// SPDX-License-Identifier: MIT
/*
Copyright 2007, 2008 by Grégoire Henry, Julien Cristau and Juliusz Chroboczek
Copyright 2011, 2012 by Matthieu Boutier and Juliusz Chroboczek
*/

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

#include <sys/time.h>
#include <sys/param.h>
#include <time.h>
#include <fcntl.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 "frrevent.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;
}