/* 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.
 */
//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 [ARGS]]"
//usage:#define brctl_full_usage "\n\n"
//usage:       "Manage ethernet bridges"
//usage:     "\nCommands:"
//usage:        IF_FEATURE_BRCTL_SHOW(
//usage:     "\n        show [BRIDGE]...        Show 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        stp BRIDGE 1/yes/on|0/no/off    STP on/off"
//usage:     "\n        setageing BRIDGE SECONDS        Set ageing time"
//usage:     "\n        setfd BRIDGE SECONDS            Set bridge forward delay"
//usage:     "\n        sethello BRIDGE SECONDS         Set hello time"
//usage:     "\n        setmaxage BRIDGE SECONDS        Set max message age"
//usage:     "\n        setbridgeprio BRIDGE PRIO       Set bridge priority"
//usage:     "\n        setportprio BRIDGE IFACE PRIO   Set port priority"
//usage:     "\n        setpathcost BRIDGE IFACE COST   Set path cost"
//usage:        )
// Not yet implemented:
//                      hairpin BRIDGE IFACE on|off     Hairpin on/off
//                      showmacs BRIDGE                 List mac addrs
//                      showstp BRIDGE                  Show stp info

#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

#if ENABLE_FEATURE_BRCTL_FANCY
static unsigned str_to_jiffies(const char *time_str)
{
        double dd;
        char *endptr;
        dd = /*bb_*/strtod(time_str, &endptr);
        if (endptr == time_str || dd < 0)
                bb_error_msg_and_die(bb_msg_invalid_arg_to, time_str, "timespec");

        dd *= 100;
        /* For purposes of brctl,
         * capping SECONDS by ~20 million seconds is quite enough:
         */
        if (dd > INT_MAX)
                dd = INT_MAX;

        return dd;
}
#endif

#define filedata bb_common_bufsiz1

#if ENABLE_FEATURE_BRCTL_SHOW
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;

#if IFNAMSIZ == 16
        sfx = pathbuf + sprintf(pathbuf, "%.16s/bridge/", name);
#else
        sfx = pathbuf + sprintf(pathbuf, "%.*s/bridge/", (int)IFNAMSIZ, name);
#endif
        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");
        fputs(filedata, stdout);

        strcpy(sfx - (sizeof("bridge/")-1), "brif");
        tabs = 0;
        ifaces = opendir(pathbuf);
        if (ifaces) {
                while ((ent = readdir(ifaces)) != NULL) {
                        if (DOT_OR_DOTDOT(ent->d_name))
                                continue; /* . or .. */
                        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;
}
#endif

#if ENABLE_FEATURE_BRCTL_FANCY
static void write_uint(const char *name, const char *leaf, unsigned val)
{
        char pathbuf[IFNAMSIZ + sizeof("/bridge/bridge_id") + 32];
        int fd, n;

#if IFNAMSIZ == 16
        sprintf(pathbuf, "%.16s/%s", name, leaf);
#else
        sprintf(pathbuf, "%.*s/%s", (int)IFNAMSIZ, name, leaf);
#endif
        fd = xopen(pathbuf, O_WRONLY);
        n = sprintf(filedata, "%u\n", val);
        if (write(fd, filedata, n) < 0)
                bb_simple_perror_msg_and_die(name);
        close(fd);
}
#endif

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)
        };

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

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

//      while (*argv)
        {
                smallint key;
                char *br;

                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 [BR]... */
                        DIR *net;
                        struct dirent *ent;
                        int need_hdr = 1;
                        int exitcode = EXIT_SUCCESS;

                        if (*argv) {
                                /* "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;
                        }

                        /* "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;
                        }
                        if (ENABLE_FEATURE_CLEAN_UP)
                                closedir(net);
                        return exitcode;
                }
#endif

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

                br = *argv++;

                if (key == ARG_addbr || key == ARG_delbr) {
                        /* addbr or delbr */
                        /* brctl from bridge-utils 1.6 still uses ioctl
                         * for SIOCBRADDBR / SIOCBRDELBR, not /sys accesses
                         */
                        int fd = xsocket(AF_INET, SOCK_STREAM, 0);
                        ioctl_or_perror_and_die(fd,
                                key == ARG_addbr ? SIOCBRADDBR : SIOCBRDELBR,
                                br, "bridge %s", br
                        );
                        //close(fd);
                        //goto done;
                        /* bridge-utils 1.6 simply ignores trailing args:
                         * "brctl addbr BR1 ARGS" ignores ARGS
                         */
                        if (ENABLE_FEATURE_CLEAN_UP)
                                close(fd);
                        return EXIT_SUCCESS;
                }

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

#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);
                        onoff = (unsigned)onoff / 4;
                        write_uint(br, "bridge/stp_state", onoff);
                        //goto done_next_argv;
                        return EXIT_SUCCESS;
                }

                if ((unsigned)(key - ARG_setageing) < 4) { /* time related ops */
                        /* setageing BR N: "N*100\n" to /sys/class/net/BR/bridge/ageing_time
                         * setfd BR N:     "N*100\n" to /sys/class/net/BR/bridge/forward_delay
                         * sethello BR N:  "N*100\n" to /sys/class/net/BR/bridge/hello_time
                         * setmaxage BR N: "N*100\n" to /sys/class/net/BR/bridge/max_age
                         */
                        write_uint(br,
                                nth_string(
                                        "bridge/ageing_time"  "\0" /* ARG_setageing */
                                        "bridge/forward_delay""\0" /* ARG_setfd     */
                                        "bridge/hello_time"   "\0" /* ARG_sethello  */
                                        "bridge/max_age",          /* ARG_setmaxage */
                                        key - ARG_setageing
                                ),
                                str_to_jiffies(*argv)
                        );
                        //goto done_next_argv;
                        return EXIT_SUCCESS;
                }

                if (key == ARG_setbridgeprio) {
                        write_uint(br, "bridge/priority", xatoi_positive(*argv));
                        //goto done_next_argv;
                        return EXIT_SUCCESS;
                }

                if (key == ARG_setpathcost
                 || key == ARG_setportprio
                ) {
                        if (!argv[1])
                                bb_show_usage();
                        /* BR is not used (and ignored!) for these commands:
                         * "setpathcost BR PORT N" writes "N\n" to
                         * /sys/class/net/PORT/brport/path_cost
                         * "setportprio BR PORT N" writes "N\n" to
                         * /sys/class/net/PORT/brport/priority
                         */
                        write_uint(argv[0],
                                nth_string(
                                        "brport/path_cost" "\0" /* ARG_setpathcost */
                                        "brport/priority",      /* ARG_setportprio */
                                        key - ARG_setpathcost
                                ),
                                xatoi_positive(argv[1])
                        );
                        //argv++;
                        //goto done_next_argv;
                        return EXIT_SUCCESS;
                }

/* TODO: "showmacs BR"
 *      port no\tmac addr\t\tis local?\tageing timer
 *      <sp><sp>1\txx:xx:xx:xx:xx:xx\tno\t\t<sp><sp><sp>1.31
 *      port no mac addr                is local?       ageing timer
 *        1     xx:xx:xx:xx:xx:xx       no                 1.31
 * Read fixed-sized records from /sys/class/net/BR/brforward:
 *      struct __fdb_entry {
 *              uint8_t  mac_addr[ETH_ALEN];
 *              uint8_t  port_no; //lsb
 *              uint8_t  is_local;
 *              uint32_t ageing_timer_value;
 *              uint8_t  port_hi;
 *              uint8_t  pad0;
 *              uint16_t unused;
 *      };
 */
#endif
                /* always true: if (key == ARG_addif || key == ARG_delif) */ {
                        /* addif or delif */
                        struct ifreq ifr;
                        int fd = xsocket(AF_INET, SOCK_STREAM, 0);

                        strncpy_IFNAMSIZ(ifr.ifr_name, br);
                        ifr.ifr_ifindex = if_nametoindex(*argv);
                        if (ifr.ifr_ifindex == 0) {
                                bb_perror_msg_and_die("iface %s", *argv);
                        }
                        ioctl_or_perror_and_die(fd,
                                key == ARG_addif ? SIOCBRADDIF : SIOCBRDELIF,
                                &ifr, "bridge %s", br
                        );
                        //close(fd);
                        //goto done_next_argv;
                        if (ENABLE_FEATURE_CLEAN_UP)
                                close(fd);
                        return EXIT_SUCCESS;
                }

// done_next_argv:
//              argv++;
// done:
        }

        return EXIT_SUCCESS;
}