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#include <stdlib.h>
#include <string.h>
#include "ibuf.h"
#include "misc.h"
#include "striter.h"
#include "dns.h"
static str data = {0};
extern ipv4port dns_use_port;
/** Read the \c /etc/resolv.conf file.
If \c $DNSRESOLVCONF is set, it names a file to read instead of \c /etc/resolv.conf . */
int dns_read_resolvconf(str *out)
{
const char *x;
x = getenv("DNSRESOLVCONF");
if (!x)
x = "/etc/resolv.conf";
return ibuf_openreadclose(x, out);
}
static int init(ipv4addr ip[DNS_MAX_IPS])
{
int i;
striter j;
int iplen = 0;
const char *x;
x = getenv("DNSCACHEPORT");
if (x && *x) {
ipv4port p = strtou(x, &x);
if (*x)
dns_use_port = p;
}
x = getenv("DNSCACHEIP");
if (x)
while (iplen <= 15) {
if (*x == ',')
++x;
else {
x = ipv4_scan(x,ip + iplen);
if (!x) break;
iplen++;
}
}
if (!iplen) {
i = dns_read_resolvconf(&data);
if (i == -1) return -1;
if (i) {
if (!str_catc(&data,'\n')) return -1;
striter_loop(&j, &data, '\n') {
if (memcmp("nameserver ", j.startptr, 11) == 0 || memcmp("nameserver\t", j.startptr, 11) == 0) {
for (i = j.start + 10; data.s[i] == ' ' || data.s[i] == '\t'; ++i)
;
if (iplen <= 15)
if (ipv4_scan(data.s + i,ip + iplen)) {
if (memcmp(ip + iplen,"\0\0\0\0",4) == 0)
memcpy(ip + iplen,"\177\0\0\1",4);
iplen++;
}
}
}
}
}
if (!iplen) {
memcpy(ip,"\177\0\0\1",4);
iplen = 4;
}
memset(ip + iplen,0,64 - iplen);
return 0;
}
static int ok = 0;
static unsigned int uses;
static struct timeval deadline;
static ipv4addr ip[DNS_MAX_IPS]; /* defined if ok */
/** Parse \c /etc/resolv.conf for a list of nameserver IPs. */
int dns_resolvconfip(ipv4addr s[DNS_MAX_IPS])
{
struct timeval now;
gettimeofday(&now,0);
if (TV_LESS(&deadline,&now)) ok = 0;
if (!uses) ok = 0;
if (!ok) {
if (init(ip) == -1) return -1;
deadline = now;
deadline.tv_sec += 600;
uses = 10000;
ok = 1;
}
--uses;
memcpy(s,ip,64);
return 0;
}
#ifdef SELFTEST_MAIN
MAIN
{
ipv4addr ips[DNS_MAX_IPS];
int i;
str rcfile = {0};
makefile(&rcfile, "nameserver 1.2.3.4\nnameserver\t 2.3.4.5\nnameserver \t3.4.5.6");
debugfn(setenv("DNSRESOLVCONF", rcfile.s, 1));
debugfn(dns_resolvconfip(ips));
for (i = 0; i < DNS_MAX_IPS; ++i) {
obuf_puts(&outbuf, ipv4_format(&ips[i]));
NL();
}
uses = 0;
debugfn(setenv("DNSCACHEIP", "192.168.1.2,192.168.1.3", 1));
debugfn(dns_resolvconfip(ips));
for (i = 0; i < DNS_MAX_IPS; ++i) {
obuf_puts(&outbuf, ipv4_format(&ips[i]));
NL();
}
unlink(rcfile.s);
}
#endif
#ifdef SELFTEST_EXP
result=0
result=0
1.2.3.4
2.3.4.5
3.4.5.6
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
result=0
result=0
192.168.1.2
192.168.1.3
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
0.0.0.0
#endif
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