/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2018 The FreeBSD Foundation
 *
 * This software was developed by Mark Johnston under sponsorship from
 * the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/dnv.h>
#include <sys/ioctl.h>
#include <sys/nv.h>
#include <sys/queue.h>

#include <net/if.h>
#include <netinet/in.h>
#include <netinet6/in6_var.h>

#include <errno.h>
#include <ifaddrs.h>
#include <string.h>
#include <unistd.h>

#include <libcasper.h>
#include <libcasper_service.h>

#include "rtsold.h"

/*
 * A service to fetch the flags for the link-local IPv6 address on the specified
 * interface.  This cannot easily be done in capability mode because we need to
 * use the routing socket sysctl API to find the link-local address of a
 * particular interface.  The SIOCGIFCONF ioctl is one other option, but as
 * currently implemented it is less flexible (it cannot report the required
 * buffer length), and hard-codes a buffer length limit.
 */

static int
llflags_get(const char *ifname, int *flagsp)
{
        struct in6_ifreq ifr6;
        struct ifaddrs *ifap, *ifa;
        struct sockaddr_in6 *sin6;
        int error, s;

        s = socket(PF_INET6, SOCK_DGRAM, 0);
        if (s < 0)
                return (-1);

        ifap = NULL;
        if (getifaddrs(&ifap) != 0) {
                error = errno;
                goto out;
        }
        error = ENOENT;
        for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
                if (strcmp(ifa->ifa_name, ifname) != 0)
                        continue;
                if (ifa->ifa_addr->sa_family != AF_INET6)
                        continue;

                sin6 = (struct sockaddr_in6 *)(void *)ifa->ifa_addr;
                if (!IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
                        continue;

                memset(&ifr6, 0, sizeof(ifr6));
                if (strlcpy(ifr6.ifr_name, ifname, sizeof(ifr6.ifr_name)) >=
                    sizeof(ifr6.ifr_name)) {
                        error = EINVAL;
                        goto out;
                }
                memcpy(&ifr6.ifr_ifru.ifru_addr, sin6, sin6->sin6_len);
                if (ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) < 0) {
                        error = errno;
                        goto out;
                }

                *flagsp = ifr6.ifr_ifru.ifru_flags6;
                error = 0;
                break;
        }
out:
        (void)close(s);
        if (ifap != NULL)
                freeifaddrs(ifap);
        if (error != 0) {
                errno = error;
                return (-1);
        } else {
                return (0);
        }
}

int
cap_llflags_get(cap_channel_t *cap, const char *ifname, int *flagsp)
{
#ifdef WITH_CASPER
        nvlist_t *nvl;
        int error;

        nvl = nvlist_create(0);
        nvlist_add_string(nvl, "cmd", "get");
        nvlist_add_string(nvl, "ifname", ifname);
        nvl = cap_xfer_nvlist(cap, nvl);
        if (nvl == NULL)
                return (-1);
        error = (int)dnvlist_get_number(nvl, "error", 0);
        if (error == 0)
                *flagsp = (int)nvlist_get_number(nvl, "flags");
        nvlist_destroy(nvl);
        if (error != 0)
                errno = error;
        return (error == 0 ? 0 : -1);
#else
        (void)cap;
        return (llflags_get(ifname, flagsp));
#endif
}

#ifdef WITH_CASPER
static int
llflags_command(const char *cmd, const nvlist_t *limits __unused,
    nvlist_t *nvlin, nvlist_t *nvlout)
{
        const char *ifname;
        int flags;

        if (strcmp(cmd, "get") != 0)
                return (EINVAL);
        ifname = nvlist_get_string(nvlin, "ifname");
        if (llflags_get(ifname, &flags) != 0)
                return (errno);
        nvlist_add_number(nvlout, "flags", flags);
        return (0);
}

CREATE_SERVICE("rtsold.llflags", NULL, llflags_command, 0);
#endif /* WITH_CASPER */