/*
 *
 * Copyright (C) 2011, 2015 Cisco Systems, Inc.
 * Copyright (C) 2015 CBA research group, Technical University of Catalonia.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <errno.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <sys/socket.h>
#include <sys/ioctl.h>

#include "iface_mgmt.h"
#include "netm_kernel.h"
#include "../net_mgr.h"
#include "../net_mgr_proc_fc.h"
#include "../../defs.h"
#include "../../oor_external.h"
#include "../../lib/oor_log.h"
#include "../../lib/prefixes.h"
#include "../../lib/sockets-util.h"


/************************* FUNCTION DECLARTAION ********************************/

void process_nl_add_address (struct nlmsghdr *nlh);
void process_nl_del_address (struct nlmsghdr *nlh);
void process_nl_new_link (struct nlmsghdr *nlh);
void process_nl_new_route (struct nlmsghdr *nlh);
void process_nl_new_unicast_route (struct rtmsg *rtm, int rt_length);
void process_nl_new_multicast_route (struct rtmsg *rtm, int rt_length);
void process_nl_del_route (struct nlmsghdr *nlh);
void process_nl_del_unicast_route(struct rtmsg *rtm, int rt_length);
void process_nl_del_multicast_route (struct rtmsg *rtm, int rt_length);
int process_nl_mcast_route_attributes(struct rtmsg *rtm, int rt_length,
        lisp_addr_t *src, lisp_addr_t *grp);


/*******************************************************************************/


int
process_netlink_msg(struct sock *sl)
{
    int len = 0;
    char buffer[4096];
    struct iovec iov;
    struct sockaddr_nl dst_addr;
    struct msghdr msgh;
    struct nlmsghdr *nlh;

    nlh = (struct nlmsghdr *) buffer;

    memset(&iov, 0, sizeof(iov));
    iov.iov_base = (void *) nlh;
    iov.iov_len = sizeof(nlh);

    memset(&msgh, 0, sizeof(msgh));
    msgh.msg_name = (void *) &(dst_addr);
    msgh.msg_namelen = sizeof(dst_addr);
    msgh.msg_iov = &iov;
    msgh.msg_iovlen = 1;

    while ((len = recv(sl->fd, nlh, 4096, MSG_DONTWAIT)) > 0) {
        for (; (NLMSG_OK(nlh, len)) && (nlh->nlmsg_type != NLMSG_DONE);
                nlh = NLMSG_NEXT(nlh, len)) {
            switch (nlh->nlmsg_type) {
            case RTM_NEWADDR:
                OOR_LOG(LDBG_2, "==>process_netlink_msg: Received new address "
                        "message");
                process_nl_add_address(nlh);
                break;
            case RTM_DELADDR:
                OOR_LOG(LDBG_2, "==>process_netlink_msg: Received del address "
                        "message");
                process_nl_del_address(nlh);
                break;
            case RTM_NEWLINK:
                OOR_LOG(LDBG_2, "==>process_netlink_msg: Received link "
                        "message");
                process_nl_new_link(nlh);
                break;
            case RTM_NEWROUTE:
                OOR_LOG(LDBG_2, "==>process_netlink_msg: Received new route "
                        "message");
                process_nl_new_route(nlh);
                break;
            case RTM_DELROUTE:
                OOR_LOG(LDBG_2, "==>process_netlink_msg: Received delete route "
                        "message");
                process_nl_del_route(nlh);
                break;
            default:
                break;

            }
        }
        nlh = (struct nlmsghdr *) buffer;
        memset(nlh, 0, 4096);
    }

    return (GOOD);
}

void
process_nl_add_address (struct nlmsghdr *nlh)
{
    struct ifaddrmsg *ifa;
    struct rtattr *rth;
    int iface_index;
    int rt_length;
    lisp_addr_t new_addr = { .lafi = LM_AFI_IP };

    /*
     * Get the new address from the net link message
     */
    ifa = (struct ifaddrmsg *) NLMSG_DATA (nlh);
    iface_index = ifa->ifa_index;

    rth = IFA_RTA (ifa);
    rt_length = IFA_PAYLOAD(nlh);
    for (;rt_length && RTA_OK (rth, rt_length);rth = RTA_NEXT (rth,rt_length))
    {
        if (ifa->ifa_family == AF_INET && rth->rta_type == IFA_LOCAL){
            lisp_addr_ip_init(&new_addr, RTA_DATA(rth), ifa->ifa_family);
            nm_process_address_change (ADD,iface_index, &new_addr);
        }
        if (ifa->ifa_family == AF_INET6 && rth->rta_type == IFA_ADDRESS){
            lisp_addr_ip_init(&new_addr, RTA_DATA(rth), ifa->ifa_family);
            nm_process_address_change (ADD, iface_index, &new_addr);
        }
    }
}

void
process_nl_del_address(struct nlmsghdr *nlh)
{
    struct ifaddrmsg *ifa;
    struct rtattr *rth;
    int iface_index;
    int rt_length;
    lisp_addr_t new_addr = { .lafi = LM_AFI_NO_ADDR };

    ifa = (struct ifaddrmsg *) NLMSG_DATA(nlh);
    iface_index = ifa->ifa_index;

    rth = IFA_RTA(ifa);
    rt_length = IFA_PAYLOAD(nlh);
    for (; rt_length && RTA_OK(rth, rt_length);rth = RTA_NEXT(rth, rt_length)) {
        if ((ifa->ifa_family == AF_INET && rth->rta_type == IFA_LOCAL)
                        || (ifa->ifa_family == AF_INET6 && rth->rta_type == IFA_ADDRESS)){
            lisp_addr_ip_init(&new_addr, RTA_DATA(rth), ifa->ifa_family);
            break;
        }
    }
    nm_process_address_change (RM,iface_index, &new_addr);
}

void
process_nl_new_link(struct nlmsghdr *nlh)
{
    struct ifinfomsg *ifi;
    iface_t *iface;
    int iface_index;
    int old_iface_index;
    uint8_t new_status;
    char iface_name[IF_NAMESIZE];

    ifi = (struct ifinfomsg *) NLMSG_DATA (nlh);
    iface_index = ifi->ifi_index;

    iface = get_interface_from_index(iface_index);

    if (iface == NULL) {
        /*
         * In some OS when a virtual interface is removed and added again,
         * the index of the interface change. Search iface_t by the interface
         * name and update the index. */
        if (if_indextoname(iface_index, iface_name) != NULL) {
            iface = get_interface(iface_name);
        }
        if (iface == NULL) {
            OOR_LOG(LDBG_2, "process_nl_new_link: the netlink message is not for "
                    "any interface associated with RLOCs  (%s)", iface_name);
            return;
        } else {
            old_iface_index = iface->iface_index;
        }
    }else{
        old_iface_index = iface_index;
    }

    /* Get the new status */
    if ((ifi->ifi_flags & IFF_RUNNING) != 0) {
        new_status = UP;
    } else {
        new_status = DOWN;
    }

    nm_process_link_change(old_iface_index, iface_index, new_status);

}

void
process_nl_new_route (struct nlmsghdr *nlh)
{
    struct rtmsg *rtm;
    int rt_length;

    rtm = (struct rtmsg *) NLMSG_DATA (nlh);
    rt_length = RTM_PAYLOAD(nlh);

    /* Interested only in unicast or multicast updates */
    if (rtm->rtm_type == RTN_UNICAST) {
        process_nl_new_unicast_route(rtm, rt_length);
    } else if (rtm->rtm_type == RTN_MULTICAST) {
        process_nl_new_multicast_route(rtm, rt_length);
    }

}

void
process_nl_new_unicast_route(struct rtmsg *rtm, int rt_length)
{
    struct rtattr *rt_attr;
    int iface_index = ~0;
    lisp_addr_t gateway = { .lafi = LM_AFI_NO_ADDR };
    lisp_addr_t src = { .lafi = LM_AFI_NO_ADDR };
    lisp_addr_t dst = { .lafi = LM_AFI_NO_ADDR };
    int src_len;
    int dst_len;

    /* Interested only in main table updates for unicast */
    if (rtm->rtm_table != RT_TABLE_MAIN)
        return;

    if ( rtm->rtm_family != AF_INET && rtm->rtm_family != AF_INET6 ) {
        OOR_LOG(LDBG_3,"process_nl_new_unicast_route: New unicast route of "
                "unknown address family %d", rtm->rtm_family);
        return;
    }
    src_len = rtm->rtm_src_len;
    dst_len = rtm->rtm_dst_len;

    rt_attr = (struct rtattr *)RTM_RTA(rtm);

    for (; RTA_OK(rt_attr, rt_length);
            rt_attr = RTA_NEXT(rt_attr, rt_length)) {
        switch (rt_attr->rta_type) {
        case RTA_OIF:
            iface_index = *(int *)RTA_DATA(rt_attr);
            break;
        case RTA_GATEWAY:
            lisp_addr_ip_init(&gateway, RTA_DATA(rt_attr), rtm->rtm_family);
            break;
        case RTA_SRC:
            lisp_addr_ip_init(&src, RTA_DATA(rt_attr), rtm->rtm_family);
            lisp_addr_set_plen(&src,src_len);
            break;
        case RTA_DST:
            lisp_addr_ip_init(&dst, RTA_DATA(rt_attr), rtm->rtm_family);
            lisp_addr_set_plen(&dst,dst_len);
            break;
        default:
            break;
        }
    }

    nm_process_route_change(ADD, iface_index, &src,&dst,&gateway);
}

void
process_nl_new_multicast_route(struct rtmsg *rtm, int rt_length)
{
//    lisp_addr_t srcaddr = {.lafi = LM_AFI_IP};
//    lisp_addr_t grpaddr = {.lafi = LM_AFI_IP};

    OOR_LOG(LDBG_1, "process_nl_new_multicast_route: Not yet implemented, ignored!");

//    /* IPv4 multicast routes are part of the default table and have
//     * family 128, while IPv6 multicast routes are part of the main table
//     * and have family 129 ... */
//    if ( !((rtm->rtm_table == RT_TABLE_DEFAULT && rtm->rtm_family == 128) ||
//           (rtm->rtm_table == RT_TABLE_MAIN && rtm->rtm_family == 129) ) )
//        return;
//
//    if (process_nl_mcast_route_attributes(rtm, rt_length, &srcaddr, &grpaddr)
//            == BAD) {
//        return;
//    }
//
//    multicast_join_channel(&srcaddr, &grpaddr);
}

int
process_nl_mcast_route_attributes(struct rtmsg *rtm, int rt_length,
        lisp_addr_t *rt_srcaddr, lisp_addr_t *rt_grpaddr)
{
    struct rtattr *rt_attr;
    iface_t *iface;
    int iface_index;
    char iface_name[IF_NAMESIZE+1];
    struct rtnexthop *rt_nh;
    int nb_oifs = 0;
    int rtnh_length = 0;
    char ifnames[1024] = { 0 };

    rt_attr = (struct rtattr *)RTM_RTA(rtm);

    for (; RTA_OK(rt_attr, rt_length);
            rt_attr = RTA_NEXT(rt_attr, rt_length)) {
        switch (rt_attr->rta_type) {
            case RTA_DST:
                switch(rtm->rtm_family) {
                    case 128:
                        lisp_addr_ip_init(rt_grpaddr, RTA_DATA(rt_attr),
                                AF_INET);
                        break;
                    case 129:
                        lisp_addr_ip_init(rt_grpaddr, RTA_DATA(rt_attr),
                                AF_INET6);
                        break;
                    default:
                        break;
                }
                break;
            case RTA_SRC:
                switch (rtm->rtm_family) {
                    case 128:
                        lisp_addr_ip_init(rt_srcaddr, RTA_DATA(rt_attr),
                                AF_INET);
                        break;
                    case 129:
                        lisp_addr_ip_init(rt_srcaddr, RTA_DATA(rt_attr),
                                AF_INET6);
                        break;
                    default:
                        break;
                }
                break;
            case RTA_MULTIPATH:
                rt_nh = (struct rtnexthop *)RTA_DATA(rt_attr);
                rtnh_length = RTA_PAYLOAD(rt_attr);
                for (; RTNH_OK(rt_nh, rtnh_length); rt_nh = RTNH_NEXT(rt_nh)) {
                    /* Check if one of the interfaces is the gateway */
                    iface = get_interface_from_index(rt_nh->rtnh_ifindex);
                    iface_index = *(int *)RTA_DATA(rt_attr);
                    iface = get_interface_from_index(iface_index);
                    if (iface != NULL){
                        if_indextoname(iface_index, iface_name);
                        OOR_LOG(LINF, "process_nl_new_multicast_route: the "
                                "multicast route message is for an interface "
                                "that has RLOCs associated (%s). Ignoring!",
                                iface_name);
                        return BAD;
                    }

                    /* Prepare output for debug */
                    if_indextoname(rt_nh->rtnh_ifindex, iface_name);
                    sprintf(ifnames, "%s ", iface_name);
                    nb_oifs++;
                }
                break;
            default:
                break;
        }
    }

    if (nb_oifs == 0){
        OOR_LOG(LDBG_1, "process_nl_new_multicast_route: New multicast route has "
                "no output interface list, ignored!");
        return BAD;
    }

    OOR_LOG(LINF, "New multicast route with source %s, group %s for interfaces "
            "%s", lisp_addr_to_char(rt_srcaddr), lisp_addr_to_char(rt_grpaddr),
            ifnames);

    return GOOD;
}

void
process_nl_del_route(struct nlmsghdr *nlh)
{

    struct rtmsg *rtm;
    int rt_length;

    rtm = (struct rtmsg *) NLMSG_DATA (nlh);
    rt_length = RTM_PAYLOAD(nlh);

    /* Interested only in unicast or multicast updates */
    if (rtm->rtm_type == RTN_UNICAST) {
        process_nl_del_unicast_route(rtm, rt_length);
    } else if (rtm->rtm_type == RTN_MULTICAST) {
        process_nl_del_multicast_route(rtm, rt_length);
    }
}

void
process_nl_del_unicast_route(struct rtmsg *rtm, int rt_length)
{
    struct rtattr *rt_attr;
    int iface_index = ~0;
    lisp_addr_t gateway = { .lafi = LM_AFI_NO_ADDR };
    lisp_addr_t src = { .lafi = LM_AFI_NO_ADDR };
    lisp_addr_t dst = { .lafi = LM_AFI_NO_ADDR };
    int src_len;
    int dst_len;

    /* Interested only in main table updates for unicast */
    if (rtm->rtm_table != RT_TABLE_MAIN)
        return;

    if ( rtm->rtm_family != AF_INET && rtm->rtm_family != AF_INET6 ) {
        OOR_LOG(LDBG_3,"process_nl_del_unicast_route: New unicast route of "
                "unknown address family %d", rtm->rtm_family);
        return;
    }

    src_len = rtm->rtm_src_len;
    dst_len = rtm->rtm_dst_len;

    rt_attr = (struct rtattr *)RTM_RTA(rtm);

    for (; RTA_OK(rt_attr, rt_length);
            rt_attr = RTA_NEXT(rt_attr, rt_length)) {
        switch (rt_attr->rta_type) {
        case RTA_OIF:
            iface_index = *(int *)RTA_DATA(rt_attr);
            break;
        case RTA_GATEWAY:
            lisp_addr_ip_init(&gateway, RTA_DATA(rt_attr), rtm->rtm_family);
            break;
        case RTA_SRC:
            lisp_addr_ip_init(&src, RTA_DATA(rt_attr), rtm->rtm_family);
            lisp_addr_set_plen(&src,src_len);
            break;
        case RTA_DST:
            lisp_addr_ip_init(&dst, RTA_DATA(rt_attr), rtm->rtm_family);
            lisp_addr_set_plen(&dst,dst_len);
            break;
        default:
            break;
        }
    }

    nm_process_route_change(RM, iface_index, &src,&dst,&gateway);
}

void
process_nl_del_multicast_route (struct rtmsg *rtm, int rt_length)
{

    lisp_addr_t  rt_groupaddr = {.lafi=LM_AFI_IP};
    lisp_addr_t  rt_srcaddr = {.lafi=LM_AFI_IP};

    if ( !((rtm->rtm_table == RT_TABLE_DEFAULT && rtm->rtm_family == 128) ||
           (rtm->rtm_table == RT_TABLE_MAIN && rtm->rtm_family == 129) ) )
        return;


    if (process_nl_mcast_route_attributes(rtm, rt_length, &rt_srcaddr, &rt_groupaddr) == BAD)
        return;

    //multicast_leave_channel(&rt_srcaddr, &rt_groupaddr);
}

void
iface_mac_address(char *iface_name, uint8_t *mac)
{
     int fd;
     struct ifreq ifr;
     int i = 0;

     fd = socket(AF_INET, SOCK_DGRAM, 0);

     memset(&ifr, 0, sizeof(ifr));
     ifr.ifr_addr.sa_family = AF_INET;
     strncpy(ifr.ifr_name, iface_name, IFNAMSIZ-1);

     ioctl(fd, SIOCGIFHWADDR, &ifr);

     close(fd);
     for (i = 0 ; i < 6 ; i++){
         mac[i] = (unsigned char)ifr.ifr_hwaddr.sa_data[i];
     }

     return;
}


lisp_addr_t *
get_network_pref_of_host(lisp_addr_t *address)
{
    lisp_addr_t net_prefix = { .lafi = LM_AFI_IP };
    int netlink_fd;
    struct sockaddr_nl addr;
    struct nlmsghdr *nlh, *rcvhdr;
    struct rtmsg *rtm, *recv_rtm;
    struct rtattr *rt_attr;
    char sndbuf[4096],rcvbuf[4096];
    int rta_len = 0, retval, readlen, recv_pyload_len, afi;

    memset(&addr, 0, sizeof(addr));
    addr.nl_family = AF_NETLINK;
    if (lisp_addr_ip_afi(address) == AF_INET){
        afi = AF_INET;
        addr.nl_groups = RTMGRP_IPV4_ROUTE;
    }else{
        afi = AF_INET6;
        addr.nl_groups = RTMGRP_IPV6_ROUTE;
    }

    netlink_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);

    if (netlink_fd < 0) {
        OOR_LOG(LERR, "get_network_associated_addrress: Failed to connect to "
                "netlink socket");
        return (NULL);
    }

    bind(netlink_fd, (struct sockaddr *) &addr, sizeof(addr));

    memset(sndbuf, 0, 4096);
    nlh = (struct nlmsghdr *)sndbuf;
    rtm = (struct rtmsg *)(CO(sndbuf,sizeof(struct nlmsghdr)));

    rta_len = sizeof(struct rtmsg);

    nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
    nlh->nlmsg_type = RTM_GETROUTE;
    nlh->nlmsg_len = NLMSG_LENGTH(rta_len);


    rtm->rtm_family = afi;
    rtm->rtm_table = RT_TABLE_MAIN;
    rtm->rtm_protocol = RTPROT_STATIC;
    rtm->rtm_scope = RT_SCOPE_UNIVERSE;
    rtm->rtm_type = RTN_UNICAST;
    rtm->rtm_src_len = 0;
    rtm->rtm_tos = 0;
    rtm->rtm_dst_len = 0;

    retval = send(netlink_fd, sndbuf, nlh->nlmsg_len, 0);

    if (retval < 0) {
        OOR_LOG(LCRIT, "get_network_associated_addrress: send netlink command failed %s", strerror(errno));
        return (NULL);
    }
    /*
     * Receive the responses from the kernel
     */

    while ((readlen = recv(netlink_fd,rcvbuf,4096,MSG_DONTWAIT)) > 0){
        rcvhdr = (struct nlmsghdr *)rcvbuf;
        /*
         * Walk through everything it sent us
         */
        for (; NLMSG_OK(rcvhdr, (unsigned int)readlen); rcvhdr = NLMSG_NEXT(rcvhdr, readlen)) {
            recv_pyload_len = RTM_PAYLOAD(rcvhdr);
            if (rcvhdr->nlmsg_type == RTM_NEWROUTE) {
                recv_rtm = (struct rtmsg *)NLMSG_DATA(rcvhdr);
                rt_attr = (struct rtattr *)RTM_RTA(recv_rtm);
                for (; RTA_OK(rt_attr, recv_pyload_len); rt_attr = RTA_NEXT(rt_attr, recv_pyload_len)) {
                    switch (rt_attr->rta_type) {
                    case RTA_DST:
                        if ((rtm->rtm_family == AF_INET && recv_rtm->rtm_dst_len == 32) ||
                                (rtm->rtm_family == AF_INET6 && recv_rtm->rtm_dst_len == 128) ){
                            break;
                        }
                        lisp_addr_ip_init(&net_prefix, RTA_DATA(rt_attr), rtm->rtm_family);
                        lisp_addr_set_plen(&net_prefix,recv_rtm->rtm_dst_len);
                        if (pref_is_addr_part_of_prefix(address,&net_prefix) == TRUE){
                            goto find;
                        }
                        break;
                    default:
                        break;
                    }
                }
            }
        }
    }
    close(netlink_fd);
    OOR_LOG(LDBG_3, "get_network_pref_of_host: No network prefix found for host %s", lisp_addr_to_char(address));
    return (NULL);

    find:
    close(netlink_fd);
    OOR_LOG(LDBG_3, "get_network_pref_of_host: Network prefix for host %s is %s",
            lisp_addr_to_char(address), lisp_addr_to_char(&net_prefix));
    return (lisp_addr_clone(&net_prefix));

}