Some quick code to use UDP-only (no TCP) with mBed. Echos received packets and sends packets when a button is pressed
autoip.c
00001 /** 00002 * @file 00003 * AutoIP Automatic LinkLocal IP Configuration 00004 * 00005 */ 00006 00007 /* 00008 * 00009 * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de> 00010 * All rights reserved. 00011 * 00012 * Redistribution and use in source and binary forms, with or without modification, 00013 * are permitted provided that the following conditions are met: 00014 * 00015 * 1. Redistributions of source code must retain the above copyright notice, 00016 * this list of conditions and the following disclaimer. 00017 * 2. Redistributions in binary form must reproduce the above copyright notice, 00018 * this list of conditions and the following disclaimer in the documentation 00019 * and/or other materials provided with the distribution. 00020 * 3. The name of the author may not be used to endorse or promote products 00021 * derived from this software without specific prior written permission. 00022 * 00023 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00024 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00025 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00026 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00027 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00028 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00029 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00030 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00031 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00032 * OF SUCH DAMAGE. 00033 * 00034 * Author: Dominik Spies <kontakt@dspies.de> 00035 * 00036 * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform 00037 * with RFC 3927. 00038 * 00039 * 00040 * Please coordinate changes and requests with Dominik Spies 00041 * <kontakt@dspies.de> 00042 */ 00043 00044 /******************************************************************************* 00045 * USAGE: 00046 * 00047 * define LWIP_AUTOIP 1 in your lwipopts.h 00048 * 00049 * If you don't use tcpip.c (so, don't call, you don't call tcpip_init): 00050 * - First, call autoip_init(). 00051 * - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces, 00052 * that should be defined in autoip.h. 00053 * I recommend a value of 100. The value must divide 1000 with a remainder almost 0. 00054 * Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 .... 00055 * 00056 * Without DHCP: 00057 * - Call autoip_start() after netif_add(). 00058 * 00059 * With DHCP: 00060 * - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h. 00061 * - Configure your DHCP Client. 00062 * 00063 */ 00064 00065 #include "lwip/opt.h" 00066 00067 #if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */ 00068 00069 #include "lwip/mem.h" 00070 #include "lwip/udp.h" 00071 #include "lwip/ip_addr.h" 00072 #include "lwip/netif.h" 00073 #include "lwip/autoip.h" 00074 #include "netif/etharp.h" 00075 00076 #include <stdlib.h> 00077 #include <string.h> 00078 00079 /* 169.254.0.0 */ 00080 #define AUTOIP_NET 0xA9FE0000 00081 /* 169.254.1.0 */ 00082 #define AUTOIP_RANGE_START (AUTOIP_NET | 0x0100) 00083 /* 169.254.254.255 */ 00084 #define AUTOIP_RANGE_END (AUTOIP_NET | 0xFEFF) 00085 00086 00087 /** Pseudo random macro based on netif informations. 00088 * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */ 00089 #ifndef LWIP_AUTOIP_RAND 00090 #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \ 00091 ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \ 00092 ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \ 00093 ((u32_t)((netif->hwaddr[4]) & 0xff))) + \ 00094 (netif->autoip?netif->autoip->tried_llipaddr:0)) 00095 #endif /* LWIP_AUTOIP_RAND */ 00096 00097 /** 00098 * Macro that generates the initial IP address to be tried by AUTOIP. 00099 * If you want to override this, define it to something else in lwipopts.h. 00100 */ 00101 #ifndef LWIP_AUTOIP_CREATE_SEED_ADDR 00102 #define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \ 00103 htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \ 00104 ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8))) 00105 #endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */ 00106 00107 /* static functions */ 00108 static void autoip_handle_arp_conflict(struct netif *netif); 00109 00110 /* creates a pseudo random LL IP-Address for a network interface */ 00111 static void autoip_create_addr(struct netif *netif, struct ip_addr *ipaddr); 00112 00113 /* sends an ARP probe */ 00114 static err_t autoip_arp_probe(struct netif *netif); 00115 00116 /* sends an ARP announce */ 00117 static err_t autoip_arp_announce(struct netif *netif); 00118 00119 /* configure interface for use with current LL IP-Address */ 00120 static err_t autoip_bind(struct netif *netif); 00121 00122 /* start sending probes for llipaddr */ 00123 static void autoip_start_probing(struct netif *netif); 00124 00125 /** 00126 * Initialize this module 00127 */ 00128 void 00129 autoip_init(void) 00130 { 00131 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_init()\n")); 00132 } 00133 00134 /** 00135 * Handle a IP address conflict after an ARP conflict detection 00136 */ 00137 static void 00138 autoip_handle_arp_conflict(struct netif *netif) 00139 { 00140 /* Somehow detect if we are defending or retreating */ 00141 unsigned char defend = 1; /* tbd */ 00142 00143 if(defend) { 00144 if(netif->autoip->lastconflict > 0) { 00145 /* retreat, there was a conflicting ARP in the last 00146 * DEFEND_INTERVAL seconds 00147 */ 00148 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 00149 ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n")); 00150 00151 /* TODO: close all TCP sessions */ 00152 autoip_start(netif); 00153 } else { 00154 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 00155 ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n")); 00156 autoip_arp_announce(netif); 00157 netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND; 00158 } 00159 } else { 00160 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 00161 ("autoip_handle_arp_conflict(): we do not defend, retreating\n")); 00162 /* TODO: close all TCP sessions */ 00163 autoip_start(netif); 00164 } 00165 } 00166 00167 /** 00168 * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255 00169 * 00170 * @param netif network interface on which create the IP-Address 00171 * @param ipaddr ip address to initialize 00172 */ 00173 static void 00174 autoip_create_addr(struct netif *netif, struct ip_addr *ipaddr) 00175 { 00176 /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255 00177 * compliant to RFC 3927 Section 2.1 00178 * We have 254 * 256 possibilities */ 00179 00180 u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif)); 00181 addr += netif->autoip->tried_llipaddr; 00182 addr = AUTOIP_NET | (addr & 0xffff); 00183 /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */ 00184 00185 if (addr < AUTOIP_RANGE_START) { 00186 addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1; 00187 } 00188 if (addr > AUTOIP_RANGE_END) { 00189 addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1; 00190 } 00191 LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) && 00192 (addr <= AUTOIP_RANGE_END)); 00193 ipaddr->addr = htonl(addr); 00194 00195 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 00196 ("autoip_create_addr(): tried_llipaddr=%"U16_F", 0x%08"X32_F"\n", 00197 (u16_t)(netif->autoip->tried_llipaddr), (u32_t)(ipaddr->addr))); 00198 } 00199 00200 /** 00201 * Sends an ARP probe from a network interface 00202 * 00203 * @param netif network interface used to send the probe 00204 */ 00205 static err_t 00206 autoip_arp_probe(struct netif *netif) 00207 { 00208 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, 00209 (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, ðzero, 00210 &netif->autoip->llipaddr, ARP_REQUEST); 00211 } 00212 00213 /** 00214 * Sends an ARP announce from a network interface 00215 * 00216 * @param netif network interface used to send the announce 00217 */ 00218 static err_t 00219 autoip_arp_announce(struct netif *netif) 00220 { 00221 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, 00222 (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, ðzero, 00223 &netif->autoip->llipaddr, ARP_REQUEST); 00224 } 00225 00226 /** 00227 * Configure interface for use with current LL IP-Address 00228 * 00229 * @param netif network interface to configure with current LL IP-Address 00230 */ 00231 static err_t 00232 autoip_bind(struct netif *netif) 00233 { 00234 struct autoip *autoip = netif->autoip; 00235 struct ip_addr sn_mask, gw_addr; 00236 00237 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, 00238 ("autoip_bind(netif=%p) %c%c%"U16_F" 0x%08"X32_F"\n", 00239 (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num, autoip->llipaddr.addr)); 00240 00241 IP4_ADDR(&sn_mask, 255, 255, 0, 0); 00242 IP4_ADDR(&gw_addr, 0, 0, 0, 0); 00243 00244 netif_set_ipaddr(netif, &autoip->llipaddr); 00245 netif_set_netmask(netif, &sn_mask); 00246 netif_set_gw(netif, &gw_addr); 00247 00248 /* bring the interface up */ 00249 netif_set_up(netif); 00250 00251 return ERR_OK; 00252 } 00253 00254 /** 00255 * Start AutoIP client 00256 * 00257 * @param netif network interface on which start the AutoIP client 00258 */ 00259 err_t 00260 autoip_start(struct netif *netif) 00261 { 00262 struct autoip *autoip = netif->autoip; 00263 err_t result = ERR_OK; 00264 00265 if(netif_is_up(netif)) { 00266 netif_set_down(netif); 00267 } 00268 00269 /* Set IP-Address, Netmask and Gateway to 0 to make sure that 00270 * ARP Packets are formed correctly 00271 */ 00272 netif->ip_addr.addr = 0; 00273 netif->netmask.addr = 0; 00274 netif->gw.addr = 0; 00275 00276 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 00277 ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], 00278 netif->name[1], (u16_t)netif->num)); 00279 if(autoip == NULL) { 00280 /* no AutoIP client attached yet? */ 00281 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 00282 ("autoip_start(): starting new AUTOIP client\n")); 00283 autoip = mem_malloc(sizeof(struct autoip)); 00284 if(autoip == NULL) { 00285 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 00286 ("autoip_start(): could not allocate autoip\n")); 00287 return ERR_MEM; 00288 } 00289 memset( autoip, 0, sizeof(struct autoip)); 00290 /* store this AutoIP client in the netif */ 00291 netif->autoip = autoip; 00292 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip")); 00293 } else { 00294 autoip->state = AUTOIP_STATE_OFF; 00295 autoip->ttw = 0; 00296 autoip->sent_num = 0; 00297 memset(&autoip->llipaddr, 0, sizeof(struct ip_addr)); 00298 autoip->lastconflict = 0; 00299 } 00300 00301 autoip_create_addr(netif, &(autoip->llipaddr)); 00302 autoip->tried_llipaddr++; 00303 autoip_start_probing(netif); 00304 00305 return result; 00306 } 00307 00308 static void 00309 autoip_start_probing(struct netif *netif) 00310 { 00311 struct autoip *autoip = netif->autoip; 00312 00313 autoip->state = AUTOIP_STATE_PROBING; 00314 autoip->sent_num = 0; 00315 00316 /* time to wait to first probe, this is randomly 00317 * choosen out of 0 to PROBE_WAIT seconds. 00318 * compliant to RFC 3927 Section 2.2.1 00319 */ 00320 autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND)); 00321 00322 /* 00323 * if we tried more then MAX_CONFLICTS we must limit our rate for 00324 * accquiring and probing address 00325 * compliant to RFC 3927 Section 2.2.1 00326 */ 00327 if(autoip->tried_llipaddr > MAX_CONFLICTS) { 00328 autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND; 00329 } 00330 } 00331 00332 /** 00333 * Handle a possible change in the network configuration. 00334 * 00335 * If there is an AutoIP address configured, take the interface down 00336 * and begin probing with the same address. 00337 */ 00338 void 00339 autoip_network_changed(struct netif *netif) 00340 { 00341 if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) { 00342 netif_set_down(netif); 00343 autoip_start_probing(netif); 00344 } 00345 } 00346 00347 /** 00348 * Stop AutoIP client 00349 * 00350 * @param netif network interface on which stop the AutoIP client 00351 */ 00352 err_t 00353 autoip_stop(struct netif *netif) 00354 { 00355 netif->autoip->state = AUTOIP_STATE_OFF; 00356 netif_set_down(netif); 00357 return ERR_OK; 00358 } 00359 00360 /** 00361 * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds 00362 */ 00363 void 00364 autoip_tmr() 00365 { 00366 struct netif *netif = netif_list; 00367 /* loop through netif's */ 00368 while (netif != NULL) { 00369 /* only act on AutoIP configured interfaces */ 00370 if (netif->autoip != NULL) { 00371 if(netif->autoip->lastconflict > 0) { 00372 netif->autoip->lastconflict--; 00373 } 00374 00375 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 00376 ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n", 00377 (u16_t)(netif->autoip->state), netif->autoip->ttw)); 00378 00379 switch(netif->autoip->state) { 00380 case AUTOIP_STATE_PROBING: 00381 if(netif->autoip->ttw > 0) { 00382 netif->autoip->ttw--; 00383 } else { 00384 if(netif->autoip->sent_num >= PROBE_NUM) { 00385 netif->autoip->state = AUTOIP_STATE_ANNOUNCING; 00386 netif->autoip->sent_num = 0; 00387 netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND; 00388 } else { 00389 autoip_arp_probe(netif); 00390 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, 00391 ("autoip_tmr() PROBING Sent Probe\n")); 00392 netif->autoip->sent_num++; 00393 /* calculate time to wait to next probe */ 00394 netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) % 00395 ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) + 00396 PROBE_MIN * AUTOIP_TICKS_PER_SECOND); 00397 } 00398 } 00399 break; 00400 00401 case AUTOIP_STATE_ANNOUNCING: 00402 if(netif->autoip->ttw > 0) { 00403 netif->autoip->ttw--; 00404 } else { 00405 if(netif->autoip->sent_num == 0) { 00406 /* We are here the first time, so we waited ANNOUNCE_WAIT seconds 00407 * Now we can bind to an IP address and use it. 00408 * 00409 * autoip_bind calls netif_set_up. This triggers a gratuitous ARP 00410 * which counts as an announcement. 00411 */ 00412 autoip_bind(netif); 00413 } else { 00414 autoip_arp_announce(netif); 00415 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, 00416 ("autoip_tmr() ANNOUNCING Sent Announce\n")); 00417 } 00418 netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND; 00419 netif->autoip->sent_num++; 00420 00421 if(netif->autoip->sent_num >= ANNOUNCE_NUM) { 00422 netif->autoip->state = AUTOIP_STATE_BOUND; 00423 netif->autoip->sent_num = 0; 00424 netif->autoip->ttw = 0; 00425 } 00426 } 00427 break; 00428 } 00429 } 00430 /* proceed to next network interface */ 00431 netif = netif->next; 00432 } 00433 } 00434 00435 /** 00436 * Handles every incoming ARP Packet, called by etharp_arp_input. 00437 * 00438 * @param netif network interface to use for autoip processing 00439 * @param hdr Incoming ARP packet 00440 */ 00441 void 00442 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr) 00443 { 00444 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_arp_reply()\n")); 00445 if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) { 00446 /* when ip.src == llipaddr && hw.src != netif->hwaddr 00447 * 00448 * when probing ip.dst == llipaddr && hw.src != netif->hwaddr 00449 * we have a conflict and must solve it 00450 */ 00451 struct ip_addr sipaddr, dipaddr; 00452 struct eth_addr netifaddr; 00453 netifaddr.addr[0] = netif->hwaddr[0]; 00454 netifaddr.addr[1] = netif->hwaddr[1]; 00455 netifaddr.addr[2] = netif->hwaddr[2]; 00456 netifaddr.addr[3] = netif->hwaddr[3]; 00457 netifaddr.addr[4] = netif->hwaddr[4]; 00458 netifaddr.addr[5] = netif->hwaddr[5]; 00459 00460 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without 00461 * structure packing (not using structure copy which breaks strict-aliasing rules). 00462 */ 00463 SMEMCPY(&sipaddr, &hdr->sipaddr, sizeof(sipaddr)); 00464 SMEMCPY(&dipaddr, &hdr->dipaddr, sizeof(dipaddr)); 00465 00466 if ((netif->autoip->state == AUTOIP_STATE_PROBING) || 00467 ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) && 00468 (netif->autoip->sent_num == 0))) { 00469 /* RFC 3927 Section 2.2.1: 00470 * from beginning to after ANNOUNCE_WAIT 00471 * seconds we have a conflict if 00472 * ip.src == llipaddr OR 00473 * ip.dst == llipaddr && hw.src != own hwaddr 00474 */ 00475 if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) || 00476 (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) && 00477 !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) { 00478 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 00479 ("autoip_arp_reply(): Probe Conflict detected\n")); 00480 autoip_start(netif); 00481 } 00482 } else { 00483 /* RFC 3927 Section 2.5: 00484 * in any state we have a conflict if 00485 * ip.src == llipaddr && hw.src != own hwaddr 00486 */ 00487 if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) && 00488 !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) { 00489 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 00490 ("autoip_arp_reply(): Conflicting ARP-Packet detected\n")); 00491 autoip_handle_arp_conflict(netif); 00492 } 00493 } 00494 } 00495 } 00496 00497 #endif /* LWIP_AUTOIP */
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