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-rw-r--r--src/dnsstub/dns_ipq.c235
1 files changed, 235 insertions, 0 deletions
diff --git a/src/dnsstub/dns_ipq.c b/src/dnsstub/dns_ipq.c
new file mode 100644
index 0000000..f298128
--- /dev/null
+++ b/src/dnsstub/dns_ipq.c
@@ -0,0 +1,235 @@
+#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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-22 08:35:33 +0000