1 /* $OpenBSD: inet.c,v 1.5 2004/09/16 21:27:44 claudio 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 "dhcpd.h" 46 47 /* 48 * Return just the network number of an internet address... 49 */ 50 struct iaddr 51 subnet_number(struct iaddr addr, struct iaddr mask) 52 { 53 struct iaddr rv; 54 int i; 55 56 rv.len = 0; 57 58 /* Both addresses must have the same length... */ 59 if (addr.len != mask.len) 60 return (rv); 61 62 rv.len = addr.len; 63 for (i = 0; i < rv.len; i++) 64 rv.iabuf[i] = addr.iabuf[i] & mask.iabuf[i]; 65 return (rv); 66 } 67 68 /* 69 * Combine a network number and a integer to produce an internet address. 70 * This won't work for subnets with more than 32 bits of host address, but 71 * maybe this isn't a problem. 72 */ 73 struct iaddr 74 ip_addr(struct iaddr subnet, struct iaddr mask, u_int32_t host_address) 75 { 76 int i, j, k; 77 u_int32_t swaddr; 78 unsigned char habuf[sizeof(swaddr)]; 79 struct iaddr rv; 80 81 swaddr = htonl(host_address); 82 memcpy(habuf, &swaddr, sizeof(swaddr)); 83 84 /* 85 * Combine the subnet address and the host address. If the 86 * host address is bigger than can fit in the subnet, return a 87 * zero-length iaddr structure. 88 */ 89 rv = subnet; 90 j = rv.len - sizeof(habuf); 91 for (i = sizeof(habuf) - 1; i >= 0; i--) { 92 if (mask.iabuf[i + j]) { 93 if (habuf[i] > (mask.iabuf[i + j] ^ 0xFF)) { 94 rv.len = 0; 95 return (rv); 96 } 97 for (k = i - 1; k >= 0; k--) 98 if (habuf[k]) { 99 rv.len = 0; 100 return (rv); 101 } 102 rv.iabuf[i + j] |= habuf[i]; 103 break; 104 } else 105 rv.iabuf[i + j] = habuf[i]; 106 } 107 108 return (rv); 109 } 110 111 u_int32_t 112 host_addr(struct iaddr addr, struct iaddr mask) 113 { 114 int i; 115 u_int32_t swaddr; 116 struct iaddr rv; 117 118 rv.len = 0; 119 120 /* Mask out the network bits... */ 121 rv.len = addr.len; 122 for (i = 0; i < rv.len; i++) 123 rv.iabuf[i] = addr.iabuf[i] & ~mask.iabuf[i]; 124 125 /* Copy out up to 32 bits... */ 126 memcpy(&swaddr, &rv.iabuf[rv.len - sizeof(swaddr)], sizeof(swaddr)); 127 128 /* Swap it and return it. */ 129 return (ntohl(swaddr)); 130 } 131 132 int 133 addr_eq(struct iaddr addr1, struct iaddr addr2) 134 { 135 if (addr1.len != addr2.len) 136 return (0); 137 return (memcmp(addr1.iabuf, addr2.iabuf, addr1.len) == 0); 138 } 139 140 char * 141 piaddr(struct iaddr addr) 142 { 143 static char pbuf[32]; 144 const char *s; 145 146 if (addr.len == 0) 147 strlcpy(pbuf, "<null address>", sizeof(pbuf)); 148 else { 149 s = inet_ntop(AF_INET, &addr.iabuf, pbuf, sizeof pbuf); 150 if (s == NULL) 151 strlcpy(pbuf, "<invalid address>", sizeof(pbuf)); 152 } 153 return (pbuf); 154 } 155