[457] | 1 | /**
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| 2 | * @file
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| 3 | * lwIP netif implementing an FDB for IEEE 802.1D MAC Bridge
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (c) 2017 Simon Goldschmidt.
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| 8 | * All rights reserved.
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without modification,
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| 11 | * are permitted provided that the following conditions are met:
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| 12 | *
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| 13 | * 1. Redistributions of source code must retain the above copyright notice,
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| 14 | * this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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| 16 | * this list of conditions and the following disclaimer in the documentation
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| 17 | * and/or other materials provided with the distribution.
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| 18 | * 3. The name of the author may not be used to endorse or promote products
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| 19 | * derived from this software without specific prior written permission.
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| 20 | *
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| 21 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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| 22 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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| 23 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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| 24 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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| 25 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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| 26 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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| 29 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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| 30 | * OF SUCH DAMAGE.
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| 31 | *
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| 32 | * This file is part of the lwIP TCP/IP stack.
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| 33 | *
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| 34 | * Author: Simon Goldschmidt <goldsimon@gmx.de>
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| 35 | *
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| 36 | */
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| 37 |
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| 38 | /**
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| 39 | * @defgroup bridgeif_fdb FDB example code
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| 40 | * @ingroup bridgeif
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| 41 | * This file implements an example for an FDB (Forwarding DataBase)
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| 42 | */
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| 43 |
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| 44 | #include "netif/bridgeif.h"
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| 45 | #include "lwip/sys.h"
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| 46 | #include "lwip/mem.h"
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| 47 | #include "lwip/timeouts.h"
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| 48 | #include <string.h>
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| 49 |
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| 50 | #define BRIDGEIF_AGE_TIMER_MS 1000
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| 51 |
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| 52 | #define BR_FDB_TIMEOUT_SEC (60*5) /* 5 minutes FDB timeout */
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| 53 |
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| 54 | typedef struct bridgeif_dfdb_entry_s {
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| 55 | u8_t used;
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| 56 | u8_t port;
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| 57 | u32_t ts;
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| 58 | struct eth_addr addr;
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| 59 | } bridgeif_dfdb_entry_t;
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| 60 |
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| 61 | typedef struct bridgeif_dfdb_s {
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| 62 | u16_t max_fdb_entries;
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| 63 | bridgeif_dfdb_entry_t *fdb;
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| 64 | } bridgeif_dfdb_t;
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| 65 |
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| 66 | /**
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| 67 | * @ingroup bridgeif_fdb
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| 68 | * A real simple and slow implementation of an auto-learning forwarding database that
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| 69 | * remembers known src mac addresses to know which port to send frames destined for that
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| 70 | * mac address.
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| 71 | *
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| 72 | * ATTENTION: This is meant as an example only, in real-world use, you should
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| 73 | * provide a better implementation :-)
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| 74 | */
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| 75 | void
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| 76 | bridgeif_fdb_update_src(void *fdb_ptr, struct eth_addr *src_addr, u8_t port_idx)
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| 77 | {
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| 78 | int i;
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| 79 | bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)fdb_ptr;
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| 80 | BRIDGEIF_DECL_PROTECT(lev);
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| 81 | BRIDGEIF_READ_PROTECT(lev);
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| 82 | for (i = 0; i < fdb->max_fdb_entries; i++) {
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| 83 | bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
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| 84 | if (e->used && e->ts) {
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| 85 | if (!memcmp(&e->addr, src_addr, sizeof(struct eth_addr))) {
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| 86 | LWIP_DEBUGF(BRIDGEIF_FDB_DEBUG, ("br: update src %02x:%02x:%02x:%02x:%02x:%02x (from %d) @ idx %d\n",
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| 87 | src_addr->addr[0], src_addr->addr[1], src_addr->addr[2], src_addr->addr[3], src_addr->addr[4], src_addr->addr[5],
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| 88 | port_idx, i));
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| 89 | BRIDGEIF_WRITE_PROTECT(lev);
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| 90 | e->ts = BR_FDB_TIMEOUT_SEC;
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| 91 | e->port = port_idx;
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| 92 | BRIDGEIF_WRITE_UNPROTECT(lev);
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| 93 | BRIDGEIF_READ_UNPROTECT(lev);
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| 94 | return;
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| 95 | }
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| 96 | }
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| 97 | }
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| 98 | /* not found, allocate new entry from free */
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| 99 | for (i = 0; i < fdb->max_fdb_entries; i++) {
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| 100 | bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
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| 101 | if (!e->used || !e->ts) {
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| 102 | BRIDGEIF_WRITE_PROTECT(lev);
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| 103 | /* check again when protected */
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| 104 | if (!e->used || !e->ts) {
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| 105 | LWIP_DEBUGF(BRIDGEIF_FDB_DEBUG, ("br: create src %02x:%02x:%02x:%02x:%02x:%02x (from %d) @ idx %d\n",
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| 106 | src_addr->addr[0], src_addr->addr[1], src_addr->addr[2], src_addr->addr[3], src_addr->addr[4], src_addr->addr[5],
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| 107 | port_idx, i));
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| 108 | memcpy(&e->addr, src_addr, sizeof(struct eth_addr));
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| 109 | e->ts = BR_FDB_TIMEOUT_SEC;
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| 110 | e->port = port_idx;
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| 111 | e->used = 1;
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| 112 | BRIDGEIF_WRITE_UNPROTECT(lev);
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| 113 | BRIDGEIF_READ_UNPROTECT(lev);
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| 114 | return;
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| 115 | }
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| 116 | BRIDGEIF_WRITE_UNPROTECT(lev);
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| 117 | }
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| 118 | }
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| 119 | BRIDGEIF_READ_UNPROTECT(lev);
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| 120 | /* not found, no free entry -> flood */
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| 121 | }
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| 122 |
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| 123 | /**
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| 124 | * @ingroup bridgeif_fdb
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| 125 | * Walk our list of auto-learnt fdb entries and return a port to forward or BR_FLOOD if unknown
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| 126 | */
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| 127 | bridgeif_portmask_t
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| 128 | bridgeif_fdb_get_dst_ports(void *fdb_ptr, struct eth_addr *dst_addr)
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| 129 | {
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| 130 | int i;
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| 131 | bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)fdb_ptr;
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| 132 | BRIDGEIF_DECL_PROTECT(lev);
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| 133 | BRIDGEIF_READ_PROTECT(lev);
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| 134 | for (i = 0; i < fdb->max_fdb_entries; i++) {
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| 135 | bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
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| 136 | if (e->used && e->ts) {
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| 137 | if (!memcmp(&e->addr, dst_addr, sizeof(struct eth_addr))) {
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| 138 | bridgeif_portmask_t ret = (bridgeif_portmask_t)(1 << e->port);
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| 139 | BRIDGEIF_READ_UNPROTECT(lev);
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| 140 | return ret;
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| 141 | }
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| 142 | }
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| 143 | }
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| 144 | BRIDGEIF_READ_UNPROTECT(lev);
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| 145 | return BR_FLOOD;
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| 146 | }
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| 147 |
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| 148 | /**
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| 149 | * @ingroup bridgeif_fdb
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| 150 | * Aging implementation of our simple fdb
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| 151 | */
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| 152 | static void
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| 153 | bridgeif_fdb_age_one_second(void *fdb_ptr)
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| 154 | {
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| 155 | int i;
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| 156 | bridgeif_dfdb_t *fdb;
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| 157 | BRIDGEIF_DECL_PROTECT(lev);
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| 158 |
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| 159 | fdb = (bridgeif_dfdb_t *)fdb_ptr;
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| 160 | BRIDGEIF_READ_PROTECT(lev);
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| 161 |
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| 162 | for (i = 0; i < fdb->max_fdb_entries; i++) {
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| 163 | bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
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| 164 | if (e->used && e->ts) {
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| 165 | BRIDGEIF_WRITE_PROTECT(lev);
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| 166 | /* check again when protected */
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| 167 | if (e->used && e->ts) {
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| 168 | if (--e->ts == 0) {
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| 169 | e->used = 0;
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| 170 | }
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| 171 | }
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| 172 | BRIDGEIF_WRITE_UNPROTECT(lev);
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| 173 | }
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| 174 | }
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| 175 | BRIDGEIF_READ_UNPROTECT(lev);
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| 176 | }
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| 177 |
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| 178 | /** Timer callback for fdb aging, called once per second */
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| 179 | static void
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| 180 | bridgeif_age_tmr(void *arg)
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| 181 | {
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| 182 | bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)arg;
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| 183 |
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| 184 | LWIP_ASSERT("invalid arg", arg != NULL);
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| 185 |
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| 186 | bridgeif_fdb_age_one_second(fdb);
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| 187 | sys_timeout(BRIDGEIF_AGE_TIMER_MS, bridgeif_age_tmr, arg);
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| 188 | }
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| 189 |
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| 190 | /**
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| 191 | * @ingroup bridgeif_fdb
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| 192 | * Init our simple fdb list
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| 193 | */
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| 194 | void *
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| 195 | bridgeif_fdb_init(u16_t max_fdb_entries)
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| 196 | {
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| 197 | bridgeif_dfdb_t *fdb;
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| 198 | size_t alloc_len_sizet = sizeof(bridgeif_dfdb_t) + (max_fdb_entries * sizeof(bridgeif_dfdb_entry_t));
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| 199 | mem_size_t alloc_len = (mem_size_t)alloc_len_sizet;
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| 200 | LWIP_ASSERT("alloc_len == alloc_len_sizet", alloc_len == alloc_len_sizet);
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| 201 | LWIP_DEBUGF(BRIDGEIF_DEBUG, ("bridgeif_fdb_init: allocating %d bytes for private FDB data\n", (int)alloc_len));
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| 202 | fdb = (bridgeif_dfdb_t *)mem_calloc(1, alloc_len);
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| 203 | if (fdb == NULL) {
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| 204 | return NULL;
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| 205 | }
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| 206 | fdb->max_fdb_entries = max_fdb_entries;
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| 207 | fdb->fdb = (bridgeif_dfdb_entry_t *)(fdb + 1);
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| 208 |
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| 209 | sys_timeout(BRIDGEIF_AGE_TIMER_MS, bridgeif_age_tmr, fdb);
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| 210 |
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| 211 | return fdb;
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| 212 | }
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