path: root/utilities/ovs-discover.c

/*
 * Copyright (c) 2008, 2009 Nicira Networks.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <config.h>
#include <getopt.h>
#include <limits.h>
#include <regex.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include "command-line.h"
#include "daemon.h"
#include "dhcp-client.h"
#include "dhcp.h"
#include "dirs.h"
#include "dynamic-string.h"
#include "fatal-signal.h"
#include "netdev.h"
#include "poll-loop.h"
#include "timeval.h"
#include "unixctl.h"
#include "util.h"

#include "vlog.h"
#define THIS_MODULE VLM_ovs_discover

struct iface {
    const char *name;
    struct dhclient *dhcp;
};

/* The interfaces that we serve. */
static struct iface *ifaces;
static int n_ifaces;

/* --accept-vconn: Regular expression specifying the class of controller vconns
 * that we will accept during autodiscovery. */
static const char *accept_controller_re = ".*";
static regex_t accept_controller_regex;

/* --exit-without-bind: Exit after discovering the controller, without binding
 * the network device to an IP address? */
static bool exit_without_bind;

/* --exit-after-bind: Exit after discovering the controller, after binding the
 * network device to an IP address? */
static bool exit_after_bind;

static bool iface_init(struct iface *, const char *netdev_name);
static void release_ifaces(void *aux UNUSED);

static void parse_options(int argc, char *argv[]);
static void usage(void) NO_RETURN;

static void modify_dhcp_request(struct dhcp_msg *, void *aux);
static bool validate_dhcp_offer(const struct dhcp_msg *, void *aux);

int
main(int argc, char *argv[])
{
    struct unixctl_server *unixctl;
    int retval;
    int i;

    set_program_name(argv[0]);
    time_init();
    vlog_init();
    parse_options(argc, argv);

    argc -= optind;
    argv += optind;
    if (argc < 1) {
        ovs_fatal(0, "need at least one non-option argument; "
                  "use --help for usage");
    }

    ifaces = xmalloc(argc * sizeof *ifaces);
    n_ifaces = 0;
    for (i = 0; i < argc; i++) {
        if (iface_init(&ifaces[n_ifaces], argv[i])) {
            n_ifaces++;
        }
    }
    if (!n_ifaces) {
        ovs_fatal(0, "failed to initialize any DHCP clients");
    }

    for (i = 0; i < n_ifaces; i++) {
        struct iface *iface = &ifaces[i];
        dhclient_init(iface->dhcp, 0);
    }
    fatal_signal_add_hook(release_ifaces, NULL, true);

    retval = regcomp(&accept_controller_regex, accept_controller_re,
                     REG_NOSUB | REG_EXTENDED);
    if (retval) {
        size_t length = regerror(retval, &accept_controller_regex, NULL, 0);
        char *buffer = xmalloc(length);
        regerror(retval, &accept_controller_regex, buffer, length);
        ovs_fatal(0, "%s: %s", accept_controller_re, buffer);
    }

    retval = unixctl_server_create(NULL, &unixctl);
    if (retval) {
        ovs_fatal(retval, "Could not listen for unixctl connections");
    }

    die_if_already_running();

    signal(SIGPIPE, SIG_IGN);
    for (;;) {
        fatal_signal_block();
        for (i = 0; i < n_ifaces; i++) {
            struct iface *iface = &ifaces[i];
            dhclient_run(iface->dhcp);
            if (dhclient_changed(iface->dhcp)) {
                bool is_bound = dhclient_is_bound(iface->dhcp);
                int j;

                /* Configure network device. */
                if (!exit_without_bind) {
                    dhclient_configure_netdev(iface->dhcp);
                    dhclient_update_resolv_conf(iface->dhcp);
                }

                if (is_bound) {
                    static bool detached = false;
                    struct ds ds;

                    /* Disable timeout, since discovery was successful. */
                    time_alarm(0);

                    /* Print discovered parameters. */
                    ds_init(&ds);
                    dhcp_msg_to_string(dhclient_get_config(iface->dhcp),
                                       true, &ds);
                    fputs(ds_cstr(&ds), stdout);
                    putchar('\n');
                    fflush(stdout);
                    ds_destroy(&ds);

                    /* Exit if the user requested it. */
                    if (exit_without_bind) {
                        VLOG_DBG("exiting because of successful binding on %s "
                                 "and --exit-without-bind specified",
                                 iface->name);
                        exit(0);
                    }
                    if (exit_after_bind) {
                        VLOG_DBG("exiting because of successful binding on %s "
                                 "and --exit-after-bind specified",
                                 iface->name);
                        exit(0);
                    }

                    /* Detach into background, if we haven't already. */
                    if (!detached) {
                        detached = true;
                        daemonize();
                    }
                }

                /* We only want an address on a single one of our interfaces.
                 * So: if we have an address on this interface, stop looking
                 * for one on the others; if we don't have an address on this
                 * interface, start looking everywhere. */
                for (j = 0; j < n_ifaces; j++) {
                    struct iface *if2 = &ifaces[j];
                    if (iface != if2) {
                        if (is_bound) {
                            dhclient_release(if2->dhcp);
                        } else {
                            dhclient_init(if2->dhcp, 0);
                        }
                    }
                }
            }
        }
        unixctl_server_run(unixctl);
        for (i = 0; i < n_ifaces; i++) {
            struct iface *iface = &ifaces[i];
            dhclient_wait(iface->dhcp);
        }
        unixctl_server_wait(unixctl);
        fatal_signal_unblock();
        poll_block();
    }

    return 0;
}

static bool
iface_init(struct iface *iface, const char *netdev_name)
{
    int retval;

    iface->name = netdev_name;
    iface->dhcp = NULL;

    if (exit_after_bind) {
        /* Bring this interface up permanently, so that the bound address
         * persists past program termination. */
        struct netdev *netdev;

        retval = netdev_open(iface->name, NETDEV_ETH_TYPE_NONE, &netdev);
        if (retval) {
            ovs_error(retval, "Could not open %s device", iface->name);
            return false;
        }
        retval = netdev_turn_flags_on(netdev, NETDEV_UP, true);
        if (retval) {
            ovs_error(retval, "Could not bring %s device up", iface->name);
            return false;
        }
        netdev_close(netdev);
    }

    retval = dhclient_create(iface->name, modify_dhcp_request,
                             validate_dhcp_offer, NULL, &iface->dhcp);
    if (retval) {
        ovs_error(retval, "%s: failed to initialize DHCP client", iface->name);
        return false;
    }

    return true;
}

static void
release_ifaces(void *aux UNUSED)
{
    int i;

    for (i = 0; i < n_ifaces; i++) {
        struct dhclient *dhcp = ifaces[i].dhcp;
        dhclient_release(dhcp);
        if (dhclient_changed(dhcp)) {
            dhclient_configure_netdev(dhcp);
        }
    }
}

static void
modify_dhcp_request(struct dhcp_msg *msg, void *aux UNUSED)
{
    dhcp_msg_put_string(msg, DHCP_CODE_VENDOR_CLASS, "OpenFlow");
}

static bool
validate_dhcp_offer(const struct dhcp_msg *msg, void *aux UNUSED)
{
    static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 60);
    char *vconn_name;
    bool accept;

    vconn_name = dhcp_msg_get_string(msg, DHCP_CODE_OFP_CONTROLLER_VCONN);
    if (!vconn_name) {
        VLOG_WARN_RL(&rl, "rejecting DHCP offer missing controller vconn");
        return false;
    }
    accept = !regexec(&accept_controller_regex, vconn_name, 0, NULL, 0);
    free(vconn_name);
    return accept;
}

static void
parse_options(int argc, char *argv[])
{
    enum {
        OPT_ACCEPT_VCONN = UCHAR_MAX + 1,
        OPT_EXIT_WITHOUT_BIND,
        OPT_EXIT_AFTER_BIND,
        OPT_NO_DETACH,
    };
    static struct option long_options[] = {
        {"accept-vconn", required_argument, 0, OPT_ACCEPT_VCONN},
        {"exit-without-bind", no_argument, 0, OPT_EXIT_WITHOUT_BIND},
        {"exit-after-bind", no_argument, 0, OPT_EXIT_AFTER_BIND},
        {"no-detach",   no_argument, 0, OPT_NO_DETACH},
        {"timeout",     required_argument, 0, 't'},
        {"pidfile",     optional_argument, 0, 'P'},
        {"force",       no_argument, 0, 'f'},
        {"verbose",     optional_argument, 0, 'v'},
        {"help",        no_argument, 0, 'h'},
        {"version",     no_argument, 0, 'V'},
        {0, 0, 0, 0},
    };
    char *short_options = long_options_to_short_options(long_options);
    bool detach_after_bind = true;

    for (;;) {
        unsigned long int timeout;
        int c;

        c = getopt_long(argc, argv, short_options, long_options, NULL);
        if (c == -1) {
            break;
        }

        switch (c) {
        case OPT_ACCEPT_VCONN:
            accept_controller_re = (optarg[0] == '^'
                                    ? optarg
                                    : xasprintf("^%s", optarg));
            break;

        case OPT_EXIT_WITHOUT_BIND:
            exit_without_bind = true;
            break;

        case OPT_EXIT_AFTER_BIND:
            exit_after_bind = true;
            break;

        case OPT_NO_DETACH:
            detach_after_bind = false;
            break;

        case 'P':
            set_pidfile(optarg);
            break;

        case 'f':
            ignore_existing_pidfile();
            break;

        case 't':
            timeout = strtoul(optarg, NULL, 10);
            if (timeout <= 0) {
                ovs_fatal(0, "value %s on -t or --timeout is not at least 1",
                          optarg);
            } else {
                time_alarm(timeout);
            }
            signal(SIGALRM, SIG_DFL);
            break;

        case 'h':
            usage();

        case 'V':
            OVS_PRINT_VERSION(0, 0);
            exit(EXIT_SUCCESS);

        case 'v':
            vlog_set_verbosity(optarg);
            break;

        case '?':
            exit(EXIT_FAILURE);

        default:
            abort();
        }
    }
    free(short_options);

    if ((exit_without_bind + exit_after_bind + !detach_after_bind) > 1) {
        ovs_fatal(0, "--exit-without-bind, --exit-after-bind, and --no-detach "
                  "are mutually exclusive");
    }
    if (detach_after_bind) {
        set_detach();
    }
}

static void
usage(void)
{
    printf("%s: a tool for discovering OpenFlow controllers.\n"
           "usage: %s [OPTIONS] NETDEV [NETDEV...]\n"
           "where each NETDEV is a network device on which to perform\n"
           "controller discovery.\n"
           "\nOrdinarily, ovs-discover runs in the foreground until it\n"
           "obtains an IP address and discovers an OpenFlow controller via\n"
           "DHCP, then it prints information about the controller to stdout\n"
           "and detaches to the background to maintain the IP address lease.\n"
           "\nNetworking options:\n"
           "  --accept-vconn=REGEX    accept matching discovered controllers\n"
           "  --exit-without-bind     exit after discovery, without binding\n"
           "  --exit-after-bind       exit after discovery, after binding\n"
           "  --no-detach             do not detach after discovery\n",
           program_name, program_name);
    vlog_usage();
    printf("\nOther options:\n"
           "  -t, --timeout=SECS      give up discovery after SECS seconds\n"
           "  -P, --pidfile[=FILE]    create pidfile (default: %s/%s.pid)\n"
           "  -f, --force             with -P, start even if already running\n"
           "  -h, --help              display this help message\n"
           "  -V, --version           display version information\n",
           ovs_rundir, program_name);
    exit(EXIT_SUCCESS);
}