1// Copyright (c) 2009 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "net/base/dns_util.h"
6
7#include <cstring>
8
9namespace net {
10
11// Based on DJB's public domain code.
12bool DNSDomainFromDot(const std::string& dotted, std::string* out) {
13  const char* buf = dotted.data();
14  unsigned n = dotted.size();
15  char label[63];
16  unsigned int labellen = 0; /* <= sizeof label */
17  char name[255];
18  unsigned int namelen = 0; /* <= sizeof name */
19  char ch;
20
21  for (;;) {
22    if (!n)
23      break;
24    ch = *buf++;
25    --n;
26    if (ch == '.') {
27      if (labellen) {
28        if (namelen + labellen + 1 > sizeof name)
29          return false;
30        name[namelen++] = labellen;
31        memcpy(name + namelen, label, labellen);
32        namelen += labellen;
33        labellen = 0;
34      }
35      continue;
36    }
37    if (labellen >= sizeof label)
38      return false;
39    label[labellen++] = ch;
40  }
41
42  if (labellen) {
43    if (namelen + labellen + 1 > sizeof name)
44      return false;
45    name[namelen++] = labellen;
46    memcpy(name + namelen, label, labellen);
47    namelen += labellen;
48    labellen = 0;
49  }
50
51  if (namelen + 1 > sizeof name)
52    return false;
53  name[namelen++] = 0;  // This is the root label (of length 0).
54
55  *out = std::string(name, namelen);
56  return true;
57}
58
59std::string DNSDomainToString(const std::string& domain) {
60  std::string ret;
61
62  for (unsigned i = 0; i < domain.size() && domain[i]; i += domain[i] + 1) {
63#if CHAR_MIN < 0
64    if (domain[i] < 0)
65      return "";
66#endif
67    if (domain[i] > 63)
68      return "";
69
70    if (i)
71      ret += ".";
72
73    if (static_cast<unsigned>(domain[i]) + i + 1 > domain.size())
74      return "";
75
76    ret += domain.substr(i + 1, domain[i]);
77  }
78  return ret;
79}
80
81bool IsSTD3ASCIIValidCharacter(char c) {
82  if (c <= 0x2c)
83    return false;
84  if (c >= 0x7b)
85    return false;
86  if (c >= 0x2e && c <= 0x2f)
87    return false;
88  if (c >= 0x3a && c <= 0x40)
89    return false;
90  if (c >= 0x5b && c <= 0x60)
91    return false;
92  return true;
93}
94
95std::string TrimEndingDot(const std::string& host) {
96  std::string host_trimmed = host;
97  size_t len = host_trimmed.length();
98  if (len > 1 && host_trimmed[len - 1] == '.')
99    host_trimmed.erase(len - 1);
100  return host_trimmed;
101}
102
103}  // namespace net
104