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
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
|
#include <u.h>
#include <libc.h>
#include <ctype.h>
static int nettrans(char*, char*, int na, char*, int);
enum
{
Maxpath= 256,
};
/*
* announce a network service.
*/
int
announce(char *addr, char *dir)
{
int ctl, n, m;
char buf[Maxpath];
char buf2[Maxpath];
char netdir[Maxpath];
char naddr[Maxpath];
char *cp;
/*
* translate the address
*/
if(nettrans(addr, naddr, sizeof(naddr), netdir, sizeof(netdir)) < 0)
return -1;
/*
* get a control channel
*/
ctl = open(netdir, ORDWR);
if(ctl<0){
werrstr("announce opening %s: %r", netdir);
return -1;
}
cp = strrchr(netdir, '/');
if(cp == nil){
werrstr("announce arg format %s", netdir);
close(ctl);
return -1;
}
*cp = 0;
/*
* find out which line we have
*/
n = snprint(buf, sizeof(buf), "%s/", netdir);
m = read(ctl, &buf[n], sizeof(buf)-n-1);
if(m <= 0){
werrstr("announce reading %s: %r", netdir);
close(ctl);
return -1;
}
buf[n+m] = 0;
/*
* make the call
*/
n = snprint(buf2, sizeof(buf2), "announce %s", naddr);
if(write(ctl, buf2, n)!=n){
werrstr("announce writing %s: %r", netdir);
close(ctl);
return -1;
}
/*
* return directory etc.
*/
if(dir){
strncpy(dir, buf, NETPATHLEN);
dir[NETPATHLEN-1] = 0;
}
return ctl;
}
/*
* listen for an incoming call
*/
int
listen(char *dir, char *newdir)
{
int ctl, n, m;
char buf[Maxpath];
char *cp;
/*
* open listen, wait for a call
*/
snprint(buf, sizeof(buf), "%s/listen", dir);
ctl = open(buf, ORDWR);
if(ctl < 0){
werrstr("listen opening %s: %r", buf);
return -1;
}
/*
* find out which line we have
*/
strncpy(buf, dir, sizeof(buf) - 1);
buf[sizeof(buf) - 1] = 0;
cp = strrchr(buf, '/');
if(cp == nil){
close(ctl);
werrstr("listen arg format %s", dir);
return -1;
}
*++cp = 0;
n = cp-buf;
m = read(ctl, cp, sizeof(buf) - n - 1);
if(m <= 0){
close(ctl);
werrstr("listen reading %s/listen: %r", dir);
return -1;
}
buf[n+m] = 0;
/*
* return directory etc.
*/
if(newdir){
strncpy(newdir, buf, NETPATHLEN);
newdir[NETPATHLEN-1] = 0;
}
return ctl;
}
/*
* accept a call, return an fd to the open data file
*/
int
accept(int ctl, char *dir)
{
char buf[Maxpath];
char *num;
long n;
num = strrchr(dir, '/');
if(num == nil)
num = dir;
else
num++;
n = snprint(buf, sizeof(buf), "accept %s", num);
write(ctl, buf, n); /* ignore return value, network might not need accepts */
snprint(buf, sizeof(buf), "%s/data", dir);
return open(buf, ORDWR);
}
/*
* reject a call, tell device the reason for the rejection
*/
int
reject(int ctl, char *dir, char *cause)
{
char buf[Maxpath];
char *num;
long n;
num = strrchr(dir, '/');
if(num == 0)
num = dir;
else
num++;
snprint(buf, sizeof(buf), "reject %s %s", num, cause);
n = strlen(buf);
if(write(ctl, buf, n) != n)
return -1;
return 0;
}
/*
* perform the identity translation (in case we can't reach cs)
*/
static int
identtrans(char *netdir, char *addr, char *naddr, int na, char *file, int nf)
{
char proto[Maxpath];
char *p;
USED(nf);
/* parse the protocol */
strncpy(proto, addr, sizeof(proto));
proto[sizeof(proto)-1] = 0;
p = strchr(proto, '!');
if(p)
*p++ = 0;
snprint(file, nf, "%s/%s/clone", netdir, proto);
strncpy(naddr, p, na);
naddr[na-1] = 0;
return 1;
}
/*
* call up the connection server and get a translation
*/
static int
nettrans(char *addr, char *naddr, int na, char *file, int nf)
{
int i, fd;
char buf[Maxpath];
char netdir[Maxpath];
char *p, *p2;
long n;
/*
* parse, get network directory
*/
p = strchr(addr, '!');
if(p == 0){
werrstr("bad dial string: %s", addr);
return -1;
}
if(*addr != '/' && *addr != '#'){
strncpy(netdir, "/net", sizeof(netdir));
netdir[sizeof(netdir) - 1] = 0;
} else {
for(p2 = p; p2 > addr && *p2 != '/'; p2--)
;
i = p2 - addr;
if(i == 0 || i >= sizeof(netdir)){
werrstr("bad dial string: %s", addr);
return -1;
}
strncpy(netdir, addr, i);
netdir[i] = 0;
addr = p2 + 1;
}
/*
* ask the connection server
*/
snprint(buf, sizeof(buf), "%s/cs", netdir);
fd = open(buf, ORDWR);
if(fd < 0)
return identtrans(netdir, addr, naddr, na, file, nf);
if(write(fd, addr, strlen(addr)) < 0){
close(fd);
return -1;
}
seek(fd, 0, 0);
n = read(fd, buf, sizeof(buf)-1);
close(fd);
if(n <= 0)
return -1;
buf[n] = 0;
/*
* parse the reply
*/
p = strchr(buf, ' ');
if(p == 0)
return -1;
*p++ = 0;
strncpy(naddr, p, na);
naddr[na-1] = 0;
if(buf[0] == '/'){
p = strchr(buf+1, '/');
if(p == nil)
p = buf;
else
p++;
}
snprint(file, nf, "%s/%s", netdir, p);
return 0;
}
|
