patch-2.4.26 linux-2.4.26/Documentation/networking/ifenslave.c

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diff -urN linux-2.4.25/Documentation/networking/ifenslave.c linux-2.4.26/Documentation/networking/ifenslave.c
@@ -4,8 +4,6 @@
  *	This program controls the Linux implementation of running multiple
  *	network interfaces in parallel.
  *
- * Usage:	ifenslave [-v] master-interface < slave-interface [metric <N>] > ...
- *
  * Author:	Donald Becker <becker@cesdis.gsfc.nasa.gov>
  *		Copyright 1994-1996 Donald Becker
  *
@@ -90,24 +88,30 @@
  * 	 - For opt_c: slave should not be set to the master's setting
  *	   while it is running. It was already set during enslave. To
  *	   simplify things, it is now handeled separately.
+ *
+ *    - 2003/12/01 - Shmulik Hen <shmulik.hen at intel dot com>
+ *	 - Code cleanup and style changes
+ *	   set version to 1.1.0
  */
 
-#define APP_VERSION	"1.0.12"
-#define APP_RELDATE	"June 30, 2003"
+#define APP_VERSION	"1.1.0"
+#define APP_RELDATE	"December 1, 2003"
 #define APP_NAME	"ifenslave"
 
 static char *version =
-APP_NAME ".c:v" APP_VERSION " (" APP_RELDATE ") "  "\nDonald Becker (becker@cesdis.gsfc.nasa.gov).\n"
-"detach support added on 2000/10/02 by Willy Tarreau (willy at meta-x.org).\n"
-"2.4 kernel support added on 2001/02/16 by Chad N. Tindel (ctindel at ieee dot org.\n";
+APP_NAME ".c:v" APP_VERSION " (" APP_RELDATE ")\n"
+"o Donald Becker (becker@cesdis.gsfc.nasa.gov).\n"
+"o Detach support added on 2000/10/02 by Willy Tarreau (willy at meta-x.org).\n"
+"o 2.4 kernel support added on 2001/02/16 by Chad N. Tindel\n"
+"  (ctindel at ieee dot org).\n";
 
 static const char *usage_msg =
-"Usage: ifenslave [-adfrvVh] <master-interface> < <slave-if> [metric <N>] > ...\n"
-"       ifenslave -c master-interface slave-if\n";
+"Usage: ifenslave [-f] <master-if> <slave-if> [<slave-if>...]\n"
+"       ifenslave -d   <master-if> <slave-if> [<slave-if>...]\n"
+"       ifenslave -c   <master-if> <slave-if>\n"
+"       ifenslave --help\n";
 
-static const char *howto_msg =
-"Usage: ifenslave [-adfrvVh] <master-interface> < <slave-if> [metric <N>] > ...\n"
-"       ifenslave -c master-interface slave-if\n"
+static const char *help_msg =
 "\n"
 "       To create a bond device, simply follow these three steps :\n"
 "       - ensure that the required drivers are properly loaded :\n"
@@ -115,18 +119,32 @@
 "       - assign an IP address to the bond device :\n"
 "         # ifconfig bond0 <addr> netmask <mask> broadcast <bcast>\n"
 "       - attach all the interfaces you need to the bond device :\n"
-"         # ifenslave bond0 eth0 eth1 eth2\n"
+"         # ifenslave [{-f|--force}] bond0 eth0 [eth1 [eth2]...]\n"
 "         If bond0 didn't have a MAC address, it will take eth0's. Then, all\n"
 "         interfaces attached AFTER this assignment will get the same MAC addr.\n"
-"\n"
-"       To detach a dead interface without setting the bond device down :\n"
-"         # ifenslave -d bond0 eth1\n"
+"         (except for ALB/TLB modes)\n"
 "\n"
 "       To set the bond device down and automatically release all the slaves :\n"
 "         # ifconfig bond0 down\n"
 "\n"
+"       To detach a dead interface without setting the bond device down :\n"
+"         # ifenslave {-d|--detach} bond0 eth0 [eth1 [eth2]...]\n"
+"\n"
 "       To change active slave :\n"
-"         # ifenslave -c bond0 eth0\n"
+"         # ifenslave {-c|--change-active} bond0 eth0\n"
+"\n"
+"       To show master interface info\n"
+"         # ifenslave bond0\n"
+"\n"
+"       To show all interfaces info\n"
+"       # ifenslave {-a|--all-interfaces}\n"
+"\n"
+"       To be more verbose\n"
+"       # ifenslave {-v|--verbose} ...\n"
+"\n"
+"       # ifenslave {-u|--usage}   Show usage\n"
+"       # ifenslave {-V|--version} Show version\n"
+"       # ifenslave {-h|--help}    This message\n"
 "\n";
 
 #include <unistd.h>
@@ -153,476 +171,332 @@
 #include <linux/ethtool.h>
 
 struct option longopts[] = {
- /* { name  has_arg  *flag  val } */
-    {"all-interfaces", 0, 0, 'a'},	/* Show all interfaces. */
-    {"force",       0, 0, 'f'},		/* Force the operation. */
-    {"help", 		0, 0, '?'},		/* Give help */
-	{"howto",       0, 0, 'h'},     /* Give some more help */
-    {"receive-slave", 0, 0, 'r'},	/* Make a receive-only slave.  */
-    {"verbose", 	0, 0, 'v'},		/* Report each action taken.  */
-    {"version", 	0, 0, 'V'},		/* Emit version information.  */
-    {"detach",       0, 0, 'd'},	/* Detach a slave interface. */
-    {"change-active", 0, 0, 'c'},	/* Change the active slave.  */
-    { 0, 0, 0, 0 }
+	/* { name  has_arg  *flag  val } */
+	{"all-interfaces",	0, 0, 'a'},	/* Show all interfaces. */
+	{"change-active",	0, 0, 'c'},	/* Change the active slave.  */
+	{"detach",		0, 0, 'd'},	/* Detach a slave interface. */
+	{"force",		0, 0, 'f'},	/* Force the operation. */
+	{"help",		0, 0, 'h'},	/* Give help */
+	{"usage",		0, 0, 'u'},	/* Give usage */
+	{"verbose",		0, 0, 'v'},	/* Report each action taken. */
+	{"version",		0, 0, 'V'},	/* Emit version information. */
+	{ 0, 0, 0, 0}
 };
 
 /* Command-line flags. */
 unsigned int
-opt_a = 0,					/* Show-all-interfaces flag. */
-opt_f = 0,					/* Force the operation. */
-opt_r = 0,					/* Set up a Rx-only slave. */
-opt_d = 0,					/* detach a slave interface. */
-opt_c = 0,					/* change-active-slave flag. */
-verbose = 0,					/* Verbose flag. */
-opt_version = 0,
-opt_howto = 0;
-int skfd = -1;					/* AF_INET socket for ioctl() calls.	*/
+opt_a = 0,	/* Show-all-interfaces flag. */
+opt_c = 0,	/* Change-active-slave flag. */
+opt_d = 0,	/* Detach a slave interface. */
+opt_f = 0,	/* Force the operation. */
+opt_h = 0,	/* Help */
+opt_u = 0,	/* Usage */
+opt_v = 0,	/* Verbose flag. */
+opt_V = 0;	/* Version */
+
+int skfd = -1;		/* AF_INET socket for ioctl() calls.*/
+int abi_ver = 0;	/* userland - kernel ABI version */
+int hwaddr_set = 0;	/* Master's hwaddr is set */
+int saved_errno;
+
+struct ifreq master_mtu, master_flags, master_hwaddr;
+struct ifreq slave_mtu, slave_flags, slave_hwaddr;
+
+struct dev_ifr {
+	struct ifreq *req_ifr;
+	char *req_name;
+	int req_type;
+};
+
+struct dev_ifr master_ifra[] = {
+	{&master_mtu,     "SIOCGIFMTU",     SIOCGIFMTU},
+	{&master_flags,   "SIOCGIFFLAGS",   SIOCGIFFLAGS},
+	{&master_hwaddr,  "SIOCGIFHWADDR",  SIOCGIFHWADDR},
+	{NULL, "", 0}
+};
+
+struct dev_ifr slave_ifra[] = {
+	{&slave_mtu,     "SIOCGIFMTU",     SIOCGIFMTU},
+	{&slave_flags,   "SIOCGIFFLAGS",   SIOCGIFFLAGS},
+	{&slave_hwaddr,  "SIOCGIFHWADDR",  SIOCGIFHWADDR},
+	{NULL, "", 0}
+};
 
 static void if_print(char *ifname);
-static int get_abi_ver(char *master_ifname);
+static int get_drv_info(char *master_ifname);
+static int get_if_settings(char *ifname, struct dev_ifr ifra[]);
+static int get_slave_flags(char *slave_ifname);
+static int set_master_hwaddr(char *master_ifname, struct sockaddr *hwaddr);
+static int set_slave_hwaddr(char *slave_ifname, struct sockaddr *hwaddr);
+static int set_slave_mtu(char *slave_ifname, int mtu);
+static int set_if_flags(char *ifname, short flags);
+static int set_if_up(char *ifname, short flags);
+static int set_if_down(char *ifname, short flags);
+static int clear_if_addr(char *ifname);
+static int set_if_addr(char *master_ifname, char *slave_ifname);
+static int change_active(char *master_ifname, char *slave_ifname);
+static int enslave(char *master_ifname, char *slave_ifname);
+static int release(char *master_ifname, char *slave_ifname);
+#define v_print(fmt, args...)	\
+	if (opt_v)		\
+		fprintf(stderr, fmt, ## args )
 
-int
-main(int argc, char **argv)
+int main(int argc, char *argv[])
 {
-	struct ifreq  ifr2, if_hwaddr, if_ipaddr, if_metric, if_mtu, if_dstaddr;
-	struct ifreq  if_netmask, if_brdaddr, if_flags;
-	int rv, goterr = 0;
-	int c, errflag = 0;
-	sa_family_t master_family;
 	char **spp, *master_ifname, *slave_ifname;
-	int hwaddr_notset;
-	int abi_ver = 0;
+	int c, i, rv;
+	int res = 0;
+	int exclusive = 0;
 
-	while ((c = getopt_long(argc, argv, "acdfrvV?h", longopts, 0)) != EOF)
+	while ((c = getopt_long(argc, argv, "acdfhuvV", longopts, 0)) != EOF) {
 		switch (c) {
-		case 'a': opt_a++; break;
-		case 'f': opt_f++; break;
-		case 'r': opt_r++; break;
-		case 'd': opt_d++; break;
-		case 'c': opt_c++; break;
-		case 'v': verbose++;		break;
-		case 'V': opt_version++;	break;
-		case 'h': opt_howto++;	break;
-		case '?': errflag++;
-		}
+		case 'a': opt_a++; exclusive++; break;
+		case 'c': opt_c++; exclusive++; break;
+		case 'd': opt_d++; exclusive++; break;
+		case 'f': opt_f++; exclusive++; break;
+		case 'h': opt_h++; exclusive++; break;
+		case 'u': opt_u++; exclusive++; break;
+		case 'v': opt_v++; break;
+		case 'V': opt_V++; exclusive++; break;
 
-	/* option check */
-	if (opt_c)
-		if(opt_a || opt_f || opt_r || opt_d || verbose || opt_version ||
-		   opt_howto || errflag ) {
+		case '?':
 			fprintf(stderr, usage_msg);
-			return 2;
+			res = 2;
+			goto out;
 		}
+	}
 
-	if (errflag) {
+	/* options check */
+	if (exclusive > 1) {
 		fprintf(stderr, usage_msg);
-		return 2;
+		res = 2;
+		goto out;
 	}
 
-	if (opt_howto) {
-		fprintf(stderr, howto_msg);
-		return 0;
+	if (opt_v || opt_V) {
+		printf(version);
+		if (opt_V) {
+			res = 0;
+			goto out;
+		}
 	}
 
-	if (verbose || opt_version) {
-		printf(version);
-		if (opt_version)
-			exit(0);
+	if (opt_u) {
+		printf(usage_msg);
+		res = 0;
+		goto out;
 	}
 
-	/* Open a basic socket. */
-	if ((skfd = socket(AF_INET, SOCK_DGRAM,0)) < 0) {
-		perror("socket");
-		exit(-1);
+	if (opt_h) {
+		printf(usage_msg);
+		printf(help_msg);
+		res = 0;
+		goto out;
 	}
 
-	if (verbose)
-		fprintf(stderr, "DEBUG: argc=%d, optind=%d and argv[optind] is %s.\n",
-				argc, optind, argv[optind]);
+	/* Open a basic socket */
+	if ((skfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+		perror("socket");
+		res = 1;
+		goto out;
+	}
 
-	/* No remaining args means show all interfaces. */
-	if (optind == argc) {
-		if_print((char *)NULL);
-		(void) close(skfd);
-		exit(0);
+	if (opt_a) {
+		if (optind == argc) {
+			/* No remaining args */
+			/* show all interfaces */
+			if_print((char *)NULL);
+			goto out;
+		} else {
+			/* Just show usage */
+			fprintf(stderr, usage_msg);
+			res = 2;
+			goto out;
+		}
 	}
 
-	/* Copy the interface name. */
+	/* Copy the interface name */
 	spp = argv + optind;
 	master_ifname = *spp++;
-	slave_ifname = *spp++;
 
-	/* Check command line. */
-	if (opt_c) {
-		char **tempp = spp;
-		if ((master_ifname == NULL)||(slave_ifname == NULL)||(*tempp++ != NULL)) {
-			fprintf(stderr, usage_msg);
-			(void) close(skfd);
-			return 2;
-		}
+	if (master_ifname == NULL) {
+		fprintf(stderr, usage_msg);
+		res = 2;
+		goto out;
 	}
 
-	/* A single args means show the configuration for this interface. */
-	if (slave_ifname == NULL) {
-		if_print(master_ifname);
-		(void) close(skfd);
-		exit(0);
+	/* exchange abi version with bonding module */
+	res = get_drv_info(master_ifname);
+	if (res) {
+		fprintf(stderr,
+			"Master '%s': Error: handshake with driver failed. "
+			"Aborting\n",
+			master_ifname);
+		goto out;
 	}
 
-	/* exchange abi version with bonding driver */
-	abi_ver = get_abi_ver(master_ifname);
-	if (abi_ver < 0) {
-		(void) close(skfd);
-		exit(1);
-	}
-
-	/* Get the vitals from the master interface. */
-	{
-		struct ifreq *ifra[7] = { &if_ipaddr, &if_mtu, &if_dstaddr,
-								  &if_brdaddr, &if_netmask, &if_flags,
-								  &if_hwaddr };
-		const char *req_name[7] = {
-			"IP address", "MTU", "destination address",
-			"broadcast address", "netmask", "status flags",
-			"hardware address" };
-		const int ioctl_req_type[7] = {
-			SIOCGIFADDR, SIOCGIFMTU, SIOCGIFDSTADDR,
-			SIOCGIFBRDADDR, SIOCGIFNETMASK, SIOCGIFFLAGS,
-			SIOCGIFHWADDR };
-		int i;
-
-		for (i = 0; i < 7; i++) {
-			strncpy(ifra[i]->ifr_name, master_ifname, IFNAMSIZ);
-			if (ioctl(skfd, ioctl_req_type[i], ifra[i]) < 0) {
-				fprintf(stderr,
-						"Something broke getting the master's %s: %s.\n",
-						req_name[i], strerror(errno));
-			}
-		}
-
-		/* check if master is up; if not then fail any operation */
-		if (!(if_flags.ifr_flags & IFF_UP)) {
-			fprintf(stderr, "Illegal operation; the specified master interface '%s' is not up.\n", master_ifname);
-			(void) close(skfd);
-			exit (1);
-		}
+	slave_ifname = *spp++;
 
-		hwaddr_notset = 1; /* assume master's address not set yet */
-		for (i = 0; hwaddr_notset && (i < 6); i++) {
-			hwaddr_notset &= ((unsigned char *)if_hwaddr.ifr_hwaddr.sa_data)[i] == 0;
+	if (slave_ifname == NULL) {
+		if (opt_d || opt_c) {
+			fprintf(stderr, usage_msg);
+			res = 2;
+			goto out;
 		}
 
-		/* The family '1' is ARPHRD_ETHER for ethernet. */
-		if (if_hwaddr.ifr_hwaddr.sa_family != 1 && !opt_f) {
-			fprintf(stderr, "The specified master interface '%s' is not"
-					" ethernet-like.\n  This program is designed to work"
-					" with ethernet-like network interfaces.\n"
-					" Use the '-f' option to force the operation.\n",
-					master_ifname);
-			(void) close(skfd);
-			exit (1);
-		}
-		master_family = if_hwaddr.ifr_hwaddr.sa_family;
-		if (verbose) {
-			unsigned char *hwaddr = (unsigned char *)if_hwaddr.ifr_hwaddr.sa_data;
-			printf("The current hardware address (SIOCGIFHWADDR) of %s is type %d  "
-				   "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n", master_ifname,
-				   if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
-				   hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
-		}
+		/* A single arg means show the
+		 * configuration for this interface
+		 */
+		if_print(master_ifname);
+		goto out;
 	}
 
+	res = get_if_settings(master_ifname, master_ifra);
+	if (res) {
+		/* Probably a good reason not to go on */
+		fprintf(stderr,
+			"Master '%s': Error: get settings failed: %s. "
+			"Aborting\n",
+			master_ifname, strerror(res));
+		goto out;
+	}
 
-	/* do this when enslaving interfaces */
-	do {
-		if (opt_d) {  /* detach a slave interface from the master */
-			strncpy(if_flags.ifr_name, master_ifname, IFNAMSIZ);
-			strncpy(if_flags.ifr_slave, slave_ifname, IFNAMSIZ);
-			if ((ioctl(skfd, SIOCBONDRELEASE, &if_flags) < 0) &&
-				(ioctl(skfd, BOND_RELEASE_OLD, &if_flags) < 0)) {
-					fprintf(stderr,	"SIOCBONDRELEASE: cannot detach %s from %s. errno=%s.\n",
-							slave_ifname, master_ifname, strerror(errno));
-			}
-			else if (abi_ver < 1) {
-			      	/* The driver is using an old ABI, so we'll set the interface
-				 * down to avoid any conflicts due to same IP/MAC
-				 */
-				strncpy(ifr2.ifr_name, slave_ifname, IFNAMSIZ);
-				if (ioctl(skfd, SIOCGIFFLAGS, &ifr2) < 0) {
-					int saved_errno = errno;
-					fprintf(stderr, "SIOCGIFFLAGS on %s failed: %s\n", slave_ifname,
-						strerror(saved_errno));
-				}
-				else {
-					ifr2.ifr_flags &= ~(IFF_UP | IFF_RUNNING);
-					if (ioctl(skfd, SIOCSIFFLAGS, &ifr2) < 0) {
-						int saved_errno = errno;
-						fprintf(stderr, "Shutting down interface %s failed: %s\n",
-							slave_ifname, strerror(saved_errno));
-					}
-				}
-			}
-		} else if (opt_c) { /* change primary slave */
-			strncpy(if_flags.ifr_name, master_ifname, IFNAMSIZ);
-			strncpy(if_flags.ifr_slave, slave_ifname, IFNAMSIZ);
-			if ((ioctl(skfd, SIOCBONDCHANGEACTIVE, &if_flags) < 0) &&
-			    (ioctl(skfd, BOND_CHANGE_ACTIVE_OLD, &if_flags) < 0)) {
-				fprintf(stderr,	"SIOCBONDCHANGEACTIVE: %s.\n", strerror(errno));
-			}
-		} else {  /* attach a slave interface to the master */
-
-			strncpy(ifr2.ifr_name, slave_ifname, IFNAMSIZ);
-			if (ioctl(skfd, SIOCGIFFLAGS, &ifr2) < 0) {
-				int saved_errno = errno;
-				fprintf(stderr, "SIOCGIFFLAGS on %s failed: %s\n", slave_ifname,
-						strerror(saved_errno));
-				(void) close(skfd);
-				return 1;
-			}
-
-			if ((ifr2.ifr_flags & IFF_SLAVE) && !opt_r) {
-				fprintf(stderr, "%s is already a slave\n", slave_ifname);
-				(void) close(skfd);
-				return 1;
-			}
-
-			/* if hwaddr_notset, assign the slave hw address to the master */
-			if (hwaddr_notset) {
-				/* assign the slave hw address to the
-				 * master since it currently does not
-				 * have one; otherwise, slaves may
-				 * have different hw addresses in
-				 * active-backup mode as seen when enslaving
-				 * using "ifenslave bond0 eth0 eth1" because
-				 * hwaddr_notset is set outside this loop.
-				 * TODO: put this and the "else" portion in
-				 *       a function.
-				 */
-				/* get the slaves MAC address */
-				strncpy(if_hwaddr.ifr_name, slave_ifname,
-					IFNAMSIZ);
-				rv = ioctl(skfd, SIOCGIFHWADDR, &if_hwaddr);
-				if (-1 == rv) {
-					fprintf(stderr, "Could not get MAC "
-						"address of %s: %s\n",
-						slave_ifname,
-						strerror(errno));
-					strncpy(if_hwaddr.ifr_name,
-						master_ifname, IFNAMSIZ);
-					goterr = 1;
-				}
-
-				if (!goterr) {
-					if (abi_ver < 1) {
-						/* In ABI versions older than 1, the
-						 * master's set_mac routine couldn't
-						 * work if it was up, because it
-						 * used the default ethernet set_mac
-						 * function.
-						 */
-						/* bring master down */
-						if_flags.ifr_flags &= ~IFF_UP;
-						if (ioctl(skfd, SIOCSIFFLAGS,
-								&if_flags) < 0) {
-							goterr = 1;
-							fprintf(stderr,
-								"Shutting down "
-								"interface %s failed: "
-								"%s\n",
-								master_ifname,
-								strerror(errno));
-						}
-					}
-
-					strncpy(if_hwaddr.ifr_name,
-						master_ifname, IFNAMSIZ);
-					if (ioctl(skfd, SIOCSIFHWADDR,
-							&if_hwaddr) < 0) {
-						fprintf(stderr,
-							"Could not set MAC "
-							"address of %s: %s\n",
-							master_ifname,
-							strerror(errno));
-						goterr=1;
-					} else {
-						hwaddr_notset = 0;
-					}
-
-					if (abi_ver < 1) {
-						/* bring master back up */
-						if_flags.ifr_flags |= IFF_UP;
-						if (ioctl(skfd, SIOCSIFFLAGS,
-							  &if_flags) < 0) {
-							fprintf(stderr,
-								"Bringing up interface "
-								"%s failed: %s\n",
-								master_ifname,
-								strerror(errno));
-						}
-					}
-				}
-			} else if (abi_ver < 1) { /* if (hwaddr_notset) */
-
-			      	/* The driver is using an old ABI, so we'll set the interface
-				 * down and assign the master's hwaddr to it
-				 */
-				if (ifr2.ifr_flags & IFF_UP) {
-					ifr2.ifr_flags &= ~IFF_UP;
-					if (ioctl(skfd, SIOCSIFFLAGS, &ifr2) < 0) {
-						int saved_errno = errno;
-						fprintf(stderr, "Shutting down interface %s failed: %s\n",
-							slave_ifname, strerror(saved_errno));
-					}
-				}
-
-				strncpy(if_hwaddr.ifr_name, slave_ifname, IFNAMSIZ);
-				if (ioctl(skfd, SIOCSIFHWADDR, &if_hwaddr) < 0) {
-					int saved_errno = errno;
-					fprintf(stderr, "SIOCSIFHWADDR on %s failed: %s\n", if_hwaddr.ifr_name,
-						strerror(saved_errno));
-					if (saved_errno == EBUSY)
-						fprintf(stderr, "  The slave device %s is busy: it must be"
-							" idle before running this command.\n", slave_ifname);
-					else if (saved_errno == EOPNOTSUPP)
-						fprintf(stderr, "  The slave device you specified does not support"
-							" setting the MAC address.\n  Your kernel likely does not"
-							" support slave devices.\n");
-					else if (saved_errno == EINVAL)
-						fprintf(stderr, "  The slave device's address type does not match"
-							" the master's address type.\n");
-				} else {
-					if (verbose) {
-						unsigned char *hwaddr = if_hwaddr.ifr_hwaddr.sa_data;
-						printf("Slave's (%s) hardware address set to "
-							   "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n", slave_ifname,
-							   hwaddr[0], hwaddr[1], hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
-					}
-				}
-			}
+	/* check if master is indeed a master;
+	 * if not then fail any operation
+	 */
+	if (!(master_flags.ifr_flags & IFF_MASTER)) {
+		fprintf(stderr,
+			"Illegal operation; the specified interface '%s' "
+			"is not a master. Aborting\n",
+			master_ifname);
+		res = 1;
+		goto out;
+	}
 
-			if (*spp  &&  !strcmp(*spp, "metric")) {
-				if (*++spp == NULL) {
-					fprintf(stderr, usage_msg);
-					(void) close(skfd);
-					exit(2);
-				}
-				if_metric.ifr_metric = atoi(*spp);
-				strncpy(if_metric.ifr_name, slave_ifname, IFNAMSIZ);
-				if (ioctl(skfd, SIOCSIFMETRIC, &if_metric) < 0) {
-					fprintf(stderr, "SIOCSIFMETRIC on %s: %s\n", slave_ifname,
-							strerror(errno));
-					goterr = 1;
-				}
-				spp++;
-			}
+	/* check if master is up; if not then fail any operation */
+	if (!(master_flags.ifr_flags & IFF_UP)) {
+		fprintf(stderr,
+			"Illegal operation; the specified master interface "
+			"'%s' is not up.\n",
+			master_ifname);
+		res = 1;
+		goto out;
+	}
 
-			if (strncpy(if_ipaddr.ifr_name, slave_ifname, IFNAMSIZ) <= 0
-				|| ioctl(skfd, SIOCSIFADDR, &if_ipaddr) < 0) {
-				fprintf(stderr,
-						"Something broke setting the slave's address: %s.\n",
-						strerror(errno));
-			} else {
-				if (verbose) {
-					unsigned char *ipaddr = if_ipaddr.ifr_addr.sa_data;
-					printf("Set the slave's (%s) IP address to %d.%d.%d.%d.\n",
-						   slave_ifname, ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);
-				}
-			}
+	/* Only for enslaving */
+	if (!opt_c && !opt_d) {
+		sa_family_t master_family = master_hwaddr.ifr_hwaddr.sa_family;
+		unsigned char *hwaddr =
+			(unsigned char *)master_hwaddr.ifr_hwaddr.sa_data;
 
-			if (strncpy(if_mtu.ifr_name, slave_ifname, IFNAMSIZ) <= 0
-				|| ioctl(skfd, SIOCSIFMTU, &if_mtu) < 0) {
-				fprintf(stderr, "Something broke setting the slave MTU: %s.\n",
-						strerror(errno));
-			} else {
-				if (verbose)
-					printf("Set the slave's (%s) MTU to %d.\n", slave_ifname, if_mtu.ifr_mtu);
-			}
+		/* The family '1' is ARPHRD_ETHER for ethernet. */
+		if (master_family != 1 && !opt_f) {
+			fprintf(stderr,
+				"Illegal operation: The specified master "
+				"interface '%s' is not ethernet-like.\n "
+				"This program is designed to work with "
+				"ethernet-like network interfaces.\n "
+				"Use the '-f' option to force the "
+				"operation.\n",
+				master_ifname);
+			res = 1;
+			goto out;
+		}
 
-			if (strncpy(if_dstaddr.ifr_name, slave_ifname, IFNAMSIZ) <= 0
-				|| ioctl(skfd, SIOCSIFDSTADDR, &if_dstaddr) < 0) {
-				fprintf(stderr, "Error setting the slave (%s) with SIOCSIFDSTADDR: %s.\n",
-						slave_ifname, strerror(errno));
-			} else {
-				if (verbose) {
-					unsigned char *ipaddr = if_dstaddr.ifr_dstaddr.sa_data;
-					printf("Set the slave's (%s) destination address to %d.%d.%d.%d.\n",
-						   slave_ifname, ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);
-				}
+		/* Check master's hw addr */
+		for (i = 0; i < 6; i++) {
+			if (hwaddr[i] != 0) {
+				hwaddr_set = 1;
+				break;
 			}
+		}
 
-			if (strncpy(if_brdaddr.ifr_name, slave_ifname, IFNAMSIZ) <= 0
-				|| ioctl(skfd, SIOCSIFBRDADDR, &if_brdaddr) < 0) {
-				fprintf(stderr,
-						"Something broke setting the slave (%s) broadcast address: %s.\n",
-						slave_ifname, strerror(errno));
-			} else {
-				if (verbose) {
-					unsigned char *ipaddr = if_brdaddr.ifr_broadaddr.sa_data;
-					printf("Set the slave's (%s) broadcast address to %d.%d.%d.%d.\n",
-						   slave_ifname, ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);
-				}
-			}
+		if (hwaddr_set) {
+			v_print("current hardware address of master '%s' "
+				"is %2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x, "
+				"type %d\n",
+				master_ifname,
+				hwaddr[0], hwaddr[1],
+				hwaddr[2], hwaddr[3],
+				hwaddr[4], hwaddr[5],
+				master_family);
+		}
+	}
 
-			if (strncpy(if_netmask.ifr_name, slave_ifname, IFNAMSIZ) <= 0
-				|| ioctl(skfd, SIOCSIFNETMASK, &if_netmask) < 0) {
-				fprintf(stderr,
-						"Something broke setting the slave (%s) netmask: %s.\n",
-						slave_ifname, strerror(errno));
-			} else {
-				if (verbose) {
-					unsigned char *ipaddr = if_netmask.ifr_netmask.sa_data;
-					printf("Set the slave's (%s) netmask to %d.%d.%d.%d.\n",
-						   slave_ifname, ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);
+	/* Accepts only one slave */
+	if (opt_c) {
+		/* change active slave */
+		res = get_slave_flags(slave_ifname);
+		if (res) {
+			fprintf(stderr,
+				"Slave '%s': Error: get flags failed. "
+				"Aborting\n",
+				slave_ifname);
+			goto out;
+		}
+		res = change_active(master_ifname, slave_ifname);
+		if (res) {
+			fprintf(stderr,
+				"Master '%s', Slave '%s': Error: "
+				"Change active failed\n",
+				master_ifname, slave_ifname);
+		}
+	} else {
+		/* Accept multiple slaves */
+		do {
+			if (opt_d) {
+				/* detach a slave interface from the master */
+				rv = get_slave_flags(slave_ifname);
+				if (rv) {
+					/* Can't work with this slave. */
+					/* remember the error and skip it*/
+					fprintf(stderr,
+						"Slave '%s': Error: get flags "
+						"failed. Skipping\n",
+						slave_ifname);
+					res = rv;
+					continue;
 				}
-			}
-
-			if (abi_ver < 1) {
-
-			      	/* The driver is using an old ABI, so we'll set the interface
-				 * up before enslaving it
-				 */
-				ifr2.ifr_flags |= IFF_UP;
-				if ((ifr2.ifr_flags &= ~(IFF_SLAVE | IFF_MASTER)) == 0
-					|| strncpy(ifr2.ifr_name, slave_ifname, IFNAMSIZ) <= 0
-					|| ioctl(skfd, SIOCSIFFLAGS, &ifr2) < 0) {
-						fprintf(stderr,
-							"Something broke setting the slave (%s) flags: %s.\n",
-							slave_ifname, strerror(errno));
-				} else {
-					if (verbose)
-						printf("Set the slave's (%s) flags %4.4x.\n",
-							slave_ifname, if_flags.ifr_flags);
+				rv = release(master_ifname, slave_ifname);
+				if (rv) {
+					fprintf(stderr,
+						"Master '%s', Slave '%s': Error: "
+						"Release failed\n",
+						master_ifname, slave_ifname);
+					res = rv;
 				}
 			} else {
-				/* the bonding module takes care of setting the slave's mac address
-			 	 * and opening its interface
-			 	 */
-				if (ifr2.ifr_flags & IFF_UP) { /* the interface will need to be down */
-					ifr2.ifr_flags &= ~IFF_UP;
-					if (ioctl(skfd, SIOCSIFFLAGS, &ifr2) < 0) {
-						int saved_errno = errno;
-						fprintf(stderr, "Shutting down interface %s failed: %s\n",
-							slave_ifname, strerror(saved_errno));
-					}
+				/* attach a slave interface to the master */
+				rv = get_if_settings(slave_ifname, slave_ifra);
+				if (rv) {
+					/* Can't work with this slave. */
+					/* remember the error and skip it*/
+					fprintf(stderr,
+						"Slave '%s': Error: get "
+						"settings failed: %s. "
+						"Skipping\n",
+						slave_ifname, strerror(rv));
+					res = rv;
+					continue;
 				}
-			}
-
-			/* Do the real thing */
-			if (!opt_r) {
-				strncpy(if_flags.ifr_name, master_ifname, IFNAMSIZ);
-				strncpy(if_flags.ifr_slave, slave_ifname, IFNAMSIZ);
-				if ((ioctl(skfd, SIOCBONDENSLAVE, &if_flags) < 0) &&
-				    (ioctl(skfd, BOND_ENSLAVE_OLD, &if_flags) < 0)) {
-					fprintf(stderr,	"SIOCBONDENSLAVE: %s.\n", strerror(errno));
+				rv = enslave(master_ifname, slave_ifname);
+				if (rv) {
+					fprintf(stderr,
+						"Master '%s', Slave '%s': Error: "
+						"Enslave failed\n",
+						master_ifname, slave_ifname);
+					res = rv;
 				}
 			}
-		}
-	} while ( (slave_ifname = *spp++) != NULL);
+		} while ((slave_ifname = *spp++) != NULL);
+	}
 
-	/* Close the socket. */
-	(void) close(skfd);
+out:
+	if (skfd >= 0) {
+		close(skfd);
+	}
 
-	return(goterr);
+	return res;
 }
 
 static short mif_flags;
@@ -631,35 +505,34 @@
 static int if_getconfig(char *ifname)
 {
 	struct ifreq ifr;
-	int metric, mtu;			/* Parameters of the master interface. */
+	int metric, mtu;	/* Parameters of the master interface. */
 	struct sockaddr dstaddr, broadaddr, netmask;
+	unsigned char *hwaddr;
 
 	strcpy(ifr.ifr_name, ifname);
 	if (ioctl(skfd, SIOCGIFFLAGS, &ifr) < 0)
 		return -1;
 	mif_flags = ifr.ifr_flags;
 	printf("The result of SIOCGIFFLAGS on %s is %x.\n",
-		   ifname, ifr.ifr_flags);
+	       ifname, ifr.ifr_flags);
 
 	strcpy(ifr.ifr_name, ifname);
 	if (ioctl(skfd, SIOCGIFADDR, &ifr) < 0)
 		return -1;
 	printf("The result of SIOCGIFADDR is %2.2x.%2.2x.%2.2x.%2.2x.\n",
-		   ifr.ifr_addr.sa_data[0], ifr.ifr_addr.sa_data[1],
-		   ifr.ifr_addr.sa_data[2], ifr.ifr_addr.sa_data[3]);
+	       ifr.ifr_addr.sa_data[0], ifr.ifr_addr.sa_data[1],
+	       ifr.ifr_addr.sa_data[2], ifr.ifr_addr.sa_data[3]);
 
 	strcpy(ifr.ifr_name, ifname);
 	if (ioctl(skfd, SIOCGIFHWADDR, &ifr) < 0)
 		return -1;
 
-	{
-		/* Gotta convert from 'char' to unsigned for printf().  */
-		unsigned char *hwaddr = (unsigned char *)ifr.ifr_hwaddr.sa_data;
-		printf("The result of SIOCGIFHWADDR is type %d  "
-			   "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
-			   ifr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
-			   hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
-	}
+	/* Gotta convert from 'char' to unsigned for printf(). */
+	hwaddr = (unsigned char *)ifr.ifr_hwaddr.sa_data;
+	printf("The result of SIOCGIFHWADDR is type %d  "
+	       "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
+	       ifr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
+	       hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
 
 	strcpy(ifr.ifr_name, ifname);
 	if (ioctl(skfd, SIOCGIFMETRIC, &ifr) < 0) {
@@ -691,7 +564,7 @@
 	} else
 		netmask = ifr.ifr_netmask;
 
-	return(0);
+	return 0;
 }
 
 static void if_print(char *ifname)
@@ -705,15 +578,16 @@
 		ifc.ifc_len = sizeof(buff);
 		ifc.ifc_buf = buff;
 		if (ioctl(skfd, SIOCGIFCONF, &ifc) < 0) {
-			fprintf(stderr, "SIOCGIFCONF: %s\n", strerror(errno));
+			perror("SIOCGIFCONF failed");
 			return;
 		}
 
 		ifr = ifc.ifc_req;
 		for (i = ifc.ifc_len / sizeof(struct ifreq); --i >= 0; ifr++) {
 			if (if_getconfig(ifr->ifr_name) < 0) {
-				fprintf(stderr, "%s: unknown interface.\n",
-						ifr->ifr_name);
+				fprintf(stderr,
+					"%s: unknown interface.\n",
+					ifr->ifr_name);
 				continue;
 			}
 
@@ -721,16 +595,18 @@
 			/*ife_print(&ife);*/
 		}
 	} else {
-		if (if_getconfig(ifname) < 0)
-			fprintf(stderr, "%s: unknown interface.\n", ifname);
+		if (if_getconfig(ifname) < 0) {
+			fprintf(stderr,
+				"%s: unknown interface.\n", ifname);
+		}
 	}
 }
 
-static int get_abi_ver(char *master_ifname)
+static int get_drv_info(char *master_ifname)
 {
 	struct ifreq ifr;
 	struct ethtool_drvinfo info;
-	int abi_ver = 0;
+	char *endptr;
 
 	memset(&ifr, 0, sizeof(ifr));
 	strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
@@ -739,24 +615,487 @@
 	info.cmd = ETHTOOL_GDRVINFO;
 	strncpy(info.driver, "ifenslave", 32);
 	snprintf(info.fw_version, 32, "%d", BOND_ABI_VERSION);
-	if (ioctl(skfd, SIOCETHTOOL, &ifr) >= 0) {
-		char *endptr;
 
-		abi_ver = strtoul(info.fw_version, &endptr, 0);
-		if (*endptr) {
-			fprintf(stderr, "Error: got invalid string as an ABI "
-				"version from the bonding module\n");
-			return -1;
+	if (ioctl(skfd, SIOCETHTOOL, &ifr) < 0) {
+		if (errno == EOPNOTSUPP) {
+			goto out;
 		}
+
+		saved_errno = errno;
+		v_print("Master '%s': Error: get bonding info failed %s\n",
+			master_ifname, strerror(saved_errno));
+		return 1;
 	}
 
-	if (verbose) {
-        	printf("ABI ver is %d\n", abi_ver);
+	abi_ver = strtoul(info.fw_version, &endptr, 0);
+	if (*endptr) {
+                v_print("Master '%s': Error: got invalid string as an ABI "
+			"version from the bonding module\n",
+			master_ifname);
+		return 1;
 	}
-	return abi_ver;
+
+out:
+	v_print("ABI ver is %d\n", abi_ver);
+
+	return 0;
 }
 
+static int change_active(char *master_ifname, char *slave_ifname)
+{
+	struct ifreq ifr;
+	int res = 0;
 
+	if (!(slave_flags.ifr_flags & IFF_SLAVE)) {
+		fprintf(stderr,
+			"Illegal operation: The specified slave interface "
+			"'%s' is not a slave\n",
+			slave_ifname);
+		return 1;
+	}
+
+	strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
+	strncpy(ifr.ifr_slave, slave_ifname, IFNAMSIZ);
+	if ((ioctl(skfd, SIOCBONDCHANGEACTIVE, &ifr) < 0) &&
+	    (ioctl(skfd, BOND_CHANGE_ACTIVE_OLD, &ifr) < 0)) {
+		saved_errno = errno;
+		v_print("Master '%s': Error: SIOCBONDCHANGEACTIVE failed: "
+			"%s\n",
+			master_ifname, strerror(saved_errno));
+		res = 1;
+	}
+
+	return res;
+}
+
+static int enslave(char *master_ifname, char *slave_ifname)
+{
+	struct ifreq ifr;
+	int res = 0;
+
+	if (slave_flags.ifr_flags & IFF_SLAVE) {
+		fprintf(stderr,
+			"Illegal operation: The specified slave interface "
+			"'%s' is already a slave\n",
+			slave_ifname);
+		return 1;
+	}
+
+	res = set_if_down(slave_ifname, slave_flags.ifr_flags);
+	if (res) {
+		fprintf(stderr,
+			"Slave '%s': Error: bring interface down failed\n",
+			slave_ifname);
+		return res;
+	}
+
+	if (abi_ver < 2) {
+		/* Older bonding versions would panic if the slave has no IP
+		 * address, so get the IP setting from the master.
+		 */
+		res = set_if_addr(master_ifname, slave_ifname);
+		if (res) {
+			fprintf(stderr,
+				"Slave '%s': Error: set address failed\n",
+				slave_ifname);
+			return res;
+		}
+	} else {
+		res = clear_if_addr(slave_ifname);
+		if (res) {
+			fprintf(stderr,
+				"Slave '%s': Error: clear address failed\n",
+				slave_ifname);
+			return res;
+		}
+	}
+
+	if (master_mtu.ifr_mtu != slave_mtu.ifr_mtu) {
+		res = set_slave_mtu(slave_ifname, master_mtu.ifr_mtu);
+		if (res) {
+			fprintf(stderr,
+				"Slave '%s': Error: set MTU failed\n",
+				slave_ifname);
+			return res;
+		}
+	}
+
+	if (hwaddr_set) {
+		/* Master already has an hwaddr
+		 * so set it's hwaddr to the slave
+		 */
+		if (abi_ver < 1) {
+			/* The driver is using an old ABI, so
+			 * the application sets the slave's
+			 * hwaddr
+			 */
+			res = set_slave_hwaddr(slave_ifname,
+					       &(master_hwaddr.ifr_hwaddr));
+			if (res) {
+				fprintf(stderr,
+					"Slave '%s': Error: set hw address "
+					"failed\n",
+					slave_ifname);
+				goto undo_mtu;
+			}
+
+			/* For old ABI the application needs to bring the
+			 * slave back up
+			 */
+			res = set_if_up(slave_ifname, slave_flags.ifr_flags);
+			if (res) {
+				fprintf(stderr,
+					"Slave '%s': Error: bring interface "
+					"down failed\n",
+					slave_ifname);
+				goto undo_slave_mac;
+			}
+		}
+		/* The driver is using a new ABI,
+		 * so the driver takes care of setting
+		 * the slave's hwaddr and bringing
+		 * it up again
+		 */
+	} else {
+		/* No hwaddr for master yet, so
+		 * set the slave's hwaddr to it
+		 */
+		if (abi_ver < 1) {
+			/* For old ABI, the master needs to be
+			 * down before setting it's hwaddr
+			 */
+			res = set_if_down(master_ifname, master_flags.ifr_flags);
+			if (res) {
+				fprintf(stderr,
+					"Master '%s': Error: bring interface "
+					"down failed\n",
+					master_ifname);
+				goto undo_mtu;
+			}
+		}
+
+		res = set_master_hwaddr(master_ifname,
+					&(slave_hwaddr.ifr_hwaddr));
+		if (res) {
+			fprintf(stderr,
+				"Master '%s': Error: set hw address "
+				"failed\n",
+				master_ifname);
+			goto undo_mtu;
+		}
+
+		if (abi_ver < 1) {
+			/* For old ABI, bring the master
+			 * back up
+			 */
+			res = set_if_up(master_ifname, master_flags.ifr_flags);
+			if (res) {
+				fprintf(stderr,
+					"Master '%s': Error: bring interface "
+					"up failed\n",
+					master_ifname);
+				goto undo_master_mac;
+			}
+		}
+
+		hwaddr_set = 1;
+	}
+
+	/* Do the real thing */
+	strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
+	strncpy(ifr.ifr_slave, slave_ifname, IFNAMSIZ);
+	if ((ioctl(skfd, SIOCBONDENSLAVE, &ifr) < 0) &&
+	    (ioctl(skfd, BOND_ENSLAVE_OLD, &ifr) < 0)) {
+		saved_errno = errno;
+		v_print("Master '%s': Error: SIOCBONDENSLAVE failed: %s\n",
+			master_ifname, strerror(saved_errno));
+		res = 1;
+	}
+
+	if (res) {
+		goto undo_master_mac;
+	}
+
+	return 0;
+
+/* rollback (best effort) */
+undo_master_mac:
+	set_master_hwaddr(master_ifname, &(master_hwaddr.ifr_hwaddr));
+	hwaddr_set = 0;
+	goto undo_mtu;
+undo_slave_mac:
+	set_slave_hwaddr(slave_ifname, &(slave_hwaddr.ifr_hwaddr));
+undo_mtu:
+	set_slave_mtu(slave_ifname, slave_mtu.ifr_mtu);
+	return res;
+}
+
+static int release(char *master_ifname, char *slave_ifname)
+{
+	struct ifreq ifr;
+	int res = 0;
+
+	if (!(slave_flags.ifr_flags & IFF_SLAVE)) {
+		fprintf(stderr,
+			"Illegal operation: The specified slave interface "
+			"'%s' is not a slave\n",
+			slave_ifname);
+		return 1;
+	}
+
+	strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
+	strncpy(ifr.ifr_slave, slave_ifname, IFNAMSIZ);
+	if ((ioctl(skfd, SIOCBONDRELEASE, &ifr) < 0) &&
+	    (ioctl(skfd, BOND_RELEASE_OLD, &ifr) < 0)) {
+		saved_errno = errno;
+		v_print("Master '%s': Error: SIOCBONDRELEASE failed: %s\n",
+			master_ifname, strerror(saved_errno));
+		return 1;
+	} else if (abi_ver < 1) {
+		/* The driver is using an old ABI, so we'll set the interface
+		 * down to avoid any conflicts due to same MAC/IP
+		 */
+		res = set_if_down(slave_ifname, slave_flags.ifr_flags);
+		if (res) {
+			fprintf(stderr,
+				"Slave '%s': Error: bring interface "
+				"down failed\n",
+				slave_ifname);
+		}
+	}
+
+	/* set to default mtu */
+	set_slave_mtu(slave_ifname, 1500);
+
+	return res;
+}
+
+static int get_if_settings(char *ifname, struct dev_ifr ifra[])
+{
+	int i;
+	int res = 0;
+
+	for (i = 0; ifra[i].req_ifr; i++) {
+		strncpy(ifra[i].req_ifr->ifr_name, ifname, IFNAMSIZ);
+		res = ioctl(skfd, ifra[i].req_type, ifra[i].req_ifr);
+		if (res < 0) {
+			saved_errno = errno;
+			v_print("Interface '%s': Error: %s failed: %s\n",
+				ifname, ifra[i].req_name,
+				strerror(saved_errno));
+
+			return saved_errno;
+		}
+	}
+
+	return 0;
+}
+
+static int get_slave_flags(char *slave_ifname)
+{
+	int res = 0;
+
+	strncpy(slave_flags.ifr_name, slave_ifname, IFNAMSIZ);
+	res = ioctl(skfd, SIOCGIFFLAGS, &slave_flags);
+	if (res < 0) {
+		saved_errno = errno;
+		v_print("Slave '%s': Error: SIOCGIFFLAGS failed: %s\n",
+			slave_ifname, strerror(saved_errno));
+	} else {
+		v_print("Slave %s: flags %04X.\n",
+			slave_ifname, slave_flags.ifr_flags);
+	}
+
+	return res;
+}
+
+static int set_master_hwaddr(char *master_ifname, struct sockaddr *hwaddr)
+{
+	unsigned char *addr = (unsigned char *)hwaddr->sa_data;
+	struct ifreq ifr;
+	int res = 0;
+
+	strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
+	memcpy(&(ifr.ifr_hwaddr), hwaddr, sizeof(struct sockaddr));
+	res = ioctl(skfd, SIOCSIFHWADDR, &ifr);
+	if (res < 0) {
+		saved_errno = errno;
+		v_print("Master '%s': Error: SIOCSIFHWADDR failed: %s\n",
+			master_ifname, strerror(saved_errno));
+		return res;
+	} else {
+		v_print("Master '%s': hardware address set to "
+			"%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
+			master_ifname, addr[0], addr[1], addr[2],
+			addr[3], addr[4], addr[5]);
+	}
+
+	return res;
+}
+
+static int set_slave_hwaddr(char *slave_ifname, struct sockaddr *hwaddr)
+{
+	unsigned char *addr = (unsigned char *)hwaddr->sa_data;
+	struct ifreq ifr;
+	int res = 0;
+
+	strncpy(ifr.ifr_name, slave_ifname, IFNAMSIZ);
+	memcpy(&(ifr.ifr_hwaddr), hwaddr, sizeof(struct sockaddr));
+	res = ioctl(skfd, SIOCSIFHWADDR, &ifr);
+	if (res < 0) {
+		saved_errno = errno;
+
+		v_print("Slave '%s': Error: SIOCSIFHWADDR failed: %s\n",
+			slave_ifname, strerror(saved_errno));
+
+		if (saved_errno == EBUSY) {
+			v_print("  The device is busy: it must be idle "
+				"before running this command.\n");
+		} else if (saved_errno == EOPNOTSUPP) {
+			v_print("  The device does not support setting "
+				"the MAC address.\n"
+				"  Your kernel likely does not support slave "
+				"devices.\n");
+		} else if (saved_errno == EINVAL) {
+			v_print("  The device's address type does not match "
+				"the master's address type.\n");
+		}
+		return res;
+	} else {
+		v_print("Slave '%s': hardware address set to "
+			"%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
+			slave_ifname, addr[0], addr[1], addr[2],
+			addr[3], addr[4], addr[5]);
+	}
+
+	return res;
+}
+
+static int set_slave_mtu(char *slave_ifname, int mtu)
+{
+	struct ifreq ifr;
+	int res = 0;
+
+	ifr.ifr_mtu = mtu;
+	strncpy(ifr.ifr_name, slave_ifname, IFNAMSIZ);
+
+	res = ioctl(skfd, SIOCSIFMTU, &ifr);
+	if (res < 0) {
+		saved_errno = errno;
+		v_print("Slave '%s': Error: SIOCSIFMTU failed: %s\n",
+			slave_ifname, strerror(saved_errno));
+	} else {
+		v_print("Slave '%s': MTU set to %d.\n", slave_ifname, mtu);
+	}
+
+	return res;
+}
+
+static int set_if_flags(char *ifname, short flags)
+{
+	struct ifreq ifr;
+	int res = 0;
+
+	ifr.ifr_flags = flags;
+	strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+
+	res = ioctl(skfd, SIOCSIFFLAGS, &ifr);
+	if (res < 0) {
+		saved_errno = errno;
+		v_print("Interface '%s': Error: SIOCSIFFLAGS failed: %s\n",
+			ifname, strerror(saved_errno));
+	} else {
+		v_print("Interface '%s': flags set to %04X.\n", ifname, flags);
+	}
+
+	return res;
+}
+
+static int set_if_up(char *ifname, short flags)
+{
+	return set_if_flags(ifname, flags | IFF_UP);
+}
+
+static int set_if_down(char *ifname, short flags)
+{
+	return set_if_flags(ifname, flags & ~IFF_UP);
+}
+
+static int clear_if_addr(char *ifname)
+{
+	struct ifreq ifr;
+	int res = 0;
+
+	strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+	ifr.ifr_addr.sa_family = AF_INET;
+	memset(ifr.ifr_addr.sa_data, 0, sizeof(ifr.ifr_addr.sa_data));
+
+	res = ioctl(skfd, SIOCSIFADDR, &ifr);
+	if (res < 0) {
+		saved_errno = errno;
+		v_print("Interface '%s': Error: SIOCSIFADDR failed: %s\n",
+			ifname, strerror(saved_errno));
+	} else {
+		v_print("Interface '%s': address cleared\n", ifname);
+	}
+
+	return res;
+}
+
+static int set_if_addr(char *master_ifname, char *slave_ifname)
+{
+	struct ifreq ifr;
+	int res;
+	unsigned char *ipaddr;
+	int i;
+	struct {
+		char *req_name;
+		char *desc;
+		int g_ioctl;
+		int s_ioctl;
+	} ifra[] = {
+		{"IFADDR", "addr", SIOCGIFADDR, SIOCSIFADDR},
+		{"DSTADDR", "destination addr", SIOCGIFDSTADDR, SIOCSIFDSTADDR},
+		{"BRDADDR", "broadcast addr", SIOCGIFBRDADDR, SIOCSIFBRDADDR},
+		{"NETMASK", "netmask", SIOCGIFNETMASK, SIOCSIFNETMASK},
+		{NULL, NULL, 0, 0},
+	};
+
+	for (i = 0; ifra[i].req_name; i++) {
+		strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
+		res = ioctl(skfd, ifra[i].g_ioctl, &ifr);
+		if (res < 0) {
+			int saved_errno = errno;
+
+			v_print("Interface '%s': Error: SIOCG%s failed: %s\n",
+				master_ifname, ifra[i].req_name,
+				strerror(saved_errno));
+
+			ifr.ifr_addr.sa_family = AF_INET;
+			memset(ifr.ifr_addr.sa_data, 0,
+			       sizeof(ifr.ifr_addr.sa_data));
+		}
+
+		strncpy(ifr.ifr_name, slave_ifname, IFNAMSIZ);
+		res = ioctl(skfd, ifra[i].s_ioctl, &ifr);
+		if (res < 0) {
+			int saved_errno = errno;
+
+			v_print("Interface '%s': Error: SIOCS%s failed: %s\n",
+				slave_ifname, ifra[i].req_name,
+				strerror(saved_errno));
+
+			return res;
+		}
+
+		ipaddr = ifr.ifr_addr.sa_data;
+		v_print("Interface '%s': set IP %s to %d.%d.%d.%d\n",
+			slave_ifname, ifra[i].desc,
+			ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);
+	}
+
+	return 0;
+}
 
 /*
  * Local variables:
@@ -768,3 +1107,4 @@
  *  compile-command: "gcc -Wall -Wstrict-prototypes -O -I/usr/src/linux/include ifenslave.c -o ifenslave"
  * End:
  */
+

FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)