Dirk-Willem van Gulik (NXP/mbed)
Bonjour/Zerconf library
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udp.c
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00001 /** 00002 * @file 00003 * User Datagram Protocol module 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 00040 /* udp.c 00041 * 00042 * The code for the User Datagram Protocol UDP & UDPLite (RFC 3828). 00043 * 00044 */ 00045 00046 /* @todo Check the use of '(struct udp_pcb).chksum_len_rx'! 00047 */ 00048 00049 #include "lwip/opt.h" 00050 00051 #if LWIP_UDP /* don't build if not configured for use in lwipopts.h */ 00052 00053 #include "lwip/udp.h" 00054 #include "lwip/def.h" 00055 #include "lwip/memp.h" 00056 #include "lwip/inet_chksum.h" 00057 #include "lwip/ip_addr.h" 00058 #include "lwip/netif.h" 00059 #include "lwip/icmp.h" 00060 #include "lwip/stats.h" 00061 #include "lwip/snmp.h" 00062 #include "arch/perf.h" 00063 #include "lwip/dhcp.h " 00064 00065 #include <string.h> 00066 00067 /* The list of UDP PCBs */ 00068 /* exported in udp.h (was static) */ 00069 struct udp_pcb *udp_pcbs; 00070 00071 /** 00072 * Process an incoming UDP datagram. 00073 * 00074 * Given an incoming UDP datagram (as a chain of pbufs) this function 00075 * finds a corresponding UDP PCB and hands over the pbuf to the pcbs 00076 * recv function. If no pcb is found or the datagram is incorrect, the 00077 * pbuf is freed. 00078 * 00079 * @param p pbuf to be demultiplexed to a UDP PCB. 00080 * @param inp network interface on which the datagram was received. 00081 * 00082 */ 00083 void 00084 udp_input(struct pbuf *p, struct netif *inp) 00085 { 00086 struct udp_hdr *udphdr; 00087 struct udp_pcb *pcb, *prev; 00088 struct udp_pcb *uncon_pcb; 00089 struct ip_hdr *iphdr; 00090 u16_t src, dest; 00091 u8_t local_match; 00092 u8_t broadcast; 00093 00094 PERF_START; 00095 00096 UDP_STATS_INC(udp.recv); 00097 00098 iphdr = (struct ip_hdr *)p->payload; 00099 00100 /* Check minimum length (IP header + UDP header) 00101 * and move payload pointer to UDP header */ 00102 if (p->tot_len < (IPH_HL(iphdr) * 4 + UDP_HLEN) || pbuf_header(p, -(s16_t)(IPH_HL(iphdr) * 4))) { 00103 /* drop short packets */ 00104 LWIP_DEBUGF(UDP_DEBUG, 00105 ("udp_input: short UDP datagram (%"U16_F" bytes) discarded\n", p->tot_len)); 00106 UDP_STATS_INC(udp.lenerr); 00107 UDP_STATS_INC(udp.drop); 00108 snmp_inc_udpinerrors(); 00109 pbuf_free(p); 00110 goto end; 00111 } 00112 00113 udphdr = (struct udp_hdr *)p->payload; 00114 00115 /* is broadcast packet ? */ 00116 broadcast = ip_addr_isbroadcast(&(iphdr->dest), inp); 00117 00118 LWIP_DEBUGF(UDP_DEBUG, ("udp_input: received datagram of length %"U16_F"\n", p->tot_len)); 00119 00120 /* convert src and dest ports to host byte order */ 00121 src = ntohs(udphdr->src); 00122 dest = ntohs(udphdr->dest); 00123 00124 udp_debug_print(udphdr); 00125 00126 /* print the UDP source and destination */ 00127 LWIP_DEBUGF(UDP_DEBUG, 00128 ("udp (%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F") <-- " 00129 "(%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F")\n", 00130 ip4_addr1_16(&iphdr->dest), ip4_addr2_16(&iphdr->dest), 00131 ip4_addr3_16(&iphdr->dest), ip4_addr4_16(&iphdr->dest), ntohs(udphdr->dest), 00132 ip4_addr1_16(&iphdr->src), ip4_addr2_16(&iphdr->src), 00133 ip4_addr3_16(&iphdr->src), ip4_addr4_16(&iphdr->src), ntohs(udphdr->src))); 00134 00135 #if LWIP_DHCP 00136 pcb = NULL; 00137 /* when LWIP_DHCP is active, packets to DHCP_CLIENT_PORT may only be processed by 00138 the dhcp module, no other UDP pcb may use the local UDP port DHCP_CLIENT_PORT */ 00139 if (dest == DHCP_CLIENT_PORT) { 00140 /* all packets for DHCP_CLIENT_PORT not coming from DHCP_SERVER_PORT are dropped! */ 00141 if (src == DHCP_SERVER_PORT) { 00142 if ((inp->dhcp != NULL) && (inp->dhcp->pcb != NULL)) { 00143 /* accept the packe if 00144 (- broadcast or directed to us) -> DHCP is link-layer-addressed, local ip is always ANY! 00145 - inp->dhcp->pcb->remote == ANY or iphdr->src */ 00146 if ((ip_addr_isany(&inp->dhcp->pcb->remote_ip) || 00147 ip_addr_cmp(&(inp->dhcp->pcb->remote_ip), &(iphdr->src)))) { 00148 pcb = inp->dhcp->pcb; 00149 } 00150 } 00151 } 00152 } else 00153 #endif /* LWIP_DHCP */ 00154 { 00155 prev = NULL; 00156 local_match = 0; 00157 uncon_pcb = NULL; 00158 /* Iterate through the UDP pcb list for a matching pcb. 00159 * 'Perfect match' pcbs (connected to the remote port & ip address) are 00160 * preferred. If no perfect match is found, the first unconnected pcb that 00161 * matches the local port and ip address gets the datagram. */ 00162 for (pcb = udp_pcbs; pcb != NULL; pcb = pcb->next) { 00163 local_match = 0; 00164 /* print the PCB local and remote address */ 00165 LWIP_DEBUGF(UDP_DEBUG, 00166 ("pcb (%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F") --- " 00167 "(%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F")\n", 00168 ip4_addr1_16(&pcb->local_ip), ip4_addr2_16(&pcb->local_ip), 00169 ip4_addr3_16(&pcb->local_ip), ip4_addr4_16(&pcb->local_ip), pcb->local_port, 00170 ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip), 00171 ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip), pcb->remote_port)); 00172 00173 /* compare PCB local addr+port to UDP destination addr+port */ 00174 if ((pcb->local_port == dest) && 00175 ((!broadcast && ip_addr_isany(&pcb->local_ip)) || 00176 ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest)) || 00177 #if LWIP_IGMP 00178 ip_addr_ismulticast(&(iphdr->dest)) || 00179 #endif /* LWIP_IGMP */ 00180 #if IP_SOF_BROADCAST_RECV 00181 (broadcast && (pcb->so_options & SOF_BROADCAST)))) { 00182 #else /* IP_SOF_BROADCAST_RECV */ 00183 (broadcast))) { 00184 #endif /* IP_SOF_BROADCAST_RECV */ 00185 local_match = 1; 00186 if ((uncon_pcb == NULL) && 00187 ((pcb->flags & UDP_FLAGS_CONNECTED) == 0)) { 00188 /* the first unconnected matching PCB */ 00189 uncon_pcb = pcb; 00190 } 00191 } 00192 /* compare PCB remote addr+port to UDP source addr+port */ 00193 if ((local_match != 0) && 00194 (pcb->remote_port == src) && 00195 (ip_addr_isany(&pcb->remote_ip) || 00196 ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)))) { 00197 /* the first fully matching PCB */ 00198 if (prev != NULL) { 00199 /* move the pcb to the front of udp_pcbs so that is 00200 found faster next time */ 00201 prev->next = pcb->next; 00202 pcb->next = udp_pcbs; 00203 udp_pcbs = pcb; 00204 } else { 00205 UDP_STATS_INC(udp.cachehit); 00206 } 00207 break; 00208 } 00209 prev = pcb; 00210 } 00211 /* no fully matching pcb found? then look for an unconnected pcb */ 00212 if (pcb == NULL) { 00213 pcb = uncon_pcb; 00214 } 00215 } 00216 00217 /* Check checksum if this is a match or if it was directed at us. */ 00218 if (pcb != NULL || ip_addr_cmp(&inp->ip_addr, &iphdr->dest)) { 00219 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: calculating checksum\n")); 00220 #if LWIP_UDPLITE 00221 if (IPH_PROTO(iphdr) == IP_PROTO_UDPLITE) { 00222 /* Do the UDP Lite checksum */ 00223 #if CHECKSUM_CHECK_UDP 00224 u16_t chklen = ntohs(udphdr->len); 00225 if (chklen < sizeof(struct udp_hdr)) { 00226 if (chklen == 0) { 00227 /* For UDP-Lite, checksum length of 0 means checksum 00228 over the complete packet (See RFC 3828 chap. 3.1) */ 00229 chklen = p->tot_len; 00230 } else { 00231 /* At least the UDP-Lite header must be covered by the 00232 checksum! (Again, see RFC 3828 chap. 3.1) */ 00233 UDP_STATS_INC(udp.chkerr); 00234 UDP_STATS_INC(udp.drop); 00235 snmp_inc_udpinerrors(); 00236 pbuf_free(p); 00237 goto end; 00238 } 00239 } 00240 if (inet_chksum_pseudo_partial(p, &iphdr->src, &iphdr->dest, 00241 IP_PROTO_UDPLITE, p->tot_len, chklen) != 0) { 00242 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, 00243 ("udp_input: UDP Lite datagram discarded due to failing checksum\n")); 00244 UDP_STATS_INC(udp.chkerr); 00245 UDP_STATS_INC(udp.drop); 00246 snmp_inc_udpinerrors(); 00247 pbuf_free(p); 00248 goto end; 00249 } 00250 #endif /* CHECKSUM_CHECK_UDP */ 00251 } else 00252 #endif /* LWIP_UDPLITE */ 00253 { 00254 #if CHECKSUM_CHECK_UDP 00255 if (udphdr->chksum != 0) { 00256 if (inet_chksum_pseudo(p, &iphdr->src, &iphdr->dest, 00257 IP_PROTO_UDP, p->tot_len) != 0) { 00258 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, 00259 ("udp_input: UDP datagram discarded due to failing checksum\n")); 00260 UDP_STATS_INC(udp.chkerr); 00261 UDP_STATS_INC(udp.drop); 00262 snmp_inc_udpinerrors(); 00263 pbuf_free(p); 00264 goto end; 00265 } 00266 } 00267 #endif /* CHECKSUM_CHECK_UDP */ 00268 } 00269 if(pbuf_header(p, -UDP_HLEN)) { 00270 /* Can we cope with this failing? Just assert for now */ 00271 LWIP_ASSERT("pbuf_header failed\n", 0); 00272 UDP_STATS_INC(udp.drop); 00273 snmp_inc_udpinerrors(); 00274 pbuf_free(p); 00275 goto end; 00276 } 00277 if (pcb != NULL) { 00278 snmp_inc_udpindatagrams(); 00279 /* callback */ 00280 if (pcb->recv != NULL) { 00281 /* now the recv function is responsible for freeing p */ 00282 pcb->recv(pcb->recv_arg, pcb, p, &iphdr->src, src); 00283 } else { 00284 /* no recv function registered? then we have to free the pbuf! */ 00285 pbuf_free(p); 00286 goto end; 00287 } 00288 } else { 00289 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: not for us.\n")); 00290 00291 #if LWIP_ICMP 00292 /* No match was found, send ICMP destination port unreachable unless 00293 destination address was broadcast/multicast. */ 00294 if (!broadcast && 00295 !ip_addr_ismulticast(&iphdr->dest)) { 00296 /* move payload pointer back to ip header */ 00297 pbuf_header(p, (IPH_HL(iphdr) * 4) + UDP_HLEN); 00298 LWIP_ASSERT("p->payload == iphdr", (p->payload == iphdr)); 00299 icmp_dest_unreach(p, ICMP_DUR_PORT); 00300 } 00301 #endif /* LWIP_ICMP */ 00302 UDP_STATS_INC(udp.proterr); 00303 UDP_STATS_INC(udp.drop); 00304 snmp_inc_udpnoports(); 00305 pbuf_free(p); 00306 } 00307 } else { 00308 pbuf_free(p); 00309 } 00310 end: 00311 PERF_STOP("udp_input"); 00312 } 00313 00314 /** 00315 * Send data using UDP. 00316 * 00317 * @param pcb UDP PCB used to send the data. 00318 * @param p chain of pbuf's to be sent. 00319 * 00320 * The datagram will be sent to the current remote_ip & remote_port 00321 * stored in pcb. If the pcb is not bound to a port, it will 00322 * automatically be bound to a random port. 00323 * 00324 * @return lwIP error code. 00325 * - ERR_OK. Successful. No error occured. 00326 * - ERR_MEM. Out of memory. 00327 * - ERR_RTE. Could not find route to destination address. 00328 * - More errors could be returned by lower protocol layers. 00329 * 00330 * @see udp_disconnect() udp_sendto() 00331 */ 00332 err_t 00333 udp_send(struct udp_pcb *pcb, struct pbuf *p) 00334 { 00335 /* send to the packet using remote ip and port stored in the pcb */ 00336 return udp_sendto(pcb, p, &pcb->remote_ip, pcb->remote_port); 00337 } 00338 00339 /** 00340 * Send data to a specified address using UDP. 00341 * 00342 * @param pcb UDP PCB used to send the data. 00343 * @param p chain of pbuf's to be sent. 00344 * @param dst_ip Destination IP address. 00345 * @param dst_port Destination UDP port. 00346 * 00347 * dst_ip & dst_port are expected to be in the same byte order as in the pcb. 00348 * 00349 * If the PCB already has a remote address association, it will 00350 * be restored after the data is sent. 00351 * 00352 * @return lwIP error code (@see udp_send for possible error codes) 00353 * 00354 * @see udp_disconnect() udp_send() 00355 */ 00356 err_t 00357 udp_sendto(struct udp_pcb *pcb, struct pbuf *p, 00358 ip_addr_t *dst_ip, u16_t dst_port) 00359 { 00360 struct netif *netif; 00361 00362 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send\n")); 00363 00364 /* find the outgoing network interface for this packet */ 00365 #if LWIP_IGMP 00366 netif = ip_route((ip_addr_ismulticast(dst_ip))?(&(pcb->multicast_ip)):(dst_ip)); 00367 #else 00368 netif = ip_route(dst_ip); 00369 #endif /* LWIP_IGMP */ 00370 00371 /* no outgoing network interface could be found? */ 00372 if (netif == NULL) { 00373 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 00374 ip4_addr1_16(dst_ip), ip4_addr2_16(dst_ip), ip4_addr3_16(dst_ip), ip4_addr4_16(dst_ip))); 00375 UDP_STATS_INC(udp.rterr); 00376 return ERR_RTE; 00377 } 00378 return udp_sendto_if(pcb, p, dst_ip, dst_port, netif); 00379 } 00380 00381 /** 00382 * Send data to a specified address using UDP. 00383 * The netif used for sending can be specified. 00384 * 00385 * This function exists mainly for DHCP, to be able to send UDP packets 00386 * on a netif that is still down. 00387 * 00388 * @param pcb UDP PCB used to send the data. 00389 * @param p chain of pbuf's to be sent. 00390 * @param dst_ip Destination IP address. 00391 * @param dst_port Destination UDP port. 00392 * @param netif the netif used for sending. 00393 * 00394 * dst_ip & dst_port are expected to be in the same byte order as in the pcb. 00395 * 00396 * @return lwIP error code (@see udp_send for possible error codes) 00397 * 00398 * @see udp_disconnect() udp_send() 00399 */ 00400 err_t 00401 udp_sendto_if(struct udp_pcb *pcb, struct pbuf *p, 00402 ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif) 00403 { 00404 struct udp_hdr *udphdr; 00405 ip_addr_t *src_ip; 00406 err_t err; 00407 struct pbuf *q; /* q will be sent down the stack */ 00408 00409 #if IP_SOF_BROADCAST 00410 /* broadcast filter? */ 00411 if ( ((pcb->so_options & SOF_BROADCAST) == 0) && ip_addr_isbroadcast(dst_ip, netif) ) { 00412 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, 00413 ("udp_sendto_if: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb)); 00414 return ERR_VAL; 00415 } 00416 #endif /* IP_SOF_BROADCAST */ 00417 00418 /* if the PCB is not yet bound to a port, bind it here */ 00419 if (pcb->local_port == 0) { 00420 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send: not yet bound to a port, binding now\n")); 00421 err = udp_bind(pcb, &pcb->local_ip, pcb->local_port); 00422 if (err != ERR_OK) { 00423 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: forced port bind failed\n")); 00424 return err; 00425 } 00426 } 00427 00428 /* not enough space to add an UDP header to first pbuf in given p chain? */ 00429 if (pbuf_header(p, UDP_HLEN)) { 00430 /* allocate header in a separate new pbuf */ 00431 q = pbuf_alloc(PBUF_IP, UDP_HLEN, PBUF_RAM); 00432 /* new header pbuf could not be allocated? */ 00433 if (q == NULL) { 00434 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: could not allocate header\n")); 00435 return ERR_MEM; 00436 } 00437 /* chain header q in front of given pbuf p */ 00438 pbuf_chain(q, p); 00439 /* first pbuf q points to header pbuf */ 00440 LWIP_DEBUGF(UDP_DEBUG, 00441 ("udp_send: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p)); 00442 } else { 00443 /* adding space for header within p succeeded */ 00444 /* first pbuf q equals given pbuf */ 00445 q = p; 00446 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: added header in given pbuf %p\n", (void *)p)); 00447 } 00448 LWIP_ASSERT("check that first pbuf can hold struct udp_hdr", 00449 (q->len >= sizeof(struct udp_hdr))); 00450 /* q now represents the packet to be sent */ 00451 udphdr = (struct udp_hdr *)q->payload; 00452 udphdr->src = htons(pcb->local_port); 00453 udphdr->dest = htons(dst_port); 00454 /* in UDP, 0 checksum means 'no checksum' */ 00455 udphdr->chksum = 0x0000; 00456 00457 /* PCB local address is IP_ANY_ADDR? */ 00458 if (ip_addr_isany(&pcb->local_ip)) { 00459 /* use outgoing network interface IP address as source address */ 00460 src_ip = &(netif->ip_addr); 00461 } else { 00462 /* check if UDP PCB local IP address is correct 00463 * this could be an old address if netif->ip_addr has changed */ 00464 if (!ip_addr_cmp(&(pcb->local_ip), &(netif->ip_addr))) { 00465 /* local_ip doesn't match, drop the packet */ 00466 if (q != p) { 00467 /* free the header pbuf */ 00468 pbuf_free(q); 00469 q = NULL; 00470 /* p is still referenced by the caller, and will live on */ 00471 } 00472 return ERR_VAL; 00473 } 00474 /* use UDP PCB local IP address as source address */ 00475 src_ip = &(pcb->local_ip); 00476 } 00477 00478 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: sending datagram of length %"U16_F"\n", q->tot_len)); 00479 00480 #if LWIP_UDPLITE 00481 /* UDP Lite protocol? */ 00482 if (pcb->flags & UDP_FLAGS_UDPLITE) { 00483 u16_t chklen, chklen_hdr; 00484 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE packet length %"U16_F"\n", q->tot_len)); 00485 /* set UDP message length in UDP header */ 00486 chklen_hdr = chklen = pcb->chksum_len_tx; 00487 if ((chklen < sizeof(struct udp_hdr)) || (chklen > q->tot_len)) { 00488 if (chklen != 0) { 00489 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE pcb->chksum_len is illegal: %"U16_F"\n", chklen)); 00490 } 00491 /* For UDP-Lite, checksum length of 0 means checksum 00492 over the complete packet. (See RFC 3828 chap. 3.1) 00493 At least the UDP-Lite header must be covered by the 00494 checksum, therefore, if chksum_len has an illegal 00495 value, we generate the checksum over the complete 00496 packet to be safe. */ 00497 chklen_hdr = 0; 00498 chklen = q->tot_len; 00499 } 00500 udphdr->len = htons(chklen_hdr); 00501 /* calculate checksum */ 00502 #if CHECKSUM_GEN_UDP 00503 udphdr->chksum = inet_chksum_pseudo_partial(q, src_ip, dst_ip, 00504 IP_PROTO_UDPLITE, q->tot_len, chklen); 00505 /* chksum zero must become 0xffff, as zero means 'no checksum' */ 00506 if (udphdr->chksum == 0x0000) { 00507 udphdr->chksum = 0xffff; 00508 } 00509 #endif /* CHECKSUM_GEN_UDP */ 00510 /* output to IP */ 00511 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,IP_PROTO_UDPLITE,)\n")); 00512 #if LWIP_NETIF_HWADDRHINT 00513 netif->addr_hint = &(pcb->addr_hint); 00514 #endif /* LWIP_NETIF_HWADDRHINT*/ 00515 err = ip_output_if(q, src_ip, dst_ip, pcb->ttl, pcb->tos, IP_PROTO_UDPLITE, netif); 00516 #if LWIP_NETIF_HWADDRHINT 00517 netif->addr_hint = NULL; 00518 #endif /* LWIP_NETIF_HWADDRHINT*/ 00519 } else 00520 #endif /* LWIP_UDPLITE */ 00521 { /* UDP */ 00522 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP packet length %"U16_F"\n", q->tot_len)); 00523 udphdr->len = htons(q->tot_len); 00524 /* calculate checksum */ 00525 #if CHECKSUM_GEN_UDP 00526 if ((pcb->flags & UDP_FLAGS_NOCHKSUM) == 0) { 00527 udphdr->chksum = inet_chksum_pseudo(q, src_ip, dst_ip, IP_PROTO_UDP, q->tot_len); 00528 /* chksum zero must become 0xffff, as zero means 'no checksum' */ 00529 if (udphdr->chksum == 0x0000) { 00530 udphdr->chksum = 0xffff; 00531 } 00532 } 00533 #endif /* CHECKSUM_GEN_UDP */ 00534 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP checksum 0x%04"X16_F"\n", udphdr->chksum)); 00535 LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,IP_PROTO_UDP,)\n")); 00536 /* output to IP */ 00537 #if LWIP_NETIF_HWADDRHINT 00538 netif->addr_hint = &(pcb->addr_hint); 00539 #endif /* LWIP_NETIF_HWADDRHINT*/ 00540 err = ip_output_if(q, src_ip, dst_ip, pcb->ttl, pcb->tos, IP_PROTO_UDP, netif); 00541 #if LWIP_NETIF_HWADDRHINT 00542 netif->addr_hint = NULL; 00543 #endif /* LWIP_NETIF_HWADDRHINT*/ 00544 } 00545 /* TODO: must this be increased even if error occured? */ 00546 snmp_inc_udpoutdatagrams(); 00547 00548 /* did we chain a separate header pbuf earlier? */ 00549 if (q != p) { 00550 /* free the header pbuf */ 00551 pbuf_free(q); 00552 q = NULL; 00553 /* p is still referenced by the caller, and will live on */ 00554 } 00555 00556 UDP_STATS_INC(udp.xmit); 00557 return err; 00558 } 00559 00560 /** 00561 * Bind an UDP PCB. 00562 * 00563 * @param pcb UDP PCB to be bound with a local address ipaddr and port. 00564 * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to 00565 * bind to all local interfaces. 00566 * @param port local UDP port to bind with. Use 0 to automatically bind 00567 * to a random port between UDP_LOCAL_PORT_RANGE_START and 00568 * UDP_LOCAL_PORT_RANGE_END. 00569 * 00570 * ipaddr & port are expected to be in the same byte order as in the pcb. 00571 * 00572 * @return lwIP error code. 00573 * - ERR_OK. Successful. No error occured. 00574 * - ERR_USE. The specified ipaddr and port are already bound to by 00575 * another UDP PCB. 00576 * 00577 * @see udp_disconnect() 00578 */ 00579 err_t 00580 udp_bind(struct udp_pcb *pcb, ip_addr_t *ipaddr, u16_t port) 00581 { 00582 struct udp_pcb *ipcb; 00583 u8_t rebind; 00584 00585 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_bind(ipaddr = ")); 00586 ip_addr_debug_print(UDP_DEBUG, ipaddr); 00587 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, (", port = %"U16_F")\n", port)); 00588 00589 rebind = 0; 00590 /* Check for double bind and rebind of the same pcb */ 00591 for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) { 00592 /* is this UDP PCB already on active list? */ 00593 if (pcb == ipcb) { 00594 /* pcb may occur at most once in active list */ 00595 LWIP_ASSERT("rebind == 0", rebind == 0); 00596 /* pcb already in list, just rebind */ 00597 rebind = 1; 00598 } 00599 00600 /* this code does not allow upper layer to share a UDP port for 00601 listening to broadcast or multicast traffic (See SO_REUSEADDR and 00602 SO_REUSEPORT under *BSD). TODO: See where it fits instead, OR 00603 combine with implementation of UDP PCB flags. Leon Woestenberg. */ 00604 #ifdef LWIP_UDP_TODO 00605 /* port matches that of PCB in list? */ 00606 else { 00607 if ((ipcb->local_port == port) && 00608 /* IP address matches, or one is IP_ADDR_ANY? */ 00609 (ip_addr_isany(&(ipcb->local_ip)) || 00610 ip_addr_isany(ipaddr) || 00611 ip_addr_cmp(&(ipcb->local_ip), ipaddr))) { 00612 /* other PCB already binds to this local IP and port */ 00613 LWIP_DEBUGF(UDP_DEBUG, 00614 ("udp_bind: local port %"U16_F" already bound by another pcb\n", port)); 00615 return ERR_USE; 00616 } 00617 } 00618 #endif 00619 } 00620 00621 ip_addr_set(&pcb->local_ip, ipaddr); 00622 00623 /* no port specified? */ 00624 if (port == 0) { 00625 #ifndef UDP_LOCAL_PORT_RANGE_START 00626 #define UDP_LOCAL_PORT_RANGE_START 4096 00627 #define UDP_LOCAL_PORT_RANGE_END 0x7fff 00628 #endif 00629 port = UDP_LOCAL_PORT_RANGE_START; 00630 ipcb = udp_pcbs; 00631 while ((ipcb != NULL) && (port != UDP_LOCAL_PORT_RANGE_END)) { 00632 if (ipcb->local_port == port) { 00633 /* port is already used by another udp_pcb */ 00634 port++; 00635 /* restart scanning all udp pcbs */ 00636 ipcb = udp_pcbs; 00637 } else { 00638 /* go on with next udp pcb */ 00639 ipcb = ipcb->next; 00640 } 00641 } 00642 if (ipcb != NULL) { 00643 /* no more ports available in local range */ 00644 LWIP_DEBUGF(UDP_DEBUG, ("udp_bind: out of free UDP ports\n")); 00645 return ERR_USE; 00646 } 00647 } 00648 pcb->local_port = port; 00649 snmp_insert_udpidx_tree(pcb); 00650 /* pcb not active yet? */ 00651 if (rebind == 0) { 00652 /* place the PCB on the active list if not already there */ 00653 pcb->next = udp_pcbs; 00654 udp_pcbs = pcb; 00655 } 00656 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 00657 ("udp_bind: bound to %"U16_F".%"U16_F".%"U16_F".%"U16_F", port %"U16_F"\n", 00658 ip4_addr1_16(&pcb->local_ip), ip4_addr2_16(&pcb->local_ip), 00659 ip4_addr3_16(&pcb->local_ip), ip4_addr4_16(&pcb->local_ip), 00660 pcb->local_port)); 00661 return ERR_OK; 00662 } 00663 /** 00664 * Connect an UDP PCB. 00665 * 00666 * This will associate the UDP PCB with the remote address. 00667 * 00668 * @param pcb UDP PCB to be connected with remote address ipaddr and port. 00669 * @param ipaddr remote IP address to connect with. 00670 * @param port remote UDP port to connect with. 00671 * 00672 * @return lwIP error code 00673 * 00674 * ipaddr & port are expected to be in the same byte order as in the pcb. 00675 * 00676 * The udp pcb is bound to a random local port if not already bound. 00677 * 00678 * @see udp_disconnect() 00679 */ 00680 err_t 00681 udp_connect(struct udp_pcb *pcb, ip_addr_t *ipaddr, u16_t port) 00682 { 00683 struct udp_pcb *ipcb; 00684 00685 if (pcb->local_port == 0) { 00686 err_t err = udp_bind(pcb, &pcb->local_ip, pcb->local_port); 00687 if (err != ERR_OK) { 00688 return err; 00689 } 00690 } 00691 00692 ip_addr_set(&pcb->remote_ip, ipaddr); 00693 pcb->remote_port = port; 00694 pcb->flags |= UDP_FLAGS_CONNECTED; 00695 /** TODO: this functionality belongs in upper layers */ 00696 #ifdef LWIP_UDP_TODO 00697 /* Nail down local IP for netconn_addr()/getsockname() */ 00698 if (ip_addr_isany(&pcb->local_ip) && !ip_addr_isany(&pcb->remote_ip)) { 00699 struct netif *netif; 00700 00701 if ((netif = ip_route(&(pcb->remote_ip))) == NULL) { 00702 LWIP_DEBUGF(UDP_DEBUG, ("udp_connect: No route to 0x%lx\n", pcb->remote_ip.addr)); 00703 UDP_STATS_INC(udp.rterr); 00704 return ERR_RTE; 00705 } 00706 /** TODO: this will bind the udp pcb locally, to the interface which 00707 is used to route output packets to the remote address. However, we 00708 might want to accept incoming packets on any interface! */ 00709 pcb->local_ip = netif->ip_addr; 00710 } else if (ip_addr_isany(&pcb->remote_ip)) { 00711 pcb->local_ip.addr = 0; 00712 } 00713 #endif 00714 LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 00715 ("udp_connect: connected to %"U16_F".%"U16_F".%"U16_F".%"U16_F",port %"U16_F"\n", 00716 ip4_addr1_16(&pcb->local_ip), ip4_addr2_16(&pcb->local_ip), 00717 ip4_addr3_16(&pcb->local_ip), ip4_addr4_16(&pcb->local_ip), 00718 pcb->local_port)); 00719 00720 /* Insert UDP PCB into the list of active UDP PCBs. */ 00721 for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) { 00722 if (pcb == ipcb) { 00723 /* already on the list, just return */ 00724 return ERR_OK; 00725 } 00726 } 00727 /* PCB not yet on the list, add PCB now */ 00728 pcb->next = udp_pcbs; 00729 udp_pcbs = pcb; 00730 return ERR_OK; 00731 } 00732 00733 /** 00734 * Disconnect a UDP PCB 00735 * 00736 * @param pcb the udp pcb to disconnect. 00737 */ 00738 void 00739 udp_disconnect(struct udp_pcb *pcb) 00740 { 00741 /* reset remote address association */ 00742 ip_addr_set_any(&pcb->remote_ip); 00743 pcb->remote_port = 0; 00744 /* mark PCB as unconnected */ 00745 pcb->flags &= ~UDP_FLAGS_CONNECTED; 00746 } 00747 00748 /** 00749 * Set a receive callback for a UDP PCB 00750 * 00751 * This callback will be called when receiving a datagram for the pcb. 00752 * 00753 * @param pcb the pcb for wich to set the recv callback 00754 * @param recv function pointer of the callback function 00755 * @param recv_arg additional argument to pass to the callback function 00756 */ 00757 void 00758 udp_recv(struct udp_pcb *pcb, udp_recv_fn recv, void *recv_arg) 00759 { 00760 /* remember recv() callback and user data */ 00761 pcb->recv = recv; 00762 pcb->recv_arg = recv_arg; 00763 } 00764 00765 /** 00766 * Remove an UDP PCB. 00767 * 00768 * @param pcb UDP PCB to be removed. The PCB is removed from the list of 00769 * UDP PCB's and the data structure is freed from memory. 00770 * 00771 * @see udp_new() 00772 */ 00773 void 00774 udp_remove(struct udp_pcb *pcb) 00775 { 00776 struct udp_pcb *pcb2; 00777 00778 snmp_delete_udpidx_tree(pcb); 00779 /* pcb to be removed is first in list? */ 00780 if (udp_pcbs == pcb) { 00781 /* make list start at 2nd pcb */ 00782 udp_pcbs = udp_pcbs->next; 00783 /* pcb not 1st in list */ 00784 } else { 00785 for (pcb2 = udp_pcbs; pcb2 != NULL; pcb2 = pcb2->next) { 00786 /* find pcb in udp_pcbs list */ 00787 if (pcb2->next != NULL && pcb2->next == pcb) { 00788 /* remove pcb from list */ 00789 pcb2->next = pcb->next; 00790 } 00791 } 00792 } 00793 memp_free(MEMP_UDP_PCB, pcb); 00794 } 00795 00796 /** 00797 * Create a UDP PCB. 00798 * 00799 * @return The UDP PCB which was created. NULL if the PCB data structure 00800 * could not be allocated. 00801 * 00802 * @see udp_remove() 00803 */ 00804 struct udp_pcb * 00805 udp_new(void) 00806 { 00807 struct udp_pcb *pcb; 00808 pcb = (struct udp_pcb *)memp_malloc(MEMP_UDP_PCB); 00809 /* could allocate UDP PCB? */ 00810 if (pcb != NULL) { 00811 /* UDP Lite: by initializing to all zeroes, chksum_len is set to 0 00812 * which means checksum is generated over the whole datagram per default 00813 * (recommended as default by RFC 3828). */ 00814 /* initialize PCB to all zeroes */ 00815 memset(pcb, 0, sizeof(struct udp_pcb)); 00816 pcb->ttl = UDP_TTL; 00817 } 00818 return pcb; 00819 } 00820 00821 #if UDP_DEBUG 00822 /** 00823 * Print UDP header information for debug purposes. 00824 * 00825 * @param udphdr pointer to the udp header in memory. 00826 */ 00827 void 00828 udp_debug_print(struct udp_hdr *udphdr) 00829 { 00830 LWIP_DEBUGF(UDP_DEBUG, ("UDP header:\n")); 00831 LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n")); 00832 LWIP_DEBUGF(UDP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n", 00833 ntohs(udphdr->src), ntohs(udphdr->dest))); 00834 LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n")); 00835 LWIP_DEBUGF(UDP_DEBUG, ("| %5"U16_F" | 0x%04"X16_F" | (len, chksum)\n", 00836 ntohs(udphdr->len), ntohs(udphdr->chksum))); 00837 LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n")); 00838 } 00839 #endif /* UDP_DEBUG */ 00840 00841 #endif /* LWIP_UDP */
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