1/**
2 * @file
3 * lwIP netif implementing an FDB for IEEE 802.1D MAC Bridge
4 */
5
6/*
7 * Copyright (c) 2017 Simon Goldschmidt.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without modification,
11 * are permitted provided that the following conditions are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright notice,
14 *    this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright notice,
16 *    this list of conditions and the following disclaimer in the documentation
17 *    and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30 * OF SUCH DAMAGE.
31 *
32 * This file is part of the lwIP TCP/IP stack.
33 *
34 * Author: Simon Goldschmidt <goldsimon@gmx.de>
35 *
36 */
37
38/**
39 * @defgroup bridgeif_fdb FDB example code
40 * @ingroup bridgeif
41 * This file implements an example for an FDB (Forwarding DataBase)
42 */
43
44#include "netif/bridgeif.h"
45#include "lwip/sys.h"
46#include "lwip/mem.h"
47#include "lwip/timeouts.h"
48#include <string.h>
49
50#define BRIDGEIF_AGE_TIMER_MS 1000
51
52#define BR_FDB_TIMEOUT_SEC  (60*5) /* 5 minutes FDB timeout */
53
54typedef struct bridgeif_dfdb_entry_s {
55  u8_t used;
56  u8_t port;
57  u32_t ts;
58  struct eth_addr addr;
59} bridgeif_dfdb_entry_t;
60
61typedef struct bridgeif_dfdb_s {
62  u16_t max_fdb_entries;
63  bridgeif_dfdb_entry_t *fdb;
64} bridgeif_dfdb_t;
65
66/**
67 * @ingroup bridgeif_fdb
68 * A real simple and slow implementation of an auto-learning forwarding database that
69 * remembers known src mac addresses to know which port to send frames destined for that
70 * mac address.
71 *
72 * ATTENTION: This is meant as an example only, in real-world use, you should
73 * provide a better implementation :-)
74 */
75void
76bridgeif_fdb_update_src(void *fdb_ptr, struct eth_addr *src_addr, u8_t port_idx)
77{
78  int i;
79  bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)fdb_ptr;
80  BRIDGEIF_DECL_PROTECT(lev);
81  BRIDGEIF_READ_PROTECT(lev);
82  for (i = 0; i < fdb->max_fdb_entries; i++) {
83    bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
84    if (e->used && e->ts) {
85      if (!memcmp(&e->addr, src_addr, sizeof(struct eth_addr))) {
86        LWIP_DEBUGF(BRIDGEIF_FDB_DEBUG, ("br: update src %02x:%02x:%02x:%02x:%02x:%02x (from %d) @ idx %d\n",
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],
88                                         port_idx, i));
89        BRIDGEIF_WRITE_PROTECT(lev);
90        e->ts = BR_FDB_TIMEOUT_SEC;
91        e->port = port_idx;
92        BRIDGEIF_WRITE_UNPROTECT(lev);
93        BRIDGEIF_READ_UNPROTECT(lev);
94        return;
95      }
96    }
97  }
98  /* not found, allocate new entry from free */
99  for (i = 0; i < fdb->max_fdb_entries; i++) {
100    bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
101    if (!e->used || !e->ts) {
102      BRIDGEIF_WRITE_PROTECT(lev);
103      /* check again when protected */
104      if (!e->used || !e->ts) {
105        LWIP_DEBUGF(BRIDGEIF_FDB_DEBUG, ("br: create src %02x:%02x:%02x:%02x:%02x:%02x (from %d) @ idx %d\n",
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],
107                                         port_idx, i));
108        memcpy(&e->addr, src_addr, sizeof(struct eth_addr));
109        e->ts = BR_FDB_TIMEOUT_SEC;
110        e->port = port_idx;
111        e->used = 1;
112        BRIDGEIF_WRITE_UNPROTECT(lev);
113        BRIDGEIF_READ_UNPROTECT(lev);
114        return;
115      }
116      BRIDGEIF_WRITE_UNPROTECT(lev);
117    }
118  }
119  BRIDGEIF_READ_UNPROTECT(lev);
120  /* not found, no free entry -> flood */
121}
122
123/**
124 * @ingroup bridgeif_fdb
125 * Walk our list of auto-learnt fdb entries and return a port to forward or BR_FLOOD if unknown
126 */
127bridgeif_portmask_t
128bridgeif_fdb_get_dst_ports(void *fdb_ptr, struct eth_addr *dst_addr)
129{
130  int i;
131  bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)fdb_ptr;
132  BRIDGEIF_DECL_PROTECT(lev);
133  BRIDGEIF_READ_PROTECT(lev);
134  for (i = 0; i < fdb->max_fdb_entries; i++) {
135    bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
136    if (e->used && e->ts) {
137      if (!memcmp(&e->addr, dst_addr, sizeof(struct eth_addr))) {
138        bridgeif_portmask_t ret = (bridgeif_portmask_t)(1 << e->port);
139        BRIDGEIF_READ_UNPROTECT(lev);
140        return ret;
141      }
142    }
143  }
144  BRIDGEIF_READ_UNPROTECT(lev);
145  return BR_FLOOD;
146}
147
148/**
149 * @ingroup bridgeif_fdb
150 * Aging implementation of our simple fdb
151 */
152static void
153bridgeif_fdb_age_one_second(void *fdb_ptr)
154{
155  int i;
156  bridgeif_dfdb_t *fdb;
157  BRIDGEIF_DECL_PROTECT(lev);
158
159  fdb = (bridgeif_dfdb_t *)fdb_ptr;
160  BRIDGEIF_READ_PROTECT(lev);
161
162  for (i = 0; i < fdb->max_fdb_entries; i++) {
163    bridgeif_dfdb_entry_t *e = &fdb->fdb[i];
164    if (e->used && e->ts) {
165      BRIDGEIF_WRITE_PROTECT(lev);
166      /* check again when protected */
167      if (e->used && e->ts) {
168        if (--e->ts == 0) {
169          e->used = 0;
170        }
171      }
172      BRIDGEIF_WRITE_UNPROTECT(lev);
173    }
174  }
175  BRIDGEIF_READ_UNPROTECT(lev);
176}
177
178/** Timer callback for fdb aging, called once per second */
179static void
180bridgeif_age_tmr(void *arg)
181{
182  bridgeif_dfdb_t *fdb = (bridgeif_dfdb_t *)arg;
183
184  LWIP_ASSERT("invalid arg", arg != NULL);
185
186  bridgeif_fdb_age_one_second(fdb);
187  sys_timeout(BRIDGEIF_AGE_TIMER_MS, bridgeif_age_tmr, arg);
188}
189
190/**
191 * @ingroup bridgeif_fdb
192 * Init our simple fdb list
193 */
194void *
195bridgeif_fdb_init(u16_t max_fdb_entries)
196{
197  bridgeif_dfdb_t *fdb;
198  size_t alloc_len_sizet = sizeof(bridgeif_dfdb_t) + (max_fdb_entries * sizeof(bridgeif_dfdb_entry_t));
199  mem_size_t alloc_len = (mem_size_t)alloc_len_sizet;
200  LWIP_ASSERT("alloc_len == alloc_len_sizet", alloc_len == alloc_len_sizet);
201  LWIP_DEBUGF(BRIDGEIF_DEBUG, ("bridgeif_fdb_init: allocating %d bytes for private FDB data\n", (int)alloc_len));
202  fdb = (bridgeif_dfdb_t *)mem_calloc(1, alloc_len);
203  if (fdb == NULL) {
204    return NULL;
205  }
206  fdb->max_fdb_entries = max_fdb_entries;
207  fdb->fdb = (bridgeif_dfdb_entry_t *)(fdb + 1);
208
209  sys_timeout(BRIDGEIF_AGE_TIMER_MS, bridgeif_age_tmr, fdb);
210
211  return fdb;
212}
213