/* * iSCSI InitiatorName creation utility * Copyright (C) 2001 Cisco Systems, Inc. * maintained by linux-iscsi-devel@lists.sourceforge.net * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published * by the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * See the file COPYING included with this distribution for more details. * * $Id: iscsi-iname.c,v 1.1.2.3 2005/03/15 06:33:44 wysochanski Exp $ * * iscsi-iname.c - Compute an iSCSI InitiatorName for this host. * Note that to ensure uniqueness, the system time is * a factor. This name must be cached and only regenerated * if there is no cached value. */ #include #include #include #include #include #include #include #include #include "md5.h" #define RANDOM_NUM_GENERATOR "/dev/urandom" /* iSCSI names have a maximum length of 223 characters, we reserve 13 to append * a seperator and 12 characters (6 random bytes in hex representation) */ #define PREFIX_MAX_LEN 210 static void usage(void) { fprintf(stderr, "Usage: iscsi-iname [-h | --help | -p ]\n"); fprintf(stderr, "where has max length of %d\n", PREFIX_MAX_LEN); } int main(int argc, char *argv[]) { struct timeval time; struct utsname system_info; long hostid; struct MD5Context context; unsigned char digest[16]; unsigned char *bytes = digest; unsigned char entropy[16]; int e; int fd; char *prefix; /* initialize */ memset(digest, 0, sizeof (digest)); memset(&context, 0, sizeof (context)); MD5Init(&context); /* take a prefix if given, otherwise use a default. */ if (argc > 1 && argv[1]) { prefix = argv[1]; if (( strcmp(prefix, "-h") == 0 ) || ( strcmp(prefix, "--help") == 0 )) { printf("\nGenerates a unique iSCSI node name " "on every invocation.\n"); exit(0); } else if ( strcmp(prefix, "-p") == 0 ) { if (argc != 3) { usage(); exit(1); } prefix = argv[2]; if (strnlen(prefix, PREFIX_MAX_LEN + 1) > PREFIX_MAX_LEN) { usage(); exit(1); } } else { usage(); exit(0); } } else { prefix = "iqn.2016-04.com.open-iscsi"; } /* try to feed some entropy from the pool to MD5 in order to get * uniqueness properties */ fd = open(RANDOM_NUM_GENERATOR, O_RDONLY); if (fd != -1) { e = read(fd, &entropy, 16); if (e >= 1) MD5Update(&context, (md5byte *)entropy, e); close(fd); } /* time the name is created is a factor in order to get * uniqueness properties */ if (gettimeofday(&time, NULL) < 0) { perror("error: gettimeofday failed"); return 1; } MD5Update(&context, (md5byte *) & time.tv_sec, sizeof (time.tv_sec)); MD5Update(&context, (md5byte *) & time.tv_usec, sizeof (time.tv_usec)); /* hostid */ hostid = gethostid(); MD5Update(&context, (md5byte *) & hostid, sizeof (hostid)); /* get the hostname and system name */ if (uname(&system_info) < 0) { perror("error: uname failed"); return 1; } MD5Update(&context, (md5byte *) system_info.sysname, sizeof (system_info.sysname)); MD5Update(&context, (md5byte *) system_info.nodename, sizeof (system_info.nodename)); MD5Update(&context, (md5byte *) system_info.release, sizeof (system_info.release)); MD5Update(&context, (md5byte *) system_info.version, sizeof (system_info.version)); MD5Update(&context, (md5byte *) system_info.machine, sizeof (system_info.machine)); /* compute the md5 hash of all the bits we just collected */ MD5Final(digest, &context); /* vary which md5 bytes we pick (though we probably don't need to do * this, since hopefully MD5 produces results such that each byte is as * good as any other). */ fd = open(RANDOM_NUM_GENERATOR, O_RDONLY); if (fd != -1) { if (read(fd, entropy, 1) == 1) bytes = &digest[(entropy[0] % (sizeof(digest) - 6))]; close(fd); } /* print the prefix followed by 6 bytes of the MD5 hash */ printf("%s:%x%x%x%x%x%x\n", prefix, bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5]); return 0; }