addr_hash.c 1.55 KB
Newer Older
pdw's avatar
iftop  
pdw committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
/* hash table */

#include <stdio.h>
#include <stdlib.h>
#include "addr_hash.h"
#include "hash.h"

#define hash_table_size 256

int compare(void* a, void* b) {
    addr_pair* aa = (addr_pair*)a;
    addr_pair* bb = (addr_pair*)b;
    return (aa->src.s_addr == bb->src.s_addr 
            && aa->dst.s_addr == bb->dst.s_addr);
}

int hash(void* key) {
    int hash;
    long addr;
    addr_pair* ap = (addr_pair*)key;
        
    addr = (long)ap->src.s_addr;

    hash = ((addr & 0x000000FF)
            + (addr & 0x0000FF00 >> 8)
            + (addr & 0x00FF0000 >> 16)
            + (addr & 0xFF000000 >> 24)) % 0xFF;

    addr = (long)ap->dst.s_addr;
    hash += ((addr & 0x000000FF)
            + (addr & 0x0000FF00 >> 8)
            + (addr & 0x00FF0000 >> 16)
            + (addr & 0xFF000000 >> 24)) % 0xFF;

    return hash;
}

void* copy_key(void* orig) {
    addr_pair* copy = malloc(sizeof(addr_pair));
    if(copy == NULL) {
        printf("Out of memory\n");
        exit(1);
    }
    *copy = *(addr_pair*)orig;
    return copy;
}

void delete_key(void* key) {
    free(key);
}

/*
 * Allocate and return a hash
 */
hash_type* addr_hash_create() {
    hash_type* hash_table;
    if ((hash_table = calloc(hash_table_size, sizeof(hash_type*))) == 0) {
        fprintf (stderr, "out of memory (hashTable)\n");
        exit(1);
    }
    hash_table->size = hash_table_size;
    hash_table->compare = &compare;
    hash_table->hash = &hash;
    hash_table->delete_key = &delete_key;
    hash_table->copy_key = &copy_key;
    hash_initialise(hash_table);
    return hash_table;
}