1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/* $Id: kissbridge.c,v 1.2 1996/08/08 20:04:46 jreuter Exp jreuter $ */
/* KISSbridge --- emulates a KISS TNC for access to a AX.25 Network Device
*
* Copyright (c) 1996 Jrg Reuter <jreuter@lykos.tng.oche.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <errno.h>
#include <linux/if_ether.h>
#define MAXMTU 1024 /* maximum frame length we support */
char *ax25_dev;
#define KISS_FEND 192
#define KISS_FESC 219
#define KISS_TFEND 220
#define KISS_TFESC 221
enum KISS_states {KISS_START, KISS_DATA, KISS_ESC};
void kiss_encode(int fd, unsigned char *buf, int len)
{
int cnt, cnt2;
unsigned char mybuf[2*MAXMTU+2];
if (len > MAXMTU)
return;
cnt2 = 0;
mybuf[cnt2++] = KISS_FEND;
for (cnt = 0; cnt < len; cnt++)
{
switch(buf[cnt])
{
case KISS_FESC:
mybuf[cnt2++] = KISS_FESC;
mybuf[cnt2++] = KISS_TFESC;
break;
case KISS_FEND:
mybuf[cnt2++] = KISS_FESC;
mybuf[cnt2++] = KISS_TFEND;
break;
default:
mybuf[cnt2++] = buf[cnt];
}
}
write(fd, mybuf, cnt2);
}
void kiss_decode(int fd, unsigned char *buf, int len)
{
static unsigned char mybuf[MAXMTU];
static int kiss_state = KISS_START;
static int cnt2 = 0;
struct sockaddr saddr;
int cnt, addrlen;
for (cnt = 0; cnt < len; cnt++)
{
switch (kiss_state)
{
case KISS_START:
if (buf[cnt] == KISS_FEND)
kiss_state = KISS_DATA;
break;
case KISS_DATA:
switch(buf[cnt])
{
case KISS_FEND:
kiss_state = KISS_START;
addrlen = sizeof(saddr);
strcpy(saddr.sa_data, ax25_dev);
saddr.sa_family = AF_AX25;
sendto(fd, mybuf, cnt2, 0, &saddr, addrlen);
cnt2 = 0;
break;
case KISS_FESC:
kiss_state = KISS_ESC;
break;
default:
mybuf[cnt2++] = buf[cnt];
}
break;
case KISS_ESC:
switch(buf[cnt])
{
case KISS_TFEND:
mybuf[cnt2++] = KISS_FEND;
break;
case KISS_TFESC:
mybuf[cnt2++] = KISS_FESC;
break;
default:
mybuf[cnt2++] = buf[cnt];
}
kiss_state = KISS_DATA;
break;
}
}
}
int main(int argc, char **argv)
{
int sock_fd, pty_fd;
struct sockaddr saddr;
int addrlen;
unsigned char buf[2*MAXMTU+2];
int len;
fd_set fdset;
struct timeval t;
if (argc < 3)
{
fprintf(stderr,"usage: %s <device> <pty>\n", argv[0]);
return 1;
}
ax25_dev = argv[1];
sock_fd = socket(AF_INET, SOCK_PACKET, htons(ETH_P_AX25));
if (sock_fd < 0)
{
perror("open socket");
return 1;
}
pty_fd = open(argv[2], O_RDWR);
if (pty_fd < 0)
{
perror("open pTTY");
return 1;
}
if (fork())
return 0;
while(1)
{
FD_ZERO(&fdset);
FD_SET(pty_fd, &fdset);
FD_SET(sock_fd,&fdset);
t.tv_sec = 0;
t.tv_usec = 0;
if (select(pty_fd+1, &fdset, NULL, NULL, NULL) < 0)
{
perror("select");
return 1;
}
if (FD_ISSET(sock_fd, &fdset))
{
addrlen = sizeof(saddr);
len = recvfrom(sock_fd, buf, sizeof(buf), 0, &saddr, &addrlen);
if (len < 0 && errno != EINTR)
{
perror("recvfrom");
return 1;
}
if (len > 0 && !strcmp(ax25_dev, saddr.sa_data))
kiss_encode(pty_fd, buf, len);
}
if (FD_ISSET(pty_fd, &fdset))
{
len = read(pty_fd, buf, sizeof(buf));
if (len < 0)
{
perror("read");
return 1;
}
if (len)
kiss_decode(sock_fd, buf, len);
}
}
}
|
