/*
 * Copyright (c) 1983, 1993
 *  The Regents of the University of California.  All rights reserved.
 * Copyright (c) 2016-2017, Marie Helene Kvello-Aune.  All rights reserved.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/ioctl.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_mib.h>
#include <netinet/in.h>
#include <netinet6/in6_var.h>
#include <netinet6/nd6.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <ifaddrs.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <net/if_vlan_var.h>

#include "libifconfig.h"
#include "libifconfig_internal.h"

#define NOTAG    ((u_short) -1)

static bool
isnd6defif(ifconfig_handle_t *h, const char *name)
{
        struct in6_ndifreq ndifreq;
        unsigned int ifindex;

        memset(&ndifreq, 0, sizeof(ndifreq));
        strlcpy(ndifreq.ifname, name, sizeof(ndifreq.ifname));
        ifindex = if_nametoindex(ndifreq.ifname);
        if (ifconfig_ioctlwrap(h, AF_INET6, SIOCGDEFIFACE_IN6, &ndifreq) < 0) {
                return (false);
        }
        h->error.errtype = OK;
        return (ndifreq.ifindex == ifindex);
}

ifconfig_handle_t *
ifconfig_open(void)
{
        ifconfig_handle_t *h;

        h = calloc(1, sizeof(*h));

        if (h == NULL) {
                return (NULL);
        }
        for (int i = 0; i <= AF_MAX; i++) {
                h->sockets[i] = -1;
        }

        return (h);
}

void
ifconfig_close(ifconfig_handle_t *h)
{

        for (int i = 0; i <= AF_MAX; i++) {
                if (h->sockets[i] != -1) {
                        (void)close(h->sockets[i]);
                }
        }
        freeifaddrs(h->ifap);
        free(h);
}

ifconfig_errtype
ifconfig_err_errtype(ifconfig_handle_t *h)
{

        return (h->error.errtype);
}

int
ifconfig_err_errno(ifconfig_handle_t *h)
{

        return (h->error.errcode);
}

unsigned long
ifconfig_err_ioctlreq(ifconfig_handle_t *h)
{

        return (h->error.ioctl_request);
}

int
ifconfig_foreach_iface(ifconfig_handle_t *h,
    ifconfig_foreach_func_t cb, void *udata)
{
        int ret;

        ret = ifconfig_getifaddrs(h);
        if (ret == 0) {
                struct ifaddrs *ifa;
                char *ifname = NULL;

                for (ifa = h->ifap; ifa; ifa = ifa->ifa_next) {
                        if (ifname != ifa->ifa_name) {
                                ifname = ifa->ifa_name;
                                cb(h, ifa, udata);
                        }
                }
        }
        /* Free ifaddrs so we don't accidentally cache stale data */
        freeifaddrs(h->ifap);
        h->ifap = NULL;

        return (ret);
}

void
ifconfig_foreach_ifaddr(ifconfig_handle_t *h, struct ifaddrs *ifa,
    ifconfig_foreach_func_t cb, void *udata)
{
        struct ifaddrs *ift;

        for (ift = ifa;
            ift != NULL &&
            ift->ifa_addr != NULL &&
            strcmp(ift->ifa_name, ifa->ifa_name) == 0;
            ift = ift->ifa_next) {
                cb(h, ift, udata);
        }
}

int
ifconfig_get_description(ifconfig_handle_t *h, const char *name,
    char **description)
{
        struct ifreq ifr;
        char *descr;
        size_t descrlen;

        descr = NULL;
        descrlen = 64;
        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        for (;;) {
                if ((descr = reallocf(descr, descrlen)) == NULL) {
                        h->error.errtype = OTHER;
                        h->error.errcode = ENOMEM;
                        return (-1);
                }

                ifr.ifr_buffer.buffer = descr;
                ifr.ifr_buffer.length = descrlen;
                if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFDESCR, &ifr) != 0) {
                        free(descr);
                        return (-1);
                }

                if (ifr.ifr_buffer.buffer == descr) {
                        if (strlen(descr) > 0) {
                                *description = strdup(descr);
                                free(descr);

                                if (description == NULL) {
                                        h->error.errtype = OTHER;
                                        h->error.errcode = ENOMEM;
                                        return (-1);
                                }

                                return (0);
                        }
                } else if (ifr.ifr_buffer.length > descrlen) {
                        descrlen = ifr.ifr_buffer.length;
                        continue;
                }
                break;
        }
        free(descr);
        h->error.errtype = OTHER;
        h->error.errcode = 0;
        return (-1);
}

int
ifconfig_set_description(ifconfig_handle_t *h, const char *name,
    const char *newdescription)
{
        struct ifreq ifr;
        int desclen;

        memset(&ifr, 0, sizeof(ifr));
        desclen = strlen(newdescription);

        /*
         * Unset description if the new description is 0 characters long.
         * TODO: Decide whether this should be an error condition instead.
         */
        if (desclen == 0) {
                return (ifconfig_unset_description(h, name));
        }

        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        ifr.ifr_buffer.length = desclen + 1;
        ifr.ifr_buffer.buffer = strdup(newdescription);

        if (ifr.ifr_buffer.buffer == NULL) {
                h->error.errtype = OTHER;
                h->error.errcode = ENOMEM;
                return (-1);
        }

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCSIFDESCR, &ifr) != 0) {
                free(ifr.ifr_buffer.buffer);
                return (-1);
        }

        free(ifr.ifr_buffer.buffer);
        return (0);
}

int
ifconfig_unset_description(ifconfig_handle_t *h, const char *name)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        ifr.ifr_buffer.length = 0;
        ifr.ifr_buffer.buffer = NULL;

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCSIFDESCR, &ifr) < 0) {
                return (-1);
        }
        return (0);
}

int
ifconfig_set_name(ifconfig_handle_t *h, const char *name, const char *newname)
{
        struct ifreq ifr;
        char *tmpname;

        memset(&ifr, 0, sizeof(ifr));
        tmpname = strdup(newname);
        if (tmpname == NULL) {
                h->error.errtype = OTHER;
                h->error.errcode = ENOMEM;
                return (-1);
        }

        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        ifr.ifr_data = tmpname;
        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCSIFNAME, &ifr) != 0) {
                free(tmpname);
                return (-1);
        }

        free(tmpname);
        return (0);
}

int
ifconfig_get_orig_name(ifconfig_handle_t *h, const char *ifname,
    char **orig_name)
{
        size_t len;
        unsigned int ifindex;
        int name[6];

        ifindex = if_nametoindex(ifname);
        if (ifindex == 0) {
                goto fail;
        }

        name[0] = CTL_NET;
        name[1] = PF_LINK;
        name[2] = NETLINK_GENERIC;
        name[3] = IFMIB_IFDATA;
        name[4] = ifindex;
        name[5] = IFDATA_DRIVERNAME;

        len = 0;
        if (sysctl(name, 6, NULL, &len, 0, 0) < 0) {
                goto fail;
        }

        *orig_name = malloc(len);
        if (*orig_name == NULL) {
                goto fail;
        }

        if (sysctl(name, 6, *orig_name, &len, 0, 0) < 0) {
                free(*orig_name);
                *orig_name = NULL;
                goto fail;
        }

        return (0);

fail:
        h->error.errtype = OTHER;
        h->error.errcode = (errno != 0) ? errno : ENOENT;
        return (-1);
}

int
ifconfig_get_fib(ifconfig_handle_t *h, const char *name, int *fib)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFFIB, &ifr) == -1) {
                return (-1);
        }

        *fib = ifr.ifr_fib;
        return (0);
}

int
ifconfig_set_mtu(ifconfig_handle_t *h, const char *name, const int mtu)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        ifr.ifr_mtu = mtu;

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCSIFMTU, &ifr) < 0) {
                return (-1);
        }

        return (0);
}

int
ifconfig_get_mtu(ifconfig_handle_t *h, const char *name, int *mtu)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFMTU, &ifr) == -1) {
                return (-1);
        }

        *mtu = ifr.ifr_mtu;
        return (0);
}

int
ifconfig_get_nd6(ifconfig_handle_t *h, const char *name,
    struct in6_ndireq *nd)
{
        memset(nd, 0, sizeof(*nd));
        strlcpy(nd->ifname, name, sizeof(nd->ifname));
        if (ifconfig_ioctlwrap(h, AF_INET6, SIOCGIFINFO_IN6, nd) == -1) {
                return (-1);
        }
        if (isnd6defif(h, name)) {
                nd->ndi.flags |= ND6_IFF_DEFAULTIF;
        } else if (h->error.errtype != OK) {
                return (-1);
        }

        return (0);
}

int
ifconfig_set_metric(ifconfig_handle_t *h, const char *name, const int metric)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        ifr.ifr_metric = metric;

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCSIFMETRIC, &ifr) < 0) {
                return (-1);
        }

        return (0);
}

int
ifconfig_get_metric(ifconfig_handle_t *h, const char *name, int *metric)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFMETRIC, &ifr) == -1) {
                return (-1);
        }

        *metric = ifr.ifr_metric;
        return (0);
}

int
ifconfig_set_capability(ifconfig_handle_t *h, const char *name,
    const int capability)
{
        struct ifreq ifr;
        struct ifconfig_capabilities ifcap;
        int flags, value;

        memset(&ifr, 0, sizeof(ifr));

        if (ifconfig_get_capability(h, name, &ifcap) != 0) {
                return (-1);
        }

        value = capability;
        flags = ifcap.curcap;
        if (value < 0) {
                value = -value;
                flags &= ~value;
        } else {
                flags |= value;
        }
        flags &= ifcap.reqcap;

        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        /*
         * TODO: Verify that it's safe to not have ifr.ifr_curcap
         * set for this request.
         */
        ifr.ifr_reqcap = flags;
        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCSIFCAP, &ifr) < 0) {
                return (-1);
        }
        return (0);
}

int
ifconfig_get_capability(ifconfig_handle_t *h, const char *name,
    struct ifconfig_capabilities *capability)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFCAP, &ifr) < 0) {
                return (-1);
        }
        capability->curcap = ifr.ifr_curcap;
        capability->reqcap = ifr.ifr_reqcap;
        return (0);
}

int
ifconfig_get_groups(ifconfig_handle_t *h, const char *name,
    struct ifgroupreq *ifgr)
{
        int len;

        memset(ifgr, 0, sizeof(*ifgr));
        strlcpy(ifgr->ifgr_name, name, IFNAMSIZ);

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFGROUP, ifgr) == -1) {
                if ((h->error.errcode == EINVAL) ||
                    (h->error.errcode == ENOTTY)) {
                        return (0);
                } else {
                        return (-1);
                }
        }

        len = ifgr->ifgr_len;
        ifgr->ifgr_groups = (struct ifg_req *)malloc(len);
        if (ifgr->ifgr_groups == NULL) {
                h->error.errtype = OTHER;
                h->error.errcode = ENOMEM;
                return (-1);
        }
        bzero(ifgr->ifgr_groups, len);
        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFGROUP, ifgr) == -1) {
                return (-1);
        }

        return (0);
}

int
ifconfig_get_ifstatus(ifconfig_handle_t *h, const char *name,
    struct ifstat *ifs)
{
        strlcpy(ifs->ifs_name, name, sizeof(ifs->ifs_name));
        return (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCGIFSTATUS, ifs));
}

int
ifconfig_destroy_interface(ifconfig_handle_t *h, const char *name)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCIFDESTROY, &ifr) < 0) {
                return (-1);
        }
        return (0);
}

int
ifconfig_create_interface(ifconfig_handle_t *h, const char *name, char **ifname)
{
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));

        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));

        /*
         * TODO:
         * Insert special snowflake handling here. See GitHub issue #12 for details.
         * In the meantime, hard-nosupport interfaces that need special handling.
         */
        if ((strncmp(name, "wlan",
            strlen("wlan")) == 0) ||
            (strncmp(name, "vlan",
            strlen("vlan")) == 0) ||
            (strncmp(name, "vxlan",
            strlen("vxlan")) == 0)) {
                h->error.errtype = OTHER;
                h->error.errcode = ENOSYS;
                return (-1);
        }

        /* No special handling for this interface type. */
        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCIFCREATE2, &ifr) < 0) {
                return (-1);
        }

        *ifname = strdup(ifr.ifr_name);
        if (ifname == NULL) {
                h->error.errtype = OTHER;
                h->error.errcode = ENOMEM;
                return (-1);
        }

        return (0);
}

int
ifconfig_create_interface_vlan(ifconfig_handle_t *h, const char *name,
    char **ifname, const char *vlandev, const unsigned short vlantag)
{
        struct ifreq ifr;
        struct vlanreq params;

        if ((vlantag == NOTAG) || (vlandev[0] == '\0')) {
                // TODO: Add proper error tracking here
                return (-1);
        }

        bzero(&params, sizeof(params));
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        params.vlr_tag = vlantag;
        (void)strlcpy(params.vlr_parent, vlandev, sizeof(params.vlr_parent));
        ifr.ifr_data = (caddr_t)&params;

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCIFCREATE2, &ifr) < 0) {
                // TODO: Add proper error tracking here
                return (-1);
        }

        *ifname = strdup(ifr.ifr_name);
        return (0);
}

int
ifconfig_set_vlantag(ifconfig_handle_t *h, const char *name,
    const char *vlandev, const unsigned short vlantag)
{
        struct ifreq ifr;
        struct vlanreq params;

        bzero(&params, sizeof(params));
        params.vlr_tag = vlantag;
        strlcpy(params.vlr_parent, vlandev, sizeof(params.vlr_parent));

        ifr.ifr_data = (caddr_t)&params;
        (void)strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCSETVLAN, &ifr) == -1) {
                return (-1);
        }
        return (0);
}

int
ifconfig_list_cloners(ifconfig_handle_t *h, char **bufp, size_t *lenp)
{
        struct if_clonereq ifcr;
        char *buf;

        memset(&ifcr, 0, sizeof(ifcr));
        *bufp = NULL;
        *lenp = 0;

        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCIFGCLONERS, &ifcr) < 0)
                return (-1);

        buf = malloc(ifcr.ifcr_total * IFNAMSIZ);
        if (buf == NULL) {
                h->error.errtype = OTHER;
                h->error.errcode = ENOMEM;
                return (-1);
        }

        ifcr.ifcr_count = ifcr.ifcr_total;
        ifcr.ifcr_buffer = buf;
        if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCIFGCLONERS, &ifcr) < 0) {
                free(buf);
                return (-1);
        }

        *bufp = buf;
        *lenp = ifcr.ifcr_total;
        return (0);
}