path: root/networking/brctl.c

/* vi: set sw=4 ts=4: */
/*
 * Small implementation of brctl for busybox.
 *
 * Copyright (C) 2008 by Bernhard Reutner-Fischer
 *
 * Some helper functions from bridge-utils are
 * Copyright (C) 2000 Lennert Buytenhek
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
/* This applet currently uses only the ioctl interface and no sysfs at all.
 * At the time of this writing this was considered a feature.
 */
//config:config BRCTL
//config:	bool "brctl (4.7 kb)"
//config:	default y
//config:	select PLATFORM_LINUX
//config:	help
//config:	Manage ethernet bridges.
//config:	Supports addbr/delbr and addif/delif.
//config:
//config:config FEATURE_BRCTL_FANCY
//config:	bool "Fancy options"
//config:	default y
//config:	depends on BRCTL
//config:	help
//config:	Add support for extended option like:
//config:		setageing, setfd, sethello, setmaxage,
//config:		setpathcost, setportprio, setbridgeprio,
//config:		stp
//config:	This adds about 600 bytes.
//config:
//config:config FEATURE_BRCTL_SHOW
//config:	bool "Support show"
//config:	default y
//config:	depends on BRCTL && FEATURE_BRCTL_FANCY
//config:	help
//config:	Add support for option which prints the current config:
//config:		show

//applet:IF_BRCTL(APPLET_NOEXEC(brctl, brctl, BB_DIR_USR_SBIN, BB_SUID_DROP, brctl))

//kbuild:lib-$(CONFIG_BRCTL) += brctl.o

//usage:#define brctl_trivial_usage
//usage:       "COMMAND [BRIDGE [INTERFACE]]"
//usage:#define brctl_full_usage "\n\n"
//usage:       "Manage ethernet bridges\n"
//usage:     "\nCommands:"
//usage:	IF_FEATURE_BRCTL_SHOW(
//usage:     "\n	show			Show a list of bridges"
//usage:	)
//usage:     "\n	addbr BRIDGE		Create BRIDGE"
//usage:     "\n	delbr BRIDGE		Delete BRIDGE"
//usage:     "\n	addif BRIDGE IFACE	Add IFACE to BRIDGE"
//usage:     "\n	delif BRIDGE IFACE	Delete IFACE from BRIDGE"
//usage:	IF_FEATURE_BRCTL_FANCY(
//usage:     "\n	setageing BRIDGE TIME		Set ageing time"
//usage:     "\n	setfd BRIDGE TIME		Set bridge forward delay"
//usage:     "\n	sethello BRIDGE TIME		Set hello time"
//usage:     "\n	setmaxage BRIDGE TIME		Set max message age"
//usage:     "\n	setpathcost BRIDGE COST		Set path cost"
//usage:     "\n	setportprio BRIDGE PRIO		Set port priority"
//usage:     "\n	setbridgeprio BRIDGE PRIO	Set bridge priority"
//usage:     "\n	stp BRIDGE [1/yes/on|0/no/off]	STP on/off"
//usage:	)

#include "libbb.h"
#include "common_bufsiz.h"
#include <linux/sockios.h>
#include <net/if.h>

#ifndef SIOCBRADDBR
# define SIOCBRADDBR BRCTL_ADD_BRIDGE
#endif
#ifndef SIOCBRDELBR
# define SIOCBRDELBR BRCTL_DEL_BRIDGE
#endif
#ifndef SIOCBRADDIF
# define SIOCBRADDIF BRCTL_ADD_IF
#endif
#ifndef SIOCBRDELIF
# define SIOCBRDELIF BRCTL_DEL_IF
#endif


/* Maximum number of ports supported per bridge interface.  */
#ifndef MAX_PORTS
# define MAX_PORTS 32
#endif

/* Use internal number parsing and not the "exact" conversion.  */
/* #define BRCTL_USE_INTERNAL 0 */ /* use exact conversion */
#define BRCTL_USE_INTERNAL 1

#if ENABLE_FEATURE_BRCTL_FANCY
/* #include <linux/if_bridge.h>
 * breaks on musl: we already included netinet/in.h in libbb.h,
 * if we include <linux/if_bridge.h> here, we get this:
 * In file included from /usr/include/linux/if_bridge.h:18,
 *                  from networking/brctl.c:67:
 * /usr/include/linux/in6.h:32: error: redefinition of 'struct in6_addr'
 * /usr/include/linux/in6.h:49: error: redefinition of 'struct sockaddr_in6'
 * /usr/include/linux/in6.h:59: error: redefinition of 'struct ipv6_mreq'
 */
/* From <linux/if_bridge.h> */
#define BRCTL_GET_VERSION 0
#define BRCTL_GET_BRIDGES 1
#define BRCTL_ADD_BRIDGE 2
#define BRCTL_DEL_BRIDGE 3
#define BRCTL_ADD_IF 4
#define BRCTL_DEL_IF 5
#define BRCTL_GET_BRIDGE_INFO 6
#define BRCTL_GET_PORT_LIST 7
#define BRCTL_SET_BRIDGE_FORWARD_DELAY 8
#define BRCTL_SET_BRIDGE_HELLO_TIME 9
#define BRCTL_SET_BRIDGE_MAX_AGE 10
#define BRCTL_SET_AGEING_TIME 11
#define BRCTL_SET_GC_INTERVAL 12
#define BRCTL_GET_PORT_INFO 13
#define BRCTL_SET_BRIDGE_STP_STATE 14
#define BRCTL_SET_BRIDGE_PRIORITY 15
#define BRCTL_SET_PORT_PRIORITY 16
#define BRCTL_SET_PATH_COST 17
#define BRCTL_GET_FDB_ENTRIES 18
struct __bridge_info {
	uint64_t designated_root;
	uint64_t bridge_id;
	uint32_t root_path_cost;
	uint32_t max_age;
	uint32_t hello_time;
	uint32_t forward_delay;
	uint32_t bridge_max_age;
	uint32_t bridge_hello_time;
	uint32_t bridge_forward_delay;
	uint8_t  topology_change;
	uint8_t  topology_change_detected;
	uint8_t  root_port;
	uint8_t  stp_enabled;
	uint32_t ageing_time;
	uint32_t gc_interval;
	uint32_t hello_timer_value;
	uint32_t tcn_timer_value;
	uint32_t topology_change_timer_value;
	uint32_t gc_timer_value;
};
/* end <linux/if_bridge.h> */

/* FIXME: These 4 funcs are not really clean and could be improved */
static ALWAYS_INLINE void bb_strtotimeval(struct timeval *tv,
		const char *time_str)
{
	double secs;
# if BRCTL_USE_INTERNAL
	char *endptr;
	secs = /*bb_*/strtod(time_str, &endptr);
	if (endptr == time_str)
# else
	if (sscanf(time_str, "%lf", &secs) != 1)
# endif
		bb_error_msg_and_die(bb_msg_invalid_arg_to, time_str, "timespec");
	tv->tv_sec = secs;
	tv->tv_usec = 1000000 * (secs - tv->tv_sec);
}

static ALWAYS_INLINE unsigned long tv_to_jiffies(const struct timeval *tv)
{
	unsigned long long jif;

	jif = 1000000ULL * tv->tv_sec + tv->tv_usec;

	return jif/10000;
}
# if 0
static void jiffies_to_tv(struct timeval *tv, unsigned long jiffies)
{
	unsigned long long tvusec;

	tvusec = 10000ULL*jiffies;
	tv->tv_sec = tvusec/1000000;
	tv->tv_usec = tvusec - 1000000 * tv->tv_sec;
}
# endif
static unsigned long str_to_jiffies(const char *time_str)
{
	struct timeval tv;
	bb_strtotimeval(&tv, time_str);
	return tv_to_jiffies(&tv);
}

static void arm_ioctl(unsigned long *args,
		unsigned long arg0, unsigned long arg1, unsigned long arg2)
{
	args[0] = arg0;
	args[1] = arg1;
	args[2] = arg2;
	args[3] = 0;
}
#endif

#define filedata bb_common_bufsiz1
static int read_file(const char *name)
{
	int n = open_read_close(name, filedata, COMMON_BUFSIZE - 1);
	if (n < 0) {
		filedata[0] = '\0';
	} else {
		filedata[n] = '\0';
		if (n != 0 && filedata[n - 1] == '\n')
			filedata[--n] = '\0';
	}
	return n;
}

/* NB: we are in /sys/class/net
 */
static int show_bridge(const char *name, int need_hdr)
{
// Output:
//bridge name	bridge id		STP enabled	interfaces
//br0		8000.000000000000	no		eth0
	char pathbuf[IFNAMSIZ + sizeof("/bridge/bridge_id") + 32];
	int tabs;
	DIR *ifaces;
	struct dirent *ent;
	char *sfx;

	sfx = pathbuf + sprintf(pathbuf, "%s/bridge/", name);
	strcpy(sfx, "bridge_id");
	if (read_file(pathbuf) < 0)
		return -1; /* this iface is not a bridge */

	if (need_hdr)
		puts("bridge name\tbridge id\t\tSTP enabled\tinterfaces");
	printf("%s\t\t", name);
	printf("%s\t", filedata);

	strcpy(sfx, "stp_state");
	read_file(pathbuf);
	if (LONE_CHAR(filedata, '0'))
		strcpy(filedata, "no");
	else
	if (LONE_CHAR(filedata, '1'))
		strcpy(filedata, "yes");
	printf(filedata);

	strcpy(sfx, "brif");
	tabs = 0;
	ifaces = opendir(pathbuf);
	if (ifaces) {
		while ((ent = readdir(ifaces)) != NULL) {
			if (tabs)
				printf("\t\t\t\t\t");
			else
				tabs = 1;
			printf("\t\t%s\n", ent->d_name);
		}
		closedir(ifaces);
	}
	if (!tabs)  /* bridge has no interfaces */
		bb_putchar('\n');
	return 0;
}

int brctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int brctl_main(int argc UNUSED_PARAM, char **argv)
{
	static const char keywords[] ALIGN1 =
		"addbr\0" "delbr\0" "addif\0" "delif\0"
	IF_FEATURE_BRCTL_FANCY(
		"stp\0"
		"setageing\0" "setfd\0" "sethello\0" "setmaxage\0"
		"setpathcost\0" "setportprio\0" "setbridgeprio\0"
	)
	IF_FEATURE_BRCTL_SHOW("show\0");

	enum { ARG_addbr = 0, ARG_delbr, ARG_addif, ARG_delif
		IF_FEATURE_BRCTL_FANCY(,
			ARG_stp,
			ARG_setageing, ARG_setfd, ARG_sethello, ARG_setmaxage,
			ARG_setpathcost, ARG_setportprio, ARG_setbridgeprio
		)
		IF_FEATURE_BRCTL_SHOW(, ARG_show)
	};

	int fd;
	smallint key;
	struct ifreq ifr;
	char *br, *brif;

	argv++;
	if (!*argv) {
		/* bare "brctl" shows --help */
		bb_show_usage();
	}

	xchdir("/sys/class/net");

	while (*argv) {
#if ENABLE_FEATURE_BRCTL_FANCY
		int ifidx[MAX_PORTS];
		unsigned long args[4];
		ifr.ifr_data = (char *) &args;
#endif

		key = index_in_strings(keywords, *argv);
		if (key == -1) /* no match found in keywords array, bail out. */
			bb_error_msg_and_die(bb_msg_invalid_arg_to, *argv, applet_name);
		argv++;

#if ENABLE_FEATURE_BRCTL_SHOW
		if (key == ARG_show) { /* show */
			DIR *net;
			struct dirent *ent;
			int need_hdr = 1;
			int exitcode = EXIT_SUCCESS;

			if (*argv) {
				/* "brctl show BR1 BR2 BR3" */
				do {
					if (show_bridge(*argv, need_hdr) >= 0) {
						need_hdr = 0;
					} else {
						bb_error_msg("bridge %s does not exist", *argv);
//TODO: if device exists, but is not a BR, brctl from bridge-utils 1.6 says this instead:
// "device eth0 is not a bridge"
						exitcode = EXIT_FAILURE;
					}
				} while (*++argv != NULL);
				return exitcode;
			}

			/* "brctl show" (if no ifaces, shows nothing, not even header) */
			net = xopendir(".");
			while ((ent = readdir(net)) != NULL) {
				if (DOT_OR_DOTDOT(ent->d_name))
					continue; /* . or .. */
				if (show_bridge(ent->d_name, need_hdr) >= 0)
					need_hdr = 0;
			}
			closedir(net);
			return exitcode;
		}
#endif

		if (!*argv) /* all but 'show' need at least one argument */
			bb_show_usage();

		fd = xsocket(AF_INET, SOCK_STREAM, 0);
		br = *argv++;

//brctl from bridge-utils 1.6 also still uses ioctl
//for SIOCBRADDBR / SIOCBRDELBR, not /sys accesses
		if (key == ARG_addbr || key == ARG_delbr) { /* addbr or delbr */
			ioctl_or_perror_and_die(fd,
					key == ARG_addbr ? SIOCBRADDBR : SIOCBRDELBR,
					br, "bridge %s", br);
			goto done;
		}

		if (!*argv) /* all but 'addbr/delbr' need at least two arguments */
			bb_show_usage();

		strncpy_IFNAMSIZ(ifr.ifr_name, br);
		if (key == ARG_addif || key == ARG_delif) { /* addif or delif */
			brif = *argv;
			ifr.ifr_ifindex = if_nametoindex(brif);
			if (!ifr.ifr_ifindex) {
				bb_perror_msg_and_die("iface %s", brif);
			}
			ioctl_or_perror_and_die(fd,
					key == ARG_addif ? SIOCBRADDIF : SIOCBRDELIF,
					&ifr, "bridge %s", br);
			goto done_next_argv;
		}
#if ENABLE_FEATURE_BRCTL_FANCY
		if (key == ARG_stp) { /* stp */
			static const char no_yes[] ALIGN1 =
				"0\0" "off\0" "n\0" "no\0"   /* 0 .. 3 */
				"1\0" "on\0"  "y\0" "yes\0"; /* 4 .. 7 */
			int onoff = index_in_strings(no_yes, *argv);
			if (onoff < 0)
				bb_error_msg_and_die(bb_msg_invalid_arg_to, *argv, applet_name);
//TODO: replace with:
//write "0\n" or "1\n" to /sys/class/net/BR/bridge/stp_state
			onoff = (unsigned)onoff / 4;
			arm_ioctl(args, BRCTL_SET_BRIDGE_STP_STATE, onoff, 0);
			goto fire;
		}
		if ((unsigned)(key - ARG_setageing) < 4) { /* time related ops */
			static const uint8_t ops[] ALIGN1 = {
				BRCTL_SET_AGEING_TIME,          /* ARG_setageing */
				BRCTL_SET_BRIDGE_FORWARD_DELAY, /* ARG_setfd     */
				BRCTL_SET_BRIDGE_HELLO_TIME,    /* ARG_sethello  */
				BRCTL_SET_BRIDGE_MAX_AGE        /* ARG_setmaxage */
			};
//TODO: replace with:
//setageing BR N: write "N*100\n" to /sys/class/net/BR/bridge/ageing_time
//setfd BR N: write "N*100\n" to /sys/class/net/BR/bridge/forward_delay
//sethello BR N: write "N*100\n" to /sys/class/net/BR/bridge/hello_time
//setmaxage BR N: write "N*100\n" to /sys/class/net/BR/bridge/max_age
			arm_ioctl(args, ops[key - ARG_setageing], str_to_jiffies(*argv), 0);
			goto fire;
		}
		if (key == ARG_setpathcost
		 || key == ARG_setportprio
		 || key == ARG_setbridgeprio
		) {
			static const uint8_t ops[] ALIGN1 = {
				BRCTL_SET_PATH_COST,      /* ARG_setpathcost   */
				BRCTL_SET_PORT_PRIORITY,  /* ARG_setportprio   */
				BRCTL_SET_BRIDGE_PRIORITY /* ARG_setbridgeprio */
			};
			int port = -1;
			unsigned arg1, arg2;

//TODO: replace with:
//setbridgeprio BR N: write "N\n" to /sys/class/net/BR/bridge/priority
//setpathcost BR PORT N: ??
//setportprio BR PORT N: ??

			if (key != ARG_setbridgeprio) {
				/* get portnum */
				unsigned i;

				port = if_nametoindex(*argv++);
				if (!port)
					bb_error_msg_and_die(bb_msg_invalid_arg_to, *argv, "port");
				memset(ifidx, 0, sizeof ifidx);
				arm_ioctl(args, BRCTL_GET_PORT_LIST, (unsigned long)ifidx,
						MAX_PORTS);
				xioctl(fd, SIOCDEVPRIVATE, &ifr);
				for (i = 0; i < MAX_PORTS; i++) {
					if (ifidx[i] == port) {
						port = i;
						break;
					}
				}
			}
			arg1 = port;
			arg2 = xatoi_positive(*argv);
			if (key == ARG_setbridgeprio) {
				arg1 = arg2;
				arg2 = 0;
			}
			arm_ioctl(args, ops[key - ARG_setpathcost], arg1, arg2);
		}
 fire:
		/* Execute the previously set command */
		xioctl(fd, SIOCDEVPRIVATE, &ifr);
#endif
 done_next_argv:
		argv++;
 done:
		close(fd);
	}

	return EXIT_SUCCESS;
}