/** * @file * User Datagram Protocol module * */ /* * Copyright (c) 2001-2004 Swedish Institute of Computer Science. * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * This file is part of the lwIP TCP/IP stack. * * Author: Adam Dunkels * */ /* udp.c * * The code for the User Datagram Protocol UDP & UDPLite (RFC 3828). * */ /* @todo Check the use of '(struct udp_pcb).chksum_len_rx'! */ #include "lwip/opt.h" #if LWIP_UDP /* don't build if not configured for use in lwipopts.h */ #include "lwip/udp.h" #include "lwip/def.h" #include "lwip/memp.h" #include "lwip/inet_chksum.h" #include "lwip/ip_addr.h" #include "lwip/ip6.h" #include "lwip/ip6_addr.h" #include "lwip/inet_chksum.h" #include "lwip/netif.h" #include "lwip/icmp.h" #include "lwip/icmp6.h" #include "lwip/stats.h" #include "lwip/snmp.h" #include "lwip/dhcp.h" #include #ifndef UDP_LOCAL_PORT_RANGE_START /* From http://www.iana.org/assignments/port-numbers: "The Dynamic and/or Private Ports are those from 49152 through 65535" */ #define UDP_LOCAL_PORT_RANGE_START 0xc000 #define UDP_LOCAL_PORT_RANGE_END 0xffff #define UDP_ENSURE_LOCAL_PORT_RANGE(port) ((u16_t)(((port) & ~UDP_LOCAL_PORT_RANGE_START) + UDP_LOCAL_PORT_RANGE_START)) #endif /* last local UDP port */ static u16_t udp_port = UDP_LOCAL_PORT_RANGE_START; /* The list of UDP PCBs */ /* exported in udp.h (was static) */ struct udp_pcb *udp_pcbs; /** * Initialize this module. */ void udp_init(void) { #if LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS && defined(LWIP_RAND) udp_port = UDP_ENSURE_LOCAL_PORT_RANGE(LWIP_RAND()); #endif /* LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS && defined(LWIP_RAND) */ } /** * Allocate a new local UDP port. * * @return a new (free) local UDP port number */ static u16_t udp_new_port(void) { u16_t n = 0; struct udp_pcb *pcb; again: if (udp_port++ == UDP_LOCAL_PORT_RANGE_END) { udp_port = UDP_LOCAL_PORT_RANGE_START; } /* Check all PCBs. */ for (pcb = udp_pcbs; pcb != NULL; pcb = pcb->next) { if (pcb->local_port == udp_port) { if (++n > (UDP_LOCAL_PORT_RANGE_END - UDP_LOCAL_PORT_RANGE_START)) { return 0; } goto again; } } return udp_port; #if 0 struct udp_pcb *ipcb = udp_pcbs; while ((ipcb != NULL) && (udp_port != UDP_LOCAL_PORT_RANGE_END)) { if (ipcb->local_port == udp_port) { /* port is already used by another udp_pcb */ udp_port++; /* restart scanning all udp pcbs */ ipcb = udp_pcbs; } else { /* go on with next udp pcb */ ipcb = ipcb->next; } } if (ipcb != NULL) { return 0; } return udp_port; #endif } /** * Process an incoming UDP datagram. * * Given an incoming UDP datagram (as a chain of pbufs) this function * finds a corresponding UDP PCB and hands over the pbuf to the pcbs * recv function. If no pcb is found or the datagram is incorrect, the * pbuf is freed. * * @param p pbuf to be demultiplexed to a UDP PCB (p->payload pointing to the UDP header) * @param inp network interface on which the datagram was received. * */ void udp_input(struct pbuf *p, struct netif *inp) { struct udp_hdr *udphdr; struct udp_pcb *pcb, *prev; struct udp_pcb *uncon_pcb; u16_t src, dest; u8_t local_match; #if LWIP_IPV4 u8_t broadcast; #endif /* LWIP_IPV4 */ u8_t for_us; LWIP_UNUSED_ARG(inp); PERF_START; UDP_STATS_INC(udp.recv); /* Check minimum length (UDP header) */ if (p->len < UDP_HLEN) { /* drop short packets */ LWIP_DEBUGF(UDP_DEBUG, ("udp_input: short UDP datagram (%"U16_F" bytes) discarded\n", p->tot_len)); UDP_STATS_INC(udp.lenerr); UDP_STATS_INC(udp.drop); MIB2_STATS_INC(mib2.udpinerrors); pbuf_free(p); goto end; } udphdr = (struct udp_hdr *)p->payload; #if LWIP_IPV4 /* is broadcast packet ? */ broadcast = ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif()); #endif /* LWIP_IPV4 */ LWIP_DEBUGF(UDP_DEBUG, ("udp_input: received datagram of length %"U16_F"\n", p->tot_len)); /* convert src and dest ports to host byte order */ src = ntohs(udphdr->src); dest = ntohs(udphdr->dest); udp_debug_print(udphdr); /* print the UDP source and destination */ LWIP_DEBUGF(UDP_DEBUG, ("udp (")); ip_addr_debug_print(UDP_DEBUG, ip_current_dest_addr()); LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F") <-- (", ntohs(udphdr->dest))); ip_addr_debug_print(UDP_DEBUG, ip_current_src_addr()); LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F")\n", ntohs(udphdr->src))); #if LWIP_DHCP pcb = NULL; /* when LWIP_DHCP is active, packets to DHCP_CLIENT_PORT may only be processed by the dhcp module, no other UDP pcb may use the local UDP port DHCP_CLIENT_PORT */ if (dest == DHCP_CLIENT_PORT) { /* all packets for DHCP_CLIENT_PORT not coming from DHCP_SERVER_PORT are dropped! */ if (src == DHCP_SERVER_PORT) { if ((inp->dhcp != NULL) && (inp->dhcp->pcb != NULL)) { /* accept the packet if (- broadcast or directed to us) -> DHCP is link-layer-addressed, local ip is always ANY! - inp->dhcp->pcb->remote == ANY or iphdr->src (no need to check for IPv6 since the dhcp struct always uses IPv4) */ if (ip_addr_isany_val(inp->dhcp->pcb->remote_ip) || ip_addr_cmp(&inp->dhcp->pcb->remote_ip, ip_current_src_addr())) { pcb = inp->dhcp->pcb; } } } } else #endif /* LWIP_DHCP */ { prev = NULL; local_match = 0; uncon_pcb = NULL; /* Iterate through the UDP pcb list for a matching pcb. * 'Perfect match' pcbs (connected to the remote port & ip address) are * preferred. If no perfect match is found, the first unconnected pcb that * matches the local port and ip address gets the datagram. */ for (pcb = udp_pcbs; pcb != NULL; pcb = pcb->next) { local_match = 0; /* print the PCB local and remote address */ LWIP_DEBUGF(UDP_DEBUG, ("pcb (")); ip_addr_debug_print(UDP_DEBUG, &pcb->local_ip); LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F") <-- (", pcb->local_port)); ip_addr_debug_print(UDP_DEBUG, &pcb->remote_ip); LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F")\n", pcb->remote_port)); /* compare PCB local addr+port to UDP destination addr+port */ if (pcb->local_port == dest) { if ( #if LWIP_IPV6 (PCB_ISIPV6(pcb) && (ip_current_is_v6()) && (ip6_addr_isany(ip_2_ip6(&pcb->local_ip)) || #if LWIP_IPV6_MLD ip6_addr_ismulticast(ip6_current_dest_addr()) || #endif /* LWIP_IPV6_MLD */ ip6_addr_cmp(ip_2_ip6(&pcb->local_ip), ip6_current_dest_addr()))) #endif /* LWIP_IPV6 */ #if LWIP_IPV4 && LWIP_IPV6 || (!PCB_ISIPV6(pcb) && (ip4_current_header() != NULL) && #endif /* LWIP_IPV4 && LWIP_IPV6 */ #if LWIP_IPV4 #if !LWIP_IPV6 ( #endif /* !LWIP_IPV6 */ ((!broadcast && ip_addr_isany(&pcb->local_ip)) || ip_addr_cmp(&pcb->local_ip, ip_current_dest_addr()) || #if LWIP_IGMP (ip_addr_isany(&pcb->local_ip) && ip_addr_ismulticast(ip_current_dest_addr())) || #endif /* LWIP_IGMP */ #if IP_SOF_BROADCAST_RECV (broadcast && ip_get_option(pcb, SOF_BROADCAST) && (ip_addr_isany(&pcb->local_ip) || ip_addr_netcmp(&pcb->local_ip, ip_current_dest_addr(), netif_ip4_netmask(inp)))))) #else /* IP_SOF_BROADCAST_RECV */ (broadcast && (ip_addr_isany(&pcb->local_ip) || ip_addr_netcmp(&pcb->local_ip, ip_current_dest_addr(), netif_ip4_netmask(inp)))))) #endif /* IP_SOF_BROADCAST_RECV */ #endif /* LWIP_IPV4 */ ) { local_match = 1; if ((uncon_pcb == NULL) && ((pcb->flags & UDP_FLAGS_CONNECTED) == 0)) { /* the first unconnected matching PCB */ uncon_pcb = pcb; } } } /* compare PCB remote addr+port to UDP source addr+port */ if ((local_match != 0) && (pcb->remote_port == src) && (ip_current_is_v6() == IP_IS_V6_VAL(pcb->remote_ip)) && (ip_addr_isany_val(pcb->remote_ip) || ip_addr_cmp(&pcb->remote_ip, ip_current_src_addr()))) { /* the first fully matching PCB */ if (prev != NULL) { /* move the pcb to the front of udp_pcbs so that is found faster next time */ prev->next = pcb->next; pcb->next = udp_pcbs; udp_pcbs = pcb; } else { UDP_STATS_INC(udp.cachehit); } break; } prev = pcb; } /* no fully matching pcb found? then look for an unconnected pcb */ if (pcb == NULL) { pcb = uncon_pcb; } } /* Check checksum if this is a match or if it was directed at us. */ if (pcb != NULL) { for_us = 1; } else { #if LWIP_IPV6 if (ip_current_is_v6()) { for_us = netif_get_ip6_addr_match(inp, ip6_current_dest_addr()) >= 0; } #if LWIP_IPV4 else #endif /* LWIP_IPV4 */ #endif /* LWIP_IPV6 */ #if LWIP_IPV4 { for_us = ip4_addr_cmp(netif_ip4_addr(inp), ip4_current_dest_addr()); } #endif /* LWIP_IPV4 */ } if (for_us) { LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: calculating checksum\n")); #if CHECKSUM_CHECK_UDP IF__NETIF_CHECKSUM_ENABLED(inp, CHECKSUM_CHECK_UDP) { #if LWIP_UDPLITE if (ip_current_header_proto() == IP_PROTO_UDPLITE) { /* Do the UDP Lite checksum */ u16_t chklen = ntohs(udphdr->len); if (chklen < sizeof(struct udp_hdr)) { if (chklen == 0) { /* For UDP-Lite, checksum length of 0 means checksum over the complete packet (See RFC 3828 chap. 3.1) */ chklen = p->tot_len; } else { /* At least the UDP-Lite header must be covered by the checksum! (Again, see RFC 3828 chap. 3.1) */ goto chkerr; } } if (ip_chksum_pseudo_partial(p, IP_PROTO_UDPLITE, p->tot_len, chklen, ip_current_src_addr(), ip_current_dest_addr()) != 0) { goto chkerr; } } else #endif /* LWIP_UDPLITE */ { if (udphdr->chksum != 0) { if (ip_chksum_pseudo(p, IP_PROTO_UDP, p->tot_len, ip_current_src_addr(), ip_current_dest_addr()) != 0) { goto chkerr; } } } } #endif /* CHECKSUM_CHECK_UDP */ if (pbuf_header(p, -UDP_HLEN)) { /* Can we cope with this failing? Just assert for now */ LWIP_ASSERT("pbuf_header failed\n", 0); UDP_STATS_INC(udp.drop); MIB2_STATS_INC(mib2.udpinerrors); pbuf_free(p); goto end; } if (pcb != NULL) { MIB2_STATS_INC(mib2.udpindatagrams); #if SO_REUSE && SO_REUSE_RXTOALL if (( #if LWIP_IPV4 broadcast || #endif /* LWIP_IPV4 */ #if LWIP_IPV6 ip6_addr_ismulticast(ip6_current_dest_addr()) || #endif /* LWIP_IPV6 */ ip_addr_ismulticast(ip_current_dest_addr())) && ip_get_option(pcb, SOF_REUSEADDR)) { /* pass broadcast- or multicast packets to all multicast pcbs if SOF_REUSEADDR is set on the first match */ struct udp_pcb *mpcb; u8_t p_header_changed = 0; s16_t hdrs_len = (s16_t)(ip_current_header_tot_len() + UDP_HLEN); for (mpcb = udp_pcbs; mpcb != NULL; mpcb = mpcb->next) { if (mpcb != pcb) { /* compare PCB local addr+port to UDP destination addr+port */ if ((mpcb->local_port == dest) && #if LWIP_IPV6 ((PCB_ISIPV6(mpcb) && (ip6_addr_ismulticast(ip6_current_dest_addr()) || ip6_addr_cmp(ip_2_ip6(&mpcb->local_ip), ip6_current_dest_addr()))) || (!PCB_ISIPV6(mpcb) && #else /* LWIP_IPV6 */ (( #endif /* LWIP_IPV6 */ (( #if LWIP_IPV4 !broadcast && #endif /* LWIP_IPV4 */ ip_addr_isany(&mpcb->local_ip)) || ip_addr_cmp(&mpcb->local_ip, ip_current_dest_addr()) || #if LWIP_IGMP (ip_addr_isany(&pcb->local_ip) && ip_addr_ismulticast(ip_current_dest_addr())) || #endif /* LWIP_IGMP */ #if IP_SOF_BROADCAST_RECV ( #if LWIP_IPV4 broadcast && #endif /* LWIP_IPV4 */ ip_get_option(mpcb, SOF_BROADCAST)))))) { #else /* IP_SOF_BROADCAST_RECV */ (broadcast))))) { #endif /* IP_SOF_BROADCAST_RECV */ /* pass a copy of the packet to all local matches */ if (mpcb->recv != NULL) { struct pbuf *q; /* for that, move payload to IP header again */ if (p_header_changed == 0) { pbuf_header_force(p, hdrs_len); p_header_changed = 1; } q = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM); if (q != NULL) { err_t err = pbuf_copy(q, p); if (err == ERR_OK) { /* move payload to UDP data */ pbuf_header(q, -hdrs_len); mpcb->recv(mpcb->recv_arg, mpcb, q, ip_current_src_addr(), src); } } } } } } if (p_header_changed) { /* and move payload to UDP data again */ pbuf_header(p, -hdrs_len); } } #endif /* SO_REUSE && SO_REUSE_RXTOALL */ /* callback */ if (pcb->recv != NULL) { /* now the recv function is responsible for freeing p */ pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr(), src); } else { /* no recv function registered? then we have to free the pbuf! */ pbuf_free(p); goto end; } } else { LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: not for us.\n")); #if LWIP_ICMP || LWIP_ICMP6 /* No match was found, send ICMP destination port unreachable unless destination address was broadcast/multicast. */ if ( #if LWIP_IPV4 !broadcast && !ip_addr_ismulticast(ip_current_dest_addr()) #if LWIP_IPV6 && #endif /* LWIP_IPV6 */ #endif /* LWIP_IPV4 */ #if LWIP_IPV6 !ip6_addr_ismulticast(ip6_current_dest_addr()) #endif /* LWIP_IPV6 */ ) { /* move payload pointer back to ip header */ pbuf_header_force(p, ip_current_header_tot_len() + UDP_HLEN); icmp_port_unreach(ip_current_is_v6(), p); } #endif /* LWIP_ICMP || LWIP_ICMP6 */ UDP_STATS_INC(udp.proterr); UDP_STATS_INC(udp.drop); MIB2_STATS_INC(mib2.udpnoports); pbuf_free(p); } } else { pbuf_free(p); } end: PERF_STOP("udp_input"); return; #if CHECKSUM_CHECK_UDP chkerr: LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("udp_input: UDP (or UDP Lite) datagram discarded due to failing checksum\n")); UDP_STATS_INC(udp.chkerr); UDP_STATS_INC(udp.drop); MIB2_STATS_INC(mib2.udpinerrors); pbuf_free(p); PERF_STOP("udp_input"); #endif /* CHECKSUM_CHECK_UDP */ } /** * Send data using UDP. * * @param pcb UDP PCB used to send the data. * @param p chain of pbuf's to be sent. * * The datagram will be sent to the current remote_ip & remote_port * stored in pcb. If the pcb is not bound to a port, it will * automatically be bound to a random port. * * @return lwIP error code. * - ERR_OK. Successful. No error occurred. * - ERR_MEM. Out of memory. * - ERR_RTE. Could not find route to destination address. * - More errors could be returned by lower protocol layers. * * @see udp_disconnect() udp_sendto() */ err_t udp_send(struct udp_pcb *pcb, struct pbuf *p) { /* send to the packet using remote ip and port stored in the pcb */ return udp_sendto(pcb, p, &pcb->remote_ip, pcb->remote_port); } #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP /** Same as udp_send() but with checksum */ err_t udp_send_chksum(struct udp_pcb *pcb, struct pbuf *p, u8_t have_chksum, u16_t chksum) { /* send to the packet using remote ip and port stored in the pcb */ return udp_sendto_chksum(pcb, p, &pcb->remote_ip, pcb->remote_port, have_chksum, chksum); } #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ /** * Send data to a specified address using UDP. * * @param pcb UDP PCB used to send the data. * @param p chain of pbuf's to be sent. * @param dst_ip Destination IP address. * @param dst_port Destination UDP port. * * dst_ip & dst_port are expected to be in the same byte order as in the pcb. * * If the PCB already has a remote address association, it will * be restored after the data is sent. * * @return lwIP error code (@see udp_send for possible error codes) * * @see udp_disconnect() udp_send() */ err_t udp_sendto(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip, u16_t dst_port) { #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP return udp_sendto_chksum(pcb, p, dst_ip, dst_port, 0, 0); } /** Same as udp_sendto(), but with checksum */ err_t udp_sendto_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip, u16_t dst_port, u8_t have_chksum, u16_t chksum) { #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ struct netif *netif; const ip_addr_t *dst_ip_route = dst_ip; if ((pcb == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) { return ERR_VAL; } LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send\n")); #if LWIP_IPV6 || (LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS) if (ip_addr_ismulticast(dst_ip_route)) { #if LWIP_IPV6 if (IP_IS_V6(dst_ip)) { /* For multicast, find a netif based on source address. */ dst_ip_route = &pcb->local_ip; } else #endif /* LWIP_IPV6 */ { #if LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS /* IPv4 does not use source-based routing by default, so we use an administratively selected interface for multicast by default. However, this can be overridden by setting an interface address in pcb->multicast_ip that is used for routing. */ if (!ip_addr_isany_val(pcb->multicast_ip) && !ip4_addr_cmp(ip_2_ip4(&pcb->multicast_ip), IP4_ADDR_BROADCAST)) { dst_ip_route = &pcb->multicast_ip; } #endif /* LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS */ } } #endif /* LWIP_IPV6 || (LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS) */ /* find the outgoing network interface for this packet */ netif = ip_route(IP_IS_V6(dst_ip_route), &pcb->local_ip, dst_ip_route); /* no outgoing network interface could be found? */ if (netif == NULL) { LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: No route to ")); ip_addr_debug_print(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, dst_ip); LWIP_DEBUGF(UDP_DEBUG, ("\n")); UDP_STATS_INC(udp.rterr); return ERR_RTE; } #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP return udp_sendto_if_chksum(pcb, p, dst_ip, dst_port, netif, have_chksum, chksum); #else /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ return udp_sendto_if(pcb, p, dst_ip, dst_port, netif); #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ } /** * Send data to a specified address using UDP. * The netif used for sending can be specified. * * This function exists mainly for DHCP, to be able to send UDP packets * on a netif that is still down. * * @param pcb UDP PCB used to send the data. * @param p chain of pbuf's to be sent. * @param dst_ip Destination IP address. * @param dst_port Destination UDP port. * @param netif the netif used for sending. * * dst_ip & dst_port are expected to be in the same byte order as in the pcb. * * @return lwIP error code (@see udp_send for possible error codes) * * @see udp_disconnect() udp_send() */ err_t udp_sendto_if(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif) { #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP return udp_sendto_if_chksum(pcb, p, dst_ip, dst_port, netif, 0, 0); } /** Same as udp_sendto_if(), but with checksum */ err_t udp_sendto_if_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif, u8_t have_chksum, u16_t chksum) { #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ const ip_addr_t *src_ip; if ((pcb == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) { return ERR_VAL; } /* PCB local address is IP_ANY_ADDR? */ #if LWIP_IPV6 if (IP_IS_V6(dst_ip)) { if (ip6_addr_isany(ip_2_ip6(&pcb->local_ip))) { src_ip = ip6_select_source_address(netif, ip_2_ip6(dst_ip)); if (src_ip == NULL) { /* No suitable source address was found. */ return ERR_RTE; } } else { /* use UDP PCB local IPv6 address as source address, if still valid. */ if (netif_get_ip6_addr_match(netif, ip_2_ip6(&pcb->local_ip)) < 0) { /* Address isn't valid anymore. */ return ERR_RTE; } src_ip = &pcb->local_ip; } } #endif /* LWIP_IPV6 */ #if LWIP_IPV4 && LWIP_IPV6 else #endif /* LWIP_IPV4 && LWIP_IPV6 */ #if LWIP_IPV4 if (ip4_addr_isany(ip_2_ip4(&pcb->local_ip))) { /* use outgoing network interface IP address as source address */ src_ip = netif_ip_addr4(netif); } else { /* check if UDP PCB local IP address is correct * this could be an old address if netif->ip_addr has changed */ if (!ip4_addr_cmp(ip_2_ip4(&(pcb->local_ip)), netif_ip4_addr(netif))) { /* local_ip doesn't match, drop the packet */ return ERR_VAL; } /* use UDP PCB local IP address as source address */ src_ip = &pcb->local_ip; } #endif /* LWIP_IPV4 */ #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP return udp_sendto_if_src_chksum(pcb, p, dst_ip, dst_port, netif, have_chksum, chksum, src_ip); #else /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ return udp_sendto_if_src(pcb, p, dst_ip, dst_port, netif, src_ip); #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ } /** Same as udp_sendto_if(), but with source address */ err_t udp_sendto_if_src(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif, const ip_addr_t *src_ip) { #if LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP return udp_sendto_if_src_chksum(pcb, p, dst_ip, dst_port, netif, 0, 0, src_ip); } /** Same as udp_sendto_if_src(), but with checksum */ err_t udp_sendto_if_src_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif, u8_t have_chksum, u16_t chksum, const ip_addr_t *src_ip) { #endif /* LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */ struct udp_hdr *udphdr; err_t err; struct pbuf *q; /* q will be sent down the stack */ u8_t ip_proto; u8_t ttl; if ((pcb == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, src_ip) || !IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) { return ERR_VAL; } #if LWIP_IPV4 && IP_SOF_BROADCAST /* broadcast filter? */ if (!ip_get_option(pcb, SOF_BROADCAST) && #if LWIP_IPV6 !IP_IS_V6(dst_ip) && #endif /* LWIP_IPV6 */ ip_addr_isbroadcast(dst_ip, netif)) { LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("udp_sendto_if: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb)); return ERR_VAL; } #endif /* LWIP_IPV4 && IP_SOF_BROADCAST */ /* if the PCB is not yet bound to a port, bind it here */ if (pcb->local_port == 0) { LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send: not yet bound to a port, binding now\n")); err = udp_bind(pcb, &pcb->local_ip, pcb->local_port); if (err != ERR_OK) { LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: forced port bind failed\n")); return err; } } /* not enough space to add an UDP header to first pbuf in given p chain? */ if (pbuf_header(p, UDP_HLEN)) { /* allocate header in a separate new pbuf */ q = pbuf_alloc(PBUF_IP, UDP_HLEN, PBUF_RAM); /* new header pbuf could not be allocated? */ if (q == NULL) { LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: could not allocate header\n")); return ERR_MEM; } if (p->tot_len != 0) { /* chain header q in front of given pbuf p (only if p contains data) */ pbuf_chain(q, p); } /* first pbuf q points to header pbuf */ LWIP_DEBUGF(UDP_DEBUG, ("udp_send: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p)); } else { /* adding space for header within p succeeded */ /* first pbuf q equals given pbuf */ q = p; LWIP_DEBUGF(UDP_DEBUG, ("udp_send: added header in given pbuf %p\n", (void *)p)); } LWIP_ASSERT("check that first pbuf can hold struct udp_hdr", (q->len >= sizeof(struct udp_hdr))); /* q now represents the packet to be sent */ udphdr = (struct udp_hdr *)q->payload; udphdr->src = htons(pcb->local_port); udphdr->dest = htons(dst_port); /* in UDP, 0 checksum means 'no checksum' */ udphdr->chksum = 0x0000; /* Multicast Loop? */ #if (LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS) || (LWIP_IPV6 && LWIP_IPV6_MLD) if (((pcb->flags & UDP_FLAGS_MULTICAST_LOOP) != 0) && ip_addr_ismulticast(dst_ip)) { q->flags |= PBUF_FLAG_MCASTLOOP; } #endif /* (LWIP_IPV4 && LWIP_MULTICAST_TX_OPTIONS) || (LWIP_IPV6 && LWIP_IPV6_MLD) */ LWIP_DEBUGF(UDP_DEBUG, ("udp_send: sending datagram of length %"U16_F"\n", q->tot_len)); #if LWIP_UDPLITE /* UDP Lite protocol? */ if (pcb->flags & UDP_FLAGS_UDPLITE) { u16_t chklen, chklen_hdr; LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE packet length %"U16_F"\n", q->tot_len)); /* set UDP message length in UDP header */ chklen_hdr = chklen = pcb->chksum_len_tx; if ((chklen < sizeof(struct udp_hdr)) || (chklen > q->tot_len)) { if (chklen != 0) { LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE pcb->chksum_len is illegal: %"U16_F"\n", chklen)); } /* For UDP-Lite, checksum length of 0 means checksum over the complete packet. (See RFC 3828 chap. 3.1) At least the UDP-Lite header must be covered by the checksum, therefore, if chksum_len has an illegal value, we generate the checksum over the complete packet to be safe. */ chklen_hdr = 0; chklen = q->tot_len; } udphdr->len = htons(chklen_hdr); /* calculate checksum */ #if CHECKSUM_GEN_UDP IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_UDP) { #if LWIP_CHECKSUM_ON_COPY if (have_chksum) { chklen = UDP_HLEN; } #endif /* LWIP_CHECKSUM_ON_COPY */ udphdr->chksum = ip_chksum_pseudo_partial(q, IP_PROTO_UDPLITE, q->tot_len, chklen, src_ip, dst_ip); #if LWIP_CHECKSUM_ON_COPY if (have_chksum) { u32_t acc; acc = udphdr->chksum + (u16_t)~(chksum); udphdr->chksum = FOLD_U32T(acc); } #endif /* LWIP_CHECKSUM_ON_COPY */ /* chksum zero must become 0xffff, as zero means 'no checksum' */ if (udphdr->chksum == 0x0000) { udphdr->chksum = 0xffff; } } #endif /* CHECKSUM_GEN_UDP */ ip_proto = IP_PROTO_UDPLITE; } else #endif /* LWIP_UDPLITE */ { /* UDP */ LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP packet length %"U16_F"\n", q->tot_len)); udphdr->len = htons(q->tot_len); /* calculate checksum */ #if CHECKSUM_GEN_UDP IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_UDP) { /* Checksum is mandatory over IPv6. */ if (IP_IS_V6(dst_ip) || (pcb->flags & UDP_FLAGS_NOCHKSUM) == 0) { u16_t udpchksum; #if LWIP_CHECKSUM_ON_COPY if (have_chksum) { u32_t acc; udpchksum = ip_chksum_pseudo_partial(q, IP_PROTO_UDP, q->tot_len, UDP_HLEN, src_ip, dst_ip); acc = udpchksum + (u16_t)~(chksum); udpchksum = FOLD_U32T(acc); } else #endif /* LWIP_CHECKSUM_ON_COPY */ { udpchksum = ip_chksum_pseudo(q, IP_PROTO_UDP, q->tot_len, src_ip, dst_ip); } /* chksum zero must become 0xffff, as zero means 'no checksum' */ if (udpchksum == 0x0000) { udpchksum = 0xffff; } udphdr->chksum = udpchksum; } } #endif /* CHECKSUM_GEN_UDP */ ip_proto = IP_PROTO_UDP; } /* Determine TTL to use */ #if LWIP_MULTICAST_TX_OPTIONS ttl = (ip_addr_ismulticast(dst_ip) ? pcb->mcast_ttl : pcb->ttl); #else /* LWIP_MULTICAST_TX_OPTIONS */ ttl = pcb->ttl; #endif /* LWIP_MULTICAST_TX_OPTIONS */ LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP checksum 0x%04"X16_F"\n", udphdr->chksum)); LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,0x%02"X16_F",)\n", (u16_t)ip_proto)); /* output to IP */ NETIF_SET_HWADDRHINT(netif, &(pcb->addr_hint)); err = ip_output_if_src(IP_IS_V6(dst_ip), q, src_ip, dst_ip, ttl, pcb->tos, ip_proto, netif); NETIF_SET_HWADDRHINT(netif, NULL); /* TODO: must this be increased even if error occurred? */ MIB2_STATS_INC(mib2.udpoutdatagrams); /* did we chain a separate header pbuf earlier? */ if (q != p) { /* free the header pbuf */ pbuf_free(q); q = NULL; /* p is still referenced by the caller, and will live on */ } UDP_STATS_INC(udp.xmit); return err; } /** * Bind an UDP PCB. * * @param pcb UDP PCB to be bound with a local address ipaddr and port. * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to * bind to all local interfaces. * @param port local UDP port to bind with. Use 0 to automatically bind * to a random port between UDP_LOCAL_PORT_RANGE_START and * UDP_LOCAL_PORT_RANGE_END. * * ipaddr & port are expected to be in the same byte order as in the pcb. * * @return lwIP error code. * - ERR_OK. Successful. No error occurred. * - ERR_USE. The specified ipaddr and port are already bound to by * another UDP PCB. * * @see udp_disconnect() */ err_t udp_bind(struct udp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port) { struct udp_pcb *ipcb; u8_t rebind; if ((pcb == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, ipaddr)) { return ERR_VAL; } LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_bind(ipaddr = ")); ip_addr_debug_print(UDP_DEBUG | LWIP_DBG_TRACE, ipaddr); LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, (", port = %"U16_F")\n", port)); rebind = 0; /* Check for double bind and rebind of the same pcb */ for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) { /* is this UDP PCB already on active list? */ if (pcb == ipcb) { rebind = 1; break; } } /* no port specified? */ if (port == 0) { port = udp_new_port(); if (port == 0) { /* no more ports available in local range */ LWIP_DEBUGF(UDP_DEBUG, ("udp_bind: out of free UDP ports\n")); return ERR_USE; } } else { for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) { if (pcb != ipcb) { /* By default, we don't allow to bind to a port that any other udp PCB is already bound to, unless *all* PCBs with that port have tha REUSEADDR flag set. */ #if SO_REUSE if (!ip_get_option(pcb, SOF_REUSEADDR) || !ip_get_option(ipcb, SOF_REUSEADDR)) #endif /* SO_REUSE */ { /* port matches that of PCB in list and REUSEADDR not set -> reject */ if ((ipcb->local_port == port) && (IP_IS_V6(ipaddr) == IP_IS_V6_VAL(ipcb->local_ip)) && /* IP address matches, or one is IP_ADDR_ANY? */ (ip_addr_isany(&ipcb->local_ip) || ip_addr_isany(ipaddr) || ip_addr_cmp(&ipcb->local_ip, ipaddr))) { /* other PCB already binds to this local IP and port */ LWIP_DEBUGF(UDP_DEBUG, ("udp_bind: local port %"U16_F" already bound by another pcb\n", port)); return ERR_USE; } } } } } ip_addr_set_ipaddr(&pcb->local_ip, ipaddr); pcb->local_port = port; mib2_udp_bind(pcb); /* pcb not active yet? */ if (rebind == 0) { /* place the PCB on the active list if not already there */ pcb->next = udp_pcbs; udp_pcbs = pcb; } LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("udp_bind: bound to ")); ip_addr_debug_print(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, &pcb->local_ip); LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, (", port %"U16_F")\n", pcb->local_port)); return ERR_OK; } /** * Connect an UDP PCB. * * This will associate the UDP PCB with the remote address. * * @param pcb UDP PCB to be connected with remote address ipaddr and port. * @param ipaddr remote IP address to connect with. * @param port remote UDP port to connect with. * * @return lwIP error code * * ipaddr & port are expected to be in the same byte order as in the pcb. * * The udp pcb is bound to a random local port if not already bound. * * @see udp_disconnect() */ err_t udp_connect(struct udp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port) { struct udp_pcb *ipcb; if ((pcb == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, ipaddr)) { return ERR_VAL; } if (pcb->local_port == 0) { err_t err = udp_bind(pcb, &pcb->local_ip, pcb->local_port); if (err != ERR_OK) { return err; } } ip_addr_set_ipaddr(&pcb->remote_ip, ipaddr); pcb->remote_port = port; pcb->flags |= UDP_FLAGS_CONNECTED; LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("udp_connect: connected to ")); ip_addr_debug_print(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, &pcb->remote_ip); LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, (", port %"U16_F")\n", pcb->remote_port)); /* Insert UDP PCB into the list of active UDP PCBs. */ for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) { if (pcb == ipcb) { /* already on the list, just return */ return ERR_OK; } } /* PCB not yet on the list, add PCB now */ pcb->next = udp_pcbs; udp_pcbs = pcb; return ERR_OK; } /** * Disconnect a UDP PCB * * @param pcb the udp pcb to disconnect. */ void udp_disconnect(struct udp_pcb *pcb) { /* reset remote address association */ ip_addr_set_any(PCB_ISIPV6(pcb), &pcb->remote_ip); pcb->remote_port = 0; /* mark PCB as unconnected */ pcb->flags &= ~UDP_FLAGS_CONNECTED; } /** * Set a receive callback for a UDP PCB * * This callback will be called when receiving a datagram for the pcb. * * @param pcb the pcb for which to set the recv callback * @param recv function pointer of the callback function * @param recv_arg additional argument to pass to the callback function */ void udp_recv(struct udp_pcb *pcb, udp_recv_fn recv, void *recv_arg) { /* remember recv() callback and user data */ pcb->recv = recv; pcb->recv_arg = recv_arg; } /** * Remove an UDP PCB. * * @param pcb UDP PCB to be removed. The PCB is removed from the list of * UDP PCB's and the data structure is freed from memory. * * @see udp_new() */ void udp_remove(struct udp_pcb *pcb) { struct udp_pcb *pcb2; mib2_udp_unbind(pcb); /* pcb to be removed is first in list? */ if (udp_pcbs == pcb) { /* make list start at 2nd pcb */ udp_pcbs = udp_pcbs->next; /* pcb not 1st in list */ } else { for (pcb2 = udp_pcbs; pcb2 != NULL; pcb2 = pcb2->next) { /* find pcb in udp_pcbs list */ if (pcb2->next != NULL && pcb2->next == pcb) { /* remove pcb from list */ pcb2->next = pcb->next; break; } } } memp_free(MEMP_UDP_PCB, pcb); } /** * Create a UDP PCB. * * @return The UDP PCB which was created. NULL if the PCB data structure * could not be allocated. * * @see udp_remove() */ struct udp_pcb * udp_new(void) { struct udp_pcb *pcb; pcb = (struct udp_pcb *)memp_malloc(MEMP_UDP_PCB); /* could allocate UDP PCB? */ if (pcb != NULL) { /* UDP Lite: by initializing to all zeroes, chksum_len is set to 0 * which means checksum is generated over the whole datagram per default * (recommended as default by RFC 3828). */ /* initialize PCB to all zeroes */ memset(pcb, 0, sizeof(struct udp_pcb)); pcb->ttl = UDP_TTL; #if LWIP_MULTICAST_TX_OPTIONS pcb->mcast_ttl = UDP_TTL; #endif /* LWIP_MULTICAST_TX_OPTIONS */ } return pcb; } #if LWIP_IPV6 /** * Create a UDP PCB for IPv6. * * @return The UDP PCB which was created. NULL if the PCB data structure * could not be allocated. * * @see udp_remove() */ struct udp_pcb * udp_new_ip6(void) { struct udp_pcb *pcb; pcb = udp_new(); #if LWIP_IPV4 ip_set_v6(pcb, 1); #endif /* LWIP_IPV4 */ return pcb; } #endif /* LWIP_IPV6 */ #if LWIP_IPV4 /** This function is called from netif.c when address is changed * * @param old_addr IPv4 address of the netif before change * @param new_addr IPv4 address of the netif after change */ void udp_netif_ipv4_addr_changed(const ip4_addr_t* old_addr, const ip4_addr_t* new_addr) { struct udp_pcb* upcb; if (!ip4_addr_isany(new_addr)) { for (upcb = udp_pcbs; upcb != NULL; upcb = upcb->next) { /* Is this an IPv4 pcb? */ if (!IP_IS_V6_VAL(upcb->local_ip)) { /* PCB bound to current local interface address? */ if (!ip4_addr_isany(ip_2_ip4(&upcb->local_ip)) && ip4_addr_cmp(ip_2_ip4(&upcb->local_ip), old_addr)) { /* The PCB is bound to the old ipaddr and * is set to bound to the new one instead */ ip_addr_copy_from_ip4(upcb->local_ip, *new_addr); } } } } } #endif /* LWIP_IPV4 */ #if UDP_DEBUG /** * Print UDP header information for debug purposes. * * @param udphdr pointer to the udp header in memory. */ void udp_debug_print(struct udp_hdr *udphdr) { LWIP_DEBUGF(UDP_DEBUG, ("UDP header:\n")); LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(UDP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n", ntohs(udphdr->src), ntohs(udphdr->dest))); LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(UDP_DEBUG, ("| %5"U16_F" | 0x%04"X16_F" | (len, chksum)\n", ntohs(udphdr->len), ntohs(udphdr->chksum))); LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n")); } #endif /* UDP_DEBUG */ #endif /* LWIP_UDP */