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#include "stralloc.h"
#include "uint_t.h"
#include "byte.h"
#include "ip.h"
#include "dnsresolv.h"
/**
* @file dns_ip.c
* @authors djb, fefe, feh
* @ref ucspi-tcp6
* @brief DNS IP query
*/
static char *q = 0;
int dns_ip4_packet(stralloc *out,const char *buf,unsigned int len)
{
unsigned int pos;
char header[12];
uint16 numanswers;
uint16 datalen;
int ranswers = 0;
if (!stralloc_copys(out,"")) return DNS_MEM;
pos = dns_packet_copy(buf,len,0,header,12); if (!pos) return DNS_ERR;
uint16_unpack_big(header + 6,&numanswers);
pos = dns_packet_skipname(buf,len,pos); if (!pos) return DNS_ERR;
pos += 4;
while (numanswers--) {
pos = dns_packet_skipname(buf,len,pos); if (!pos) return DNS_ERR;
pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) return DNS_ERR;
uint16_unpack_big(header + 8,&datalen);
if (byte_equal(header,2,DNS_T_A))
if (byte_equal(header + 2,2,DNS_C_IN))
if (datalen == 4) {
if (!dns_packet_copy(buf,len,pos,header,4)) return DNS_ERR;
if (!stralloc_catb(out,header,4)) return DNS_MEM;
}
pos += datalen;
++ranswers;
}
dns_sortip4(out->s,out->len);
return ranswers;
}
int dns_ip4(stralloc *out,stralloc *fqdn)
{
unsigned int i;
char code = 0;
int dot = 0;
char ch;
char ip[4];
int r;
int rc = 0;
if (!stralloc_copys(out,"")) return DNS_MEM;
if (!stralloc_readyplus(fqdn,1)) return DNS_MEM;
fqdn->s[fqdn->len] = 0; /* test FQDN string */
for (i = 1; i < fqdn->len; i++) {
if (fqdn->s[i] >= '_') { code = 127; break; }
if (fqdn->s[i] == '.') dot++;
}
if (code != 127 && dot == 3) /* if FQDN is just IPv4 */
if (ip4_scan(fqdn->s,ip) || ip4_scanbracket(fqdn->s,ip)) {
if (!stralloc_copyb(out,ip,4)) return DNS_MEM;
return 1;
}
code = 0;
for (i = 0; i <= fqdn->len; ++i) {
if (i < fqdn->len)
ch = fqdn->s[i];
else
ch = '.';
if ((ch == '[') || (ch == ']')) continue;
if (ch == '.') {
if (!stralloc_append(out,&code)) return DNS_MEM;
code = 0;
continue;
}
if ((ch >= '0') && (ch <= '9')) {
code *= 10;
code += ch - '0';
continue;
}
if (dns_domain_fromdot(&q,fqdn->s,fqdn->len) <= 0) return DNS_ERR; // fdqn -> A query -> response
if (dns_resolve(q,DNS_T_A) >= 0) {
if ((r = dns_ip4_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen)) < 0) return DNS_ERR;
dns_transmit_free(&dns_resolve_tx);
dns_domain_free(&q);
rc += r;
}
return rc;
}
out->len &= ~3;
return 0;
}
int dns_ip6_packet(stralloc *out,const char *buf,unsigned int len)
{
unsigned int pos;
char header[16];
uint16 numanswers;
uint16 datalen;
int ranswers = 0;
if (!stralloc_copys(out,"")) return DNS_MEM;
pos = dns_packet_copy(buf,len,0,header,12); if (!pos) return DNS_ERR;
uint16_unpack_big(header + 6,&numanswers);
pos = dns_packet_skipname(buf,len,pos); if (!pos) return DNS_ERR;
pos += 4;
while (numanswers--) {
pos = dns_packet_skipname(buf,len,pos); if (!pos) return DNS_ERR;
pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) return DNS_ERR;
uint16_unpack_big(header + 8,&datalen);
if (byte_equal(header,2,DNS_T_AAAA)) {
if (byte_equal(header + 2,2,DNS_C_IN))
if (datalen == 16) {
if (!dns_packet_copy(buf,len,pos,header,16)) return DNS_ERR;
if (!stralloc_catb(out,header,16)) return DNS_MEM;
}
} else if (byte_equal(header,2,DNS_T_A))
if (byte_equal(header + 2,2,DNS_C_IN))
if (datalen == 4) {
byte_copy(header,12,V4mappedprefix);
if (!dns_packet_copy(buf,len,pos,header + 12,4)) return DNS_ERR;
if (!stralloc_catb(out,header,16)) return DNS_MEM;
}
pos += datalen;
++ranswers;
}
dns_sortip6(out->s,out->len);
return ranswers;
}
int dns_ip6(stralloc *out,stralloc *fqdn)
{
unsigned int i;
char code;
char ch;
char ip[16];
int r;
int rc = 0;
if (!stralloc_copys(out,"")) return DNS_MEM;
if (!stralloc_readyplus(fqdn,1)) return DNS_MEM;
fqdn->s[fqdn->len] = 0; /* if FQDN is just IPv6 */
if (ip6_scan(fqdn->s,ip) || ip6_scanbracket(fqdn->s,ip)) {
if (!stralloc_copyb(out,ip,16)) return DNS_MEM;
return 1;
}
code = 0;
for (i = 0; i <= fqdn->len; ++i) {
if (i < fqdn->len)
ch = fqdn->s[i];
else
ch = '.';
if ((ch == '[') || (ch == ']')) continue;
if (ch == '.') {
if (!stralloc_append(out,&code)) return DNS_MEM;
code = 0;
continue;
}
if ((ch >= '0') && (ch <= '9')) {
code *= 10;
code += ch - '0';
continue;
}
if (dns_domain_fromdot(&q,fqdn->s,fqdn->len) <= 0) return DNS_ERR; // fqdn -> AAAA query -> response
if (dns_resolve(q,DNS_T_AAAA) >= 0) {
if ((r = dns_ip6_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen)) < 0) return DNS_ERR;
dns_transmit_free(&dns_resolve_tx);
dns_domain_free(&q);
rc += r;
}
return rc;
}
out->len &= ~3;
return 0;
}
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