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/**
* @file
* lwIP netif implementing an FDB for IEEE 802.1D MAC Bridge
*/
/*
* Copyright (c) 2017 Simon Goldschmidt.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Simon Goldschmidt <goldsimon@gmx.de>
*
*/
/**
* @defgroup bridgeif_fdb FDB example code
* @ingroup bridgeif
* This file implements an example for an FDB (Forwarding DataBase)
*/
#include "netif/bridgeif.h"
#include "lwip/sys.h"
#include "lwip/mem.h"
#include "lwip/timeouts.h"
#include <string.h>
#define BRIDGEIF_AGE_TIMER_MS 1000
#define BR_FDB_TIMEOUT_SEC (60*5) /* 5 minutes FDB timeout */
typedef struct bridgeif_dfdb_entry_s {
u8_t used;
u8_t port;
u32_t ts;
struct eth_addr addr;
} bridgeif_dfdb_entry_t;
typedef struct bridgeif_dfdb_s {
u16_t max_fdb_entries;
bridgeif_dfdb_entry_t *fdb;
} bridgeif_dfdb_t;
/**
* @ingroup bridgeif_fdb
* A real simple and slow implementation of an auto-learning forwarding database that
* remembers known src mac addresses to know which port to send frames destined for that
* mac address.
*
* ATTENTION: This is meant as an example only, in real-world use, you should
* provide a better implementation :-)
*/
void
bridgeif_fdb_update_src(void *fdb_ptr, struct eth_addr *src_addr, u8_t port_idx)
{
int i;
bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)fdb_ptr;
BRIDGEIF_DECL_PROTECT(lev);
BRIDGEIF_READ_PROTECT(lev);
for (i = 0; i < fdb->max_fdb_entries; i++) {
bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
if (e->used && e->ts) {
if (!memcmp(&e->addr, src_addr, sizeof(struct eth_addr))) {
LWIP_DEBUGF(BRIDGEIF_FDB_DEBUG, ("br: update src %02x:%02x:%02x:%02x:%02x:%02x (from %d) @ idx %d\n",
src_addr->addr[0], src_addr->addr[1], src_addr->addr[2], src_addr->addr[3], src_addr->addr[4], src_addr->addr[5],
port_idx, i));
BRIDGEIF_WRITE_PROTECT(lev);
e->ts = BR_FDB_TIMEOUT_SEC;
e->port = port_idx;
BRIDGEIF_WRITE_UNPROTECT(lev);
BRIDGEIF_READ_UNPROTECT(lev);
return;
}
}
}
/* not found, allocate new entry from free */
for (i = 0; i < fdb->max_fdb_entries; i++) {
bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
if (!e->used || !e->ts) {
BRIDGEIF_WRITE_PROTECT(lev);
/* check again when protected */
if (!e->used || !e->ts) {
LWIP_DEBUGF(BRIDGEIF_FDB_DEBUG, ("br: create src %02x:%02x:%02x:%02x:%02x:%02x (from %d) @ idx %d\n",
src_addr->addr[0], src_addr->addr[1], src_addr->addr[2], src_addr->addr[3], src_addr->addr[4], src_addr->addr[5],
port_idx, i));
memcpy(&e->addr, src_addr, sizeof(struct eth_addr));
e->ts = BR_FDB_TIMEOUT_SEC;
e->port = port_idx;
e->used = 1;
BRIDGEIF_WRITE_UNPROTECT(lev);
BRIDGEIF_READ_UNPROTECT(lev);
return;
}
BRIDGEIF_WRITE_UNPROTECT(lev);
}
}
BRIDGEIF_READ_UNPROTECT(lev);
/* not found, no free entry -> flood */
}
/**
* @ingroup bridgeif_fdb
* Walk our list of auto-learnt fdb entries and return a port to forward or BR_FLOOD if unknown
*/
bridgeif_portmask_t
bridgeif_fdb_get_dst_ports(void *fdb_ptr, struct eth_addr *dst_addr)
{
int i;
bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)fdb_ptr;
BRIDGEIF_DECL_PROTECT(lev);
BRIDGEIF_READ_PROTECT(lev);
for (i = 0; i < fdb->max_fdb_entries; i++) {
bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
if (e->used && e->ts) {
if (!memcmp(&e->addr, dst_addr, sizeof(struct eth_addr))) {
bridgeif_portmask_t ret = (bridgeif_portmask_t)(1 << e->port);
BRIDGEIF_READ_UNPROTECT(lev);
return ret;
}
}
}
BRIDGEIF_READ_UNPROTECT(lev);
return BR_FLOOD;
}
/**
* @ingroup bridgeif_fdb
* Aging implementation of our simple fdb
*/
static void
bridgeif_fdb_age_one_second(void *fdb_ptr)
{
int i;
bridgeif_dfdb_t *fdb;
BRIDGEIF_DECL_PROTECT(lev);
fdb = (bridgeif_dfdb_t *)fdb_ptr;
BRIDGEIF_READ_PROTECT(lev);
for (i = 0; i < fdb->max_fdb_entries; i++) {
bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
if (e->used && e->ts) {
BRIDGEIF_WRITE_PROTECT(lev);
/* check again when protected */
if (e->used && e->ts) {
if (--e->ts == 0) {
e->used = 0;
}
}
BRIDGEIF_WRITE_UNPROTECT(lev);
}
}
BRIDGEIF_READ_UNPROTECT(lev);
}
/** Timer callback for fdb aging, called once per second */
static void
bridgeif_age_tmr(void *arg)
{
bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)arg;
LWIP_ASSERT("invalid arg", arg != NULL);
bridgeif_fdb_age_one_second(fdb);
sys_timeout(BRIDGEIF_AGE_TIMER_MS, bridgeif_age_tmr, arg);
}
/**
* @ingroup bridgeif_fdb
* Init our simple fdb list
*/
void *
bridgeif_fdb_init(u16_t max_fdb_entries)
{
bridgeif_dfdb_t *fdb;
size_t alloc_len_sizet = sizeof(bridgeif_dfdb_t) + (max_fdb_entries * sizeof(bridgeif_dfdb_entry_t));
mem_size_t alloc_len = (mem_size_t)alloc_len_sizet;
LWIP_ASSERT("alloc_len == alloc_len_sizet", alloc_len == alloc_len_sizet);
LWIP_DEBUGF(BRIDGEIF_DEBUG, ("bridgeif_fdb_init: allocating %d bytes for private FDB data\n", (int)alloc_len));
fdb = (bridgeif_dfdb_t *)mem_calloc(1, alloc_len);
if (fdb == NULL) {
return NULL;
}
fdb->max_fdb_entries = max_fdb_entries;
fdb->fdb = (bridgeif_dfdb_entry_t *)(fdb + 1);
sys_timeout(BRIDGEIF_AGE_TIMER_MS, bridgeif_age_tmr, fdb);
return fdb;
}
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