All my Pcmcia cards are 'eth0'

PATCH In review Jean Tourrilhes 3 participants 4 messages Nov 21, 2003

Share & tools

Jean Tourrilhes

author

2003-11-21 03:13 UTC #0 lore raw

PATCH 1/1 All my Pcmcia cards are 'eth0'

	Hi,

	I've got a pile of Pcmcia wireless cards. I'm trying to make

them work with hotplug (currently using the old Pcmcia scripts).

One of the main problem is that they are all assigned 'eth0',
and therefore all configured with the same IP address. This is really pathetic.

The usual answer is : you should use 'nameif' :
http://www.xenotime.net/linux/doc/network-interface-names.txt
Well, of course, nobody ever bothered to try it, so it doesn't
work. No comments.

To make it work you will need :
1) The attached "improved" version of nameif
2) Modify /etc/hotplug/net.agent with the following code :
---------------------------------------
# Run nameif as needed - Jean II
# Remap interface names based on MAC address. This workaround # the dreaded configuration problem "all my cards are 'eth0'"... if [ -e /etc/mactab ]; then
debug_mesg invoke nameif -i $INTERFACE NEWNAME=/usr/local/bin/nameif -i $INTERFACE
if [ -n "$NEWNAME" ]; then
debug_mesg iface $INTERFACE is remapped to $NEWNAME INTERFACE=$NEWNAME
fi;
fi
---------------------------------------

Note that this is currently very rough and "works for me". In
particular, I bet that the code above doesn't process error from nameif properly. I'm sure someone more knowlegeable in shell scripts will straighten all that.

	Have fun...

	Jean

P.S. : Now, I just need to figure out how to implement schemes...

/*
* Name Interfaces based on MAC address.
* Writen 2000 by Andi Kleen.
* Subject to the Gnu Public License, version 2.
* TODO: make it support token ring etc.
* $Id: nameif.c,v 1.3 2003/03/06 23:26:52 ecki Exp $ */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdio.h>
#include <getopt.h>
#include <sys/syslog.h>
#include <errno.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <stdarg.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <linux/sockios.h>
#include <errno.h>
#include "intl.h"

const char default_conf[] = "/etc/mactab";
const char *fname = default_conf;
int use_syslog;
int ctl_sk = -1;

void err(char *msg)

{ 
	if (use_syslog) { 
		syslog(LOG_ERR,"%s: %m", msg); 
	} else { 
		perror(msg); 
	} 
	exit(1); 
}

void complain(char *fmt, ...)

{ 
	va_list ap;
	va_start(ap,fmt);
	if (use_syslog) { 
		vsyslog(LOG_ERR,fmt,ap);
	} else {
		vfprintf(stderr,fmt,ap);
		fputc('\n',stderr); 
	}
	va_end(ap); 
	exit(1);
}

void warning(char *fmt, ...)

{ 
	va_list ap;
	va_start(ap,fmt);
	if (use_syslog) { 
		vsyslog(LOG_ERR,fmt,ap);
	} else {
		vfprintf(stderr,fmt,ap);
		fputc('\n',stderr); 
	}
	va_end(ap); 
}

/*
* Extract a MAC address out of the config file.
* We now accept wildcards in MAC addresses, either '*' or 'XX'.
* Also avoid 'mac' overrun ;-)
* Jean II
*/
int parsemac(char *str, unsigned short *mac)

{ 
	char *s;
	int i = 0;
	while (((s = strsep(&str, ":")) != NULL) && (i < 6)) { 
		unsigned byte;
		if (!strcmp(s, "*") || !strcmp(s, "XX"))
			/* Wildcard */
			byte = 0x100;
		else
			/* Standard hex digits */
			if (sscanf(s,"%x", &byte) != 1 || byte > 0xff) 
				return -1;
		mac[i++] = byte;
	}
	return 0;
}

/*
* Compare a mac address to a mac filter - Jean II
* With wilcards, the most generic wildcard must come first,
* and the most specific last. This is because the linked list is
* built by inserting later entries in front. Jean II */
int matchmac(unsigned short *match, unsigned char *mac)

{
	int i;
	int same = 1;
	for(i = 0; i < 6; i++) {
		if((match[i] != 0x100) && (match[i] != mac[i]))
			same = 0;
	}
	return same;
}

void *xmalloc(unsigned sz)

{ 
	void *p = calloc(sz,1);
	if (!p) errno=ENOMEM, err("xmalloc"); 
	return p; 
}

void opensock(void)

{
	if (ctl_sk < 0) 
		ctl_sk = socket(PF_INET,SOCK_DGRAM,0); 
}

#ifndef ifr_newname
#define ifr_newname ifr_ifru.ifru_slave
#endif

int setname(char *oldname, char *newname)

{
	struct ifreq ifr;
	opensock(); 
	memset(&ifr,0,sizeof(struct ifreq));
	strcpy(ifr.ifr_name, oldname); 
	strcpy(ifr.ifr_newname, newname); 
	return ioctl(ctl_sk, SIOCSIFNAME, &ifr);
}

int getmac(char *name, unsigned char *mac)

{
	int r;
	struct ifreq ifr;
	opensock(); 
	memset(&ifr,0,sizeof(struct ifreq));
	strncpy(ifr.ifr_name, name, IFNAMSIZ); 
	r = ioctl(ctl_sk, SIOCGIFHWADDR, &ifr);
	memcpy(mac, ifr.ifr_hwaddr.sa_data, 6); 
	return r; 
}

struct change { 
	struct change *next;
	int found;
	char ifname[IFNAMSIZ+1];
	unsigned short mac[6];
};

struct change *clist;

struct change *lookupmac(unsigned char *mac)

{ 
	struct change *ch;
	for (ch = clist;ch;ch = ch->next) 
		if (matchmac(ch->mac, mac))
			return ch;
	return NULL; 
}

int addchange(char *p, struct change *ch, char *pos)

{
	if (strchr(ch->ifname, ':'))
		warning(_("alias device %s at %s probably has no mac"), 
			ch->ifname, pos); 
	if (parsemac(p,ch->mac) < 0) 
		complain(_("cannot parse MAC `%s' at %s"), p, pos); 
	ch->next = clist;
	clist = ch;
	return 0; 
}

void readconf(void)

{
	char *line; 
	size_t linel; 
	int linenum; 
	FILE *ifh;
	char *p;
	int n;

	ifh = fopen(fname, "r");
	if (!ifh) 
		complain(_("opening configuration file %s: %s"),fname,strerror(errno)); 

	line = NULL; 
	linel = 0;
	linenum = 1; 
	while (getdelim(&line, &linel, '\n', ifh) > 0) {
		struct change *ch = xmalloc(sizeof(struct change)); 
		char pos[20]; 

		sprintf(pos, _("line %d"), linenum); 

		if ((p = strchr(line,'#')) != NULL)
			*p = '\0';
		p = line; 
		while (isspace(*p))
			++p; 
		if (*p == '\0')
			continue; 
		n = strcspn(p, " \t"); 
		if (n > IFNAMSIZ) 
			complain(_("interface name too long at line %d"), line);  
		memcpy(ch->ifname, p, n); 
		ch->ifname[n] = 0; 
		p += n; 
		p += strspn(p, " \t"); 
		n = strspn(p, "0123456789ABCDEFabcdef:*X"); 
		p[n] = 0; 
		addchange(p, ch, pos);
		linenum++;
	}   
	fclose(ifh); 
}

/*
* Boot time processing.
* Process all network interface present on the system.
* Jean II
*/
void processiflist(void)

{
	FILE *ifh; 
	char *p;
	int n;
	int linenum; 
	char *line = NULL;
	size_t linel = 0;

	ifh = fopen("/proc/net/dev", "r"); 
	if (!ifh)  complain(_("open of /proc/net/dev: %s"), strerror(errno)); 


	linenum = 0;
	while (getdelim(&line, &linel, '\n', ifh) > 0) {
		struct change *ch; 
		unsigned char mac[6];

		if (linenum++ < 2) 
			continue;
			
		p = line; 
		while (isspace(*p)) 
			++p;
		n = strcspn(p, ": \t");  
		p[n] = 0; 
		
		if (n > IFNAMSIZ-1) 
			complain(_("interface name `%s' too long"), p); 
			
		if (getmac(p, mac) < 0) 
			continue;
			
		ch = lookupmac(mac); 
		if (!ch) 
			continue;
		
		ch->found = 1;	
		if (strcmp(p, ch->ifname)) { 
			if (setname(p, ch->ifname) < 0)  
				complain(_("cannot change name of %s to %s: %s"),
						p, ch->ifname, strerror(errno)); 
		} 
	} 
	fclose(ifh); 
	
	while (clist) { 
		struct change *ch = clist;
		clist = clist->next;
		if (!ch->found)
			warning(_("interface '%s' not found"), ch->ifname); 
		free(ch); 
	}
}

/*
* HotPlug processing.
* Process the new network interface found by hotplug.
* Jean II
*/
void processifname(char *ifname)

{
	struct change *ch; 
	unsigned char mac[6];

	if (getmac(ifname, mac) < 0) 
		return;

	ch = lookupmac(mac); 
	if (!ch) 
		return;

	if (strcmp(ifname, ch->ifname)) { 
		if (setname(ifname, ch->ifname) < 0)
			complain(_("cannot change name of %s to %s: %s"),
					ifname, ch->ifname, strerror(errno)); 
	}

	/* Always print out the *new* interface name so that
	 * the calling script can pick it up. Jean II */
	printf("%s\n", ch->ifname);
}

struct option lopt[] = { 
	{"syslog", 0, NULL, 's' },
	{"config-file", 1, NULL, 'c' },
	{"help", 0, NULL, '?' }, 
	{NULL}, 
};

void usage(void)

{
	fprintf(stderr, _("usage: nameif [-c configurationfile] [-i ifname] [-s] {ifname macaddress}\n")); 
	exit(1); 
}

int main(int ac, char **av)

{
	char *ifname = NULL;

	for (;;) {
		int c = getopt_long(ac,av,"c:i:s",lopt,NULL);
		if (c == -1) break;
		switch (c) { 
		default:
		case '?':
			usage(); 
		case 'c':
			fname = optarg;
			break;
		case 'i':
			ifname = optarg;
			break;
		case 's':
			use_syslog = 1;
			break;
		}
	}

	if (use_syslog) 
		openlog("nameif",0,LOG_LOCAL0);
		
	while (optind < ac) { 
		struct change *ch = xmalloc(sizeof(struct change)); 
		char pos[30];

		if ((ac-optind) & 1) 
			usage();
		if (strlen(av[optind])+1>IFNAMSIZ) 
			complain(_("interface name `%s' too long"), av[optind]);
		strcpy(ch->ifname, av[optind]); 
		optind++; 
		sprintf(pos,_("argument %d"),optind); 
		addchange(av[optind], ch, pos); 
		optind++; 
	} 

	if (!clist || fname != default_conf) 
		readconf(); 

	/* Check if interface name was specified */
	if (ifname) {
		processifname(ifname);
	} else {
		processiflist();
	}

	if (use_syslog)
		closelog();
	return 0;
}

Bill Nottingham

2003-11-21 03:28 UTC #1 lore raw

Quoted 8 lines · Jean Tourrilhes

One of the main problem is that they are all assigned 'eth0',
and therefore all configured with the same IP address. This is really pathetic.
The usual answer is : you should use 'nameif' :
http://www.xenotime.net/linux/doc/network-interface-names.txt
Well, of course, nobody ever bothered to try it, so it doesn't
work. No comments.

Well, no offense, but I'd think comments are necessary about no one bothering to try it and it not working. I've had an orinoco_cs device 'bob' using nameif for a while.

There are some situations where you have to jump through hoops because it can't atomically swap two device names (i.e., eth0 <-> eth1, but the code itself seems to work ok in use here...

Bill

-------------------------------------------------------
This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel

Randy.Dunlap

2003-11-21 03:40 UTC #2 lore raw

In reply to Jean Tourrilhes

On Thu, 20 Nov 2003 22:28:19 -0500 Bill Nottingham <[email protected]> wrote:

| Jean Tourrilhes ([email protected]) said: 
| > 	One of the main problem is that they are all assigned 'eth0',
| > and therefore all configured with the same IP address. This is really
| > pathetic.
| > 
| > 	The usual answer is : you should use 'nameif' :
| > http://www.xenotime.net/linux/doc/network-interface-names.txt
| > 	Well, of course, nobody ever bothered to try it, so it doesn't
| > work. No comments.
| 
| Well, no offense, but I'd think comments are necessary about no
| one bothering to try it and it not working. I've had an orinoco_cs
| device 'bob' using nameif for a while.

Jean, have you given me any feedback on that small howto and it not working? If so, I've missed it and I apologize for that.

I use that method both at home and at work all the time, with no problems, but I haven't tried it with PCMCIA cards, so that's something that might need some work, as you have discovered.

home:
[rddunlap@midway rddunlap]$ ifconfig
ethmain Link encap:Ethernet HWaddr 00:07:E9:09:09:A8

          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:134362 errors:0 dropped:0 overruns:0 frame:0
          TX packets:166363 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:72537067 (69.1 Mb)  TX bytes:22872312 (21.8 Mb)
          Interrupt:11 Base address:0xde80 Memory:ff9a0000-0

work:
[rddunlap@gargoyle rddunlap]$ /sbin/ifconfig
ethmain Link encap:Ethernet HWaddr 00:02:55:1A:35:D4

          inet addr:172.20.1.49  Bcast:172.20.255.255  Mask:255.255.0.0
          UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:17339 errors:0 dropped:0 overruns:0 frame:0
          TX packets:777 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1668859 (1.5 Mb)  TX bytes:103545 (101.1 Kb)
          Interrupt:16 Base address:0x7000

| There are some situations where you have to jump through hoops
| because it can't atomically swap two device names (i.e.,
| eth0 <-> eth1, but the code itself seems to work ok in use here...

--
~Randy

Jean Tourrilhes

author

2003-11-21 17:22 UTC #3 lore raw

In reply to Jean Tourrilhes

Quoted 16 lines · Randy.Dunlap

On Thu, 20 Nov 2003 22:28:19 -0500 Bill Nottingham <[email protected]> wrote:

| Jean Tourrilhes ([email protected]) said: 
| > 	One of the main problem is that they are all assigned 'eth0',
| > and therefore all configured with the same IP address. This is really
| > pathetic.
| > 
| > 	The usual answer is : you should use 'nameif' :
| > http://www.xenotime.net/linux/doc/network-interface-names.txt
| > 	Well, of course, nobody ever bothered to try it, so it doesn't
| > work. No comments.
| 
| Well, no offense, but I'd think comments are necessary about no
| one bothering to try it and it not working. I've had an orinoco_cs
| device 'bob' using nameif for a while.

Quoted 2 lines

Jean, have you given me any feedback on that small howto and it not working? If so, I've missed it and I apologize for that.

I may be real dense, but your Howto only describe using nameif
at boot time, which is mostly useless for Pcmcia cards (unless you want to solder Pcmcia cards in their slots).

Quoted 3 lines

I use that method both at home and at work all the time, with no problems, but I haven't tried it with PCMCIA cards, so that's something that might need some work, as you have discovered.

That's the point. If you want it to work with Pcmcia cards
(and other dynamic devices such as USB), 'nameif" *must* be called from the hotplug scripts (pretty obvious, isn't it ?). And currently you can't do that properly, which is the reason of my changes.
Note that once you add nameif in the hotplug scripts, you no
longer need to call it at boot time, so with one bird you kill two stones.

Quoted 1 line

~Randy

Thanks for looking into that.

Jean