1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * Portions of this source code were derived from Berkeley 4.3 BSD 32 * under license from the Regents of the University of California. 33 */ 34 35 #include <sys/types.h> 36 #include <errno.h> 37 #include <sys/socket.h> 38 #include <netinet/in.h> 39 #include <netinet/tcp.h> 40 #include <netinet/udp.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 #ifdef SYSV 45 #define bzero(s, len) (void) memset((s), 0, (len)) 46 #endif 47 48 49 /* 50 * Bind a socket to a privileged IP port 51 */ 52 int 53 bindresvport(int sd, struct sockaddr_in *sin) 54 { 55 struct sockaddr_in myaddr; 56 struct sockaddr_in *bindaddr; 57 int level, optname; 58 int optval, len; 59 int ret; 60 61 bindaddr = sin; 62 if (bindaddr == (struct sockaddr_in *)0) { 63 bindaddr = &myaddr; 64 bzero(bindaddr, sizeof (*bindaddr)); 65 bindaddr->sin_family = AF_INET; 66 } else if (bindaddr->sin_family != AF_INET) { 67 errno = EPFNOSUPPORT; 68 return (-1); 69 } 70 71 len = sizeof (optval); 72 if (getsockopt(sd, SOL_SOCKET, SO_TYPE, &optval, &len) < 0) { 73 return (-1); 74 } 75 /* 76 * Use *_ANONPRIVBIND to ask the kernel to pick a port in the 77 * priviledged range for us. 78 */ 79 if (optval == SOCK_STREAM) { 80 level = IPPROTO_TCP; 81 optname = TCP_ANONPRIVBIND; 82 } else if (optval == SOCK_DGRAM) { 83 level = IPPROTO_UDP; 84 optname = UDP_ANONPRIVBIND; 85 } else { 86 errno = EPROTONOSUPPORT; 87 return (-1); 88 } 89 90 optval = 1; 91 if (setsockopt(sd, level, optname, &optval, sizeof (optval)) < 0) { 92 return (-1); 93 } 94 95 bindaddr->sin_port = 0; 96 ret = bind(sd, (struct sockaddr *)bindaddr, 97 sizeof (struct sockaddr_in)); 98 99 /* 100 * Always turn off the option when we are done. Note that by doing 101 * this, if the caller has set this option before calling 102 * bindresvport(), it will be unset. But this should never happen... 103 */ 104 optval = 0; 105 (void) setsockopt(sd, level, optname, &optval, sizeof (optval)); 106 107 if (ret >= 0 && sin != NULL) { 108 /* 109 * Historical note: 110 * 111 * Past versions of this bindresvport() code have 112 * returned with the reserved port number bound 113 * filled in its "sin" parameter (if passed in), perhaps 114 * "accidently" because of the structure of historical code. 115 * 116 * This is not documented but the behavior is 117 * explicitly retained here for compatibility to minimize 118 * risk to applications, even though it is not clear if this 119 * was a design intent. 120 */ 121 len = sizeof (struct sockaddr_in); 122 (void) getsockname(sd, (struct sockaddr *)bindaddr, &len); 123 } 124 return (ret); 125 } 126