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71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
#include "stralloc.h"
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#include "uint16.h"
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#include "byte.h"
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#include "dns.h"
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#include "ip6.h"
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static char *q = 0;
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int dns_name_packet(stralloc *out,const char *buf,unsigned int len)
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{
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unsigned int pos;
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char header[12];
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uint16 numanswers;
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uint16 datalen;
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if (!stralloc_copys(out,"")) return -1;
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pos = dns_packet_copy(buf,len,0,header,12); if (!pos) return -1;
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uint16_unpack_big(header + 6,&numanswers);
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pos = dns_packet_skipname(buf,len,pos); if (!pos) return -1;
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pos += 4;
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while (numanswers--) {
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pos = dns_packet_skipname(buf,len,pos); if (!pos) return -1;
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pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) return -1;
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uint16_unpack_big(header + 8,&datalen);
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if (byte_equal(header,2,DNS_T_PTR))
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if (byte_equal(header + 2,2,DNS_C_IN)) {
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if (!dns_packet_getname(buf,len,pos,&q)) return -1;
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if (!dns_domain_todot_cat(out,q)) return -1;
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return 0;
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}
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pos += datalen;
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}
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return 0;
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}
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int dns_name4(stralloc *out,const char ip[4])
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{
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char name[DNS_NAME4_DOMAIN];
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dns_name4_domain(name,ip);
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if (dns_resolve(name,DNS_T_PTR) == -1) return -1;
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if (dns_name_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
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dns_transmit_free(&dns_resolve_tx);
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dns_domain_free(&q);
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return 0;
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}
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static int dns_name6_inner(stralloc *out,const char ip[16],int t)
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{
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char name[DNS_NAME6_DOMAIN];
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dns_name6_domain(name,ip,t);
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if (dns_resolve(name,DNS_T_PTR) == -1) return -1;
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if (dns_name_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
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dns_transmit_free(&dns_resolve_tx);
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dns_domain_free(&q);
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return 0;
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}
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int dns_name6(stralloc *out,const char ip[16])
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{
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if (ip6_isv4mapped(ip))
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return dns_name4(out,ip+12);
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if (dns_name6_inner(out,ip,DNS_IP6_ARPA)) return -1;
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if (!out->len) return dns_name6_inner(out,ip,DNS_IP6_INT);
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return 0;
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}
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