Various changes. Add configuration grammar to help text. Change to
[fwd] / chan.c
CommitLineData
e82f7154 1/* -*-c-*-
2 *
3 * $Id: chan.c,v 1.1 1999/07/01 08:56:23 mdw Exp $
4 *
5 * Channel management
6 *
7 * (c) 1999 Mark Wooding
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of the `fw' port forwarder.
13 *
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.
18 *
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.
23 *
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.
27 */
28
29/*----- Revision history --------------------------------------------------*
30 *
31 * $Log: chan.c,v $
32 * Revision 1.1 1999/07/01 08:56:23 mdw
33 * Initial revision
34 *
35 */
36
37/*----- Header files ------------------------------------------------------*/
38
39#include "config.h"
40
41#include <errno.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45
46#include <sys/types.h>
47#include <sys/time.h>
48#include <unistd.h>
49#include <sys/uio.h>
50
51#include <sys/socket.h>
52#include <netinet/in.h>
53#include <arpa/inet.h>
54
55#include <mLib/alloc.h>
56#include <mLib/conn.h>
57#include <mLib/sel.h>
58
59#include "chan.h"
60#include "fw.h"
61
62/*----- Main code ---------------------------------------------------------*/
63
64/* --- @writechan@ --- *
65 *
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
69 *
70 * Returns: ---
71 *
72 * Use: Writes to a channel.
73 */
74
75static void writechan(int fd, unsigned mode, void *vp)
76{
77 chan *c = vp;
78 int w;
79 unsigned base = c->base;
80 unsigned len = c->len;
81
82 /* --- Write data from my buffer --- */
83
84 if (len) {
85
86 /* --- Do the write --- */
87
88 if (base + len <= CHAN_BUFSZ)
89 w = write(fd, c->buf + base, len);
90 else {
91 struct iovec iov[2];
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);
97 }
98
99 /* --- Sift through the results --- */
100
101 if (w < 0) {
102 if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
103 return;
104 goto close;
105 }
106 else if (w == 0)
107 goto close;
108 else if (c->len == CHAN_BUFSZ && !(c->f & CHANF_CLOSE))
109 sel_addfile(&c->r);
110 c->len -= w;
111 }
112 if (c->len == 0)
113 sel_rmfile(&c->w);
114
115 /* --- Close the output end if necessary --- */
116
117 if (c->len == 0 && (c->f & CHANF_CLOSE)) {
118 shutdown(fd, 1);
119 c->func(c->p);
120 }
121 return;
122
123 /* --- Force a close if an error occurred --- */
124
125close:
126 chan_close(c);
127 c->func(c->p);
128}
129
130/* --- @readchan@ --- *
131 *
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
135 *
136 * Returns: ---
137 *
138 * Use: Reads from a channel.
139 */
140
141static void readchan(int fd, unsigned mode, void *vp)
142{
143 chan *c = vp;
144 int r;
145 unsigned base = (c->base + c->len) & (CHAN_BUFSZ - 1);
146 unsigned len = CHAN_BUFSZ - c->len;
147
148 /* --- Do the read --- */
149
150 if (base + len <= CHAN_BUFSZ)
151 r = read(fd, c->buf + base, len);
152 else {
153 struct iovec iov[2];
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);
159 }
160
161 /* --- Sift through the results --- */
162
163 if (r < 0) {
164 if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
165 return;
166 goto close;
167 }
168 else if (r == 0)
169 goto close;
170 else if (c->len == 0 && !(c->f & CHANF_READY))
171 sel_addfile(&c->w);
172 c->len += r;
173 if (c->len == CHAN_BUFSZ)
174 sel_rmfile(&c->r);
175 return;
176
177 /* --- Close the read end of the channel --- */
178
179close:
180 c->f |= CHANF_CLOSE;
181 if (!c->len)
182 sel_addfile(&c->w);
183 sel_rmfile(&c->r);
184}
185
186/* --- @chan_close@ --- *
187 *
188 * Arguments: @chan *c@ = pointer to channel
189 *
190 * Returns: ---
191 *
192 * Use: Closes down a channel prematurely.
193 */
194
195void chan_close(chan *c)
196{
197 if (!(c->f & CHANF_CLOSE) && c->len != CHAN_BUFSZ)
198 sel_rmfile(&c->r);
199 if ((c->f & CHANF_READY) && c->len != 0)
200 sel_rmfile(&c->w);
201}
202
203/* --- @chan_dest@ --- *
204 *
205 * Arguments: @chan *c@ = pointer to channel
206 * @int fd@ = destination file descriptor for channel
207 *
208 * Returns: ---
209 *
210 * Use: Sets the channel's destination so it knows where to put
211 * data.
212 */
213
214void chan_dest(chan *c, int fd)
215{
216 if (c->f & CHANF_READY)
217 return;
218 sel_initfile(sel, &c->w, fd, SEL_WRITE, writechan, c);
219 if (c->len)
220 sel_addfile(&c->w);
221}
222
223/* --- @chan_open@ --- *
224 *
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
229 *
230 * Returns: ---
231 *
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.
235 */
236
237void chan_open(chan *c, int from, int to,
238 void (*func)(void */*p*/), void *p)
239{
240 c->func = func;
241 c->p = p;
242
243 c->base = 0;
244 c->len = 0;
245 c->f = 0;
246
247 sel_initfile(sel, &c->r, from, SEL_READ, readchan, c);
248 sel_addfile(&c->r);
249
250 if (to != -1)
251 chan_dest(c, to);
252}
253
254/*----- That's all, folks -------------------------------------------------*/