Some quick code to use UDP-only (no TCP) with mBed. Echos received packets and sends packets when a button is pressed
raw.c
00001 /** 00002 * @file 00003 * Implementation of raw protocol PCBs for low-level handling of 00004 * different types of protocols besides (or overriding) those 00005 * already available in lwIP. 00006 * 00007 */ 00008 00009 /* 00010 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 00011 * All rights reserved. 00012 * 00013 * Redistribution and use in source and binary forms, with or without modification, 00014 * are permitted provided that the following conditions are met: 00015 * 00016 * 1. Redistributions of source code must retain the above copyright notice, 00017 * this list of conditions and the following disclaimer. 00018 * 2. Redistributions in binary form must reproduce the above copyright notice, 00019 * this list of conditions and the following disclaimer in the documentation 00020 * and/or other materials provided with the distribution. 00021 * 3. The name of the author may not be used to endorse or promote products 00022 * derived from this software without specific prior written permission. 00023 * 00024 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00025 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00026 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00027 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00028 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00029 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00030 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00031 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00032 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00033 * OF SUCH DAMAGE. 00034 * 00035 * This file is part of the lwIP TCP/IP stack. 00036 * 00037 * Author: Adam Dunkels <adam@sics.se> 00038 * 00039 */ 00040 00041 #include "lwip/opt.h" 00042 00043 #if LWIP_RAW /* don't build if not configured for use in lwipopts.h */ 00044 00045 #include "lwip/def.h" 00046 #include "lwip/memp.h" 00047 #include "lwip/inet.h" 00048 #include "lwip/ip_addr.h" 00049 #include "lwip/netif.h" 00050 #include "lwip/raw.h" 00051 #include "lwip/stats.h" 00052 #include "lwip/snmp.h" 00053 #include "arch/perf.h" 00054 00055 #include <string.h> 00056 00057 /** The list of RAW PCBs */ 00058 static struct raw_pcb *raw_pcbs; 00059 00060 /** 00061 * Determine if in incoming IP packet is covered by a RAW PCB 00062 * and if so, pass it to a user-provided receive callback function. 00063 * 00064 * Given an incoming IP datagram (as a chain of pbufs) this function 00065 * finds a corresponding RAW PCB and calls the corresponding receive 00066 * callback function. 00067 * 00068 * @param p pbuf to be demultiplexed to a RAW PCB. 00069 * @param inp network interface on which the datagram was received. 00070 * @return - 1 if the packet has been eaten by a RAW PCB receive 00071 * callback function. The caller MAY NOT not reference the 00072 * packet any longer, and MAY NOT call pbuf_free(). 00073 * @return - 0 if packet is not eaten (pbuf is still referenced by the 00074 * caller). 00075 * 00076 */ 00077 u8_t 00078 raw_input(struct pbuf *p, struct netif *inp) 00079 { 00080 struct raw_pcb *pcb, *prev; 00081 struct ip_hdr *iphdr; 00082 s16_t proto; 00083 u8_t eaten = 0; 00084 00085 LWIP_UNUSED_ARG(inp); 00086 00087 iphdr = p->payload; 00088 proto = IPH_PROTO(iphdr); 00089 00090 prev = NULL; 00091 pcb = raw_pcbs; 00092 /* loop through all raw pcbs until the packet is eaten by one */ 00093 /* this allows multiple pcbs to match against the packet by design */ 00094 while ((eaten == 0) && (pcb != NULL)) { 00095 if (pcb->protocol == proto) { 00096 #if IP_SOF_BROADCAST_RECV 00097 /* broadcast filter? */ 00098 if ((pcb->so_options & SOF_BROADCAST) || !ip_addr_isbroadcast(&(iphdr->dest), inp)) 00099 #endif /* IP_SOF_BROADCAST_RECV */ 00100 { 00101 /* receive callback function available? */ 00102 if (pcb->recv != NULL) { 00103 /* the receive callback function did not eat the packet? */ 00104 if (pcb->recv(pcb->recv_arg, pcb, p, &(iphdr->src)) != 0) { 00105 /* receive function ate the packet */ 00106 p = NULL; 00107 eaten = 1; 00108 if (prev != NULL) { 00109 /* move the pcb to the front of raw_pcbs so that is 00110 found faster next time */ 00111 prev->next = pcb->next; 00112 pcb->next = raw_pcbs; 00113 raw_pcbs = pcb; 00114 } 00115 } 00116 } 00117 /* no receive callback function was set for this raw PCB */ 00118 } 00119 /* drop the packet */ 00120 } 00121 prev = pcb; 00122 pcb = pcb->next; 00123 } 00124 return eaten; 00125 } 00126 00127 /** 00128 * Bind a RAW PCB. 00129 * 00130 * @param pcb RAW PCB to be bound with a local address ipaddr. 00131 * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to 00132 * bind to all local interfaces. 00133 * 00134 * @return lwIP error code. 00135 * - ERR_OK. Successful. No error occured. 00136 * - ERR_USE. The specified IP address is already bound to by 00137 * another RAW PCB. 00138 * 00139 * @see raw_disconnect() 00140 */ 00141 err_t 00142 raw_bind(struct raw_pcb *pcb, struct ip_addr *ipaddr) 00143 { 00144 ip_addr_set(&pcb->local_ip, ipaddr); 00145 return ERR_OK; 00146 } 00147 00148 /** 00149 * Connect an RAW PCB. This function is required by upper layers 00150 * of lwip. Using the raw api you could use raw_sendto() instead 00151 * 00152 * This will associate the RAW PCB with the remote address. 00153 * 00154 * @param pcb RAW PCB to be connected with remote address ipaddr and port. 00155 * @param ipaddr remote IP address to connect with. 00156 * 00157 * @return lwIP error code 00158 * 00159 * @see raw_disconnect() and raw_sendto() 00160 */ 00161 err_t 00162 raw_connect(struct raw_pcb *pcb, struct ip_addr *ipaddr) 00163 { 00164 ip_addr_set(&pcb->remote_ip, ipaddr); 00165 return ERR_OK; 00166 } 00167 00168 00169 /** 00170 * Set the callback function for received packets that match the 00171 * raw PCB's protocol and binding. 00172 * 00173 * The callback function MUST either 00174 * - eat the packet by calling pbuf_free() and returning non-zero. The 00175 * packet will not be passed to other raw PCBs or other protocol layers. 00176 * - not free the packet, and return zero. The packet will be matched 00177 * against further PCBs and/or forwarded to another protocol layers. 00178 * 00179 * @return non-zero if the packet was free()d, zero if the packet remains 00180 * available for others. 00181 */ 00182 void 00183 raw_recv(struct raw_pcb *pcb, 00184 u8_t (* recv)(void *arg, struct raw_pcb *upcb, struct pbuf *p, 00185 struct ip_addr *addr), 00186 void *recv_arg) 00187 { 00188 /* remember recv() callback and user data */ 00189 pcb->recv = recv; 00190 pcb->recv_arg = recv_arg; 00191 } 00192 00193 /** 00194 * Send the raw IP packet to the given address. Note that actually you cannot 00195 * modify the IP headers (this is inconsistent with the receive callback where 00196 * you actually get the IP headers), you can only specify the IP payload here. 00197 * It requires some more changes in lwIP. (there will be a raw_send() function 00198 * then.) 00199 * 00200 * @param pcb the raw pcb which to send 00201 * @param p the IP payload to send 00202 * @param ipaddr the destination address of the IP packet 00203 * 00204 */ 00205 err_t 00206 raw_sendto(struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr) 00207 { 00208 err_t err; 00209 struct netif *netif; 00210 struct ip_addr *src_ip; 00211 struct pbuf *q; /* q will be sent down the stack */ 00212 00213 LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_sendto\n")); 00214 00215 /* not enough space to add an IP header to first pbuf in given p chain? */ 00216 if (pbuf_header(p, IP_HLEN)) { 00217 /* allocate header in new pbuf */ 00218 q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM); 00219 /* new header pbuf could not be allocated? */ 00220 if (q == NULL) { 00221 LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 2, ("raw_sendto: could not allocate header\n")); 00222 return ERR_MEM; 00223 } 00224 /* chain header q in front of given pbuf p */ 00225 pbuf_chain(q, p); 00226 /* { first pbuf q points to header pbuf } */ 00227 LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p)); 00228 } else { 00229 /* first pbuf q equals given pbuf */ 00230 q = p; 00231 if(pbuf_header(q, -IP_HLEN)) { 00232 LWIP_ASSERT("Can't restore header we just removed!", 0); 00233 return ERR_MEM; 00234 } 00235 } 00236 00237 if ((netif = ip_route(ipaddr)) == NULL) { 00238 LWIP_DEBUGF(RAW_DEBUG | 1, ("raw_sendto: No route to 0x%"X32_F"\n", ipaddr->addr)); 00239 /* free any temporary header pbuf allocated by pbuf_header() */ 00240 if (q != p) { 00241 pbuf_free(q); 00242 } 00243 return ERR_RTE; 00244 } 00245 00246 #if IP_SOF_BROADCAST 00247 /* broadcast filter? */ 00248 if ( ((pcb->so_options & SOF_BROADCAST) == 0) && ip_addr_isbroadcast(ipaddr, netif) ) { 00249 LWIP_DEBUGF(RAW_DEBUG | 1, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb)); 00250 /* free any temporary header pbuf allocated by pbuf_header() */ 00251 if (q != p) { 00252 pbuf_free(q); 00253 } 00254 return ERR_VAL; 00255 } 00256 #endif /* IP_SOF_BROADCAST */ 00257 00258 if (ip_addr_isany(&pcb->local_ip)) { 00259 /* use outgoing network interface IP address as source address */ 00260 src_ip = &(netif->ip_addr); 00261 } else { 00262 /* use RAW PCB local IP address as source address */ 00263 src_ip = &(pcb->local_ip); 00264 } 00265 00266 #if LWIP_NETIF_HWADDRHINT 00267 netif->addr_hint = &(pcb->addr_hint); 00268 #endif /* LWIP_NETIF_HWADDRHINT*/ 00269 err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif); 00270 #if LWIP_NETIF_HWADDRHINT 00271 netif->addr_hint = NULL; 00272 #endif /* LWIP_NETIF_HWADDRHINT*/ 00273 00274 /* did we chain a header earlier? */ 00275 if (q != p) { 00276 /* free the header */ 00277 pbuf_free(q); 00278 } 00279 return err; 00280 } 00281 00282 /** 00283 * Send the raw IP packet to the address given by raw_connect() 00284 * 00285 * @param pcb the raw pcb which to send 00286 * @param p the IP payload to send 00287 * 00288 */ 00289 err_t 00290 raw_send(struct raw_pcb *pcb, struct pbuf *p) 00291 { 00292 return raw_sendto(pcb, p, &pcb->remote_ip); 00293 } 00294 00295 /** 00296 * Remove an RAW PCB. 00297 * 00298 * @param pcb RAW PCB to be removed. The PCB is removed from the list of 00299 * RAW PCB's and the data structure is freed from memory. 00300 * 00301 * @see raw_new() 00302 */ 00303 void 00304 raw_remove(struct raw_pcb *pcb) 00305 { 00306 struct raw_pcb *pcb2; 00307 /* pcb to be removed is first in list? */ 00308 if (raw_pcbs == pcb) { 00309 /* make list start at 2nd pcb */ 00310 raw_pcbs = raw_pcbs->next; 00311 /* pcb not 1st in list */ 00312 } else { 00313 for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) { 00314 /* find pcb in raw_pcbs list */ 00315 if (pcb2->next != NULL && pcb2->next == pcb) { 00316 /* remove pcb from list */ 00317 pcb2->next = pcb->next; 00318 } 00319 } 00320 } 00321 memp_free(MEMP_RAW_PCB, pcb); 00322 } 00323 00324 /** 00325 * Create a RAW PCB. 00326 * 00327 * @return The RAW PCB which was created. NULL if the PCB data structure 00328 * could not be allocated. 00329 * 00330 * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP) 00331 * 00332 * @see raw_remove() 00333 */ 00334 struct raw_pcb * 00335 raw_new(u8_t proto) { 00336 struct raw_pcb *pcb; 00337 00338 LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_new\n")); 00339 00340 pcb = memp_malloc(MEMP_RAW_PCB); 00341 /* could allocate RAW PCB? */ 00342 if (pcb != NULL) { 00343 /* initialize PCB to all zeroes */ 00344 memset(pcb, 0, sizeof(struct raw_pcb)); 00345 pcb->protocol = proto; 00346 pcb->ttl = RAW_TTL; 00347 pcb->next = raw_pcbs; 00348 raw_pcbs = pcb; 00349 } 00350 return pcb; 00351 } 00352 00353 #endif /* LWIP_RAW */
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