1 /**
2 * Copy an uncompressed domain name from a message.
3 *
4 * The caller must allocate at least #WDNS_MAXLEN_NAME bytes for
5 * the destination buffer.
6 *
7 * \param[in] p pointer to message
8 * \param[in] eop pointer to end of message
9 * \param[in] src pointer to domain name
10 * \param[out] dst caller-allocated buffer for domain name
11 * \param[out] sz total length of domain name (may be NULL)
12 *
13 * \return
14 */
15
16 wdns_res
wdns_copy_uname(const uint8_t * p,const uint8_t * eop,const uint8_t * src,uint8_t * dst,size_t * sz)17 wdns_copy_uname(const uint8_t *p, const uint8_t *eop, const uint8_t *src,
18 uint8_t *dst, size_t *sz)
19 {
20 uint8_t c;
21
22 size_t total_len = 0;
23
24 if (p >= eop || src >= eop || src < p)
25 return (wdns_res_out_of_bounds);
26
27 while ((c = *src++) != 0) {
28 if (c <= 63) {
29 total_len++;
30 if (total_len >= WDNS_MAXLEN_NAME)
31 return (wdns_res_name_overflow);
32 *dst++ = c;
33
34 total_len += c;
35 if (total_len >= WDNS_MAXLEN_NAME)
36 return (wdns_res_name_overflow);
37 if (src + c > eop)
38 return (wdns_res_out_of_bounds);
39 memcpy(dst, src, c);
40
41 dst += c;
42 src += c;
43 } else {
44 return (wdns_res_invalid_length_octet);
45 }
46 }
47 *dst = '\0';
48 total_len++;
49
50 if (sz)
51 *sz = total_len;
52 return (wdns_res_success);
53 }
54