1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <arpa/inet.h>
18#include <netinet/in.h>
19#include <stdlib.h>
20
21#include "private/ErrnoRestorer.h"
22
23// The difference between inet_network(3) and inet_addr(3) is that
24// inet_network uses host order and inet_addr network order.
25in_addr_t inet_network(const char* cp) {
26  in_addr_t network_order = inet_addr(cp);
27  return ntohl(network_order);
28}
29
30in_addr_t inet_addr(const char* cp) {
31  in_addr addr;
32  return inet_aton(cp, &addr) ? addr.s_addr : INADDR_NONE;
33}
34
35int inet_aton(const char* cp, in_addr* addr) {
36  ErrnoRestorer errno_restorer;
37
38  unsigned long parts[4];
39  size_t i;
40  for (i = 0; i < 4; ++i) {
41    char* end;
42    errno = 0;
43    parts[i] = strtoul(cp, &end, 0);
44    if (errno != 0 || end == cp || (*end != '.' && *end != '\0')) return 0;
45    if (*end == '\0') break;
46    cp = end + 1;
47  }
48
49  uint32_t result = 0;
50  if (i == 0) {
51    // a (a 32-bit).
52    if (parts[0] > 0xffffffff) return 0;
53    result = parts[0];
54  } else if (i == 1) {
55    // a.b (b 24-bit).
56    if (parts[0] > 0xff || parts[1] > 0xffffff) return 0;
57    result = (parts[0] << 24) | parts[1];
58  } else if (i == 2) {
59    // a.b.c (c 16-bit).
60    if (parts[0] > 0xff || parts[1] > 0xff || parts[2] > 0xffff) return 0;
61    result = (parts[0] << 24) | (parts[1] << 16) | parts[2];
62  } else if (i == 3) {
63    // a.b.c.d (d 8-bit).
64    if (parts[0] > 0xff || parts[1] > 0xff || parts[2] > 0xff || parts[3] > 0xff) return 0;
65    result = (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8) | parts[3];
66  } else {
67    return 0;
68  }
69
70  if (addr != nullptr) addr->s_addr = htonl(result);
71  return 1;
72}
73