network_util.cc revision 2a99a7e74a7f215066514fe81d2bfa6639d9eddd 
1// Copyright (c) 2012 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 "chromeos/network/network_util.h"
6
7#include "base/stringprintf.h"
8#include "base/strings/string_tokenizer.h"
9
10namespace chromeos {
11
12SMS::SMS() : validity(0), msgclass(0) {
13}
14
15SMS::~SMS() {
16}
17
18WifiAccessPoint::WifiAccessPoint()
19    : signal_strength(0),
20      signal_to_noise(0),
21      channel(0) {
22}
23
24WifiAccessPoint::~WifiAccessPoint() {
25}
26
27namespace network_util {
28
29std::string PrefixLengthToNetmask(int32 prefix_length) {
30  std::string netmask;
31  // Return the empty string for invalid inputs.
32  if (prefix_length < 0 || prefix_length > 32)
33    return netmask;
34  for (int i = 0; i < 4; i++) {
35    int remainder = 8;
36    if (prefix_length >= 8) {
37      prefix_length -= 8;
38    } else {
39      remainder = prefix_length;
40      prefix_length = 0;
41    }
42    if (i > 0)
43      netmask += ".";
44    int value = remainder == 0 ? 0 :
45        ((2L << (remainder - 1)) - 1) << (8 - remainder);
46    netmask += base::StringPrintf("%d", value);
47  }
48  return netmask;
49}
50
51int32 NetmaskToPrefixLength(const std::string& netmask) {
52  int count = 0;
53  int prefix_length = 0;
54  base::StringTokenizer t(netmask, ".");
55  while (t.GetNext()) {
56    // If there are more than 4 numbers, then it's invalid.
57    if (count == 4)
58      return -1;
59
60    std::string token = t.token();
61    // If we already found the last mask and the current one is not
62    // "0" then the netmask is invalid. For example, 255.224.255.0
63    if (prefix_length / 8 != count) {
64      if (token != "0")
65        return -1;
66    } else if (token == "255") {
67      prefix_length += 8;
68    } else if (token == "254") {
69      prefix_length += 7;
70    } else if (token == "252") {
71      prefix_length += 6;
72    } else if (token == "248") {
73      prefix_length += 5;
74    } else if (token == "240") {
75      prefix_length += 4;
76    } else if (token == "224") {
77      prefix_length += 3;
78    } else if (token == "192") {
79      prefix_length += 2;
80    } else if (token == "128") {
81      prefix_length += 1;
82    } else if (token == "0") {
83      prefix_length += 0;
84    } else {
85      // mask is not a valid number.
86      return -1;
87    }
88    count++;
89  }
90  if (count < 4)
91    return -1;
92  return prefix_length;
93}
94
95}  // namespace network_util
96}  // namespace chromeos
97