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/*
* Ouroboros - Copyright (C) 2016 - 2021
*
* Packet forwarding table (PFT) with chaining on collisions
*
* Dimitri Staessens <dimitri.staessens@ugent.be>
* Sander Vrijders <sander.vrijders@ugent.be>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., http://www.fsf.org/about/contact/.
*/
#if defined(__linux__) || defined(__CYGWIN__)
#define _DEFAULT_SOURCE
#endif
#include <ouroboros/list.h>
#include <ouroboros/errno.h>
#include <ouroboros/hash.h>
#include "pft.h"
#include <assert.h>
#include <string.h>
/* store <len> output fds for dst addr */
struct pft_entry {
struct list_head next;
uint64_t dst;
int * fds;
size_t len;
};
struct pft {
struct list_head * buckets;
bool hash_key;
uint64_t buckets_size;
};
struct pft * pft_create(uint64_t buckets,
bool hash_key)
{
struct pft * tmp;
unsigned int i;
if (buckets == 0)
return NULL;
buckets--;
buckets |= buckets >> 1;
buckets |= buckets >> 2;
buckets |= buckets >> 4;
buckets |= buckets >> 8;
buckets |= buckets >> 16;
buckets |= buckets >> 32;
buckets++;
tmp = malloc(sizeof(*tmp));
if (tmp == NULL)
return NULL;
tmp->hash_key = hash_key;
tmp->buckets_size = buckets;
tmp->buckets = malloc(buckets * sizeof(*tmp->buckets));
if (tmp->buckets == NULL) {
free(tmp);
return NULL;
}
for (i = 0; i < buckets; i++)
list_head_init(&(tmp->buckets[i]));
return tmp;
}
void pft_destroy(struct pft * pft)
{
assert(pft);
assert(pft->buckets);
pft_flush(pft);
free(pft->buckets);
free(pft);
}
void pft_flush(struct pft * pft)
{
unsigned int i;
struct list_head * p;
struct list_head * h;
struct pft_entry * entry;
assert(pft);
for (i = 0; i < pft->buckets_size; i++) {
list_for_each_safe(p, h, &(pft->buckets[i])) {
entry = list_entry(p, struct pft_entry, next);
list_del(&entry->next);
free(entry->fds);
free(entry);
}
}
}
static uint64_t hash(uint64_t key)
{
void * res;
uint64_t ret;
uint8_t keys[4];
memcpy(keys, &key, 4);
mem_hash(HASH_MD5, &res, keys, 4);
ret = (* (uint64_t *) res);
free(res);
return ret;
}
static uint64_t calc_key(struct pft * pft,
uint64_t dst)
{
if (pft->hash_key)
dst = hash(dst);
return (dst & (pft->buckets_size - 1));
}
int pft_insert(struct pft * pft,
uint64_t dst,
int * fds,
size_t len)
{
struct pft_entry * entry;
uint64_t lookup_key;
struct list_head * p;
assert(pft);
assert(len > 0);
lookup_key = calc_key(pft, dst);
list_for_each(p, &(pft->buckets[lookup_key])) {
entry = list_entry(p, struct pft_entry, next);
if (entry->dst == dst)
return -EPERM;
}
entry = malloc(sizeof(*entry));
if (entry == NULL)
return -ENOMEM;
entry->dst = dst;
entry->fds = fds;
entry->len = len;
list_add(&entry->next, &(pft->buckets[lookup_key]));
return 0;
}
int pft_lookup(struct pft * pft,
uint64_t dst,
int ** fds,
size_t * len)
{
struct pft_entry * entry;
struct list_head * p;
uint64_t lookup_key;
assert(pft);
lookup_key = calc_key(pft, dst);
list_for_each(p, &(pft->buckets[lookup_key])) {
entry = list_entry(p, struct pft_entry, next);
if (entry->dst == dst) {
*fds = entry->fds;
*len = entry->len;
return 0;
}
}
return -1;
}
int pft_delete(struct pft * pft,
uint64_t dst)
{
struct pft_entry * entry;
uint64_t lookup_key;
struct list_head * p;
struct list_head * h;
assert(pft);
lookup_key = calc_key(pft, dst);
list_for_each_safe(p, h, &(pft->buckets[lookup_key])) {
entry = list_entry(p, struct pft_entry, next);
if (entry->dst == dst) {
list_del(&entry->next);
free(entry->fds);
free(entry);
return 0;
}
}
return -1;
}
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