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Example_RTOS
Rtos API example
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lwip_icmp.c
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00001 /** 00002 * @file 00003 * ICMP - Internet Control Message Protocol 00004 * 00005 */ 00006 00007 /* 00008 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 00009 * All rights reserved. 00010 * 00011 * Redistribution and use in source and binary forms, with or without modification, 00012 * are permitted provided that the following conditions are met: 00013 * 00014 * 1. Redistributions of source code must retain the above copyright notice, 00015 * this list of conditions and the following disclaimer. 00016 * 2. Redistributions in binary form must reproduce the above copyright notice, 00017 * this list of conditions and the following disclaimer in the documentation 00018 * and/or other materials provided with the distribution. 00019 * 3. The name of the author may not be used to endorse or promote products 00020 * derived from this software without specific prior written permission. 00021 * 00022 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00023 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00024 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00025 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00026 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00027 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00028 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00029 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00030 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00031 * OF SUCH DAMAGE. 00032 * 00033 * This file is part of the lwIP TCP/IP stack. 00034 * 00035 * Author: Adam Dunkels <adam@sics.se> 00036 * 00037 */ 00038 00039 /* Some ICMP messages should be passed to the transport protocols. This 00040 is not implemented. */ 00041 00042 #include "lwip/opt.h" 00043 00044 #if LWIP_IPV4 && LWIP_ICMP /* don't build if not configured for use in lwipopts.h */ 00045 00046 #include "lwip/icmp.h" 00047 #include "lwip/inet_chksum.h" 00048 #include "lwip/ip.h" 00049 #include "lwip/def.h" 00050 #include "lwip/stats.h" 00051 00052 #include <string.h> 00053 00054 #ifdef LWIP_HOOK_FILENAME 00055 #include LWIP_HOOK_FILENAME 00056 #endif 00057 00058 /** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be 00059 * used to modify and send a response packet (and to 1 if this is not the case, 00060 * e.g. when link header is stripped of when receiving) */ 00061 #ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 00062 #define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1 00063 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ 00064 00065 /* The amount of data from the original packet to return in a dest-unreachable */ 00066 #define ICMP_DEST_UNREACH_DATASIZE 8 00067 00068 static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code); 00069 00070 /** 00071 * Processes ICMP input packets, called from ip_input(). 00072 * 00073 * Currently only processes icmp echo requests and sends 00074 * out the echo response. 00075 * 00076 * @param p the icmp echo request packet, p->payload pointing to the icmp header 00077 * @param inp the netif on which this packet was received 00078 */ 00079 void 00080 icmp_input(struct pbuf *p, struct netif *inp) 00081 { 00082 u8_t type; 00083 #ifdef LWIP_DEBUG 00084 u8_t code; 00085 #endif /* LWIP_DEBUG */ 00086 struct icmp_echo_hdr *iecho; 00087 const struct ip_hdr *iphdr_in; 00088 u16_t hlen; 00089 const ip4_addr_t* src; 00090 00091 ICMP_STATS_INC(icmp.recv); 00092 MIB2_STATS_INC(mib2.icmpinmsgs); 00093 00094 iphdr_in = ip4_current_header(); 00095 hlen = IPH_HL(iphdr_in) * 4; 00096 if (hlen < IP_HLEN) { 00097 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short IP header (%"S16_F" bytes) received\n", hlen)); 00098 goto lenerr; 00099 } 00100 if (p->len < sizeof(u16_t)*2) { 00101 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len)); 00102 goto lenerr; 00103 } 00104 00105 type = *((u8_t *)p->payload); 00106 #ifdef LWIP_DEBUG 00107 code = *(((u8_t *)p->payload)+1); 00108 #endif /* LWIP_DEBUG */ 00109 switch (type) { 00110 case ICMP_ER: 00111 /* This is OK, echo reply might have been parsed by a raw PCB 00112 (as obviously, an echo request has been sent, too). */ 00113 MIB2_STATS_INC(mib2.icmpinechoreps); 00114 break; 00115 case ICMP_ECHO: 00116 MIB2_STATS_INC(mib2.icmpinechos); 00117 src = ip4_current_dest_addr(); 00118 /* multicast destination address? */ 00119 if (ip4_addr_ismulticast(ip4_current_dest_addr())) { 00120 #if LWIP_MULTICAST_PING 00121 /* For multicast, use address of receiving interface as source address */ 00122 src = netif_ip4_addr(inp); 00123 #else /* LWIP_MULTICAST_PING */ 00124 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast pings\n")); 00125 goto icmperr; 00126 #endif /* LWIP_MULTICAST_PING */ 00127 } 00128 /* broadcast destination address? */ 00129 if (ip4_addr_isbroadcast(ip4_current_dest_addr(), ip_current_netif())) { 00130 #if LWIP_BROADCAST_PING 00131 /* For broadcast, use address of receiving interface as source address */ 00132 src = netif_ip4_addr(inp); 00133 #else /* LWIP_BROADCAST_PING */ 00134 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to broadcast pings\n")); 00135 goto icmperr; 00136 #endif /* LWIP_BROADCAST_PING */ 00137 } 00138 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n")); 00139 if (p->tot_len < sizeof(struct icmp_echo_hdr)) { 00140 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n")); 00141 goto lenerr; 00142 } 00143 #if CHECKSUM_CHECK_ICMP 00144 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP) { 00145 if (inet_chksum_pbuf(p) != 0) { 00146 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n")); 00147 pbuf_free(p); 00148 ICMP_STATS_INC(icmp.chkerr); 00149 MIB2_STATS_INC(mib2.icmpinerrors); 00150 return; 00151 } 00152 } 00153 #endif 00154 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 00155 if (pbuf_header(p, (s16_t)(hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) { 00156 /* p is not big enough to contain link headers 00157 * allocate a new one and copy p into it 00158 */ 00159 struct pbuf *r; 00160 /* allocate new packet buffer with space for link headers */ 00161 r = pbuf_alloc(PBUF_LINK, p->tot_len + hlen, PBUF_RAM); 00162 if (r == NULL) { 00163 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n")); 00164 goto icmperr; 00165 } 00166 if (r->len < hlen + sizeof(struct icmp_echo_hdr)) { 00167 LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("first pbuf cannot hold the ICMP header")); 00168 pbuf_free(r); 00169 goto icmperr; 00170 } 00171 /* copy the ip header */ 00172 MEMCPY(r->payload, iphdr_in, hlen); 00173 /* switch r->payload back to icmp header (cannot fail) */ 00174 if (pbuf_header(r, (s16_t)-hlen)) { 00175 LWIP_ASSERT("icmp_input: moving r->payload to icmp header failed\n", 0); 00176 pbuf_free(r); 00177 goto icmperr; 00178 } 00179 /* copy the rest of the packet without ip header */ 00180 if (pbuf_copy(r, p) != ERR_OK) { 00181 LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("icmp_input: copying to new pbuf failed")); 00182 pbuf_free(r); 00183 goto icmperr; 00184 } 00185 /* free the original p */ 00186 pbuf_free(p); 00187 /* we now have an identical copy of p that has room for link headers */ 00188 p = r; 00189 } else { 00190 /* restore p->payload to point to icmp header (cannot fail) */ 00191 if (pbuf_header(p, -(s16_t)(hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) { 00192 LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0); 00193 goto icmperr; 00194 } 00195 } 00196 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ 00197 /* At this point, all checks are OK. */ 00198 /* We generate an answer by switching the dest and src ip addresses, 00199 * setting the icmp type to ECHO_RESPONSE and updating the checksum. */ 00200 iecho = (struct icmp_echo_hdr *)p->payload; 00201 if (pbuf_header(p, (s16_t)hlen)) { 00202 LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Can't move over header in packet")); 00203 } else { 00204 err_t ret; 00205 struct ip_hdr *iphdr = (struct ip_hdr*)p->payload; 00206 ip4_addr_copy(iphdr->src, *src); 00207 ip4_addr_copy(iphdr->dest, *ip4_current_src_addr()); 00208 ICMPH_TYPE_SET(iecho, ICMP_ER); 00209 #if CHECKSUM_GEN_ICMP 00210 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP) { 00211 /* adjust the checksum */ 00212 if (iecho->chksum > PP_HTONS(0xffffU - (ICMP_ECHO << 8))) { 00213 iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1; 00214 } else { 00215 iecho->chksum += PP_HTONS(ICMP_ECHO << 8); 00216 } 00217 } 00218 #if LWIP_CHECKSUM_CTRL_PER_NETIF 00219 else { 00220 iecho->chksum = 0; 00221 } 00222 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */ 00223 #else /* CHECKSUM_GEN_ICMP */ 00224 iecho->chksum = 0; 00225 #endif /* CHECKSUM_GEN_ICMP */ 00226 00227 /* Set the correct TTL and recalculate the header checksum. */ 00228 IPH_TTL_SET(iphdr, ICMP_TTL); 00229 IPH_CHKSUM_SET(iphdr, 0); 00230 #if CHECKSUM_GEN_IP 00231 IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_IP) { 00232 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, hlen)); 00233 } 00234 #endif /* CHECKSUM_GEN_IP */ 00235 00236 ICMP_STATS_INC(icmp.xmit); 00237 /* increase number of messages attempted to send */ 00238 MIB2_STATS_INC(mib2.icmpoutmsgs); 00239 /* increase number of echo replies attempted to send */ 00240 MIB2_STATS_INC(mib2.icmpoutechoreps); 00241 00242 /* send an ICMP packet */ 00243 ret = ip4_output_if(p, src, LWIP_IP_HDRINCL, 00244 ICMP_TTL, 0, IP_PROTO_ICMP, inp); 00245 if (ret != ERR_OK) { 00246 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %s\n", lwip_strerr(ret))); 00247 } 00248 } 00249 break; 00250 default: 00251 if (type == ICMP_DUR) { 00252 MIB2_STATS_INC(mib2.icmpindestunreachs); 00253 } else if (type == ICMP_TE) { 00254 MIB2_STATS_INC(mib2.icmpintimeexcds); 00255 } else if (type == ICMP_PP) { 00256 MIB2_STATS_INC(mib2.icmpinparmprobs); 00257 } else if (type == ICMP_SQ) { 00258 MIB2_STATS_INC(mib2.icmpinsrcquenchs); 00259 } else if (type == ICMP_RD) { 00260 MIB2_STATS_INC(mib2.icmpinredirects); 00261 } else if (type == ICMP_TS) { 00262 MIB2_STATS_INC(mib2.icmpintimestamps); 00263 } else if (type == ICMP_TSR) { 00264 MIB2_STATS_INC(mib2.icmpintimestampreps); 00265 } else if (type == ICMP_AM) { 00266 MIB2_STATS_INC(mib2.icmpinaddrmasks); 00267 } else if (type == ICMP_AMR) { 00268 MIB2_STATS_INC(mib2.icmpinaddrmaskreps); 00269 } 00270 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n", 00271 (s16_t)type, (s16_t)code)); 00272 ICMP_STATS_INC(icmp.proterr); 00273 ICMP_STATS_INC(icmp.drop); 00274 } 00275 pbuf_free(p); 00276 return; 00277 lenerr: 00278 pbuf_free(p); 00279 ICMP_STATS_INC(icmp.lenerr); 00280 MIB2_STATS_INC(mib2.icmpinerrors); 00281 return; 00282 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN || !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING 00283 icmperr: 00284 pbuf_free(p); 00285 ICMP_STATS_INC(icmp.err); 00286 MIB2_STATS_INC(mib2.icmpinerrors); 00287 return; 00288 #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN || !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */ 00289 } 00290 00291 /** 00292 * Send an icmp 'destination unreachable' packet, called from ip_input() if 00293 * the transport layer protocol is unknown and from udp_input() if the local 00294 * port is not bound. 00295 * 00296 * @param p the input packet for which the 'unreachable' should be sent, 00297 * p->payload pointing to the IP header 00298 * @param t type of the 'unreachable' packet 00299 */ 00300 void 00301 icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t) 00302 { 00303 MIB2_STATS_INC(mib2.icmpoutdestunreachs); 00304 icmp_send_response(p, ICMP_DUR, t); 00305 } 00306 00307 #if IP_FORWARD || IP_REASSEMBLY 00308 /** 00309 * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0. 00310 * 00311 * @param p the input packet for which the 'time exceeded' should be sent, 00312 * p->payload pointing to the IP header 00313 * @param t type of the 'time exceeded' packet 00314 */ 00315 void 00316 icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t) 00317 { 00318 MIB2_STATS_INC(mib2.icmpouttimeexcds); 00319 icmp_send_response(p, ICMP_TE, t); 00320 } 00321 00322 #endif /* IP_FORWARD || IP_REASSEMBLY */ 00323 00324 /** 00325 * Send an icmp packet in response to an incoming packet. 00326 * 00327 * @param p the input packet for which the 'unreachable' should be sent, 00328 * p->payload pointing to the IP header 00329 * @param type Type of the ICMP header 00330 * @param code Code of the ICMP header 00331 */ 00332 static void 00333 icmp_send_response(struct pbuf *p, u8_t type, u8_t code) 00334 { 00335 struct pbuf *q; 00336 struct ip_hdr *iphdr; 00337 /* we can use the echo header here */ 00338 struct icmp_echo_hdr *icmphdr; 00339 ip4_addr_t iphdr_src; 00340 struct netif *netif; 00341 00342 /* increase number of messages attempted to send */ 00343 MIB2_STATS_INC(mib2.icmpoutmsgs); 00344 00345 /* ICMP header + IP header + 8 bytes of data */ 00346 q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE, 00347 PBUF_RAM); 00348 if (q == NULL) { 00349 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n")); 00350 MIB2_STATS_INC(mib2.icmpouterrors); 00351 return; 00352 } 00353 LWIP_ASSERT("check that first pbuf can hold icmp message", 00354 (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE))); 00355 00356 iphdr = (struct ip_hdr *)p->payload; 00357 LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from ")); 00358 ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->src); 00359 LWIP_DEBUGF(ICMP_DEBUG, (" to ")); 00360 ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->dest); 00361 LWIP_DEBUGF(ICMP_DEBUG, ("\n")); 00362 00363 icmphdr = (struct icmp_echo_hdr *)q->payload; 00364 icmphdr->type = type; 00365 icmphdr->code = code; 00366 icmphdr->id = 0; 00367 icmphdr->seqno = 0; 00368 00369 /* copy fields from original packet */ 00370 SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload, 00371 IP_HLEN + ICMP_DEST_UNREACH_DATASIZE); 00372 00373 ip4_addr_copy(iphdr_src, iphdr->src); 00374 #ifdef LWIP_HOOK_IP4_ROUTE_SRC 00375 { 00376 ip4_addr_t iphdr_dst; 00377 ip4_addr_copy(iphdr_dst, iphdr->dest); 00378 netif = ip4_route_src(&iphdr_src, &iphdr_dst); 00379 } 00380 #else 00381 netif = ip4_route(&iphdr_src); 00382 #endif 00383 if (netif != NULL) { 00384 /* calculate checksum */ 00385 icmphdr->chksum = 0; 00386 #if CHECKSUM_GEN_ICMP 00387 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP) { 00388 icmphdr->chksum = inet_chksum(icmphdr, q->len); 00389 } 00390 #endif 00391 ICMP_STATS_INC(icmp.xmit); 00392 ip4_output_if(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP, netif); 00393 } 00394 pbuf_free(q); 00395 } 00396 00397 #endif /* LWIP_IPV4 && LWIP_ICMP */
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