3 * $Id: chan.c,v 1.1 1999/07/01 08:56:23 mdw Exp $
7 * (c) 1999 Mark Wooding
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the `fw' port forwarder.
14 * `fw' is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * `fw' is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with `fw'; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.1 1999/07/01 08:56:23 mdw
37 /*----- Header files ------------------------------------------------------*/
46 #include <sys/types.h>
51 #include <sys/socket.h>
52 #include <netinet/in.h>
53 #include <arpa/inet.h>
55 #include <mLib/alloc.h>
56 #include <mLib/conn.h>
62 /*----- Main code ---------------------------------------------------------*/
64 /* --- @writechan@ --- *
66 * Arguments: @int fd@ = file descriptor to write to
67 * @unsigned mode@ = what the descriptor is ready for
68 * @void *vp@ = pointer to channel block
72 * Use: Writes to a channel.
75 static void writechan(int fd, unsigned mode, void *vp)
79 unsigned base = c->base;
80 unsigned len = c->len;
82 /* --- Write data from my buffer --- */
86 /* --- Do the write --- */
88 if (base + len <= CHAN_BUFSZ)
89 w = write(fd, c->buf + base, len);
92 iov[0].iov_base = c->buf + base;
93 iov[0].iov_len = CHAN_BUFSZ - base;
94 iov[1].iov_base = c->buf;
95 iov[1].iov_len = len - iov[0].iov_len;
96 w = writev(fd, iov, 2);
99 /* --- Sift through the results --- */
102 if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
108 else if (c->len == CHAN_BUFSZ && !(c->f & CHANF_CLOSE))
115 /* --- Close the output end if necessary --- */
117 if (c->len == 0 && (c->f & CHANF_CLOSE)) {
123 /* --- Force a close if an error occurred --- */
130 /* --- @readchan@ --- *
132 * Arguments: @int fd@ = file descriptor to read from
133 * @unsigned mode@ = what the descriptor is ready for
134 * @void *vp@ = pointer to channel block
138 * Use: Reads from a channel.
141 static void readchan(int fd, unsigned mode, void *vp)
145 unsigned base = (c->base + c->len) & (CHAN_BUFSZ - 1);
146 unsigned len = CHAN_BUFSZ - c->len;
148 /* --- Do the read --- */
150 if (base + len <= CHAN_BUFSZ)
151 r = read(fd, c->buf + base, len);
154 iov[0].iov_base = c->buf + base;
155 iov[0].iov_len = CHAN_BUFSZ - base;
156 iov[1].iov_base = c->buf;
157 iov[1].iov_len = len - iov[0].iov_len;
158 r = readv(fd, iov, 2);
161 /* --- Sift through the results --- */
164 if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
170 else if (c->len == 0 && !(c->f & CHANF_READY))
173 if (c->len == CHAN_BUFSZ)
177 /* --- Close the read end of the channel --- */
186 /* --- @chan_close@ --- *
188 * Arguments: @chan *c@ = pointer to channel
192 * Use: Closes down a channel prematurely.
195 void chan_close(chan *c)
197 if (!(c->f & CHANF_CLOSE) && c->len != CHAN_BUFSZ)
199 if ((c->f & CHANF_READY) && c->len != 0)
203 /* --- @chan_dest@ --- *
205 * Arguments: @chan *c@ = pointer to channel
206 * @int fd@ = destination file descriptor for channel
210 * Use: Sets the channel's destination so it knows where to put
214 void chan_dest(chan *c, int fd)
216 if (c->f & CHANF_READY)
218 sel_initfile(sel, &c->w, fd, SEL_WRITE, writechan, c);
223 /* --- @chan_open@ --- *
225 * Arguments: @chan *c@ = pointer to channel to open
226 * @int from, to@ = source and destination file descriptors
227 * @void (*func)(void *p)@ = function to call on closure
228 * @void *p@ = argument to pass to function
232 * Use: Opens a channel. Data is copied from the source to the
233 * destination. The @to@ argument may be @-1@ if the file
234 * descriptor isn't known yet.
237 void chan_open(chan *c, int from, int to,
238 void (*func)(void */*p*/), void *p)
247 sel_initfile(sel, &c->r, from, SEL_READ, readchan, c);
254 /*----- That's all, folks -------------------------------------------------*/