ifconfig.c

ifconfig源码

/* ifconfig
 *
 * Similar to the standard Unix ifconfig, but with only the necessary
 * parts for AF_INET, and without any printing of if info (for now).
 *
 * Bjorn Wesen, Axis Communications AB
 *
 *
 * Authors of the original ifconfig was:      
 *              Fred N. van Kempen, <[e-mail]>
 *
 * 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.
 *
 * $Id$
 *
 */

/*
 * Heavily modified by Manuel Novoa III       Mar 6, 2001
 *
 * From initial port to busybox, removed most of the redundancy by
 * converting to a table-driven approach.  Added several (optional)
 * args missing from initial port.
 *
 * Still missing:  media, tunnel.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>   // strcmp and friends
#include <ctype.h>    // isdigit and friends
#include <stddef.h>				/* offsetof */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <linux/if_ether.h>
#include "busybox.h"

#ifdef BB_FEATURE_IFCONFIG_SLIP
#include <linux/if_slip.h>
#endif

/* I don't know if this is needed for busybox or not.  Anyone? */
#define QUESTIONABLE_ALIAS_CASE


/* Defines for glibc2.0 users. */
#ifndef SIOCSIFTXQLEN
#define SIOCSIFTXQLEN      0x8943
#define SIOCGIFTXQLEN      0x8942
#endif

/* ifr_qlen is ifru_ivalue, but it isn't present in 2.0 kernel headers */
#ifndef ifr_qlen
#define ifr_qlen        ifr_ifru.ifru_mtu
#endif

#ifndef IFF_DYNAMIC
#define IFF_DYNAMIC     0x8000  /* dialup device with changing addresses */
#endif

/*
 * Here are the bit masks for the "flags" member of struct options below.
 * N_ signifies no arg prefix; M_ signifies arg prefixed by '-'.
 * CLR clears the flag; SET sets the flag; ARG signifies (optional) arg.
 */
#define N_CLR            0x01
#define M_CLR            0x02
#define N_SET            0x04
#define M_SET            0x08
#define N_ARG            0x10
#define M_ARG            0x20

#define M_MASK           (M_CLR | M_SET | M_ARG)
#define N_MASK           (N_CLR | N_SET | N_ARG)
#define SET_MASK         (N_SET | M_SET)
#define CLR_MASK         (N_CLR | M_CLR)
#define SET_CLR_MASK     (SET_MASK | CLR_MASK)
#define ARG_MASK         (M_ARG | N_ARG)

/*
 * Here are the bit masks for the "arg_flags" member of struct options below.
 */

/*
 * cast type:
 *   00 int
 *   01 char *
 *   02 HOST_COPY in_ether
 *   03 HOST_COPY INET_resolve
 */
#define A_CAST_TYPE      0x03
/*
 * map type:
 *   00 not a map type (mem_start, io_addr, irq)
 *   04 memstart (unsigned long)
 *   08 io_addr  (unsigned short)
 *   0C irq      (unsigned char)
 */
#define A_MAP_TYPE       0x0C
#define A_ARG_REQ        0x10	/* Set if an arg is required. */
#define A_NETMASK        0x20	/* Set if netmask (check for multiple sets). */
#define A_SET_AFTER      0x40	/* Set a flag at the end. */
#define A_COLON_CHK      0x80	/* Is this needed?  See below. */
#define A_HOSTNAME      0x100	/* Set if it is ip addr. */
#define A_BROADCAST     0x200	/* Set if it is broadcast addr. */

/*
 * These defines are for dealing with the A_CAST_TYPE field.
 */
#define A_CAST_CHAR_PTR  0x01
#define A_CAST_RESOLVE   0x01
#define A_CAST_HOST_COPY 0x02
#define A_CAST_HOST_COPY_IN_ETHER    A_CAST_HOST_COPY
#define A_CAST_HOST_COPY_RESOLVE     (A_CAST_HOST_COPY | A_CAST_RESOLVE)

/*
 * These defines are for dealing with the A_MAP_TYPE field.
 */
#define A_MAP_ULONG      0x04	/* memstart */
#define A_MAP_USHORT     0x08	/* io_addr */
#define A_MAP_UCHAR      0x0C	/* irq */

/*
 * Define the bit masks signifying which operations to perform for each arg.
 */

#define ARG_METRIC       (A_ARG_REQ /*| A_CAST_INT*/)
#define ARG_MTU          (A_ARG_REQ /*| A_CAST_INT*/)
#define ARG_TXQUEUELEN   (A_ARG_REQ /*| A_CAST_INT*/)
#define ARG_MEM_START    (A_ARG_REQ | A_MAP_ULONG)
#define ARG_IO_ADDR      (A_ARG_REQ | A_MAP_USHORT)
#define ARG_IRQ          (A_ARG_REQ | A_MAP_UCHAR)
#define ARG_DSTADDR      (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE)
#define ARG_NETMASK      (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_NETMASK)
#define ARG_BROADCAST    (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER | A_BROADCAST)
#define ARG_HW           (A_ARG_REQ | A_CAST_HOST_COPY_IN_ETHER)
#define ARG_POINTOPOINT  (A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER)
#define ARG_KEEPALIVE    (A_ARG_REQ | A_CAST_CHAR_PTR)
#define ARG_OUTFILL      (A_ARG_REQ | A_CAST_CHAR_PTR)
#define ARG_HOSTNAME     (A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER | A_COLON_CHK | A_HOSTNAME)


/*
 * Set up the tables.  Warning!  They must have corresponding order!
 */

struct arg1opt {
	const char *name;
	unsigned short selector;
	unsigned short ifr_offset;
};

struct options {
	const char *name;
	const unsigned char flags;
	const unsigned int arg_flags;
	const unsigned short selector;
};

#define ifreq_offsetof(x)  offsetof(struct ifreq, x)

static const struct arg1opt Arg1Opt[] = {
	{"SIOCSIFMETRIC",  SIOCSIFMETRIC,  ifreq_offsetof(ifr_metric)},
	{"SIOCSIFMTU",     SIOCSIFMTU,     ifreq_offsetof(ifr_mtu)},
	{"SIOCSIFTXQLEN",  SIOCSIFTXQLEN,  ifreq_offsetof(ifr_qlen)},
	{"SIOCSIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr)},
	{"SIOCSIFNETMASK", SIOCSIFNETMASK, ifreq_offsetof(ifr_netmask)},
	{"SIOCSIFBRDADDR", SIOCSIFBRDADDR, ifreq_offsetof(ifr_broadaddr)},
#ifdef BB_FEATURE_IFCONFIG_HW
	{"SIOCSIFHWADDR",  SIOCSIFHWADDR,  ifreq_offsetof(ifr_hwaddr)},
#endif
	{"SIOCSIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr)},
#ifdef SIOCSKEEPALIVE
	{"SIOCSKEEPALIVE", SIOCSKEEPALIVE, ifreq_offsetof(ifr_data)},
#endif
#ifdef SIOCSOUTFILL
	{"SIOCSOUTFILL",   SIOCSOUTFILL,   ifreq_offsetof(ifr_data)},
#endif
#ifdef BB_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
	{"SIOCSIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.mem_start)},
	{"SIOCSIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.base_addr)},
	{"SIOCSIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.irq)},
#endif
	/* Last entry if for unmatched (possibly hostname) arg. */
	{"SIOCSIFADDR",    SIOCSIFADDR,    ifreq_offsetof(ifr_addr)},
};

static const struct options OptArray[] = {
	{"metric",       N_ARG,         ARG_METRIC,      0},
    {"mtu",          N_ARG,         ARG_MTU,         0},
	{"txqueuelen",   N_ARG,         ARG_TXQUEUELEN,  0},
	{"dstaddr",      N_ARG,         ARG_DSTADDR,     0},
	{"netmask",      N_ARG,         ARG_NETMASK,     0},
	{"broadcast",    N_ARG | M_CLR, ARG_BROADCAST,   IFF_BROADCAST},
#ifdef BB_FEATURE_IFCONFIG_HW
	{"hw",           N_ARG,         ARG_HW,          0},
#endif
	{"pointopoint",  N_ARG | M_CLR, ARG_POINTOPOINT, IFF_POINTOPOINT},
#ifdef SIOCSKEEPALIVE
	{"keepalive",    N_ARG,         ARG_KEEPALIVE,   0},
#endif
#ifdef SIOCSOUTFILL
	{"outfill",      N_ARG,         ARG_OUTFILL,     0},
#endif
#ifdef BB_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
	{"mem_start",    N_ARG,         ARG_MEM_START,   0},
	{"io_addr",      N_ARG,         ARG_IO_ADDR,     0},
	{"irq",          N_ARG,         ARG_IRQ,         0},
#endif
	{"arp",          N_CLR | M_SET, 0,               IFF_NOARP},
	{"trailers",     N_CLR | M_SET, 0,               IFF_NOTRAILERS},
	{"promisc",      N_SET | M_CLR, 0,               IFF_PROMISC},
	{"multicast",    N_SET | M_CLR, 0,               IFF_MULTICAST},
	{"allmulti",     N_SET | M_CLR, 0,               IFF_ALLMULTI},
	{"dynamic",      N_SET | M_CLR, 0,               IFF_DYNAMIC},
	{"up",           N_SET        , 0,               (IFF_UP | IFF_RUNNING)},
	{"down",         N_CLR        , 0,               IFF_UP},
	{ NULL,          0,             ARG_HOSTNAME,    (IFF_UP | IFF_RUNNING)}
};

/*
 * A couple of prototypes.
 */

#ifdef BB_FEATURE_IFCONFIG_HW
static int in_ether(char *bufp, struct sockaddr *sap);
#endif

#ifdef BB_FEATURE_IFCONFIG_STATUS
extern int interface_opt_a;
extern int display_interfaces(char *ifname);
#endif

/*
 * Our main function.
 */

int main(int argc, char **argv)
{
	struct ifreq ifr;
	struct sockaddr_in sai;
	struct sockaddr_in sai_hostname, sai_netmask;
#ifdef BB_FEATURE_IFCONFIG_HW
	struct sockaddr sa;
#endif
	const struct arg1opt *a1op;
	const struct options *op;
	int sockfd;  /* socket fd we use to manipulate stuff with */
	int goterr;
	int selector;
	char *p;
	char host[128];
	unsigned int mask;
	unsigned int did_flags;

	goterr = 0;
	did_flags = 0;

	/* skip argv[0] */
	++argv;
	--argc;

#ifdef BB_FEATURE_IFCONFIG_STATUS
	if ((argc > 0) && (strcmp(*argv,"-a") == 0)) {
		interface_opt_a = 1;
		--argc;
		++argv;
	}
#endif

	if(argc <= 1) {
#ifdef BB_FEATURE_IFCONFIG_STATUS
		return display_interfaces(argc ? *argv : NULL);
#else
		error_msg_and_die( "ifconfig was not compiled with interface status display support.");
#endif
	}

	/* Create a channel to the NET kernel. */
	if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
		perror_msg_and_die("socket");
	}

	/* get interface name */
	safe_strncpy(ifr.ifr_name, *argv, IFNAMSIZ);

	/* Process the remaining arguments. */
	while (*++argv != (char *) NULL) {
		p = *argv;
		mask = N_MASK;
		if (*p == '-') {		/* If the arg starts with '-'... */
			++p;				/*    advance past it and */
			mask = M_MASK;		/*    set the appropriate mask. */
		}
		for (op = OptArray ; op->name ; op++) {	/* Find table entry. */
			if (strcmp(p,op->name) == 0) { /* If name matches... */
				if ((mask &= op->flags)) { /* set the mask and go. */
				    goto FOUND_ARG;;
				}
				/* If we get here, there was a valid arg with an */
				/* invalid '-' prefix. */
				++goterr;
				goto LOOP;
			}
		}
		
		/* We fell through, so treat as possible hostname. */
		a1op = Arg1Opt + (sizeof(Arg1Opt) / sizeof(Arg1Opt[0])) - 1;
		mask = op->arg_flags;
		goto HOSTNAME;

	FOUND_ARG:
		if (mask & ARG_MASK) {
			mask = op->arg_flags;
			a1op = Arg1Opt + (op - OptArray);
			if (mask & A_NETMASK & did_flags) {
				show_usage();
			}
			if (*++argv == NULL) {
				if (mask & A_ARG_REQ) {
					show_usage();
				} else {
					--argv;
					mask &= A_SET_AFTER; /* just for broadcast */
				}
			} else {			/* got an arg so process it */
			HOSTNAME:
				did_flags |= (mask & (A_NETMASK|A_HOSTNAME));
				if (mask & A_CAST_HOST_COPY) {
#ifdef BB_FEATURE_IFCONFIG_HW
					if (mask & A_CAST_RESOLVE) {
#endif
						safe_strncpy(host, *argv, (sizeof host));
						sai.sin_family = AF_INET;
						sai.sin_port = 0;
						if (!strcmp(host, "default")) {
							/* Default is special, meaning 0.0.0.0. */
							sai.sin_addr.s_addr = INADDR_ANY;
						} else if ((!strcmp(host, "+")) && (mask & A_BROADCAST) &&
								 (did_flags & (A_NETMASK|A_HOSTNAME))) {
							/* + is special, meaning broadcast is derived. */
							sai.sin_addr.s_addr = (~sai_netmask.sin_addr.s_addr) |
								(sai_hostname.sin_addr.s_addr & sai_netmask.sin_addr.s_addr);
						} else if (inet_aton(host, &sai.sin_addr) == 0) {
							/* It's not a dotted quad. */
							++goterr;
							continue;
						}
						if(mask & A_HOSTNAME)
							sai_hostname = sai;
						if(mask & A_NETMASK)
							sai_netmask = sai;
						p = (char *) &sai;
#ifdef BB_FEATURE_IFCONFIG_HW
					} else { /* A_CAST_HOST_COPY_IN_ETHER */
						/* This is the "hw" arg case. */
						if (strcmp("ether", *argv) || (*++argv == NULL)) {
							show_usage();
						}
						safe_strncpy(host, *argv, (sizeof host));
						if (in_ether(host, &sa)) {
							fprintf(stderr, "invalid hw-addr %s\n", host);
							++goterr;
							continue;
						}
						p = (char *) &sa;
					}
#endif
					memcpy((((char *)(&ifr)) + a1op->ifr_offset),
						   p, sizeof(struct sockaddr));
				} else {
					unsigned int i = strtoul(*argv,NULL,0);
					p = ((char *)(&ifr)) + a1op->ifr_offset;
#ifdef BB_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
					if (mask & A_MAP_TYPE) {
						if (ioctl(sockfd, SIOCGIFMAP, &ifr) < 0) {
							++goterr;
							continue;
						}
						if ((mask & A_MAP_UCHAR) == A_MAP_UCHAR) {
							*((unsigned char *) p) = i;
						} else if (mask & A_MAP_USHORT) {
							*((unsigned short *) p) = i;
						} else {
							*((unsigned long *) p) = i;
						}
					} else
#endif
					if (mask & A_CAST_CHAR_PTR) {
						*((caddr_t *) p) = (caddr_t) i;
					} else { /* A_CAST_INT */
						*((int *) p) = i;
					}
				}
						
				if (ioctl(sockfd, a1op->selector, &ifr) < 0) {
					perror(a1op->name);
					++goterr;
					continue;
				}

#ifdef QUESTIONABLE_ALIAS_CASE
				if (mask & A_COLON_CHK) {
					/*
					 * Don't do the set_flag() if the address is an alias with
					 * a - at the end, since it's deleted already! - Roman
					 *
					 * Should really use regex.h here, not sure though how well
					 * it'll go with the cross-platform support etc. 
					 */
					char *ptr;
					short int found_colon = 0;
					for (ptr = ifr.ifr_name; *ptr; ptr++ ) {
						if (*ptr == ':') {
							found_colon++;
						}
					}
			
					if (found_colon && *(ptr - 1) == '-') {
						continue;
					}
				}
#endif
			}
			if (!(mask & A_SET_AFTER)) {
				continue;
			}
			mask = N_SET;
		}

		if (ioctl(sockfd, SIOCGIFFLAGS, &ifr) < 0) {
			perror("SIOCGIFFLAGS"); 
			++goterr;
		} else {
			selector = op->selector;
			if (mask & SET_MASK) {
				ifr.ifr_flags |= selector;
			} else {
				ifr.ifr_flags &= ~selector;
			}
			if (ioctl(sockfd, SIOCSIFFLAGS, &ifr) < 0) {
				perror("SIOCSIFFLAGS"); 
				++goterr;
			}
		}
	LOOP:;
	} /* end of while-loop */

	return goterr;
}

#ifdef BB_FEATURE_IFCONFIG_HW
/* Input an Ethernet address and convert to binary. */
static int
in_ether(char *bufp, struct sockaddr *sap)
{
	unsigned char *ptr;
	int i, j;
	unsigned char val;
	unsigned char c;
	
	sap->sa_family = ARPHRD_ETHER;
	ptr = sap->sa_data;
	
	for (i = 0 ; i < ETH_ALEN ; i++) {
		val = 0;

		/* We might get a semicolon here - not required. */
		if (i && (*bufp == ':')) {
			bufp++;
		}

		for (j=0 ; j<2 ; j++) {
			c = *bufp;
			if (c >= '0' && c <= '9') {
				c -= '0';
			} else if (c >= 'a' && c <= 'f') {
				c -= ('a' - 10);
			} else if (c >= 'A' && c <= 'F') {
				c -= ('A' - 10);
			} else if (j && (c == ':' || c == 0)) {
				break;
			} else {
				return -1;
			}
			++bufp;
			val <<= 4;
			val += c;
		}
		*ptr++ = val;
	}

	return (int) (*bufp);		/* Error if we don't end at end of string. */
}
#endif