lwip_udp.c

00001 /**
00002  * @file
00003  * User Datagram Protocol module\n
00004  * The code for the User Datagram Protocol UDP & UDPLite (RFC 3828).\n
00005  * See also @ref udp_raw
00006  *
00007  * @defgroup udp_raw UDP
00008  * @ingroup callbackstyle_api
00009  * User Datagram Protocol module\n
00010  * @see @ref api
00011  */
00012 
00013 /*
00014  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00015  * All rights reserved.
00016  *
00017  * Redistribution and use in source and binary forms, with or without modification,
00018  * are permitted provided that the following conditions are met:
00019  *
00020  * 1. Redistributions of source code must retain the above copyright notice,
00021  *    this list of conditions and the following disclaimer.
00022  * 2. Redistributions in binary form must reproduce the above copyright notice,
00023  *    this list of conditions and the following disclaimer in the documentation
00024  *    and/or other materials provided with the distribution.
00025  * 3. The name of the author may not be used to endorse or promote products
00026  *    derived from this software without specific prior written permission.
00027  *
00028  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00029  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00030  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00031  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00032  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00033  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00034  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00035  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00036  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00037  * OF SUCH DAMAGE.
00038  *
00039  * This file is part of the lwIP TCP/IP stack.
00040  *
00041  * Author: Adam Dunkels <adam@sics.se>
00042  *
00043  */
00044 
00045 /* @todo Check the use of '(struct udp_pcb).chksum_len_rx'!
00046  */
00047 
00048 #include "lwip/opt.h"
00049 
00050 #if LWIP_UDP /* don't build if not configured for use in lwipopts.h */
00051 
00052 #include "lwip/udp.h"
00053 #include "lwip/def.h"
00054 #include "lwip/memp.h"
00055 #include "lwip/inet_chksum.h"
00056 #include "lwip/ip_addr.h"
00057 #include "lwip/ip6.h"
00058 #include "lwip/ip6_addr.h"
00059 #include "lwip/netif.h"
00060 #include "lwip/icmp.h"
00061 #include "lwip/icmp6.h"
00062 #include "lwip/stats.h"
00063 #include "lwip/snmp.h"
00064 #include "lwip/dhcp.h"
00065 
00066 #include <string.h>
00067 
00068 #ifndef UDP_LOCAL_PORT_RANGE_START
00069 /* From http://www.iana.org/assignments/port-numbers:
00070    "The Dynamic and/or Private Ports are those from 49152 through 65535" */
00071 #define UDP_LOCAL_PORT_RANGE_START  0xc000
00072 #define UDP_LOCAL_PORT_RANGE_END    0xffff
00073 #define UDP_ENSURE_LOCAL_PORT_RANGE(port) ((u16_t)(((port) & (u16_t)~UDP_LOCAL_PORT_RANGE_START) + UDP_LOCAL_PORT_RANGE_START))
00074 #endif
00075 
00076 /* last local UDP port */
00077 static u16_t udp_port = UDP_LOCAL_PORT_RANGE_START;
00078 
00079 /* The list of UDP PCBs */
00080 /* exported in udp.h (was static) */
00081 struct udp_pcb *udp_pcbs;
00082 
00083 /**
00084  * Initialize this module.
00085  */
00086 void
00087 udp_init(void)
00088 {
00089 #ifdef LWIP_RAND
00090   udp_port = UDP_ENSURE_LOCAL_PORT_RANGE(LWIP_RAND());
00091 #endif /* LWIP_RAND */
00092 }
00093 
00094 /**
00095  * Allocate a new local UDP port.
00096  *
00097  * @return a new (free) local UDP port number
00098  */
00099 static u16_t
00100 udp_new_port(void)
00101 {
00102   u16_t n = 0;
00103   struct udp_pcb *pcb;
00104 
00105 again:
00106   if (udp_port++ == UDP_LOCAL_PORT_RANGE_END) {
00107     udp_port = UDP_LOCAL_PORT_RANGE_START;
00108   }
00109   /* Check all PCBs. */
00110   for (pcb = udp_pcbs; pcb != NULL; pcb = pcb->next) {
00111     if (pcb->local_port == udp_port) {
00112       if (++n > (UDP_LOCAL_PORT_RANGE_END - UDP_LOCAL_PORT_RANGE_START)) {
00113         return 0;
00114       }
00115       goto again;
00116     }
00117   }
00118   return udp_port;
00119 }
00120 
00121 /** Common code to see if the current input packet matches the pcb
00122  * (current input packet is accessed via ip(4/6)_current_* macros)
00123  *
00124  * @param pcb pcb to check
00125  * @param inp network interface on which the datagram was received (only used for IPv4)
00126  * @param broadcast 1 if his is an IPv4 broadcast (global or subnet-only), 0 otherwise (only used for IPv4)
00127  * @return 1 on match, 0 otherwise
00128  */
00129 static u8_t
00130 udp_input_local_match(struct udp_pcb *pcb, struct netif *inp, u8_t broadcast)
00131 {
00132   LWIP_UNUSED_ARG(inp);       /* in IPv6 only case */
00133   LWIP_UNUSED_ARG(broadcast); /* in IPv6 only case */
00134 
00135   LWIP_ASSERT("udp_input_local_match: invalid pcb", pcb != NULL);
00136   LWIP_ASSERT("udp_input_local_match: invalid netif", inp != NULL);
00137 
00138   /* check if PCB is bound to specific netif */
00139   if ((pcb->netif_idx != NETIF_NO_INDEX) &&
00140       (pcb->netif_idx != netif_get_index(ip_data.current_input_netif))) {
00141     return 0;
00142   }
00143 
00144   /* Dual-stack: PCBs listening to any IP type also listen to any IP address */
00145   if (IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
00146 #if LWIP_IPV4 && IP_SOF_BROADCAST_RECV
00147     if ((broadcast != 0) && !ip_get_option(pcb, SOF_BROADCAST)) {
00148       return 0;
00149     }
00150 #endif /* LWIP_IPV4 && IP_SOF_BROADCAST_RECV */
00151     return 1;
00152   }
00153 
00154   /* Only need to check PCB if incoming IP version matches PCB IP version */
00155   if (IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ip_current_dest_addr())) {
00156 #if LWIP_IPV4
00157     /* Special case: IPv4 broadcast: all or broadcasts in my subnet
00158      * Note: broadcast variable can only be 1 if it is an IPv4 broadcast */
00159     if (broadcast != 0) {
00160 #if IP_SOF_BROADCAST_RECV
00161       if (ip_get_option(pcb, SOF_BROADCAST))
00162 #endif /* IP_SOF_BROADCAST_RECV */
00163       {
00164         if (ip4_addr_isany(ip_2_ip4(&pcb->local_ip)) ||
00165             ((ip4_current_dest_addr()->addr == IPADDR_BROADCAST)) ||
00166             ip4_addr_netcmp(ip_2_ip4(&pcb->local_ip), ip4_current_dest_addr(), netif_ip4_netmask(inp))) {
00167           return 1;
00168         }
00169       }
00170     } else
00171 #endif /* LWIP_IPV4 */
00172       /* Handle IPv4 and IPv6: all or exact match */
00173       if (ip_addr_isany(&pcb->local_ip) || ip_addr_cmp(&pcb->local_ip, ip_current_dest_addr())) {
00174         return 1;
00175       }
00176   }
00177 
00178   return 0;
00179 }
00180 
00181 /**
00182  * Process an incoming UDP datagram.
00183  *
00184  * Given an incoming UDP datagram (as a chain of pbufs) this function
00185  * finds a corresponding UDP PCB and hands over the pbuf to the pcbs
00186  * recv function. If no pcb is found or the datagram is incorrect, the
00187  * pbuf is freed.
00188  *
00189  * @param p pbuf to be demultiplexed to a UDP PCB (p->payload pointing to the UDP header)
00190  * @param inp network interface on which the datagram was received.
00191  *
00192  */
00193 void
00194 udp_input(struct pbuf *p, struct netif *inp)
00195 {
00196   struct udp_hdr *udphdr;
00197   struct udp_pcb *pcb, *prev;
00198   struct udp_pcb *uncon_pcb;
00199   u16_t src, dest;
00200   u8_t broadcast;
00201   u8_t for_us = 0;
00202 
00203   LWIP_UNUSED_ARG(inp);
00204 
00205   LWIP_ASSERT_CORE_LOCKED();
00206 
00207   LWIP_ASSERT("udp_input: invalid pbuf", p != NULL);
00208   LWIP_ASSERT("udp_input: invalid netif", inp != NULL);
00209 
00210   PERF_START;
00211 
00212   UDP_STATS_INC(udp.recv);
00213 
00214   /* Check minimum length (UDP header) */
00215   if (p->len < UDP_HLEN) {
00216     /* drop short packets */
00217     LWIP_DEBUGF(UDP_DEBUG,
00218                 ("udp_input: short UDP datagram (%"U16_F" bytes) discarded\n", p->tot_len));
00219     UDP_STATS_INC(udp.lenerr);
00220     UDP_STATS_INC(udp.drop);
00221     MIB2_STATS_INC(mib2.udpinerrors);
00222     pbuf_free(p);
00223     goto end;
00224   }
00225 
00226   udphdr = (struct udp_hdr *)p->payload;
00227 
00228   /* is broadcast packet ? */
00229   broadcast = ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif());
00230 
00231   LWIP_DEBUGF(UDP_DEBUG, ("udp_input: received datagram of length %"U16_F"\n", p->tot_len));
00232 
00233   /* convert src and dest ports to host byte order */
00234   src = lwip_ntohs(udphdr->src);
00235   dest = lwip_ntohs(udphdr->dest);
00236 
00237   udp_debug_print(udphdr);
00238 
00239   /* print the UDP source and destination */
00240   LWIP_DEBUGF(UDP_DEBUG, ("udp ("));
00241   ip_addr_debug_print_val(UDP_DEBUG, *ip_current_dest_addr());
00242   LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F") <-- (", lwip_ntohs(udphdr->dest)));
00243   ip_addr_debug_print_val(UDP_DEBUG, *ip_current_src_addr());
00244   LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F")\n", lwip_ntohs(udphdr->src)));
00245 
00246   pcb = NULL;
00247   prev = NULL;
00248   uncon_pcb = NULL;
00249   /* Iterate through the UDP pcb list for a matching pcb.
00250    * 'Perfect match' pcbs (connected to the remote port & ip address) are
00251    * preferred. If no perfect match is found, the first unconnected pcb that
00252    * matches the local port and ip address gets the datagram. */
00253   for (pcb = udp_pcbs; pcb != NULL; pcb = pcb->next) {
00254     /* print the PCB local and remote address */
00255     LWIP_DEBUGF(UDP_DEBUG, ("pcb ("));
00256     ip_addr_debug_print_val(UDP_DEBUG, pcb->local_ip);
00257     LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F") <-- (", pcb->local_port));
00258     ip_addr_debug_print_val(UDP_DEBUG, pcb->remote_ip);
00259     LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F")\n", pcb->remote_port));
00260 
00261     /* compare PCB local addr+port to UDP destination addr+port */
00262     if ((pcb->local_port == dest) &&
00263         (udp_input_local_match(pcb, inp, broadcast) != 0)) {
00264       if ((pcb->flags & UDP_FLAGS_CONNECTED) == 0) {
00265         if (uncon_pcb == NULL) {
00266           /* the first unconnected matching PCB */
00267           uncon_pcb = pcb;
00268 #if LWIP_IPV4
00269         } else if (broadcast && ip4_current_dest_addr()->addr == IPADDR_BROADCAST) {
00270           /* global broadcast address (only valid for IPv4; match was checked before) */
00271           if (!IP_IS_V4_VAL(uncon_pcb->local_ip) || !ip4_addr_cmp(ip_2_ip4(&uncon_pcb->local_ip), netif_ip4_addr(inp))) {
00272             /* uncon_pcb does not match the input netif, check this pcb */
00273             if (IP_IS_V4_VAL(pcb->local_ip) && ip4_addr_cmp(ip_2_ip4(&pcb->local_ip), netif_ip4_addr(inp))) {
00274               /* better match */
00275               uncon_pcb = pcb;
00276             }
00277           }
00278 #endif /* LWIP_IPV4 */
00279         }
00280 #if SO_REUSE
00281         else if (!ip_addr_isany(&pcb->local_ip)) {
00282           /* prefer specific IPs over catch-all */
00283           uncon_pcb = pcb;
00284         }
00285 #endif /* SO_REUSE */
00286       }
00287 
00288       /* compare PCB remote addr+port to UDP source addr+port */
00289       if ((pcb->remote_port == src) &&
00290           (ip_addr_isany_val(pcb->remote_ip) ||
00291            ip_addr_cmp(&pcb->remote_ip, ip_current_src_addr()))) {
00292         /* the first fully matching PCB */
00293         if (prev != NULL) {
00294           /* move the pcb to the front of udp_pcbs so that is
00295              found faster next time */
00296           prev->next = pcb->next;
00297           pcb->next = udp_pcbs;
00298           udp_pcbs = pcb;
00299         } else {
00300           UDP_STATS_INC(udp.cachehit);
00301         }
00302         break;
00303       }
00304     }
00305 
00306     prev = pcb;
00307   }
00308   /* no fully matching pcb found? then look for an unconnected pcb */
00309   if (pcb == NULL) {
00310     pcb = uncon_pcb;
00311   }
00312 
00313   /* Check checksum if this is a match or if it was directed at us. */
00314   if (pcb != NULL) {
00315     for_us = 1;
00316   } else {
00317 #if LWIP_IPV6
00318     if (ip_current_is_v6()) {
00319       for_us = netif_get_ip6_addr_match(inp, ip6_current_dest_addr()) >= 0;
00320     }
00321 #endif /* LWIP_IPV6 */
00322 #if LWIP_IPV4
00323     if (!ip_current_is_v6()) {
00324       for_us = ip4_addr_cmp(netif_ip4_addr(inp), ip4_current_dest_addr());
00325     }
00326 #endif /* LWIP_IPV4 */
00327   }
00328 
00329   if (for_us) {
00330     LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: calculating checksum\n"));
00331 #if CHECKSUM_CHECK_UDP
00332     IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_UDP) {
00333 #if LWIP_UDPLITE
00334       if (ip_current_header_proto() == IP_PROTO_UDPLITE) {
00335         /* Do the UDP Lite checksum */
00336         u16_t chklen = lwip_ntohs(udphdr->len);
00337         if (chklen < sizeof(struct udp_hdr)) {
00338           if (chklen == 0) {
00339             /* For UDP-Lite, checksum length of 0 means checksum
00340                over the complete packet (See RFC 3828 chap. 3.1) */
00341             chklen = p->tot_len;
00342           } else {
00343             /* At least the UDP-Lite header must be covered by the
00344                checksum! (Again, see RFC 3828 chap. 3.1) */
00345             goto chkerr;
00346           }
00347         }
00348         if (ip_chksum_pseudo_partial(p, IP_PROTO_UDPLITE,
00349                                      p->tot_len, chklen,
00350                                      ip_current_src_addr(), ip_current_dest_addr()) != 0) {
00351           goto chkerr;
00352         }
00353       } else
00354 #endif /* LWIP_UDPLITE */
00355       {
00356         if (udphdr->chksum != 0) {
00357           if (ip_chksum_pseudo(p, IP_PROTO_UDP, p->tot_len,
00358                                ip_current_src_addr(),
00359                                ip_current_dest_addr()) != 0) {
00360             goto chkerr;
00361           }
00362         }
00363       }
00364     }
00365 #endif /* CHECKSUM_CHECK_UDP */
00366     if (pbuf_remove_header(p, UDP_HLEN)) {
00367       /* Can we cope with this failing? Just assert for now */
00368       LWIP_ASSERT("pbuf_remove_header failed\n", 0);
00369       UDP_STATS_INC(udp.drop);
00370       MIB2_STATS_INC(mib2.udpinerrors);
00371       pbuf_free(p);
00372       goto end;
00373     }
00374 
00375     if (pcb != NULL) {
00376       MIB2_STATS_INC(mib2.udpindatagrams);
00377 #if SO_REUSE && SO_REUSE_RXTOALL
00378       if (ip_get_option(pcb, SOF_REUSEADDR) &&
00379           (broadcast || ip_addr_ismulticast(ip_current_dest_addr()))) {
00380         /* pass broadcast- or multicast packets to all multicast pcbs
00381            if SOF_REUSEADDR is set on the first match */
00382         struct udp_pcb *mpcb;
00383         for (mpcb = udp_pcbs; mpcb != NULL; mpcb = mpcb->next) {
00384           if (mpcb != pcb) {
00385             /* compare PCB local addr+port to UDP destination addr+port */
00386             if ((mpcb->local_port == dest) &&
00387                 (udp_input_local_match(mpcb, inp, broadcast) != 0)) {
00388               /* pass a copy of the packet to all local matches */
00389               if (mpcb->recv != NULL) {
00390                 struct pbuf *q;
00391                 q = pbuf_clone(PBUF_RAW, PBUF_POOL, p);
00392                 if (q != NULL) {
00393                   mpcb->recv(mpcb->recv_arg, mpcb, q, ip_current_src_addr(), src);
00394                 }
00395               }
00396             }
00397           }
00398         }
00399       }
00400 #endif /* SO_REUSE && SO_REUSE_RXTOALL */
00401       /* callback */
00402       if (pcb->recv != NULL) {
00403         /* now the recv function is responsible for freeing p */
00404         pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr(), src);
00405       } else {
00406         /* no recv function registered? then we have to free the pbuf! */
00407         pbuf_free(p);
00408         goto end;
00409       }
00410     } else {
00411       LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: not for us.\n"));
00412 
00413 #if LWIP_ICMP || LWIP_ICMP6
00414       /* No match was found, send ICMP destination port unreachable unless
00415          destination address was broadcast/multicast. */
00416       if (!broadcast && !ip_addr_ismulticast(ip_current_dest_addr())) {
00417         /* move payload pointer back to ip header */
00418         pbuf_header_force(p, (s16_t)(ip_current_header_tot_len() + UDP_HLEN));
00419         icmp_port_unreach(ip_current_is_v6(), p);
00420       }
00421 #endif /* LWIP_ICMP || LWIP_ICMP6 */
00422       UDP_STATS_INC(udp.proterr);
00423       UDP_STATS_INC(udp.drop);
00424       MIB2_STATS_INC(mib2.udpnoports);
00425       pbuf_free(p);
00426     }
00427   } else {
00428     pbuf_free(p);
00429   }
00430 end:
00431   PERF_STOP("udp_input");
00432   return;
00433 #if CHECKSUM_CHECK_UDP
00434 chkerr:
00435   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
00436               ("udp_input: UDP (or UDP Lite) datagram discarded due to failing checksum\n"));
00437   UDP_STATS_INC(udp.chkerr);
00438   UDP_STATS_INC(udp.drop);
00439   MIB2_STATS_INC(mib2.udpinerrors);
00440   pbuf_free(p);
00441   PERF_STOP("udp_input");
00442 #endif /* CHECKSUM_CHECK_UDP */
00443 }
00444 
00445 /**
00446  * @ingroup udp_raw
00447  * Sends the pbuf p using UDP. The pbuf is not deallocated.
00448  *
00449  *
00450  * @param pcb UDP PCB used to send the data.
00451  * @param p chain of pbuf's to be sent.
00452  *
00453  * The datagram will be sent to the current remote_ip & remote_port
00454  * stored in pcb. If the pcb is not bound to a port, it will
00455  * automatically be bound to a random port.
00456  *
00457  * @return lwIP error code.
00458  * - ERR_OK. Successful. No error occurred.
00459  * - ERR_MEM. Out of memory.
00460  * - ERR_RTE. Could not find route to destination address.
00461  * - ERR_VAL. No PCB or PCB is dual-stack
00462  * - More errors could be returned by lower protocol layers.
00463  *
00464  * @see udp_disconnect() udp_sendto()
00465  */
00466 err_t
00467 udp_send(struct udp_pcb *pcb, struct pbuf *p)
00468 {
00469   LWIP_ERROR("udp_send: invalid pcb", pcb != NULL, return ERR_ARG);
00470   LWIP_ERROR("udp_send: invalid pbuf", p != NULL, return ERR_ARG);
00471 
00472   if (IP_IS_ANY_TYPE_VAL(pcb->remote_ip)) {
00473     return ERR_VAL;
00474   }
00475 
00476   /* send to the packet using remote ip and port stored in the pcb */
00477   return udp_sendto(pcb, p, &pcb->remote_ip, pcb->remote_port);
00478 }
00479 
00480 #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP
00481 /** @ingroup udp_raw
00482  * Same as udp_send() but with checksum
00483  */
00484 err_t
00485 udp_send_chksum(struct udp_pcb *pcb, struct pbuf *p,
00486                 u8_t have_chksum, u16_t chksum)
00487 {
00488   LWIP_ERROR("udp_send_chksum: invalid pcb", pcb != NULL, return ERR_ARG);
00489   LWIP_ERROR("udp_send_chksum: invalid pbuf", p != NULL, return ERR_ARG);
00490 
00491   if (IP_IS_ANY_TYPE_VAL(pcb->remote_ip)) {
00492     return ERR_VAL;
00493   }
00494 
00495   /* send to the packet using remote ip and port stored in the pcb */
00496   return udp_sendto_chksum(pcb, p, &pcb->remote_ip, pcb->remote_port,
00497                            have_chksum, chksum);
00498 }
00499 #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00500 
00501 /**
00502  * @ingroup udp_raw
00503  * Send data to a specified address using UDP.
00504  *
00505  * @param pcb UDP PCB used to send the data.
00506  * @param p chain of pbuf's to be sent.
00507  * @param dst_ip Destination IP address.
00508  * @param dst_port Destination UDP port.
00509  *
00510  * dst_ip & dst_port are expected to be in the same byte order as in the pcb.
00511  *
00512  * If the PCB already has a remote address association, it will
00513  * be restored after the data is sent.
00514  *
00515  * @return lwIP error code (@see udp_send for possible error codes)
00516  *
00517  * @see udp_disconnect() udp_send()
00518  */
00519 err_t
00520 udp_sendto(struct udp_pcb *pcb, struct pbuf *p,
00521            const ip_addr_t *dst_ip, u16_t dst_port)
00522 {
00523 #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP
00524   return udp_sendto_chksum(pcb, p, dst_ip, dst_port, 0, 0);
00525 }
00526 
00527 /** @ingroup udp_raw
00528  * Same as udp_sendto(), but with checksum */
00529 err_t
00530 udp_sendto_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip,
00531                   u16_t dst_port, u8_t have_chksum, u16_t chksum)
00532 {
00533 #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00534   struct netif *netif;
00535 
00536   LWIP_ERROR("udp_sendto: invalid pcb", pcb != NULL, return ERR_ARG);
00537   LWIP_ERROR("udp_sendto: invalid pbuf", p != NULL, return ERR_ARG);
00538   LWIP_ERROR("udp_sendto: invalid dst_ip", dst_ip != NULL, return ERR_ARG);
00539 
00540   if (!IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) {
00541     return ERR_VAL;
00542   }
00543 
00544   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send\n"));
00545 
00546   if (pcb->netif_idx != NETIF_NO_INDEX) {
00547     netif = netif_get_by_index(pcb->netif_idx);
00548   } else {
00549 #if LWIP_MULTICAST_TX_OPTIONS
00550     netif = NULL;
00551     if (ip_addr_ismulticast(dst_ip)) {
00552       /* For IPv6, the interface to use for packets with a multicast destination
00553        * is specified using an interface index. The same approach may be used for
00554        * IPv4 as well, in which case it overrides the IPv4 multicast override
00555        * address below. Here we have to look up the netif by going through the
00556        * list, but by doing so we skip a route lookup. If the interface index has
00557        * gone stale, we fall through and do the regular route lookup after all. */
00558       if (pcb->mcast_ifindex != NETIF_NO_INDEX) {
00559         netif = netif_get_by_index(pcb->mcast_ifindex);
00560       }
00561 #if LWIP_IPV4
00562       else
00563 #if LWIP_IPV6
00564         if (IP_IS_V4(dst_ip))
00565 #endif /* LWIP_IPV6 */
00566         {
00567           /* IPv4 does not use source-based routing by default, so we use an
00568              administratively selected interface for multicast by default.
00569              However, this can be overridden by setting an interface address
00570              in pcb->mcast_ip4 that is used for routing. If this routing lookup
00571              fails, we try regular routing as though no override was set. */
00572           if (!ip4_addr_isany_val(pcb->mcast_ip4) &&
00573               !ip4_addr_cmp(&pcb->mcast_ip4, IP4_ADDR_BROADCAST)) {
00574             netif = ip4_route_src(ip_2_ip4(&pcb->local_ip), &pcb->mcast_ip4);
00575           }
00576         }
00577 #endif /* LWIP_IPV4 */
00578     }
00579 
00580     if (netif == NULL)
00581 #endif /* LWIP_MULTICAST_TX_OPTIONS */
00582     {
00583       /* find the outgoing network interface for this packet */
00584       netif = ip_route(&pcb->local_ip, dst_ip);
00585     }
00586   }
00587 
00588   /* no outgoing network interface could be found? */
00589   if (netif == NULL) {
00590     LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: No route to "));
00591     ip_addr_debug_print(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, dst_ip);
00592     LWIP_DEBUGF(UDP_DEBUG, ("\n"));
00593     UDP_STATS_INC(udp.rterr);
00594     return ERR_RTE;
00595   }
00596 #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP
00597   return udp_sendto_if_chksum(pcb, p, dst_ip, dst_port, netif, have_chksum, chksum);
00598 #else /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00599   return udp_sendto_if(pcb, p, dst_ip, dst_port, netif);
00600 #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00601 }
00602 
00603 /**
00604  * @ingroup udp_raw
00605  * Send data to a specified address using UDP.
00606  * The netif used for sending can be specified.
00607  *
00608  * This function exists mainly for DHCP, to be able to send UDP packets
00609  * on a netif that is still down.
00610  *
00611  * @param pcb UDP PCB used to send the data.
00612  * @param p chain of pbuf's to be sent.
00613  * @param dst_ip Destination IP address.
00614  * @param dst_port Destination UDP port.
00615  * @param netif the netif used for sending.
00616  *
00617  * dst_ip & dst_port are expected to be in the same byte order as in the pcb.
00618  *
00619  * @return lwIP error code (@see udp_send for possible error codes)
00620  *
00621  * @see udp_disconnect() udp_send()
00622  */
00623 err_t
00624 udp_sendto_if(struct udp_pcb *pcb, struct pbuf *p,
00625               const ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif)
00626 {
00627 #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP
00628   return udp_sendto_if_chksum(pcb, p, dst_ip, dst_port, netif, 0, 0);
00629 }
00630 
00631 /** Same as udp_sendto_if(), but with checksum */
00632 err_t
00633 udp_sendto_if_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip,
00634                      u16_t dst_port, struct netif *netif, u8_t have_chksum,
00635                      u16_t chksum)
00636 {
00637 #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00638   const ip_addr_t *src_ip;
00639 
00640   LWIP_ERROR("udp_sendto_if: invalid pcb", pcb != NULL, return ERR_ARG);
00641   LWIP_ERROR("udp_sendto_if: invalid pbuf", p != NULL, return ERR_ARG);
00642   LWIP_ERROR("udp_sendto_if: invalid dst_ip", dst_ip != NULL, return ERR_ARG);
00643   LWIP_ERROR("udp_sendto_if: invalid netif", netif != NULL, return ERR_ARG);
00644 
00645   if (!IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) {
00646     return ERR_VAL;
00647   }
00648 
00649   /* PCB local address is IP_ANY_ADDR or multicast? */
00650 #if LWIP_IPV6
00651   if (IP_IS_V6(dst_ip)) {
00652     if (ip6_addr_isany(ip_2_ip6(&pcb->local_ip)) ||
00653         ip6_addr_ismulticast(ip_2_ip6(&pcb->local_ip))) {
00654       src_ip = ip6_select_source_address(netif, ip_2_ip6(dst_ip));
00655       if (src_ip == NULL) {
00656         /* No suitable source address was found. */
00657         return ERR_RTE;
00658       }
00659     } else {
00660       /* use UDP PCB local IPv6 address as source address, if still valid. */
00661       if (netif_get_ip6_addr_match(netif, ip_2_ip6(&pcb->local_ip)) < 0) {
00662         /* Address isn't valid anymore. */
00663         return ERR_RTE;
00664       }
00665       src_ip = &pcb->local_ip;
00666     }
00667   }
00668 #endif /* LWIP_IPV6 */
00669 #if LWIP_IPV4 && LWIP_IPV6
00670   else
00671 #endif /* LWIP_IPV4 && LWIP_IPV6 */
00672 #if LWIP_IPV4
00673     if (ip4_addr_isany(ip_2_ip4(&pcb->local_ip)) ||
00674         ip4_addr_ismulticast(ip_2_ip4(&pcb->local_ip))) {
00675       /* if the local_ip is any or multicast
00676        * use the outgoing network interface IP address as source address */
00677       src_ip = netif_ip_addr4(netif);
00678     } else {
00679       /* check if UDP PCB local IP address is correct
00680        * this could be an old address if netif->ip_addr has changed */
00681       if (!ip4_addr_cmp(ip_2_ip4(&(pcb->local_ip)), netif_ip4_addr(netif))) {
00682         /* local_ip doesn't match, drop the packet */
00683         return ERR_RTE;
00684       }
00685       /* use UDP PCB local IP address as source address */
00686       src_ip = &pcb->local_ip;
00687     }
00688 #endif /* LWIP_IPV4 */
00689 #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP
00690   return udp_sendto_if_src_chksum(pcb, p, dst_ip, dst_port, netif, have_chksum, chksum, src_ip);
00691 #else /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00692   return udp_sendto_if_src(pcb, p, dst_ip, dst_port, netif, src_ip);
00693 #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00694 }
00695 
00696 /** @ingroup udp_raw
00697  * Same as @ref udp_sendto_if, but with source address */
00698 err_t
00699 udp_sendto_if_src(struct udp_pcb *pcb, struct pbuf *p,
00700                   const ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif, const ip_addr_t *src_ip)
00701 {
00702 #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP
00703   return udp_sendto_if_src_chksum(pcb, p, dst_ip, dst_port, netif, 0, 0, src_ip);
00704 }
00705 
00706 /** Same as udp_sendto_if_src(), but with checksum */
00707 err_t
00708 udp_sendto_if_src_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip,
00709                          u16_t dst_port, struct netif *netif, u8_t have_chksum,
00710                          u16_t chksum, const ip_addr_t *src_ip)
00711 {
00712 #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
00713   struct udp_hdr *udphdr;
00714   err_t err;
00715   struct pbuf *q; /* q will be sent down the stack */
00716   u8_t ip_proto;
00717   u8_t ttl;
00718 
00719   LWIP_ASSERT_CORE_LOCKED();
00720 
00721   LWIP_ERROR("udp_sendto_if_src: invalid pcb", pcb != NULL, return ERR_ARG);
00722   LWIP_ERROR("udp_sendto_if_src: invalid pbuf", p != NULL, return ERR_ARG);
00723   LWIP_ERROR("udp_sendto_if_src: invalid dst_ip", dst_ip != NULL, return ERR_ARG);
00724   LWIP_ERROR("udp_sendto_if_src: invalid src_ip", src_ip != NULL, return ERR_ARG);
00725   LWIP_ERROR("udp_sendto_if_src: invalid netif", netif != NULL, return ERR_ARG);
00726 
00727   if (!IP_ADDR_PCB_VERSION_MATCH(pcb, src_ip) ||
00728       !IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) {
00729     return ERR_VAL;
00730   }
00731 
00732 #if LWIP_IPV4 && IP_SOF_BROADCAST
00733   /* broadcast filter? */
00734   if (!ip_get_option(pcb, SOF_BROADCAST) &&
00735 #if LWIP_IPV6
00736       IP_IS_V4(dst_ip) &&
00737 #endif /* LWIP_IPV6 */
00738       ip_addr_isbroadcast(dst_ip, netif)) {
00739     LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
00740                 ("udp_sendto_if: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
00741     return ERR_VAL;
00742   }
00743 #endif /* LWIP_IPV4 && IP_SOF_BROADCAST */
00744 
00745   /* if the PCB is not yet bound to a port, bind it here */
00746   if (pcb->local_port == 0) {
00747     LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send: not yet bound to a port, binding now\n"));
00748     err = udp_bind(pcb, &pcb->local_ip, pcb->local_port);
00749     if (err != ERR_OK) {
00750       LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: forced port bind failed\n"));
00751       return err;
00752     }
00753   }
00754 
00755   /* packet too large to add a UDP header without causing an overflow? */
00756   if ((u16_t)(p->tot_len + UDP_HLEN) < p->tot_len) {
00757     return ERR_MEM;
00758   }
00759   /* not enough space to add an UDP header to first pbuf in given p chain? */
00760   if (pbuf_add_header(p, UDP_HLEN)) {
00761     /* allocate header in a separate new pbuf */
00762     q = pbuf_alloc(PBUF_IP, UDP_HLEN, PBUF_RAM);
00763     /* new header pbuf could not be allocated? */
00764     if (q == NULL) {
00765       LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: could not allocate header\n"));
00766       return ERR_MEM;
00767     }
00768     if (p->tot_len != 0) {
00769       /* chain header q in front of given pbuf p (only if p contains data) */
00770       pbuf_chain(q, p);
00771     }
00772     /* first pbuf q points to header pbuf */
00773     LWIP_DEBUGF(UDP_DEBUG,
00774                 ("udp_send: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
00775   } else {
00776     /* adding space for header within p succeeded */
00777     /* first pbuf q equals given pbuf */
00778     q = p;
00779     LWIP_DEBUGF(UDP_DEBUG, ("udp_send: added header in given pbuf %p\n", (void *)p));
00780   }
00781   LWIP_ASSERT("check that first pbuf can hold struct udp_hdr",
00782               (q->len >= sizeof(struct udp_hdr)));
00783   /* q now represents the packet to be sent */
00784   udphdr = (struct udp_hdr *)q->payload;
00785   udphdr->src = lwip_htons(pcb->local_port);
00786   udphdr->dest = lwip_htons(dst_port);
00787   /* in UDP, 0 checksum means 'no checksum' */
00788   udphdr->chksum = 0x0000;
00789 
00790   /* Multicast Loop? */
00791 #if LWIP_MULTICAST_TX_OPTIONS
00792   if (((pcb->flags & UDP_FLAGS_MULTICAST_LOOP) != 0) && ip_addr_ismulticast(dst_ip)) {
00793     q->flags |= PBUF_FLAG_MCASTLOOP;
00794   }
00795 #endif /* LWIP_MULTICAST_TX_OPTIONS */
00796 
00797   LWIP_DEBUGF(UDP_DEBUG, ("udp_send: sending datagram of length %"U16_F"\n", q->tot_len));
00798 
00799 #if LWIP_UDPLITE
00800   /* UDP Lite protocol? */
00801   if (pcb->flags & UDP_FLAGS_UDPLITE) {
00802     u16_t chklen, chklen_hdr;
00803     LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE packet length %"U16_F"\n", q->tot_len));
00804     /* set UDP message length in UDP header */
00805     chklen_hdr = chklen = pcb->chksum_len_tx;
00806     if ((chklen < sizeof(struct udp_hdr)) || (chklen > q->tot_len)) {
00807       if (chklen != 0) {
00808         LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE pcb->chksum_len is illegal: %"U16_F"\n", chklen));
00809       }
00810       /* For UDP-Lite, checksum length of 0 means checksum
00811          over the complete packet. (See RFC 3828 chap. 3.1)
00812          At least the UDP-Lite header must be covered by the
00813          checksum, therefore, if chksum_len has an illegal
00814          value, we generate the checksum over the complete
00815          packet to be safe. */
00816       chklen_hdr = 0;
00817       chklen = q->tot_len;
00818     }
00819     udphdr->len = lwip_htons(chklen_hdr);
00820     /* calculate checksum */
00821 #if CHECKSUM_GEN_UDP
00822     IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_UDP) {
00823 #if LWIP_CHECKSUM_ON_COPY
00824       if (have_chksum) {
00825         chklen = UDP_HLEN;
00826       }
00827 #endif /* LWIP_CHECKSUM_ON_COPY */
00828       udphdr->chksum = ip_chksum_pseudo_partial(q, IP_PROTO_UDPLITE,
00829                        q->tot_len, chklen, src_ip, dst_ip);
00830 #if LWIP_CHECKSUM_ON_COPY
00831       if (have_chksum) {
00832         u32_t acc;
00833         acc = udphdr->chksum + (u16_t)~(chksum);
00834         udphdr->chksum = FOLD_U32T(acc);
00835       }
00836 #endif /* LWIP_CHECKSUM_ON_COPY */
00837 
00838       /* chksum zero must become 0xffff, as zero means 'no checksum' */
00839       if (udphdr->chksum == 0x0000) {
00840         udphdr->chksum = 0xffff;
00841       }
00842     }
00843 #endif /* CHECKSUM_GEN_UDP */
00844 
00845     ip_proto = IP_PROTO_UDPLITE;
00846   } else
00847 #endif /* LWIP_UDPLITE */
00848   {      /* UDP */
00849     LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP packet length %"U16_F"\n", q->tot_len));
00850     udphdr->len = lwip_htons(q->tot_len);
00851     /* calculate checksum */
00852 #if CHECKSUM_GEN_UDP
00853     IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_UDP) {
00854       /* Checksum is mandatory over IPv6. */
00855       if (IP_IS_V6(dst_ip) || (pcb->flags & UDP_FLAGS_NOCHKSUM) == 0) {
00856         u16_t udpchksum;
00857 #if LWIP_CHECKSUM_ON_COPY
00858         if (have_chksum) {
00859           u32_t acc;
00860           udpchksum = ip_chksum_pseudo_partial(q, IP_PROTO_UDP,
00861                                                q->tot_len, UDP_HLEN, src_ip, dst_ip);
00862           acc = udpchksum + (u16_t)~(chksum);
00863           udpchksum = FOLD_U32T(acc);
00864         } else
00865 #endif /* LWIP_CHECKSUM_ON_COPY */
00866         {
00867           udpchksum = ip_chksum_pseudo(q, IP_PROTO_UDP, q->tot_len,
00868                                        src_ip, dst_ip);
00869         }
00870 
00871         /* chksum zero must become 0xffff, as zero means 'no checksum' */
00872         if (udpchksum == 0x0000) {
00873           udpchksum = 0xffff;
00874         }
00875         udphdr->chksum = udpchksum;
00876       }
00877     }
00878 #endif /* CHECKSUM_GEN_UDP */
00879     ip_proto = IP_PROTO_UDP;
00880   }
00881 
00882   /* Determine TTL to use */
00883 #if LWIP_MULTICAST_TX_OPTIONS
00884   ttl = (ip_addr_ismulticast(dst_ip) ? udp_get_multicast_ttl(pcb) : pcb->ttl);
00885 #else /* LWIP_MULTICAST_TX_OPTIONS */
00886   ttl = pcb->ttl;
00887 #endif /* LWIP_MULTICAST_TX_OPTIONS */
00888 
00889   LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP checksum 0x%04"X16_F"\n", udphdr->chksum));
00890   LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,0x%02"X16_F",)\n", (u16_t)ip_proto));
00891   /* output to IP */
00892   NETIF_SET_HINTS(netif, &(pcb->netif_hints));
00893   err = ip_output_if_src(q, src_ip, dst_ip, ttl, pcb->tos, ip_proto, netif);
00894   NETIF_RESET_HINTS(netif);
00895 
00896   /* @todo: must this be increased even if error occurred? */
00897   MIB2_STATS_INC(mib2.udpoutdatagrams);
00898 
00899   /* did we chain a separate header pbuf earlier? */
00900   if (q != p) {
00901     /* free the header pbuf */
00902     pbuf_free(q);
00903     q = NULL;
00904     /* p is still referenced by the caller, and will live on */
00905   }
00906 
00907   UDP_STATS_INC(udp.xmit);
00908   return err;
00909 }
00910 
00911 /**
00912  * @ingroup udp_raw
00913  * Bind an UDP PCB.
00914  * 
00915  * @param pcb UDP PCB to be bound with a local address ipaddr and port.
00916  * @param ipaddr local IP address to bind with. Use IP_ANY_TYPE to
00917  * bind to all local interfaces.
00918  * @param port local UDP port to bind with. Use 0 to automatically bind
00919  * to a random port between UDP_LOCAL_PORT_RANGE_START and
00920  * UDP_LOCAL_PORT_RANGE_END.
00921  *
00922  * ipaddr & port are expected to be in the same byte order as in the pcb.
00923  *
00924  * @return lwIP error code.
00925  * - ERR_OK. Successful. No error occurred.
00926  * - ERR_USE. The specified ipaddr and port are already bound to by
00927  * another UDP PCB.
00928  *
00929  * @see udp_disconnect()
00930  */
00931 err_t
00932 udp_bind(struct udp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port)
00933 {
00934   struct udp_pcb *ipcb;
00935   u8_t rebind;
00936 #if LWIP_IPV6 && LWIP_IPV6_SCOPES
00937   ip_addr_t zoned_ipaddr;
00938 #endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */
00939 
00940   LWIP_ASSERT_CORE_LOCKED();
00941 
00942 #if LWIP_IPV4
00943   /* Don't propagate NULL pointer (IPv4 ANY) to subsequent functions */
00944   if (ipaddr == NULL) {
00945     ipaddr = IP4_ADDR_ANY;
00946   }
00947 #else /* LWIP_IPV4 */
00948   LWIP_ERROR("udp_bind: invalid ipaddr", ipaddr != NULL, return ERR_ARG);
00949 #endif /* LWIP_IPV4 */
00950 
00951   LWIP_ERROR("udp_bind: invalid pcb", pcb != NULL, return ERR_ARG);
00952 
00953   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_bind(ipaddr = "));
00954   ip_addr_debug_print(UDP_DEBUG | LWIP_DBG_TRACE, ipaddr);
00955   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, (", port = %"U16_F")\n", port));
00956 
00957   rebind = 0;
00958   /* Check for double bind and rebind of the same pcb */
00959   for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) {
00960     /* is this UDP PCB already on active list? */
00961     if (pcb == ipcb) {
00962       rebind = 1;
00963       break;
00964     }
00965   }
00966 
00967 #if LWIP_IPV6 && LWIP_IPV6_SCOPES
00968   /* If the given IP address should have a zone but doesn't, assign one now.
00969    * This is legacy support: scope-aware callers should always provide properly
00970    * zoned source addresses. Do the zone selection before the address-in-use
00971    * check below; as such we have to make a temporary copy of the address. */
00972   if (IP_IS_V6(ipaddr) && ip6_addr_lacks_zone(ip_2_ip6(ipaddr), IP6_UNKNOWN)) {
00973     ip_addr_copy(zoned_ipaddr, *ipaddr);
00974     ip6_addr_select_zone(ip_2_ip6(&zoned_ipaddr), ip_2_ip6(&zoned_ipaddr));
00975     ipaddr = &zoned_ipaddr;
00976   }
00977 #endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */
00978 
00979   /* no port specified? */
00980   if (port == 0) {
00981     port = udp_new_port();
00982     if (port == 0) {
00983       /* no more ports available in local range */
00984       LWIP_DEBUGF(UDP_DEBUG, ("udp_bind: out of free UDP ports\n"));
00985       return ERR_USE;
00986     }
00987   } else {
00988     for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) {
00989       if (pcb != ipcb) {
00990         /* By default, we don't allow to bind to a port that any other udp
00991            PCB is already bound to, unless *all* PCBs with that port have tha
00992            REUSEADDR flag set. */
00993 #if SO_REUSE
00994         if (!ip_get_option(pcb, SOF_REUSEADDR) ||
00995             !ip_get_option(ipcb, SOF_REUSEADDR))
00996 #endif /* SO_REUSE */
00997         {
00998           /* port matches that of PCB in list and REUSEADDR not set -> reject */
00999           if ((ipcb->local_port == port) &&
01000               /* IP address matches or any IP used? */
01001               (ip_addr_cmp(&ipcb->local_ip, ipaddr) || ip_addr_isany(ipaddr) ||
01002               ip_addr_isany(&ipcb->local_ip))) {
01003             /* other PCB already binds to this local IP and port */
01004             LWIP_DEBUGF(UDP_DEBUG,
01005                         ("udp_bind: local port %"U16_F" already bound by another pcb\n", port));
01006             return ERR_USE;
01007           }
01008         }
01009       }
01010     }
01011   }
01012 
01013   ip_addr_set_ipaddr(&pcb->local_ip, ipaddr);
01014 
01015   pcb->local_port = port;
01016   mib2_udp_bind(pcb);
01017   /* pcb not active yet? */
01018   if (rebind == 0) {
01019     /* place the PCB on the active list if not already there */
01020     pcb->next = udp_pcbs;
01021     udp_pcbs = pcb;
01022   }
01023   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("udp_bind: bound to "));
01024   ip_addr_debug_print_val(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, pcb->local_ip);
01025   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, (", port %"U16_F")\n", pcb->local_port));
01026   return ERR_OK;
01027 }
01028 
01029 /**
01030  * @ingroup udp_raw
01031  * Bind an UDP PCB to a specific netif.
01032  * After calling this function, all packets received via this PCB
01033  * are guaranteed to have come in via the specified netif, and all
01034  * outgoing packets will go out via the specified netif.
01035  *
01036  * @param pcb UDP PCB to be bound.
01037  * @param netif netif to bind udp pcb to. Can be NULL.
01038  *
01039  * @see udp_disconnect()
01040  */
01041 void
01042 udp_bind_netif(struct udp_pcb *pcb, const struct netif *netif)
01043 {
01044   LWIP_ASSERT_CORE_LOCKED();
01045 
01046   if (netif != NULL) {
01047     pcb->netif_idx = netif_get_index(netif);
01048   } else {
01049     pcb->netif_idx = NETIF_NO_INDEX;
01050   }
01051 }
01052 
01053 /**
01054  * @ingroup udp_raw
01055  * Sets the remote end of the pcb. This function does not generate any
01056  * network traffic, but only sets the remote address of the pcb.
01057  *
01058  * @param pcb UDP PCB to be connected with remote address ipaddr and port.
01059  * @param ipaddr remote IP address to connect with.
01060  * @param port remote UDP port to connect with.
01061  *
01062  * @return lwIP error code
01063  *
01064  * ipaddr & port are expected to be in the same byte order as in the pcb.
01065  *
01066  * The udp pcb is bound to a random local port if not already bound.
01067  *
01068  * @see udp_disconnect()
01069  */
01070 err_t
01071 udp_connect(struct udp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port)
01072 {
01073   struct udp_pcb *ipcb;
01074 
01075   LWIP_ASSERT_CORE_LOCKED();
01076 
01077   LWIP_ERROR("udp_connect: invalid pcb", pcb != NULL, return ERR_ARG);
01078   LWIP_ERROR("udp_connect: invalid ipaddr", ipaddr != NULL, return ERR_ARG);
01079 
01080   if (pcb->local_port == 0) {
01081     err_t err = udp_bind(pcb, &pcb->local_ip, pcb->local_port);
01082     if (err != ERR_OK) {
01083       return err;
01084     }
01085   }
01086 
01087   ip_addr_set_ipaddr(&pcb->remote_ip, ipaddr);
01088 #if LWIP_IPV6 && LWIP_IPV6_SCOPES
01089   /* If the given IP address should have a zone but doesn't, assign one now,
01090    * using the bound address to make a more informed decision when possible. */
01091   if (IP_IS_V6(&pcb->remote_ip) &&
01092       ip6_addr_lacks_zone(ip_2_ip6(&pcb->remote_ip), IP6_UNKNOWN)) {
01093     ip6_addr_select_zone(ip_2_ip6(&pcb->remote_ip), ip_2_ip6(&pcb->local_ip));
01094   }
01095 #endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */
01096 
01097   pcb->remote_port = port;
01098   pcb->flags |= UDP_FLAGS_CONNECTED;
01099 
01100   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("udp_connect: connected to "));
01101   ip_addr_debug_print_val(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
01102                           pcb->remote_ip);
01103   LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, (", port %"U16_F")\n", pcb->remote_port));
01104 
01105   /* Insert UDP PCB into the list of active UDP PCBs. */
01106   for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) {
01107     if (pcb == ipcb) {
01108       /* already on the list, just return */
01109       return ERR_OK;
01110     }
01111   }
01112   /* PCB not yet on the list, add PCB now */
01113   pcb->next = udp_pcbs;
01114   udp_pcbs = pcb;
01115   return ERR_OK;
01116 }
01117 
01118 /**
01119  * @ingroup udp_raw
01120  * Remove the remote end of the pcb. This function does not generate
01121  * any network traffic, but only removes the remote address of the pcb.
01122  *
01123  * @param pcb the udp pcb to disconnect.
01124  */
01125 void
01126 udp_disconnect(struct udp_pcb *pcb)
01127 {
01128   LWIP_ASSERT_CORE_LOCKED();
01129 
01130   LWIP_ERROR("udp_disconnect: invalid pcb", pcb != NULL, return);
01131 
01132   /* reset remote address association */
01133 #if LWIP_IPV4 && LWIP_IPV6
01134   if (IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
01135     ip_addr_copy(pcb->remote_ip, *IP_ANY_TYPE);
01136   } else {
01137 #endif
01138     ip_addr_set_any(IP_IS_V6_VAL(pcb->remote_ip), &pcb->remote_ip);
01139 #if LWIP_IPV4 && LWIP_IPV6
01140   }
01141 #endif
01142   pcb->remote_port = 0;
01143   pcb->netif_idx = NETIF_NO_INDEX;
01144   /* mark PCB as unconnected */
01145   udp_clear_flags(pcb, UDP_FLAGS_CONNECTED);
01146 }
01147 
01148 /**
01149  * @ingroup udp_raw
01150  * Set a receive callback for a UDP PCB.
01151  * This callback will be called when receiving a datagram for the pcb.
01152  *
01153  * @param pcb the pcb for which to set the recv callback
01154  * @param recv function pointer of the callback function
01155  * @param recv_arg additional argument to pass to the callback function
01156  */
01157 void
01158 udp_recv(struct udp_pcb *pcb, udp_recv_fn recv, void *recv_arg)
01159 {
01160   LWIP_ASSERT_CORE_LOCKED();
01161 
01162   LWIP_ERROR("udp_recv: invalid pcb", pcb != NULL, return);
01163 
01164   /* remember recv() callback and user data */
01165   pcb->recv = recv;
01166   pcb->recv_arg = recv_arg;
01167 }
01168 
01169 /**
01170  * @ingroup udp_raw
01171  * Removes and deallocates the pcb.  
01172  * 
01173  * @param pcb UDP PCB to be removed. The PCB is removed from the list of
01174  * UDP PCB's and the data structure is freed from memory.
01175  *
01176  * @see udp_new()
01177  */
01178 void
01179 udp_remove(struct udp_pcb *pcb)
01180 {
01181   struct udp_pcb *pcb2;
01182 
01183   LWIP_ASSERT_CORE_LOCKED();
01184 
01185   LWIP_ERROR("udp_remove: invalid pcb", pcb != NULL, return);
01186 
01187   mib2_udp_unbind(pcb);
01188   /* pcb to be removed is first in list? */
01189   if (udp_pcbs == pcb) {
01190     /* make list start at 2nd pcb */
01191     udp_pcbs = udp_pcbs->next;
01192     /* pcb not 1st in list */
01193   } else {
01194     for (pcb2 = udp_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
01195       /* find pcb in udp_pcbs list */
01196       if (pcb2->next != NULL && pcb2->next == pcb) {
01197         /* remove pcb from list */
01198         pcb2->next = pcb->next;
01199         break;
01200       }
01201     }
01202   }
01203   memp_free(MEMP_UDP_PCB, pcb);
01204 }
01205 
01206 /**
01207  * @ingroup udp_raw
01208  * Creates a new UDP pcb which can be used for UDP communication. The
01209  * pcb is not active until it has either been bound to a local address
01210  * or connected to a remote address.
01211  *
01212  * @return The UDP PCB which was created. NULL if the PCB data structure
01213  * could not be allocated.
01214  *
01215  * @see udp_remove()
01216  */
01217 struct udp_pcb *
01218 udp_new(void)
01219 {
01220   struct udp_pcb *pcb;
01221 
01222   LWIP_ASSERT_CORE_LOCKED();
01223 
01224   pcb = (struct udp_pcb *)memp_malloc(MEMP_UDP_PCB);
01225   /* could allocate UDP PCB? */
01226   if (pcb != NULL) {
01227     /* UDP Lite: by initializing to all zeroes, chksum_len is set to 0
01228      * which means checksum is generated over the whole datagram per default
01229      * (recommended as default by RFC 3828). */
01230     /* initialize PCB to all zeroes */
01231     memset(pcb, 0, sizeof(struct udp_pcb));
01232     pcb->ttl = UDP_TTL;
01233 #if LWIP_MULTICAST_TX_OPTIONS
01234     udp_set_multicast_ttl(pcb, UDP_TTL);
01235 #endif /* LWIP_MULTICAST_TX_OPTIONS */
01236   }
01237   return pcb;
01238 }
01239 
01240 /**
01241  * @ingroup udp_raw
01242  * Create a UDP PCB for specific IP type.
01243  * The pcb is not active until it has either been bound to a local address
01244  * or connected to a remote address.
01245  * 
01246  * @param type IP address type, see @ref lwip_ip_addr_type definitions.
01247  * If you want to listen to IPv4 and IPv6 (dual-stack) packets,
01248  * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE.
01249  * @return The UDP PCB which was created. NULL if the PCB data structure
01250  * could not be allocated.
01251  *
01252  * @see udp_remove()
01253  */
01254 struct udp_pcb *
01255 udp_new_ip_type(u8_t type)
01256 {
01257   struct udp_pcb *pcb;
01258 
01259   LWIP_ASSERT_CORE_LOCKED();
01260 
01261   pcb = udp_new();
01262 #if LWIP_IPV4 && LWIP_IPV6
01263   if (pcb != NULL) {
01264     IP_SET_TYPE_VAL(pcb->local_ip,  type);
01265     IP_SET_TYPE_VAL(pcb->remote_ip, type);
01266   }
01267 #else
01268   LWIP_UNUSED_ARG(type);
01269 #endif /* LWIP_IPV4 && LWIP_IPV6 */
01270   return pcb;
01271 }
01272 
01273 /** This function is called from netif.c when address is changed
01274  *
01275  * @param old_addr IP address of the netif before change
01276  * @param new_addr IP address of the netif after change
01277  */
01278 void udp_netif_ip_addr_changed(const ip_addr_t *old_addr, const ip_addr_t *new_addr)
01279 {
01280   struct udp_pcb *upcb;
01281 
01282   if (!ip_addr_isany(old_addr) && !ip_addr_isany(new_addr)) {
01283     for (upcb = udp_pcbs; upcb != NULL; upcb = upcb->next) {
01284       /* PCB bound to current local interface address? */
01285       if (ip_addr_cmp(&upcb->local_ip, old_addr)) {
01286         /* The PCB is bound to the old ipaddr and
01287          * is set to bound to the new one instead */
01288         ip_addr_copy(upcb->local_ip, *new_addr);
01289       }
01290     }
01291   }
01292 }
01293 
01294 #if UDP_DEBUG
01295 /**
01296  * Print UDP header information for debug purposes.
01297  *
01298  * @param udphdr pointer to the udp header in memory.
01299  */
01300 void
01301 udp_debug_print(struct udp_hdr *udphdr)
01302 {
01303   LWIP_DEBUGF(UDP_DEBUG, ("UDP header:\n"));
01304   LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n"));
01305   LWIP_DEBUGF(UDP_DEBUG, ("|     %5"U16_F"     |     %5"U16_F"     | (src port, dest port)\n",
01306                           lwip_ntohs(udphdr->src), lwip_ntohs(udphdr->dest)));
01307   LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n"));
01308   LWIP_DEBUGF(UDP_DEBUG, ("|     %5"U16_F"     |     0x%04"X16_F"    | (len, chksum)\n",
01309                           lwip_ntohs(udphdr->len), lwip_ntohs(udphdr->chksum)));
01310   LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n"));
01311 }
01312 #endif /* UDP_DEBUG */
01313 
01314 #endif /* LWIP_UDP */