/*
Copyright 2007, 2008 by Grégoire Henry, Julien Cristau and Juliusz Chroboczek
Copyright 2011, 2012 by Matthieu Boutier and Juliusz Chroboczek

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/time.h>
#include <sys/param.h>
#include <time.h>

#include "babeld.h"


#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>

#include <zebra.h>
#include "prefix.h"
#include "zclient.h"
#include "kernel.h"
#include "privs.h"
#include "command.h"
#include "vty.h"
#include "memory.h"
#include "thread.h"
#include "nexthop.h"

#include "util.h"
#include "babel_interface.h"
#include "babel_zebra.h"


static int
zebra_route(int add, int familt, const unsigned char *pref, unsigned short plen,
            const unsigned char *gate, int ifindex, unsigned int metric);

int
kernel_interface_operational(struct interface *interface)
{
    return if_is_operative(interface);
}

int
kernel_interface_mtu(struct interface *interface)
{
    return MIN(interface->mtu, interface->mtu6);
}

int
kernel_interface_wireless(struct interface *interface)
{
    return 0;
}

int
kernel_route(enum babel_kernel_routes operation, const unsigned char *pref,
	     unsigned short plen, const unsigned char *gate, int ifindex,
	     unsigned int metric, const unsigned char *newgate, int newifindex,
             unsigned int newmetric)
{
    int rc;
    int family;

    /* Check that the protocol family is consistent. */
    if(plen >= 96 && v4mapped(pref)) {
        if(!v4mapped(gate)) {
            errno = EINVAL;
            return -1;
        }
        family = AF_INET;
    } else {
        if(v4mapped(gate)) {
            errno = EINVAL;
            return -1;
        }
        family = AF_INET6;
    }

    switch (operation) {
        case ROUTE_ADD:
            return zebra_route(1, family, pref, plen, gate, ifindex, metric);
        case ROUTE_FLUSH:
            return zebra_route(0, family, pref, plen, gate, ifindex, metric);
        case ROUTE_MODIFY:
            if(newmetric == metric && memcmp(newgate, gate, 16) == 0 &&
               newifindex == ifindex)
                return 0;
            debugf(BABEL_DEBUG_ROUTE, "Modify route: delete old; add new.");
            rc = zebra_route(0, family, pref, plen, gate, ifindex, metric);
            if (rc < 0)
                return -1;

            rc = zebra_route(1, family, pref, plen, newgate, newifindex,
                             newmetric);
            return rc;
    }

    return 0;
}

static int
zebra_route(int add, int family, const unsigned char *pref, unsigned short plen,
            const unsigned char *gate, int ifindex, unsigned int metric)
{
    struct zapi_route api;               /* quagga's communication system */
    struct prefix quagga_prefix;         /* quagga's prefix */
    union g_addr babel_prefix_addr;      /* babeld's prefix addr */
    struct zapi_nexthop *api_nh;         /* next router to go - no ECMP */

    api_nh = &api.nexthops[0];

    /* convert to be understandable by quagga */
    /* convert given addresses */
    switch (family) {
    case AF_INET:
        uchar_to_inaddr(&babel_prefix_addr.ipv4, pref);
        break;
    case AF_INET6:
        uchar_to_in6addr(&babel_prefix_addr.ipv6, pref);
        break;
    }

    /* make prefix structure */
    memset (&quagga_prefix, 0, sizeof(quagga_prefix));
    quagga_prefix.family = family;
    switch (family) {
    case AF_INET:
        IPV4_ADDR_COPY (&quagga_prefix.u.prefix4, &babel_prefix_addr.ipv4);
        /* our plen is for v4mapped's addr */
        quagga_prefix.prefixlen = plen - 96;
        break;
    case AF_INET6:
        IPV6_ADDR_COPY (&quagga_prefix.u.prefix6, &babel_prefix_addr.ipv6);
        quagga_prefix.prefixlen = plen;
        break;
    }
    apply_mask(&quagga_prefix);

    memset(&api, 0, sizeof(api));
    api.type  = ZEBRA_ROUTE_BABEL;
    api.safi = SAFI_UNICAST;
    api.vrf_id = VRF_DEFAULT;
    api.prefix = quagga_prefix;

    if(metric >= KERNEL_INFINITY) {
	zapi_route_set_blackhole(&api, BLACKHOLE_REJECT);
    } else {
        SET_FLAG(api.message, ZAPI_MESSAGE_NEXTHOP);
        api.nexthop_num = 1;
        api_nh->ifindex = ifindex;
	api_nh->vrf_id = VRF_DEFAULT;
	switch (family) {
        case AF_INET:
            uchar_to_inaddr(&api_nh->gate.ipv4, gate);
	    if (IPV4_ADDR_SAME(&api_nh->gate.ipv4, &quagga_prefix.u.prefix4)
		&& quagga_prefix.prefixlen == IPV4_MAX_BITLEN) {
		    api_nh->type = NEXTHOP_TYPE_IFINDEX;
	    } else {
		    api_nh->type = NEXTHOP_TYPE_IPV4_IFINDEX;
            }
            break;
        case AF_INET6:
            uchar_to_in6addr(&api_nh->gate.ipv6, gate);
            /* difference to IPv4: always leave the linklocal as nexthop */
            api_nh->type = NEXTHOP_TYPE_IPV6_IFINDEX;
            break;
        }
        SET_FLAG(api.message, ZAPI_MESSAGE_METRIC);
        api.metric = metric;
    }

    debugf(BABEL_DEBUG_ROUTE, "%s route (%s) to zebra",
           add ? "adding" : "removing",
           (family == AF_INET) ? "ipv4" : "ipv6");
    return zclient_route_send (add ? ZEBRA_ROUTE_ADD : ZEBRA_ROUTE_DELETE,
                               zclient, &api);
}

int
if_eui64(int ifindex, unsigned char *eui)
{
    struct interface *ifp = if_lookup_by_index(ifindex, VRF_DEFAULT);
    if (ifp == NULL) {
        return -1;
    }

    uint8_t len = (uint8_t)ifp->hw_addr_len;
    char *tmp = (void*) ifp->hw_addr;

    if (len == 8) {
        memcpy(eui, tmp, 8);
        eui[0] ^= 2;
    } else if (len == 6) {
        memcpy(eui,   tmp,   3);
        eui[3] = 0xFF;
        eui[4] = 0xFE;
        memcpy(eui+5, tmp+3, 3);
    } else {
        return -1;
    }
    return 0;
}

/* Like gettimeofday, but returns monotonic time.  If POSIX clocks are not
   available, falls back to gettimeofday but enforces monotonicity. */
void
gettime(struct timeval *tv)
{
    monotime(tv);
}

/* If /dev/urandom doesn't exist, this will fail with ENOENT, which the
   caller will deal with gracefully. */

int
read_random_bytes(void *buf, size_t len)
{
    int fd;
    int rc;

    fd = open("/dev/urandom", O_RDONLY);
    if(fd < 0) {
        rc = -1;
    } else {
        rc = read(fd, buf, len);
        if(rc < 0 || (unsigned) rc < len)
            rc = -1;
        close(fd);
    }
    return rc;
}
