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76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
23 years ago
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#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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int dns_ip4_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_A))
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if (byte_equal(header + 2,2,DNS_C_IN))
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if (datalen == 4) {
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if (!dns_packet_copy(buf,len,pos,header,4)) return -1;
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if (!stralloc_catb(out,header,4)) return -1;
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}
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pos += datalen;
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}
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dns_sortip(out->s,out->len);
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return 0;
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}
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static char *q = 0;
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int dns_ip4(stralloc *out,const stralloc *fqdn)
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{
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unsigned int i;
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char code;
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char ch;
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if (!stralloc_copys(out,"")) return -1;
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code = 0;
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for (i = 0;i <= fqdn->len;++i) {
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if (i < fqdn->len)
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ch = fqdn->s[i];
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else
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ch = '.';
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if ((ch == '[') || (ch == ']')) continue;
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if (ch == '.') {
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if (!stralloc_append(out,&code)) return -1;
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code = 0;
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continue;
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}
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if ((ch >= '0') && (ch <= '9')) {
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code *= 10;
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code += ch - '0';
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continue;
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}
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if (!dns_domain_fromdot(&q,fqdn->s,fqdn->len)) return -1;
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if (dns_resolve(q,DNS_T_A) == -1) return -1;
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if (dns_ip4_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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out->len &= ~3;
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return 0;
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}
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