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#include "alloc.h"
#include "byte.h"
#include "dnsresolv.h"
#include "error.h"
/**
@file dns_dfd.c
@author djb
@ref ucspi-tcp
@brief domain name qualification (domain from dot)
*/
int dns_domain_fromdot(char **out, const char *buf, unsigned int n)
{
char label[63];
unsigned int labellen = 0; /* <= sizeof label */
char name[255];
unsigned int namelen = 0; /* <= sizeof name */
char ch;
char *x;
errno = EPROTO;
for (;;) {
if (!n) break;
ch = *buf++;
--n;
if (ch == '.') {
if (labellen) {
if (namelen + labellen + 1 > sizeof(name)) return 0;
name[namelen++] = labellen;
byte_copy(name + namelen, labellen, label);
namelen += labellen;
labellen = 0;
}
continue;
}
if (ch == '\\') { // octal -> decimal
if (!n) break;
ch = *buf++;
--n;
if ((ch >= '0') && (ch <= '7')) {
ch -= '0';
if (n && (*buf >= '0') && (*buf <= '7')) {
ch <<= 3;
ch += *buf - '0';
++buf;
--n;
if (n && (*buf >= '0') && (*buf <= '7')) {
ch <<= 3;
ch += *buf - '0';
++buf;
--n;
}
}
}
}
if (labellen >= sizeof(label)) return 0;
label[labellen++] = ch;
}
if (labellen) {
if (namelen + labellen + 1 > sizeof(name)) return 0;
name[namelen++] = labellen;
byte_copy(name + namelen, labellen, label);
namelen += labellen;
labellen = 0;
}
if (namelen + 1 > sizeof(name)) return 0;
name[namelen++] = 0;
x = alloc(namelen);
if (!x) return DNS_MEM;
byte_copy(x, namelen, name);
if (*out) alloc_free(*out);
*out = x;
return 1;
}
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