/** Common code to see if the current input packet matches the pcb * (current input packet is accessed via ip(4/6)_current_* macros) * * @param pcb pcb to check * @param inp network interface on which the datagram was received (only used for IPv4) * @param broadcast 1 if his is an IPv4 broadcast (global or subnet-only), 0 otherwise (only used for IPv4) * @return 1 on match, 0 otherwise */ static u8_t ESP_IRAM_ATTR udp_input_local_match(struct udp_pcb *pcb, struct netif *inp, u8_t broadcast) { LWIP_UNUSED_ARG(inp); /* in IPv6 only case */ LWIP_UNUSED_ARG(broadcast); /* in IPv6 only case */ /* Dual-stack: PCBs listening to any IP type also listen to any IP address */ if(IP_IS_ANY_TYPE_VAL(pcb->local_ip)) { #if LWIP_IPV4 && IP_SOF_BROADCAST_RECV if((broadcast != 0) && !ip_get_option(pcb, SOF_BROADCAST)) { return 0; } #endif /* LWIP_IPV4 && IP_SOF_BROADCAST_RECV */ return 1; } /* Only need to check PCB if incoming IP version matches PCB IP version */ if(IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ip_current_dest_addr())) { LWIP_ASSERT("UDP PCB: inconsistent local/remote IP versions", IP_IS_V6_VAL(pcb->local_ip) == IP_IS_V6_VAL(pcb->remote_ip)); #if LWIP_IPV4 /* Special case: IPv4 broadcast: all or broadcasts in my subnet * Note: broadcast variable can only be 1 if it is an IPv4 broadcast */ if(broadcast != 0) { #if IP_SOF_BROADCAST_RECV if(ip_get_option(pcb, SOF_BROADCAST)) #endif /* IP_SOF_BROADCAST_RECV */ { if(ip4_addr_isany(ip_2_ip4(&pcb->local_ip)) || ((ip4_current_dest_addr()->addr == IPADDR_BROADCAST)) || ip4_addr_netcmp(ip_2_ip4(&pcb->local_ip), ip4_current_dest_addr(), netif_ip4_netmask(inp))) { return 1; } } } else #endif /* LWIP_IPV4 */ /* Handle IPv4 and IPv6: all, multicast or exact match */ if(ip_addr_isany(&pcb->local_ip) || #if LWIP_IPV6_MLD (ip_current_is_v6() && ip6_addr_ismulticast(ip6_current_dest_addr())) || #endif /* LWIP_IPV6_MLD */ #if LWIP_IGMP (!ip_current_is_v6() && ip4_addr_ismulticast(ip4_current_dest_addr())) || #endif /* LWIP_IGMP */ ip_addr_cmp(&pcb->local_ip, ip_current_dest_addr())) { return 1; } } return 0; }
/** * 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 broadcast; u8_t for_us = 0; 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; /* is broadcast packet ? */ broadcast = ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif()); 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 = lwip_ntohs(udphdr->src); dest = lwip_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") <-- (", lwip_ntohs(udphdr->dest))); ip_addr_debug_print(UDP_DEBUG, ip_current_src_addr()); LWIP_DEBUGF(UDP_DEBUG, (", %"U16_F")\n", lwip_ntohs(udphdr->src))); pcb = NULL; prev = NULL; 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) { /* 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) && (udp_input_local_match(pcb, inp, broadcast) != 0)) { if (((pcb->flags & UDP_FLAGS_CONNECTED) == 0) && ((uncon_pcb == NULL) #if SO_REUSE /* prefer specific IPs over cath-all */ || !ip_addr_isany(&pcb->local_ip) #endif /* SO_REUSE */ )) { /* the first unconnected matching PCB */ uncon_pcb = pcb; } /* compare PCB remote addr+port to UDP source addr+port */ if ((pcb->remote_port == src) && (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; } #endif /* LWIP_IPV6 */ #if LWIP_IPV4 if (!ip_current_is_v6()) { 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 = lwip_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 (ip_get_option(pcb, SOF_REUSEADDR) && (broadcast || ip_addr_ismulticast(ip_current_dest_addr()))) { /* 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) && (udp_input_local_match(mpcb, inp, broadcast) != 0)) { /* 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 (!broadcast && !ip_addr_ismulticast(ip_current_dest_addr())) { /* 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 {
/** * Processes ICMP input packets, called from ip_input(). * * Currently only processes icmp echo requests and sends * out the echo response. * * @param p the icmp echo request packet, p->payload pointing to the icmp header * @param inp the netif on which this packet was received */ void icmp_input(struct pbuf *p, struct netif *inp) { u8_t type; #ifdef LWIP_DEBUG u8_t code; #endif /* LWIP_DEBUG */ struct icmp_echo_hdr *iecho; const struct ip_hdr *iphdr_in; struct ip_hdr *iphdr; s16_t hlen; const ip4_addr_t* src; ICMP_STATS_INC(icmp.recv); MIB2_STATS_INC(mib2.icmpinmsgs); iphdr_in = ip4_current_header(); hlen = IPH_HL(iphdr_in) * 4; if (p->len < sizeof(u16_t)*2) { LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len)); goto lenerr; } type = *((u8_t *)p->payload); #ifdef LWIP_DEBUG code = *(((u8_t *)p->payload)+1); #endif /* LWIP_DEBUG */ switch (type) { case ICMP_ER: /* This is OK, echo reply might have been parsed by a raw PCB (as obviously, an echo request has been sent, too). */ break; case ICMP_ECHO: src = ip4_current_dest_addr(); /* multicast destination address? */ if (ip_addr_ismulticast(ip_current_dest_addr())) { #if LWIP_MULTICAST_PING /* For multicast, use address of receiving interface as source address */ src = netif_ip4_addr(inp); #else /* LWIP_MULTICAST_PING */ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast pings\n")); goto icmperr; #endif /* LWIP_MULTICAST_PING */ } /* broadcast destination address? */ if (ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif())) { #if LWIP_BROADCAST_PING /* For broadcast, use address of receiving interface as source address */ src = netif_ip4_addr(inp); #else /* LWIP_BROADCAST_PING */ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to broadcast pings\n")); goto icmperr; #endif /* LWIP_BROADCAST_PING */ } LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n")); if (p->tot_len < sizeof(struct icmp_echo_hdr)) { LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n")); goto lenerr; } #if CHECKSUM_CHECK_ICMP IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP) { if (inet_chksum_pbuf(p) != 0) { LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n")); pbuf_free(p); ICMP_STATS_INC(icmp.chkerr); MIB2_STATS_INC(mib2.icmpinerrors); return; } } #endif #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) { /* p is not big enough to contain link headers * allocate a new one and copy p into it */ struct pbuf *r; /* allocate new packet buffer with space for link headers */ r = pbuf_alloc(PBUF_LINK, p->tot_len + hlen, PBUF_RAM); if (r == NULL) { LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n")); goto icmperr; } LWIP_ASSERT("check that first pbuf can hold struct the ICMP header", (r->len >= hlen + sizeof(struct icmp_echo_hdr))); /* copy the ip header */ MEMCPY(r->payload, iphdr_in, hlen); iphdr = (struct ip_hdr *)r->payload; /* switch r->payload back to icmp header */ if (pbuf_header(r, -hlen)) { LWIP_ASSERT("icmp_input: moving r->payload to icmp header failed\n", 0); goto icmperr; } /* copy the rest of the packet without ip header */ if (pbuf_copy(r, p) != ERR_OK) { LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0); goto icmperr; } /* free the original p */ pbuf_free(p); /* we now have an identical copy of p that has room for link headers */ p = r; } else { /* restore p->payload to point to icmp header */ if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) { LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0); goto icmperr; } } #endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */ /* At this point, all checks are OK. */ /* We generate an answer by switching the dest and src ip addresses, * setting the icmp type to ECHO_RESPONSE and updating the checksum. */ iecho = (struct icmp_echo_hdr *)p->payload; if(pbuf_header(p, hlen)) { LWIP_ASSERT("Can't move over header in packet", 0); } else { err_t ret; iphdr = (struct ip_hdr*)p->payload; ip4_addr_copy(iphdr->src, *src); ip4_addr_copy(iphdr->dest, *ip4_current_src_addr()); ICMPH_TYPE_SET(iecho, ICMP_ER); #if CHECKSUM_GEN_ICMP IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP) { /* adjust the checksum */ if (iecho->chksum > PP_HTONS(0xffffU - (ICMP_ECHO << 8))) { iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1; } else { iecho->chksum += PP_HTONS(ICMP_ECHO << 8); } } #if LWIP_CHECKSUM_CTRL_PER_NETIF else { iecho->chksum = 0; } #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */ #else /* CHECKSUM_GEN_ICMP */ iecho->chksum = 0; #endif /* CHECKSUM_GEN_ICMP */ /* Set the correct TTL and recalculate the header checksum. */ IPH_TTL_SET(iphdr, ICMP_TTL); IPH_CHKSUM_SET(iphdr, 0); #if CHECKSUM_GEN_IP IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_IP) { IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN)); } #endif /* CHECKSUM_GEN_IP */ ICMP_STATS_INC(icmp.xmit); /* increase number of messages attempted to send */ MIB2_STATS_INC(mib2.icmpoutmsgs); /* increase number of echo replies attempted to send */ MIB2_STATS_INC(mib2.icmpoutechoreps); /* send an ICMP packet */ ret = ip4_output_if(p, src, IP_HDRINCL, ICMP_TTL, 0, IP_PROTO_ICMP, inp); if (ret != ERR_OK) { LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret)); } }