1 /* $OpenBSD: inet.c,v 1.6 2016/02/06 23:50:10 krw Exp $ */ 2 3 /* 4 * Subroutines to manipulate internet addresses in a safely portable 5 * way... 6 */ 7 8 /* 9 * Copyright (c) 1996 The Internet Software Consortium. All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of The Internet Software Consortium nor the names 21 * of its contributors may be used to endorse or promote products derived 22 * from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 25 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 26 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 27 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 28 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 29 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 32 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 33 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 34 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 35 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * This software has been written for the Internet Software Consortium 39 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 40 * Enterprises. To learn more about the Internet Software Consortium, 41 * see ``http://www.vix.com/isc''. To learn more about Vixie 42 * Enterprises, see ``http://www.vix.com''. 43 */ 44 45 #include <sys/types.h> 46 #include <sys/socket.h> 47 48 #include <arpa/inet.h> 49 50 #include <net/if.h> 51 52 #include <netinet/in.h> 53 54 #include <stdio.h> 55 #include <string.h> 56 57 #include "dhcp.h" 58 #include "tree.h" 59 #include "dhcpd.h" 60 61 /* 62 * Return just the network number of an internet address... 63 */ 64 struct iaddr 65 subnet_number(struct iaddr addr, struct iaddr mask) 66 { 67 struct iaddr rv; 68 int i; 69 70 rv.len = 0; 71 72 /* Both addresses must have the same length... */ 73 if (addr.len != mask.len) 74 return (rv); 75 76 rv.len = addr.len; 77 for (i = 0; i < rv.len; i++) 78 rv.iabuf[i] = addr.iabuf[i] & mask.iabuf[i]; 79 return (rv); 80 } 81 82 /* 83 * Combine a network number and a integer to produce an internet address. 84 * This won't work for subnets with more than 32 bits of host address, but 85 * maybe this isn't a problem. 86 */ 87 struct iaddr 88 ip_addr(struct iaddr subnet, struct iaddr mask, u_int32_t host_address) 89 { 90 int i, j, k; 91 u_int32_t swaddr; 92 unsigned char habuf[sizeof(swaddr)]; 93 struct iaddr rv; 94 95 swaddr = htonl(host_address); 96 memcpy(habuf, &swaddr, sizeof(swaddr)); 97 98 /* 99 * Combine the subnet address and the host address. If the 100 * host address is bigger than can fit in the subnet, return a 101 * zero-length iaddr structure. 102 */ 103 rv = subnet; 104 j = rv.len - sizeof(habuf); 105 for (i = sizeof(habuf) - 1; i >= 0; i--) { 106 if (mask.iabuf[i + j]) { 107 if (habuf[i] > (mask.iabuf[i + j] ^ 0xFF)) { 108 rv.len = 0; 109 return (rv); 110 } 111 for (k = i - 1; k >= 0; k--) 112 if (habuf[k]) { 113 rv.len = 0; 114 return (rv); 115 } 116 rv.iabuf[i + j] |= habuf[i]; 117 break; 118 } else 119 rv.iabuf[i + j] = habuf[i]; 120 } 121 122 return (rv); 123 } 124 125 u_int32_t 126 host_addr(struct iaddr addr, struct iaddr mask) 127 { 128 int i; 129 u_int32_t swaddr; 130 struct iaddr rv; 131 132 rv.len = 0; 133 134 /* Mask out the network bits... */ 135 rv.len = addr.len; 136 for (i = 0; i < rv.len; i++) 137 rv.iabuf[i] = addr.iabuf[i] & ~mask.iabuf[i]; 138 139 /* Copy out up to 32 bits... */ 140 memcpy(&swaddr, &rv.iabuf[rv.len - sizeof(swaddr)], sizeof(swaddr)); 141 142 /* Swap it and return it. */ 143 return (ntohl(swaddr)); 144 } 145 146 int 147 addr_eq(struct iaddr addr1, struct iaddr addr2) 148 { 149 if (addr1.len != addr2.len) 150 return (0); 151 return (memcmp(addr1.iabuf, addr2.iabuf, addr1.len) == 0); 152 } 153 154 char * 155 piaddr(struct iaddr addr) 156 { 157 static char pbuf[32]; 158 const char *s; 159 160 if (addr.len == 0) 161 strlcpy(pbuf, "<null address>", sizeof(pbuf)); 162 else { 163 s = inet_ntop(AF_INET, &addr.iabuf, pbuf, sizeof pbuf); 164 if (s == NULL) 165 strlcpy(pbuf, "<invalid address>", sizeof(pbuf)); 166 } 167 return (pbuf); 168 } 169