1 #include <u.h>
2 #include <libc.h>
3 #include <bio.h>
4 #include <ctype.h>
5 #include <ndb.h>
6 #include "dns.h"
7 #include "ip.h"
8
9 static int domount;
10 static char *mtpt, *dns, *srv;
11
12 static int
setup(int argc,char ** argv)13 setup(int argc, char **argv)
14 {
15 int fd;
16
17 if(argc == 1){
18 domount = 0;
19 mtpt = argv[0];
20 }
21
22 fd = open(dns, ORDWR);
23 if(fd < 0){
24 if(domount == 0)
25 sysfatal("can't open %s: %r", dns);
26 fd = open(srv, ORDWR);
27 if(fd < 0)
28 sysfatal("can't open %s: %r", srv);
29 if(mount(fd, -1, mtpt, MBEFORE, "") < 0)
30 sysfatal("can't mount(%s, %s): %r", srv, mtpt);
31 fd = open(dns, ORDWR);
32 if(fd < 0)
33 sysfatal("can't open %s: %r", dns);
34 }
35 return fd;
36 }
37
38 static void
querydns(int fd,char * line,int n)39 querydns(int fd, char *line, int n)
40 {
41 char buf[1024];
42
43 seek(fd, 0, 0);
44 if(write(fd, line, n) != n) {
45 print("!%r\n");
46 return;
47 }
48 seek(fd, 0, 0);
49 buf[0] = '\0';
50 while((n = read(fd, buf, sizeof(buf))) > 0){
51 buf[n] = '\0';
52 print("%s\n", buf);
53 }
54 }
55
56 static void
query(int fd)57 query(int fd)
58 {
59 int n, len;
60 char *lp, *p, *np;
61 char buf[1024], line[1024];
62 Biobuf in;
63
64 Binit(&in, 0, OREAD);
65 for(print("> "); lp = Brdline(&in, '\n'); print("> ")){
66 n = Blinelen(&in) -1;
67 while(isspace(lp[n]))
68 lp[n--] = 0;
69 n++;
70 while(isspace(*lp)){
71 lp++;
72 n--;
73 }
74 if(!*lp)
75 continue;
76 strcpy(line, lp);
77
78 /* default to an "ip" request if alpha, "ptr" if numeric */
79 if(strchr(line, ' ') == nil)
80 if(strcmp(ipattr(line), "ip") == 0) {
81 strcat(line, " ptr");
82 n += 4;
83 } else {
84 strcat(line, " ip");
85 n += 3;
86 }
87
88 /* inverse queries may need to be permuted */
89 if(n > 4 && strcmp(" ptr", &line[n-4]) == 0 &&
90 cistrstr(line, ".arpa") == nil){
91 /* TODO: reversing v6 addrs is harder */
92 for(p = line; *p; p++)
93 if(*p == ' '){
94 *p = '.';
95 break;
96 }
97 np = buf;
98 len = 0;
99 while(p >= line){
100 len++;
101 p--;
102 if(*p == '.'){
103 memmove(np, p+1, len);
104 np += len;
105 len = 0;
106 }
107 }
108 memmove(np, p+1, len);
109 np += len;
110 strcpy(np, "in-addr.arpa ptr"); /* TODO: ip6.arpa for v6 */
111 strcpy(line, buf);
112 n = strlen(line);
113 }
114
115 querydns(fd, line, n);
116 }
117 Bterm(&in);
118 }
119
120 void
main(int argc,char * argv[])121 main(int argc, char *argv[])
122 {
123 mtpt = "/net";
124 dns = "/net/dns";
125 srv = "/srv/dns";
126 domount = 1;
127 ARGBEGIN {
128 case 'x':
129 mtpt = "/net.alt";
130 dns = "/net.alt/dns";
131 srv = "/srv/dns_net.alt";
132 break;
133 default:
134 fprint(2, "usage: %s [-x] [dns-mount-point]\n", argv0);
135 exits("usage");
136 } ARGEND;
137
138 query(setup(argc, argv));
139 exits(0);
140 }
141