#include <stdio.h>
#include <sys/socket.h>
#include <linux/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/if.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include "util.h"
#include "nlapi.h"

static int callback(struct nlmsghdr *n, void *u) {
    int (*cb)(int b, int index, unsigned short type, const char *name) = u;

    if (n->nlmsg_type == RTM_NEWLINK || n->nlmsg_type == RTM_DELLINK) {
        struct rtattr *a;
        struct ifinfomsg *i;
        char ifname[IFNAMSIZ+1];
        int la;
        
        i = NLMSG_DATA(n);
        
        if (n->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifinfomsg))) {
            fprintf(stderr, "NETLINK: Packet too small or truncated! (2)\n");
            return -1;
        }

        memset(&ifname, 0, sizeof(ifname));
        
        a = (void*) i + NLMSG_ALIGN(sizeof(struct ifinfomsg));
        la = NLMSG_PAYLOAD(n, sizeof(struct ifinfomsg));
                
        while (RTA_OK(a, la)) {
            
            if(a->rta_type == IFLA_IFNAME)
                strncpy(ifname, RTA_DATA(a), MIN(RTA_PAYLOAD(a), IFNAMSIZ));
                        
            a = RTA_NEXT(a, la);
        }

        if (cb(n->nlmsg_type == RTM_NEWLINK, i->ifi_index, i->ifi_type, ifname[0] ? ifname : NULL) < 0)
            return -1;
    }

    
    return 0;
}


int ifmonitor_init(int (*cb) (int b, int index, unsigned short type, const char *name)) {
    return nlapi_register(callback, cb);
}

#if 0

int test(int b, int index, unsigned short type, const char * name) {
    printf("CALLBACK %s %s %i %i\n", b ? "new" : "del", name, index, type);
    return 0;
}

int main(int argc, char *argv[]) {
    int r = 1;

    if (nlapi_open(RTMGRP_LINK) < 0)
        goto finish;

    if (ifmonitor_init(test) < 0)
        goto finish;
    
    for (;;)
        if (nlapi_work() < 0)
            goto finish;

    r = 0;
    
finish:
    nlapi_close();
    
    return r;
}

#endif