1 /***************************************************************************
2 * Copyright (C) 2006 by Gerd v. Egidy *
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. *
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. *
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 ***************************************************************************/
24 #include <sys/types.h>
25 #include <sys/socket.h>
28 #include <arpa/inet.h>
29 #include <netinet/in.h>
40 #include "socket_handler.hxx"
41 #include "t2n_exception.hxx"
49 socket_handler::socket_handler(int _sock, socket_type_value _socket_type)
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)
59 /// set options like fast reuse and keepalive every socket should have
60 void socket_handler::set_socket_options(int sock)
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));
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));
74 fdflags=fcntl(sock,F_GETFD, 0);
76 EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno));
78 fdflags |= FD_CLOEXEC;
79 if (fcntl(sock,F_SETFD,fdflags) < 0)
80 EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno));
82 /* non-blocking mode */
84 flflags=fcntl(sock,F_GETFL,0);
86 EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno));
88 flflags |= O_NONBLOCK;
89 if (fcntl(sock,F_SETFL,flflags) < 0)
90 EXCEPTIONSTREAM(error,t2n_communication_error,"fcntl error on socket: " << strerror(errno));
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()
98 shutdown(sock,SHUT_RDWR);
102 /// is the underlying socket connection still open?
103 bool socket_handler::is_closed()
105 int r=fcntl(sock,F_GETFL);
107 return !(r & O_ACCMODE);
112 * @brief set a new size for the receive buffer.
113 * @param new_recv_buffer_size the new size for the receive buffer.
115 * The receive buffer determines the amount of data which is tried to read at once
116 * from the underlying socket.
118 * The value is normalized to be at least 512 bytes and at max 32K bytes.
120 void socket_handler::set_recv_buffer_size(unsigned int new_recv_buffer_size)
122 recv_buffer_size= std::max( 512u, std::min( 32u * 1024u, new_recv_buffer_size ));
127 * @brief set new size for the data chunks when writeing.
128 * @param new_write_block_size the new chunk size.
130 * The write block size determines the amount of data which is tried to write
131 * to the socket when data needs to be sended.
132 * Since writing data is done in a loop, this does not limit the amunt of data which can
135 * The value is normalized to be at least 512 bytes and at max 32K bytes.
137 void socket_handler::set_write_block_size(unsigned int new_write_block_size)
139 write_block_size= std::max( 512u, std::min( 32u * 1024u, new_write_block_size ));
144 * @brief set new timeout for writing a block
145 * @param new_write_timeout the new timeout in usecs, -1: wait endless
147 * The write timeout determines the maximum amount of time that is waited
148 * between writing each block. If the timeout is exceeded, write will
149 * throw t2n_transfer_error
151 void socket_handler::set_write_timeout(long long new_write_timeout)
153 write_block_size=new_write_timeout;
157 /** @brief check if new data is waiting on the raw socket
158 @param[in,out] usec_timeout wait until new data is found, max timeout usecs.
162 bool socket_handler::data_waiting(long long usec_timeout,long long* usec_timeout_remaining)
165 fd_set active_fd_set;
166 FD_ZERO (&active_fd_set);
167 FD_SET (sock, &active_fd_set);
171 struct timeval *timeout_ptr;
173 if (usec_timeout == -1)
179 // convert timeout from long long usec to int sec + int usec
180 tval.tv_sec = usec_timeout / 1000000;
181 tval.tv_usec = usec_timeout % 1000000;
184 int ret=select (FD_SETSIZE, &active_fd_set, NULL, NULL, timeout_ptr);
186 // return the timeout we did not use
187 // todo: this is linux specific according to man 2 select
188 if (usec_timeout > 0 && usec_timeout_remaining != NULL)
189 *usec_timeout_remaining=(tval.tv_sec*1000000)+tval.tv_usec;
197 /** @brief read data from the raw socket and copy it into the provided buffer
198 @param buffer the buffer where to append the new data
199 @param[in,out] usec_timeout wait until new data is found, max timeout usecs.
203 bool socket_handler::fill_buffer(std::string& buffer, long long usec_timeout, long long *timeout_remaining)
205 // fast path for timeout==0
206 if (usec_timeout==0 || data_waiting(usec_timeout,timeout_remaining))
207 return fill_buffer(buffer);
212 /** @brief read data from the raw socket and copy it into the provided buffer. Returns
213 instantly if no data is waiting.
214 @param buffer the buffer where to append the new data
216 bool socket_handler::fill_buffer(std::string& buffer)
218 bool try_again=false;
220 char socket_buffer[recv_buffer_size];
222 int nbytes = read (sock, socket_buffer, recv_buffer_size);
226 return false; // no data was waiting
227 else if (errno == EINTR)
229 // interrupted, try again
230 LOGSTREAM(debug,"EINTR received on read(), trying again");
234 EXCEPTIONSTREAM(error,t2n_transfer_error,"error reading from socket : " << strerror(errno));
238 if (nbytes == 0 && !try_again)
240 LOGSTREAM(debug,"0 bytes received on read(), closing connection");
245 // Data read -> store it
248 buffer.append(socket_buffer,nbytes);
249 LOGSTREAM(debug,nbytes << " bytes read");
252 // more data waiting -> recurse
262 /// writes raw data to the socket. Don't use directly, use the write() function provided by the
263 /// connection because it encapsulates the data.
264 void socket_handler::socket_write(const std::string& data)
267 while (offset < data.size())
269 unsigned int write_size=write_block_size;
271 if (offset+write_size > data.size())
272 write_size = data.size()-offset;
275 while ((rtn=::write(sock, data.data()+offset, write_size)) == -1 &&
276 (errno == EAGAIN || errno == EINTR))
278 wait_ready_to_write(sock,write_timeout);
279 LOGSTREAM(debug,"resuming write() call after EAGAIN or EINTR");
283 EXCEPTIONSTREAM(error,t2n_transfer_error,"write() returned " << strerror(errno));
284 else if (rtn != write_size)
286 LOGSTREAM(debug,"write() wrote " << rtn << " bytes, should have been "
287 << write_size << " (complete: " << data.size() << ")");
292 offset += write_size;
295 LOGSTREAM(debug,"wrote " << data.size() << " bytes");
298 } // eo socket_handler::socket_write(const std::string&)
300 /// wait until the socket is ready to write again
301 void socket_handler::wait_ready_to_write(int socket, long long write_block_timeout)
303 // prepare socket sets
305 fd_set except_set[1];
308 FD_SET(socket, write_set);
309 FD_SET(socket, except_set);
311 // prepare timeout struct
313 struct timeval *timeout_ptr;
315 if (write_block_timeout == -1)
321 // convert timeout from long long usec to int sec + int usec
322 tval.tv_sec = write_block_timeout / 1000000;
323 tval.tv_usec = write_block_timeout % 1000000;
326 // let's wait for the socket to become writable again...
328 while ((rtn=::select(socket+1, NULL, write_set, except_set, timeout_ptr)) ==-1 && errno == EINTR);
330 if (rtn > 0 && (!FD_ISSET(socket,write_set)) && FD_ISSET(socket, except_set))
332 // if we are selected but cannot write and have an exception
333 // we have serious trouble...
334 EXCEPTIONSTREAM(error,t2n_transfer_error,"exception on socket; cannot write any more.");
338 EXCEPTIONSTREAM(error,t2n_transfer_error,"timeout on select() for write");
341 EXCEPTIONSTREAM(error,t2n_transfer_error,"cannot select() for write: " << strerror(errno));