/* 
 * This file is part of the Palacios Virtual Machine Monitor developed
 * by the V3VEE Project with funding from the United States National 
 * Science Foundation and the Department of Energy.  
 *
 * The V3VEE Project is a joint project between Northwestern University
 * and the University of New Mexico.  You can find out more at 
 * http://www.v3vee.org
 *
 * Copyright (c) 2009, Lei Xia <lxia@northwestern.edu> 
 * Copyright (c) 2009, Yuan Tang <ytang@northwestern.edu> 
 * Copyright (c) 2009, Jack Lange <jarusl@cs.northwestern.edu> 
 * Copyright (c) 2009, Peter Dinda <pdinda@northwestern.edu>
 * Copyright (c) 2009, The V3VEE Project <http://www.v3vee.org> 
 * All rights reserved.
 *
 * Author: Lei Xia <lxia@northwestern.edu>
 *	   Yuan Tang <ytang@northwestern.edu>
 *	   Jack Lange <jarusl@cs.northwestern.edu> 
 *	   Peter Dinda <pdinda@northwestern.edu
 *
 * This is free software.  You are permitted to use,
 * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
 */
 
#include <palacios/vmm_vnet.h>

static const char any_type_str[] = "any";
static const char not_type_str[] = "not";
static const char none_type_str[] = "none";
static const char empty_type_str[] = "empty";

static const char link_interface_str[] = "INTERFACE";
static const char link_edge_str[] = "EDGE";
static const char link_any_str[] = "ANY";

static const char link_prot_tcp_str[] = "tcp";
static const char link_prot_udp_str[] = "udp";

typedef enum {MAC_ANY, MAC_NOT, MAC_NONE, MAC_EMPTY} mac_type_t; //for 'src_mac_qual' and 'dst_mac_qual'
typedef enum {LINK_INTERFACE, LINK_EDGE, LINK_ANY} link_type_t; //for 'type' and 'src_type' in struct routing
typedef enum {TCP_TYPE, UDP_TYPE} link_prot_type_t;

static const uint_t hash_key_size = 16;
static SOCK g_udp_sockfd;
static struct gen_queue * g_inpkt_q;
static bool use_tcp = false;
static uint_t vnet_udp_port = 1022;

struct raw_ethernet_pkt {
  int  size;
  int type; // vm or link type:  INTERFACE|EDGE
  char  data[ETHERNET_PACKET_LEN];
};

//static char *vnet_version = "0.9";
//static int vnet_server = 0;


#define MAX_LINKS 1
#define MAX_ROUTES 1
#define MAX_DEVICES 16

static struct topology g_links[MAX_LINKS];
static int g_num_links; //The current number of links
static int g_first_link;
static int g_last_link;

static struct routing g_routes[MAX_ROUTES];
static int g_num_routes; //The current number of routes
static int g_first_route;
static int g_last_route;

static struct device_list g_devices[MAX_DEVICES];
static int g_num_devices;
static int g_first_device;
static int g_last_device;


static void print_packet(char *pkt, int size) {
    PrintDebug("Vnet: print_data_packet: size: %d\n", size);
    v3_hexdump(pkt, size, NULL, 0);
}

#if 0
static void print_packet_addr(char *pkt) {
    PrintDebug("Vnet: print_packet_destination_addr: ");
    v3_hexdump(pkt + 8, 6, NULL, 0);
    
    PrintDebug("Vnet: print_packet_source_addr: ");
    v3_hexdump(pkt + 14, 6, NULL, 0);
}

static void print_device_addr(char *ethaddr) {
    PrintDebug("Vnet: print_device_addr: ");
    v3_hexdump(ethaddr, 6, NULL, 0);
} 
#endif


//network connection functions 
static inline void raw_ethernet_packet_init(struct raw_ethernet_pkt * pt, const char * data, const size_t size) {
    pt->size = size;
    memcpy(pt->data, data, size);
}



/* Hash key format:
 * 0-5:     src_eth_addr
 * 6-11:    dest_eth_addr
 * 12:      src type
 * 13-16:   src index
 */
typedef char * route_hashkey_t;

// This is the hash value, Format: 0: num_matched_routes, 1...n: matches[] -- TY
struct route_cache_entry {
    int num_matched_routes;
    int * matches; 
};

#define HASH_KEY_LEN 16
#define MIN_CACHE_SIZE 100


//Header of the route cache
static struct hashtable * g_route_cache; 

static uint_t hash_from_key_fn(addr_t hashkey) {    
    uint8_t * key = (uint8_t *)hashkey;
    return v3_hash_buffer(key, HASH_KEY_LEN);
}

static int hash_key_equal(addr_t key1, addr_t key2) {
    uint8_t * buf1 = (uint8_t *)key1;
    uint8_t * buf2 = (uint8_t *)key2;
    return (memcmp(buf1, buf2, HASH_KEY_LEN) == 0);
}

static int init_route_cache() {
    g_route_cache = v3_create_htable(MIN_CACHE_SIZE, &hash_from_key_fn, &hash_key_equal);

    if (g_route_cache == NULL){
        PrintError("Vnet: Route Cache Initiate Failurely\n");
        return -1;
    }

    return 0;
}

static void make_hash_key(route_hashkey_t hashkey, char src_addr[6], char dest_addr[6], char src_type, int src_index) {
    int j;

    for (j = 0; j < 6; j++) {
	hashkey[j] = src_addr[j];
	hashkey[j + 6] = dest_addr[j] + 1;
    }

    hashkey[12] = src_type;

    *(int *)(hashkey + 12) = src_index;
}
static int add_route_to_cache(route_hashkey_t hashkey, int num_matched_r, int * matches) {
    struct route_cache_entry * new_entry = NULL;
    int i;
    
    new_entry = (struct route_cache_entry *)V3_Malloc(sizeof(struct route_cache_entry));
    if (new_entry == NULL){
	PrintError("Vnet: Malloc fails\n");
	return -1;
    }
    
    new_entry->num_matched_routes = num_matched_r;

    new_entry->matches = (int *)V3_Malloc(num_matched_r * sizeof(int));
    
    if (new_entry->matches == NULL){
	PrintError("Vnet: Malloc fails\n");
	return -1;
    }
    
    for (i = 0; i < num_matched_r; i++) {
	new_entry->matches[i] = matches[i];
    }
    
    //here, when v3_htable_insert return 0, it means insert fails
    if (v3_htable_insert(g_route_cache, (addr_t)hashkey, (addr_t)new_entry) == 0){
	PrintError("Vnet: Insert new route entry to cache failed\n");
	V3_Free(new_entry->matches);
	V3_Free(new_entry);
    }
    
    return 0;
}

static int clear_hash_cache() {
    v3_free_htable(g_route_cache, 1, 1);
		
    g_route_cache = v3_create_htable(MIN_CACHE_SIZE, hash_from_key_fn, hash_key_equal);
    
    if (g_route_cache == NULL){
        PrintError("Vnet: Route Cache Create Failurely\n");
        return -1;
    }

    return 0;
}

static int look_into_cache(route_hashkey_t hashkey, int * matches) {
    int n_matches = -1;
    int i = 0;
    struct route_cache_entry * found = NULL;
    
    found = (struct route_cache_entry *)v3_htable_search(g_route_cache, (addr_t)hashkey);
   
    if (found != NULL) {
        n_matches = found->num_matched_routes;

        for (i = 0; i < n_matches; i++) {
            matches[i] = found->matches[i];
	}
    }

    return n_matches;
}




static inline uint8_t hex_nybble_to_nybble(const uint8_t hexnybble) {
    uint8_t x = toupper(hexnybble);

    if (isdigit(x)) {
	return x - '0';
    } else {
	return 10 + (x - 'A');
    }
}

static inline uint8_t hex_byte_to_byte(const uint8_t hexbyte[2]) {
    return ((hex_nybble_to_nybble(hexbyte[0]) << 4) + 
	    (hex_nybble_to_nybble(hexbyte[1]) & 0xf));
}


static inline void string_to_mac(const char * str, uint8_t mac[6]) {
    int k;

    for (k = 0; k < 6; k++) {
	mac[k] = hex_byte_to_byte(&(str[(2 * k) + k]));
    }
}

static inline void mac_to_string(int mac[6], char * buf) {
    snprintf(buf, 20, "%x:%x:%x:%x:%x:%x", 
	     mac[0], mac[1], mac[2],
	     mac[3], mac[4], mac[5]);
}

#if 0
static void ip_to_string(uint32_t addr, char * buf) {
    uint32_t addr_st;
    char * tmp_str;
    
    addr_st = v3_htonl(addr);
    tmp_str = v3_inet_ntoa(addr_st);
    
    memcpy(buf, tmp_str, strlen(tmp_str));
}
#endif

int find_link_by_fd(SOCK sock) {
    int i;

    FOREACH_LINK(i, g_links, g_first_link) {
	if (g_links[i].link_sock == sock) {
	    return i;
	}
    }
    
    return -1;
}

int vnet_add_link_entry(unsigned long dest, int type, int data_port,  SOCK fd) {
    int i;
    
    for (i = 0; i < MAX_LINKS; i++) {
	if (g_links[i].use == 0) {
	    g_links[i].dest = dest;
	    g_links[i].type = type;
	    g_links[i].link_sock = fd;
	    g_links[i].remote_port = data_port;
	    g_links[i].use = 1;

	    if (g_first_link == -1) {
	        g_first_link = i;
	    }

	    g_links[i].prev = g_last_link;
	    g_links[i].next = -1;
	    
	    if (g_last_link != -1) {
	        g_links[g_last_link].next = i;
	    }
	    
	    g_last_link = i;
	    
	    g_num_links++;
	    
	    return i;
	}
    }
    
    return -1;
}


int add_sock(struct sock_list *socks, int  len, int *first_sock, int *last_sock, SOCK fd) {
    int i;

    for (i = 0; i < len; i++) {
	if (socks[i].sock == -1) {
	    socks[i].sock = fd;
	    
	    if (*first_sock == -1) {
		*first_sock = i;
	    }
	    
	    socks[i].prev = *last_sock;
	    socks[i].next = -1;
	    
	    if (*last_sock != -1) {
		socks[*last_sock].next = i;
	    }
	    
	    *last_sock = i;
	    
	    return i;
	}
    }
    return -1;
}


int vnet_add_route_entry(char src_mac[6], char dest_mac[6], int src_mac_qual, int dest_mac_qual, int dest, int type, int src, int src_type) {
    int i;
    
    for(i = 0; i < MAX_ROUTES; i++) {
	if (g_routes[i].use == 0) {
	    
	    if ((src_mac_qual != MAC_ANY) && (src_mac_qual != MAC_NONE)) {
	        memcpy(g_routes[i].src_mac, src_mac, 6);
	    } else {
	        memset(g_routes[i].src_mac, 0, 6);
	    }
	    
	    if ((dest_mac_qual != MAC_ANY) && (dest_mac_qual != MAC_NONE)) {
	        memcpy(g_routes[i].dest_mac, dest_mac, 6);
	    } else {
	        memset(g_routes[i].dest_mac, 0, 6);
	    }
	    
	    g_routes[i].src_mac_qual = src_mac_qual;
	    g_routes[i].dest_mac_qual = dest_mac_qual;
	    g_routes[i].dest = dest;
	    g_routes[i].type = type;
	    g_routes[i].src = src;
	    g_routes[i].src_type = src_type;
	    g_routes[i].use = 1;
	    
	    if (g_first_route == -1) {
		g_first_route = i;
	    }
	    
	    g_routes[i].prev = g_last_route;
	    g_routes[i].next = -1;
	    
	    if (g_last_route != -1) {
	        g_routes[g_last_route].next = i;
	    }
	    
	    g_last_route = i;
	    
	    g_num_routes++;
	    
	    return i;
	}
    }
    
    clear_hash_cache();
    
    return -1;
}


static int find_link_entry(unsigned long dest, int type) {
    int i;

    FOREACH_LINK(i, g_links, g_first_link) {
	if ((g_links[i].dest == dest) && 
	    ((type == -1) || (g_links[i].type == type)) ) {
	    return i;
	}
    } 
    
    return -1;
}

static int delete_link_entry(int index) {
    int next_i;
    int prev_i;
  
    if (g_links[index].use == 0) {
	return -1;
    }

    g_links[index].dest = 0;
    g_links[index].type = 0;
    g_links[index].link_sock = -1;
    g_links[index].use = 0;

    prev_i = g_links[index].prev;
    next_i = g_links[index].next;

    if (prev_i != -1) {
	g_links[prev_i].next = g_links[index].next;
    }    

    if (next_i != -1) {
	g_links[next_i].prev = g_links[index].prev;
    }
    
    if (g_first_link == index) {
	g_first_link = g_links[index].next;
    }    

    if (g_last_link == index) {
	g_last_link = g_links[index].prev;
    }    

    g_links[index].next = -1;
    g_links[index].prev = -1;
    
    g_num_links--;
    
    return 0;
}

int vnet_delete_link_entry_by_addr(unsigned long dest, int type) {
    int index = find_link_entry(dest, type);
  
    if (index == -1) {
	return -1;
    }

    return delete_link_entry(index);
}


static int find_route_entry(char src_mac[6], 
			    char dest_mac[6], 
			    int src_mac_qual, 
			    int dest_mac_qual, 
			    int dest, 
			    int type, 
			    int src, 
			    int src_type) {
    int i;
    char temp_src_mac[6];
    char temp_dest_mac[6];
  
    if ((src_mac_qual != MAC_ANY) && (src_mac_qual != MAC_NONE)) {
	memcpy(temp_src_mac, src_mac, 6);
    } else {
	memset(temp_src_mac, 0, 6);
    }
    
    if ((dest_mac_qual != MAC_ANY) && (dest_mac_qual != MAC_NONE)) {
	memcpy(temp_dest_mac, dest_mac, 6);
    } else {
	memset(temp_dest_mac, 0, 6);
    }
    
    FOREACH_LINK(i, g_routes, g_first_route) {
	if ( (memcmp(temp_src_mac, g_routes[i].src_mac, 6) == 0) && 
	     (memcmp(temp_dest_mac, g_routes[i].dest_mac, 6) == 0) &&
	     (g_routes[i].src_mac_qual == src_mac_qual) &&
	     (g_routes[i].dest_mac_qual == dest_mac_qual)  &&
	     ( (type == -1) || 
	       ( (type == g_routes[i].type) && (g_routes[i].dest == dest)) ) &&
	     ( (src_type == -1) || 
	       ( (src_type == g_routes[i].src_type) && (g_routes[i].src == src)) ) ) {
	    return i;
	}
    } 
    
    return -1;
}

static int delete_route_entry(int index) {
    int next_i;
    int prev_i;

    memset(g_routes[index].src_mac, 0, 6);
    memset(g_routes[index].dest_mac, 0, 6);

    g_routes[index].dest = 0;
    g_routes[index].src = 0;
    g_routes[index].src_mac_qual = 0;
    g_routes[index].dest_mac_qual = 0;
    g_routes[index].type = -1;
    g_routes[index].src_type = -1;
    g_routes[index].use = 0;

    prev_i = g_routes[index].prev;
    next_i = g_routes[index].next;
  
    if (prev_i != -1) {
	g_routes[prev_i].next = g_routes[index].next;
    }
    
    if (next_i != -1) {
	g_routes[next_i].prev = g_routes[index].prev;
    }
    
    if (g_first_route == index) {
	g_first_route = g_routes[index].next;
    }    

    if (g_last_route == index) {
	g_last_route = g_routes[index].prev;
    }    

    g_routes[index].next = -1;
    g_routes[index].prev = -1;
    
    g_num_routes--;
    
    clear_hash_cache();
    
    return 0;
}

int vnet_delete_route_entry_by_addr(char src_mac[6], 
				    char dest_mac[6], 
				    int src_mac_qual, 
				    int dest_mac_qual, 
				    int dest, 
				    int type, 
				    int src, 
				    int src_type) {
    int index = find_route_entry(src_mac, dest_mac, src_mac_qual, 
				 dest_mac_qual, dest, type, src, src_type);
    
    if (index == -1) {
	return -1;
    }
    
    delete_route_entry(index);
    
    return 0;
}

int delete_sock(struct sock_list * socks, int * first_sock, int * last_sock, SOCK fd) {
    int i;
    int prev_i;
    int next_i;
    
  
    FOREACH_SOCK(i, socks, (*first_sock)) {
	if (socks[i].sock == fd) {
	    V3_Close_Socket(socks[i].sock);
	    socks[i].sock = -1;
	    
	    prev_i = socks[i].prev;
	    next_i = socks[i].next;
	    
	    if (prev_i != -1) {
		socks[prev_i].next = socks[i].next;
	    }
	    
	    if (next_i != -1) {
		socks[next_i].prev = socks[i].prev;
	    }
	    
	    if (*first_sock == i) {
		*first_sock = socks[i].next;
	    }
	    
	    if (*last_sock == i) {
		*last_sock = socks[i].prev;
	    }
	    
	    socks[i].next = -1;
	    socks[i].prev = -1;
	    
	    return 0;
	}
    }
    return -1;
}

//setup the topology of the testing network
static void store_topologies(SOCK fd) {
    int i;
    int src_mac_qual = MAC_ANY;
    int dest_mac_qual = MAC_ANY;
    uint_t dest;
#ifndef VNET_SERVER
    dest = (0 | 172 << 24 | 23 << 16 | 1 );
    PrintDebug("VNET: store_topologies. NOT VNET_SERVER, dest = %x\n", dest);
#else
    dest = (0 | 172 << 24 | 23 << 16 | 2 );
    PrintDebug("VNET: store_topologies. VNET_SERVER, dest = %x\n", dest);
#endif

    int type = UDP_TYPE;
    int src = 0;
    int src_type= LINK_ANY; //ANY_SRC_TYPE
    int data_port = 22;
    
    //store link table
    for (i = 0; i < MAX_LINKS; i++) {
	if (g_links[i].use == 0) {
	    g_links[i].dest = (int)dest;
	    g_links[i].type = type;
	    g_links[i].link_sock = fd;
	    g_links[i].remote_port = data_port;
	    g_links[i].use = 1;
	    
	    if (g_first_link == -1) {
		g_first_link = i;
	    }	    

	    g_links[i].prev = g_last_link;
	    g_links[i].next = -1;
	    
	    if (g_last_link != -1) {
		g_links[g_last_link].next = i;
	    }
	    
	    g_last_link = i;
	    
	    g_num_links++;
	    PrintDebug("VNET: store_topologies. new link: socket: %d, remote %x:[%d]\n", g_links[i].link_sock, (uint_t)g_links[i].dest, g_links[i].remote_port);
	}
    }
    
    
    //store route table
    
    type = LINK_EDGE;
    dest = 0;
    
    for (i = 0; i < MAX_ROUTES; i++) {
	if (g_routes[i].use == 0) {
	    if ((src_mac_qual != MAC_ANY) && (src_mac_qual != MAC_NONE)) {
		//		    memcpy(g_routes[i].src_mac, src_mac, 6);
	    } else {
		memset(g_routes[i].src_mac, 0, 6);
	    }
	    
	    if ((dest_mac_qual != MAC_ANY) && (dest_mac_qual != MAC_NONE)) {
		//		    memcpy(g_routes[i].dest_mac, dest_mac, 6);
	    } else {
		memset(g_routes[i].dest_mac, 0, 6);
	    }
	    
	    g_routes[i].src_mac_qual = src_mac_qual;
	    g_routes[i].dest_mac_qual = dest_mac_qual;
	    g_routes[i].dest = (int)dest;
	    g_routes[i].type = type;
	    g_routes[i].src = src;
	    g_routes[i].src_type = src_type;
	    
	    g_routes[i].use = 1;
	    
	    if (g_first_route == -1) {
		g_first_route = i;
	    }
	    
	    g_routes[i].prev = g_last_route;
	    g_routes[i].next = -1;
	    
	    if (g_last_route != -1) {
		g_routes[g_last_route].next = i;
	    }
	    
	    g_last_route = i;
	    
	    g_num_routes++;
	    
	    PrintDebug("VNET: store_topologies. new route: src_mac: %s, dest_mac: %s, dest: %d\n", g_routes[i].src_mac, g_routes[i].dest_mac, dest);
	    
	}
    }
}

static int match_route(uint8_t * src_mac, uint8_t * dst_mac, int src_type, int src_index, int * matches) { 
    int values[MAX_ROUTES];
    int matched_routes[MAX_ROUTES];
    
    int num_matches = 0;
    int i;
    int max = 0;
    int no = 0;
    int exact_match = 0;
    
    FOREACH_ROUTE(i, g_routes, g_first_route) {
	if ((g_routes[i].src_type != LINK_ANY) &&
	    ((g_routes[i].src_type != src_type) ||
	     ((g_routes[i].src != src_index) &&
	      (g_routes[i].src != -1)))) {
	    PrintDebug("Vnet: MatchRoute: Source route is on and does not match\n");
	    continue;
	}
	
	if ( (g_routes[i].dest_mac_qual == MAC_ANY) &&
	     (g_routes[i].src_mac_qual == MAC_ANY) ) {      
	    matched_routes[num_matches] = i;
	    values[num_matches] = 3;
	    num_matches++;
	}
	
	if (memcmp((void *)&g_routes[i].src_mac, (void *)src_mac, 6) == 0) {
	    if (g_routes[i].src_mac_qual !=  MAC_NOT) {
		if (g_routes[i].dest_mac_qual == MAC_ANY) {
		    matched_routes[num_matches] = i;
		    values[num_matches] = 6;
		    
		    num_matches++;
		} else if (memcmp((void *)&g_routes[i].dest_mac, (void *)dst_mac, 6) == 0) {
		    if (g_routes[i].dest_mac_qual != MAC_NOT) {   
			matched_routes[num_matches] = i;
			values[num_matches] = 8;    
			exact_match = 1;
			num_matches++;
		    }
		}
	    }
	}
	
	if (memcmp((void *)&g_routes[i].dest_mac, (void *)dst_mac, 6) == 0) {
	    if (g_routes[i].dest_mac_qual != MAC_NOT) {
		if (g_routes[i].src_mac_qual == MAC_ANY) {
		    matched_routes[num_matches] = i;
		    values[num_matches] = 6;
		    
		    num_matches++;
		} else if (memcmp((void *)&g_routes[i].src_mac, (void *)src_mac, 6) == 0) {
		    if (g_routes[i].src_mac_qual != MAC_NOT) {
			if (exact_match == 0) {
			    matched_routes[num_matches] = i;
			    values[num_matches] = 8;
			    num_matches++;
			}
		    }
		}
	    }
	}
	
	if ((g_routes[i].dest_mac_qual == MAC_NOT) &&
	    (memcmp((void *)&g_routes[i].dest_mac, (void *)dst_mac, 6) != 0)) {
	    if (g_routes[i].src_mac_qual == MAC_ANY) {
		matched_routes[num_matches] = i;
		values[num_matches] = 5;		    
		num_matches++;    
	    } else if (memcmp((void *)&g_routes[i].src_mac, (void *)src_mac, 6) == 0) {
		if (g_routes[i].src_mac_qual != MAC_NOT) {      
		    matched_routes[num_matches] = i;
		    values[num_matches] = 7;		      
		    num_matches++;
		}
	    }
	}
	
	if ((g_routes[i].src_mac_qual == MAC_NOT) &&
	    (memcmp((void *)&g_routes[i].src_mac, (void *)src_mac, 6) != 0)) {
	    if (g_routes[i].dest_mac_qual == MAC_ANY) {
		matched_routes[num_matches] = i;
		values[num_matches] = 5;	    
		num_matches++;
	    } else if (memcmp((void *)&g_routes[i].dest_mac, (void *)dst_mac, 6) == 0) {
		if (g_routes[i].dest_mac_qual != MAC_NOT) { 
		    matched_routes[num_matches] = i;
		    values[num_matches] = 7;
		    num_matches++;
		}
	    }
	}
    }
    //end FOREACH_ROUTE
    
    FOREACH_ROUTE(i, g_routes, g_first_route) {
    	if ((memcmp((void *)&g_routes[i].src_mac, (void *)src_mac, 6) == 0) &&
	    (g_routes[i].dest_mac_qual == MAC_NONE) &&
	    ((g_routes[i].src_type == LINK_ANY) ||
	     ((g_routes[i].src_type == src_type) &&
	      ((g_routes[i].src == src_index) ||
	       (g_routes[i].src == -1))))) {
	    matched_routes[num_matches] = i;
	    values[num_matches] = 4;
	    PrintDebug("Vnet: MatchRoute: We matched a default route (%d)\n", i);
	    num_matches++;
    	}
    }
    
    //If many rules have been matched, we choose one which has the highest value rating
    if (num_matches == 0) {
    	return 0;
    }
    
    for (i = 0; i < num_matches; i++) {
    	if (values[i] > max) {
	    no = 0;
	    max = values[i];
	    matches[no] = matched_routes[i];
	    no++;
    	} else if (values[i] == max) {
	    matches[no] = matched_routes[i];
	    no++;
    	}
    }
    
    return no;
}


static int process_udpdata() {
    struct raw_ethernet_pkt * pt;

    uint32_t dest = 0;
    uint16_t remote_port = 0;
    SOCK link_sock = g_udp_sockfd;
    int length = sizeof(struct raw_ethernet_pkt) - (2 * sizeof(int));   //minus the "size" and "type" 

    //run in a loop to get packets from outside network, adding them to the incoming packet queue
    while (1) {
	pt = (struct raw_ethernet_pkt *)V3_Malloc(sizeof(struct raw_ethernet_pkt));

	if (pt == NULL){
	    PrintError("Vnet: process_udp: Malloc fails\n");
	    continue;
	}
	
	PrintDebug("Vnet: route_thread: socket: [%d]. ready to receive from ip [%x], port [%d] or from VMs\n", link_sock, (uint_t)dest, remote_port);
	pt->size = V3_RecvFrom_IP( link_sock, dest, remote_port, pt->data, length);
	PrintDebug("Vnet: route_thread: socket: [%d] receive from ip [%x], port [%d]\n", link_sock, (uint_t)dest, remote_port);
	
	if (pt->size <= 0) {
	    PrintDebug("Vnet: process_udp: receiving packet from UDP fails\n");
	    V3_Free(pt);
	    return -1;
	}
	
	PrintDebug("Vnet: process_udp: get packet\n");
	print_packet(pt->data, pt->size);

	
	//V3_Yield();
    }
}



static int indata_handler( )
{
      if (!use_tcp)
      	   process_udpdata();	  

      return 0;   
}

static int start_recv_data()
{
	if (use_tcp){
		
	} else {
  		SOCK udp_data_socket;
  
  		if ((udp_data_socket = V3_Create_UDP_Socket()) < 0){
	      		PrintError("VNET: Can't setup udp socket\n");
	      		return -1; 
  		}
  		PrintDebug("Vnet: vnet_setup_udp: get socket: %d\n", udp_data_socket);
		g_udp_sockfd = udp_data_socket;

  		store_topologies(udp_data_socket);

  		if (V3_Bind_Socket(udp_data_socket, vnet_udp_port) < 0){ 
	          	PrintError("VNET: Can't bind socket\n");
	          	return -1;
  		}
  		PrintDebug("VNET: vnet_setup_udp: bind socket successful\n");
	}

	V3_CREATE_THREAD(&indata_handler, NULL, "VNET_DATA_HANDLER");
	return 0;
}


static inline int if_write_pkt(struct vnet_if_device *iface, struct raw_ethernet_pkt * pkt) {
    return iface->input((uchar_t *)pkt->data, pkt->size);
}

static int handle_one_pkt(struct raw_ethernet_pkt * pkt) {
    int src_link_index = 0;	//the value of src_link_index of udp always is 0
    int i;
    char src_mac[6];
    char dst_mac[6];

    int matches[g_num_routes];
    int num_matched_routes = 0;

    struct HEADERS headers;
  
    // get the ethernet and ip headers from the packet
    memcpy((void *)&headers, (void *)pkt->data, sizeof(headers));

    int j;
    for (j = 0;j < 6; j++) {
	src_mac[j] = headers.ethernetsrc[j];
	dst_mac[j] = headers.ethernetdest[j];
    }


#ifdef DEBUG
    char dest_str[18];
    char src_str[18];
    
    mac_to_string(src_mac, src_str);  
    mac_to_string(dst_mac, dest_str);
    
    PrintDebug("Vnet: HandleDataOverLink. SRC(%s), DEST(%s)\n", src_str, dest_str);
#endif
    
    char hash_key[hash_key_size];
    make_hash_key(hash_key, src_mac, dst_mac, LINK_EDGE, src_link_index);//link_edge -> pt->type???
    
    num_matched_routes = look_into_cache((route_hashkey_t)hash_key, matches);
    
    if (num_matched_routes == -1) {  //no match
        num_matched_routes = match_route(src_mac, dst_mac, pkt->type, src_link_index, matches);
	
	if (num_matched_routes > 0) {
	    add_route_to_cache(hash_key, num_matched_routes,matches);      
	}
    }
    
    PrintDebug("Vnet: HandleDataOverLink: Matches=%d\n", num_matched_routes);
    
    for (i = 0; i < num_matched_routes; i++) {
        int route_index = -1;
        int link_index = -1;
        int dev_index = -1;
	
        route_index = matches[i];
	
        PrintDebug("Vnet: HandleDataOverLink: Forward packet from link according to Route entry %d\n", route_index);
	
        if (g_routes[route_index].type == LINK_EDGE) {
            link_index = g_routes[route_index].dest;
	    
            if(g_links[link_index].type == UDP_TYPE) {
                int size;

				
		  PrintDebug("===Vnet: HandleDataOverLink: Serializing UDP Packet to link_sock [%d], dest [%x], remote_port [%d], size [%d]\n", g_links[link_index].link_sock, (uint_t)g_links[link_index].dest,  g_links[link_index].remote_port, (int)pkt->size);
		
                if ((size = V3_SendTo_IP(g_links[link_index].link_sock,  g_links[link_index].dest,  g_links[link_index].remote_port, pkt->data, pkt->size)) != pkt->size)  {
                    PrintError("Vnet: sending by UDP Exception, %x\n", size);
                    return -1;
                }
		
                PrintDebug("Vnet: HandleDataOverLink: Serializing UDP Packet to link_sock [%d], dest [%x], remote_port [%d], size [%d]\n", g_links[link_index].link_sock, (uint_t)g_links[link_index].dest,  g_links[link_index].remote_port, (int)pkt->size);
		
            } else if (g_links[link_index].type == TCP_TYPE) {
		
            }
        } else if (g_routes[route_index].type == LINK_INTERFACE) {
            dev_index = g_routes[route_index].dest;
      
            PrintDebug("Writing Packet to device=%s\n", g_devices[dev_index].device->name);

            if (if_write_pkt(g_devices[dev_index].device, pkt) == -1) {
		PrintDebug("Can't write output packet to link\n");
                return -1;
            }
        } else {
            PrintDebug("Vnet: Wrong Edge type\n");
        }
    }

     return 0;
}

static int send_ethernet_pkt(char * buf, int length) {
	struct raw_ethernet_pkt * pt;

	pt = (struct raw_ethernet_pkt *)V3_Malloc(sizeof(struct raw_ethernet_pkt));
	raw_ethernet_packet_init(pt, buf, length);  //====here we copy sending data once 
	
	PrintDebug("VNET: vm_send_pkt: transmitting packet: (size:%d)\n", (int)pt->size);
	print_packet((char *)buf, length);
	
	v3_enqueue(g_inpkt_q, (addr_t)pt);
	return 0;
	
}

int v3_Send_pkt(uchar_t *buf, int length) {
    PrintDebug("VNET: In V3_Send_pkt: pkt length %d\n", length);
    
    return send_ethernet_pkt((char *)buf, length);
}

static int add_device_to_table(struct vnet_if_device*device, int type) {
    int i;
    
    for (i = 0; i < MAX_DEVICES; i++) {
	if (g_devices[i].use == 0) {
	    g_devices[i].type = type;
	    g_devices[i].use = 1;
	    
	    if (g_first_device == -1) {
	        g_first_device = i;
	    }	    

	    g_devices[i].prev = g_last_device;
	    g_devices[i].next = -1;
	    
	    if (g_last_device != -1) {
	        g_devices[g_last_device].next = i;
	    }

	    g_last_device = i;
	    g_num_devices++;
	    
	    return i;
	}
    }
    
    return -1;
}

static int search_device(char *device_name) {
    int i;

    for (i = 0; i < MAX_DEVICES; i++) {
        if (g_devices[i].use == 1) {
	    if (!strcmp(device_name, g_devices[i].device->name)) {
		return i;
	    }
        }
    }
    
    return -1;
}

static struct vnet_if_device * delete_device_from_table(int index) {
    int next_i;
    int prev_i;
    struct vnet_if_device * device = NULL;

    if (g_devices[index].use == 0) {
	return NULL;
    }

    g_devices[index].use = 0;

    prev_i = g_devices[index].prev;
    next_i = g_devices[index].next;

    if (prev_i != -1) {
        g_devices[prev_i].next = g_devices[index].next;
    }

    if (next_i != -1) {
        g_devices[next_i].prev = g_devices[index].prev;
    }

    if (g_first_device == index) {
        g_first_device = g_devices[index].next;
    }

    if (g_last_device == index) {
        g_last_device = g_devices[index].prev;
    }

    g_devices[index].next = -1;
    g_devices[index].prev = -1;

    device = g_devices[index].device;
    g_devices[index].device = NULL;

    g_num_devices--;

    return device;
}


int vnet_register_device(char * dev_name, int (*netif_input)(uchar_t * pkt, uint_t size), void * data) {
    struct vnet_if_device * dev;
    
    dev = (struct vnet_if_device *)V3_Malloc(sizeof(struct vnet_if_device));
    
    if (dev == NULL){
	PrintError("VNET: Malloc fails\n");
	return -1;
    }
    
    strncpy(dev->name, dev_name, 50);
    dev->input = netif_input;
    dev->data = data;
    
    if (add_device_to_table(dev, GENERAL_NIC) == -1) {
	return -1;
    }
    
    return 0;
}

int vnet_unregister_device(char * dev_name) {
    int i;

    i = search_device(dev_name);
    
    if (i == -1) {
        return -1;
    }

    struct vnet_if_device * device = delete_device_from_table(i);

    if (device == NULL) {
	return -1;
    }

    V3_Free(device);

    return 0;
}

int v3_Register_pkt_event(int (*netif_input)(uchar_t * pkt, uint_t size)) {
    return vnet_register_device("NE2000", netif_input, NULL);
}

int v3_vnet_pkt_process() {
    struct raw_ethernet_pkt * pt;

    PrintDebug("VNET: In vnet_check\n");
	
    while ((pt = (struct raw_ethernet_pkt *)v3_dequeue(g_inpkt_q)) != NULL) {
	PrintDebug("VNET: In vnet_check: pt length %d, pt type %d\n", (int)pt->size, (int)pt->type);
	v3_hexdump(pt->data, pt->size, NULL, 0);
	
	if(handle_one_pkt(pt)) {
	    PrintDebug("VNET: vnet_check: handle one packet!\n");  
	}
	
	V3_Free(pt); //be careful here
    }
    
    return 0;
}

static void init_link_table() {
    int i;

    for (i = 0; i < MAX_LINKS; i++) {
        g_links[i].use = 0;
        g_links[i].next = -1;
        g_links[i].prev = -1;
    }
	
    g_first_link = -1;
    g_last_link = -1;
    g_num_links = 0;
}

static void init_device_table() {
    int i;

    for (i = 0; i < MAX_DEVICES; i++) {
        g_devices[i].use = 0;
        g_devices[i].next = -1;
        g_devices[i].prev = -1;
    }
	
    g_first_device = -1;
    g_last_device = -1;
    g_num_devices = 0;
}

static void init_route_table() {	
    int i;

    for (i = 0; i < MAX_ROUTES; i++) {
        g_routes[i].use = 0;
        g_routes[i].next = -1;
        g_routes[i].prev = -1;
    }
	
     g_first_route = -1;
     g_last_route = -1;
     g_num_routes = 0;
}

static void init_tables() {
    init_link_table();
    init_device_table();
    init_route_table();
    init_route_cache();
}

static void init_pkt_queue()
{
    PrintDebug("VNET Init package receiving queue\n");

    g_inpkt_q = v3_create_queue();
    v3_init_queue(g_inpkt_q);
}



void v3_vnet_init() {	

	PrintDebug("VNET Init: Vnet input queue successful.\n");

	init_tables();

	init_pkt_queue();
	
	//store_topologies(udp_data_socket);

	start_recv_data();
}