMODE); |
| 109 | } |
| 110 | |
| 111 | |
| 112 | /** |
| 113 | * @brief set a new size for the receive buffer. |
| 114 | * @param new_recv_buffer_size the new size for the receive buffer. |
| 115 | * |
| 116 | * The receive buffer determines the amount of data which is tried to read at once |
| 117 | * from the underlying socket. |
| 118 | * |
| 119 | * The value is normalized to be at least 512 bytes and at max 32K bytes. |
| 120 | */ |
| 121 | void socket_handler::set_recv_buffer_size(unsigned int new_recv_buffer_size) |
| 122 | { |
| 123 | recv_buffer_size= std::max( 512u, std::min( 32u * 1024u, new_recv_buffer_size )); |
| 124 | } // |
| 125 | |
| 126 | |
| 127 | /** |
| 128 | * @brief set new size for the data chunks when writeing. |
| 129 | * @param new_write_block_size the new chunk size. |
| 130 | * |
| 131 | * The write block size determines the amount of data which is tried to write |
| 132 | * to the socket when data needs to be sended. |
| 133 | * Since writing data is done in a loop, this does not limit the amunt of data which can |
| 134 | * be written. |
| 135 | * |
| 136 | * The value is normalized to be at least 512 bytes and at max 32K bytes. |
| 137 | */ |
| 138 | void socket_handler::set_write_block_size(unsigned int new_write_block_size) |
| 139 | { |
| 140 | write_block_size= std::max( 512u, std::min( 32u * 1024u, new_write_block_size )); |
| 141 | } // |
| 142 | |
| 143 | |
| 144 | /** |
| 145 | * @brief set new timeout for writing a block |
| 146 | * @param new_write_timeout the new timeout in usecs, -1: wait endless |
| 147 | * |
| 148 | * The write timeout determines the maximum amount of time that is waited |
| 149 | * between writing each block. If the timeout is exceeded, write will |
| 150 | * throw t2n_transfer_error |
| 151 | */ |
| 152 | void socket_handler::set_write_timeout(long long new_write_timeout) |
| 153 | { |
| 154 | write_block_size=new_write_timeout; |
| 155 | } // |
| 156 | |
| 157 | |
| 158 | /** @brief check if new data is waiting on the raw socket |
| 159 | @param[in,out] usec_timeout wait until new data is found, max timeout usecs. |
| 160 | -1: wait endless |
| 161 | 0: return instantly |
| 162 | */ |
| 163 | bool socket_handler::data_waiting(long long usec_timeout,long long* usec_timeout_remaining) |
| 164 | { |
| 165 | // just our socket |
| 166 | fd_set active_fd_set; |
| 167 | FD_ZERO (&active_fd_set); |
| 168 | FD_SET (sock, &active_fd_set); |
| 169 | |
| 170 | /* set timeout */ |
| 171 | struct timeval tval; |
| 172 | struct timeval *timeout_ptr; |
| 173 | |
| 174 | if (usec_timeout == -1) |
| 175 | timeout_ptr = NULL; |
| 176 | else |
| 177 | { |
| 178 | timeout_ptr = &tval; |
| 179 | |
| 180 | // convert timeout from long long usec to int sec + int usec |
| 181 | tval.tv_sec = usec_timeout / 1000000; |
| 182 | tval.tv_usec = usec_timeout % 1000000; |
| 183 | } |
| 184 | |
| 185 | int ret=select (FD_SETSIZE, &active_fd_set, NULL, NULL, timeout_ptr); |
| 186 | |
| 187 | // return the timeout we did not use |
| 188 | // todo: this is linux specific according to man 2 select |
| 189 | if (usec_timeout > 0 && usec_timeout_remaining != NULL) |
| 190 | *usec_timeout_remaining=(tval.tv_sec*1000000)+tval.tv_usec; |
| 191 | |
| 192 | if (ret > 0) |
| 193 | return true; |
| 194 | else |
| 195 | return false; |
| 196 | } |
| 197 | |
| 198 | /** @brief read data from the raw socket and copy it into the provided buffer |
| 199 | @param buffer the buffer where to append the new data |
| 200 | @param[in,out] usec_timeout wait until new data is found, max timeout usecs. |
| 201 | -1: wait endless |
| 202 | 0: return instantly |
| 203 | */ |
| 204 | bool socket_handler::fill_buffer(std::string& buffer, long long usec_timeout, long long *timeout_remaining) |
| 205 | { |
| 206 | // fast path for timeout==0 |
| 207 | if (usec_timeout==0 || data_waiting(usec_timeout,timeout_remaining)) |
| 208 | return fill_buffer(buffer); |
| 209 | else |
| 210 | return false; |
| 211 | } |
| 212 | |
| 213 | /** @brief read data from the raw socket and copy it into the provided buffer. Returns |
| 214 | instantly if no data is waiting. |
| 215 | @param buffer the buffer where to append the new data |
| 216 | */ |
| 217 | bool socket_handler::fill_buffer(std::string& buffer) |
| 218 | { |
| 219 | bool try_again=false; |
| 220 | |
| 221 | char socket_buffer[recv_buffer_size]; |
| 222 | |
| 223 | int nbytes = read (sock, socket_buffer, recv_buffer_size); |
| 224 | |
| 225 | if (nbytes < 0) |
| 226 | { |
| 227 | if (errno == EAGAIN) |
| 228 | return false; // no data was waiting |
| 229 | else if (errno == EINTR) |
| 230 | { |
| 231 | // interrupted, try again |
| 232 | LOGSTREAM(debug,"EINTR received on read(), trying again"); |
| 233 | try_again=true; |
| 234 | } |
| 235 | else |
| 236 | EXCEPTIONSTREAM(error,t2n_transfer_error,"error reading from socket : " << strerror(errno)); |
| 237 | } |
| 238 | |
| 239 | // End-of-file |
| 240 | if (nbytes == 0 && !try_again) |
| 241 | { |
| 242 | LOGSTREAM(debug,"0 bytes received on read(), closing connection"); |
| 243 | close(); |
| 244 | return false; |
| 245 | } |
| 246 | |
| 247 | // Data read -> store it |
| 248 | if (nbytes > 0) |
| 249 | { |
| 250 | buffer.append(socket_buffer,nbytes); |
| 251 | LOGSTREAM(debug,nbytes << " bytes read"); |
| 252 | } |
| 253 | |
| 254 | // more data waiting -> recurse |
| 255 | if (data_waiting(0)) |
| 256 | fill_buffer(buffer); |
| 257 | |
| 258 | if (nbytes > 0) |
| 259 | return true; |
| 260 | else |
| 261 | return false; |
| 262 | } |
| 263 | |
| 264 | /// writes raw data to the socket. Don't use directly, use the write() function provided by the |
| 265 | /// connection because it encapsulates the data. |
| 266 | void socket_handler::socket_write(const std::string& data) |
| 267 | { |
| 268 | int offset = 0; |
| 269 | while (offset < data.size()) |
| 270 | { |
| 271 | unsigned int write_size=write_block_size; |
| 272 | |
| 273 | if (offset+write_size > data.size()) |
| 274 | write_size = data.size()-offset; |
| 275 | |
| 276 | int rtn; |
| 277 | while ((rtn=::write(sock, data.data()+offset, write_size)) == -1 && |
| 278 | (errno == EAGAIN || errno == EINTR)) |
| 279 | { |
| 280 | wait_ready_to_write(sock,write_timeout); |
| 281 | LOGSTREAM(debug,"resuming write() call after EAGAIN or EINTR"); |
| 282 | } |
| 283 | |
| 284 | if (rtn == -1) |
| 285 | EXCEPTIONSTREAM(error,t2n_transfer_error,"write() returned " << strerror(errno)); |
| 286 | else if (rtn != write_size) |
| 287 | { |
| 288 | LOGSTREAM(debug,"write() wrote " << rtn << " bytes, should have been " |
| 289 | << write_size << " (complete: " << data.size() << ")"); |
| 290 | |
| 291 | write_size = rtn; |
| 292 | } |
| 293 | |
| 294 | offset += write_size; |
| 295 | } |
| 296 | |
| 297 | LOGSTREAM(debug,"wrote " << data.size() << " bytes"); |
| 298 | |
| 299 | return; |
| 300 | } // eo socket_handler::socket_write(const std::string&) |
| 301 | |
| 302 | /// wait until the socket is ready to write again |
| 303 | void socket_handler::wait_ready_to_write(int socket, long long write_block_timeout) |
| 304 | { |
| 305 | // prepare socket sets |
| 306 | fd_set write_set[1]; |
| 307 | fd_set except_set[1]; |
| 308 | FD_ZERO(write_set); |
| 309 | FD_ZERO(except_set); |
| 310 | FD_SET(socket, write_set); |
| 311 | FD_SET(socket, except_set); |
| 312 | |
| 313 | // prepare timeout struct |
| 314 | struct timeval tval; |
| 315 | struct timeval *timeout_ptr; |
| 316 | |
| 317 | if (write_block_timeout == -1) |
| 318 | timeout_ptr = NULL; |
| 319 | else |
| 320 | { |
| 321 | timeout_ptr = &tval; |
| 322 | |
| 323 | // convert timeout from long long usec to int sec + int usec |
| 324 | tval.tv_sec = write_block_timeout / 1000000; |
| 325 | tval.tv_usec = write_block_timeout % 1000000; |
| 326 | } |
| 327 | |
| 328 | // let's wait for the socket to become writable again... |
| 329 | int rtn; |
| 330 | while ((rtn=::select(socket+1, NULL, write_set, except_set, timeout_ptr)) ==-1 && errno == EINTR); |
| 331 | |
| 332 | if (rtn > 0 && (!FD_ISSET(socket,write_set)) && FD_ISSET(socket, except_set)) |
| 333 | { |
| 334 | // if we are selected but cannot write and have an exception |
| 335 | // we have serious trouble... |
| 336 | EXCEPTIONSTREAM(error,t2n_transfer_error,"exception on socket; cannot write any more."); |
| 337 | } |
| 338 | |
| 339 | if (rtn==0) |
| 340 | EXCEPTIONSTREAM(error,t2n_transfer_error,"timeout on select() for write"); |
| 341 | |
| 342 | if (rtn==-1) |
| 343 | EXCEPTIONSTREAM(error,t2n_transfer_error,"cannot select() for write: " << strerror(errno)); |
| 344 | } |
| 345 | |
| 346 | |
| 347 | } |