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#include "case.h"
#include "byte.h"
#include "str.h"
#include "stralloc.h"
#include "dnsresolv.h"
#include "socket_if.h"
#include "ip.h"
/**
* @file dns_ipq.c
* @authors djb, feh
* @ref ucspi-tcp
* @brief DNS hostname qualification for ipv4 and ipv6
*/
/** @fn int doit -> @return number of added chars to name */
static int doit(stralloc *work,const char *rule)
{
char ch;
unsigned int colon;
unsigned int prefixlen;
ch = *rule++;
if ((ch != '?') && (ch != '=') && (ch != '*') && (ch != '-')) return 1;
colon = str_chr((char *)rule,':');
if (!rule[colon]) return 1;
if (work->len < colon) return 1;
prefixlen = work->len - colon;
if ((ch == '=') && prefixlen) return 1;
if (case_diffb((char *)rule,colon,work->s + prefixlen)) return 1;
if (ch == '?') {
if (byte_chr(work->s,prefixlen,'.') < prefixlen) return 1;
if (byte_chr(work->s,prefixlen,'[') < prefixlen) return 1;
if (byte_chr(work->s,prefixlen,']') < prefixlen) return 1;
}
work->len = prefixlen;
if (ch == '-') work->len = 0;
return stralloc_cats(work,rule + colon + 1);
}
/** @fn int dns_ip4_qualify_rules -> @return number of IPv4 addresss with rules */
int dns_ip4_qualify_rules(stralloc *ipout,stralloc *fqdn,const stralloc *in,const stralloc *rules)
{
unsigned int i;
unsigned int j;
unsigned int plus;
unsigned int fqdnlen;
int rc = 0;
if (!stralloc_copy(fqdn,(stralloc *)in)) return DNS_MEM;
for (j = i = 0; j < rules->len; ++j)
if (!rules->s[j]) {
if (!doit(fqdn,rules->s + i)) return DNS_INT;
i = j + 1;
}
fqdnlen = fqdn->len;
plus = byte_chr(fqdn->s,fqdnlen,'+');
if (plus >= fqdnlen)
return dns_ip4(ipout,fqdn);
i = plus + 1;
for (;;) {
j = byte_chr(fqdn->s + i,fqdnlen - i,'+');
byte_copy(fqdn->s + plus,j,fqdn->s + i);
fqdn->len = plus + j;
if (rc += dns_ip4(ipout,fqdn) < 0) return DNS_ERR;
i += j;
if (i >= fqdnlen) return rc;
++i;
}
return 0;
}
/** @fn int dns_ip4_qualify -> @return number of IPv4 addresss qualified */
int dns_ip4_qualify(stralloc *ipout,stralloc *fqdn,const stralloc *in)
{
int r;
static stralloc rules;
if ((r = dns_ip_qualify_localhost(ipout,fqdn,in)) > 0 ) return r;
if (dns_resolvconfrewrite(&rules) < 0) return DNS_INT;
return dns_ip4_qualify_rules(ipout,fqdn,in,&rules);
}
/** @fn int dns_ip4_qualify_rules -> @return number of IPv6 addresss with rules */
int dns_ip6_qualify_rules(stralloc *ipout,stralloc *fqdn,const stralloc *in,const stralloc *rules)
{
unsigned int i;
unsigned int j;
unsigned int plus;
unsigned int fqdnlen;
int rc = 0;
if (!stralloc_copy(fqdn,(stralloc *)in)) return DNS_MEM;
for (j = i = 0; j < rules->len; ++j)
if (!rules->s[j]) {
if (!doit(fqdn,rules->s + i)) return DNS_INT;
i = j + 1;
}
fqdnlen = fqdn->len;
plus = byte_chr(fqdn->s,fqdnlen,'+');
if (plus >= fqdnlen)
return dns_ip6(ipout,fqdn);
i = plus + 1;
for (;;) {
j = byte_chr(fqdn->s + i,fqdnlen - i,'+');
byte_copy(fqdn->s + plus,j,fqdn->s + i);
fqdn->len = plus + j;
if ((rc += dns_ip6(ipout,fqdn)) < 0) return DNS_ERR;
i += j;
if (i >= fqdnlen) return rc;
++i;
}
return 0;
}
/** @fn int dns_ip6_qualify -> @return number of IPv6 addresss qualified */
int dns_ip6_qualify(stralloc *ipout,stralloc *fqdn,const stralloc *in)
{
int r;
static stralloc rules;
if ((r = dns_ip_qualify_localhost(ipout,fqdn,in)) > 0) return r;
if (dns_resolvconfrewrite(&rules) < 0) return DNS_INT;
return dns_ip6_qualify_rules(ipout,fqdn,in,&rules);
}
/** @fn int dns_ip_qualify_rules -> @return number of IPv6+IPv4 addresss with rules */
int dns_ip_qualify_rules(stralloc *ipout,stralloc *fqdn,const stralloc *in,const stralloc *rules)
{
unsigned int i;
unsigned int j;
unsigned int k;
unsigned int plus;
unsigned int fqdnlen;
stralloc tmp = {0};
int rc = 0;
if (!stralloc_copy(fqdn,(stralloc *)in)) return DNS_MEM;
if (!stralloc_copys(ipout,"")) return DNS_MEM;
for (j = i = 0; j < rules->len; ++j)
if (!rules->s[j]) {
if (!doit(fqdn,rules->s + i)) return DNS_INT;
i = j + 1;
}
fqdnlen = fqdn->len;
plus = byte_chr(fqdn->s,fqdnlen,'+');
if (plus >= fqdnlen) {
rc = dns_ip6(ipout,fqdn);
if (dns_ip4(&tmp,fqdn) > 0) {
for (k = 0; k < tmp.len; k += 4) {
if (!stralloc_catb(ipout,(const char *) V4mappedprefix,12)) return DNS_MEM;
if (!stralloc_catb(ipout,tmp.s + k,4)) return DNS_MEM;
rc++;
}
}
return rc;
}
i = plus + 1;
for (;;) {
j = byte_chr(fqdn->s + i,fqdnlen - i,'+');
byte_copy(fqdn->s + plus,j,fqdn->s + i);
fqdn->len = plus + j;
if (!stralloc_copys(ipout,"")) return DNS_MEM;
rc = dns_ip6(&tmp,fqdn);
if (rc) if (!stralloc_cat(ipout,&tmp)) return DNS_MEM;
if (dns_ip4(&tmp,fqdn) > 0) {
for (k = 0; k < tmp.len; k += 4) {
if (!stralloc_catb(ipout,(const char *) V4mappedprefix,12)) return DNS_MEM;
if (!stralloc_catb(ipout,tmp.s + k,4)) return DNS_MEM;
rc++;
}
}
if (rc < 0) return DNS_ERR;
i += j;
if (i >= fqdnlen) return rc;
++i;
}
return 0;
}
/** @fn int dns_ip_qualify_localhost -> @return number of IP addresss */
int dns_ip_qualify_localhost(stralloc *ipout,stralloc *fqdn,const stralloc *in)
{
if (!stralloc_copys(ipout,"")) return DNS_MEM;
if (!stralloc_copys(fqdn,"")) return DNS_MEM;
ipout->len = 0;
if (byte_equal(in->s,9,LOCALHOST)) {
if (!stralloc_copyb(ipout,(const char *) V6loopback,16)) return DNS_MEM;
if (!stralloc_catb(ipout,(const char *) V46loopback,16)) return DNS_MEM;
if (!stralloc_copys(fqdn,"localhost.localhost.")) return DNS_MEM;
}
if (byte_equal(in->s,13,IP4_LOOPBACK)) {
if (!stralloc_copyb(ipout,(const char *) V46loopback,16)) return DNS_MEM;
if (!stralloc_copys(fqdn,"ip4-loopback.localhost.")) return DNS_MEM;
}
if (byte_equal(in->s,13,IP6_LOOPBACK)) {
if (!stralloc_copyb(ipout,(const char *) V6loopback,16)) return DNS_MEM;
if (!stralloc_copys(fqdn,"ip6-loopback.localhost.")) return DNS_MEM;
}
// if (!stralloc_0(fqdn)) return DNS_MEM; // don't do it
return ipout->len ? ipout->len % 15 : 0;
}
/** @fn int dns_ip_qualify -> @return number of IP addresss */
int dns_ip_qualify(stralloc *ipout,stralloc *fqdn,const stralloc *in)
{
int r;
static stralloc rules;
if ((r = dns_ip_qualify_localhost(ipout,fqdn,in)) > 0 ) return r;
if (dns_resolvconfrewrite(&rules) < 0) return DNS_INT;
return dns_ip_qualify_rules(ipout,fqdn,in,&rules);
}
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