--- /dev/null
+/**
+ * @file
+ * ICMP - Internet Control Message Protocol
+ *
+ */
+
+/*
+ * 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 <adam@sics.se>
+ *
+ */
+
+/* Some ICMP messages should be passed to the transport protocols. This
+ is not implemented. */
+
+#include "lwip/opt.h"
+
+#if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/icmp.h"
+#include "lwip/inet.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/ip.h"
+#include "lwip/def.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+
+#include <string.h>
+
+/* The amount of data from the original packet to return in a dest-unreachable */
+#define ICMP_DEST_UNREACH_DATASIZE 8
+
+/**
+ * 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 ip 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;
+ struct ip_hdr *iphdr;
+ struct ip_addr tmpaddr;
+ s16_t hlen;
+
+ ICMP_STATS_INC(icmp.recv);
+ snmp_inc_icmpinmsgs();
+
+
+ iphdr = p->payload;
+ hlen = IPH_HL(iphdr) * 4;
+ if (pbuf_header(p, -hlen) || (p->tot_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_ECHO:
+ /* broadcast or multicast destination address? */
+ if (ip_addr_isbroadcast(&iphdr->dest, inp) || ip_addr_ismulticast(&iphdr->dest)) {
+ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
+ ICMP_STATS_INC(icmp.err);
+ pbuf_free(p);
+ return;
+ }
+ 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 (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);
+ snmp_inc_icmpinerrors();
+ return;
+ }
+ if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
+ /* p is not big enough to contain link headers
+ * allocate a new one and copy p into it
+ */
+ struct pbuf *r;
+ /* switch p->payload to ip header */
+ if (pbuf_header(p, hlen)) {
+ LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0);
+ goto memerr;
+ }
+ /* allocate new packet buffer with space for link headers */
+ r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
+ if (r == NULL) {
+ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
+ goto memerr;
+ }
+ LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
+ (r->len >= hlen + sizeof(struct icmp_echo_hdr)));
+ /* copy the whole packet including ip header */
+ if (pbuf_copy(r, p) != ERR_OK) {
+ LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
+ goto memerr;
+ }
+ iphdr = r->payload;
+ /* switch r->payload back to icmp header */
+ if (pbuf_header(r, -hlen)) {
+ LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
+ goto memerr;
+ }
+ /* 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))) {
+ LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
+ goto memerr;
+ }
+ }
+ /* 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 = p->payload;
+ tmpaddr.addr = iphdr->src.addr;
+ iphdr->src.addr = iphdr->dest.addr;
+ iphdr->dest.addr = tmpaddr.addr;
+ ICMPH_TYPE_SET(iecho, ICMP_ER);
+ /* adjust the checksum */
+ if (iecho->chksum >= htons(0xffff - (ICMP_ECHO << 8))) {
+ iecho->chksum += htons(ICMP_ECHO << 8) + 1;
+ } else {
+ iecho->chksum += htons(ICMP_ECHO << 8);
+ }
+
+ /* Set the correct TTL and recalculate the header checksum. */
+ IPH_TTL_SET(iphdr, ICMP_TTL);
+ IPH_CHKSUM_SET(iphdr, 0);
+#if 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 */
+ snmp_inc_icmpoutmsgs();
+ /* increase number of echo replies attempted to send */
+ snmp_inc_icmpoutechoreps();
+
+ if(pbuf_header(p, hlen)) {
+ LWIP_ASSERT("Can't move over header in packet", 0);
+ } else {
+ err_t ret;
+ ret = ip_output_if(p, &(iphdr->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));
+ }
+ }
+ break;
+ default:
+ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n",
+ (s16_t)type, (s16_t)code));
+ ICMP_STATS_INC(icmp.proterr);
+ ICMP_STATS_INC(icmp.drop);
+ }
+ pbuf_free(p);
+ return;
+lenerr:
+ pbuf_free(p);
+ ICMP_STATS_INC(icmp.lenerr);
+ snmp_inc_icmpinerrors();
+ return;
+memerr:
+ pbuf_free(p);
+ ICMP_STATS_INC(icmp.err);
+ snmp_inc_icmpinerrors();
+ return;
+}
+
+/**
+ * Send an icmp 'destination unreachable' packet, called from ip_input() if
+ * the transport layer protocol is unknown and from udp_input() if the local
+ * port is not bound.
+ *
+ * @param p the input packet for which the 'unreachable' should be sent,
+ * p->payload pointing to the IP header
+ * @param t type of the 'unreachable' packet
+ */
+void
+icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
+{
+ struct pbuf *q;
+ struct ip_hdr *iphdr;
+ struct icmp_dur_hdr *idur;
+
+ /* ICMP header + IP header + 8 bytes of data */
+ q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
+ PBUF_RAM);
+ if (q == NULL) {
+ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
+ return;
+ }
+ LWIP_ASSERT("check that first pbuf can hold icmp message",
+ (q->len >= (sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
+
+ iphdr = p->payload;
+
+ idur = q->payload;
+ ICMPH_TYPE_SET(idur, ICMP_DUR);
+ ICMPH_CODE_SET(idur, t);
+
+ SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_dur_hdr), p->payload,
+ IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
+
+ /* calculate checksum */
+ idur->chksum = 0;
+ idur->chksum = inet_chksum(idur, q->len);
+ ICMP_STATS_INC(icmp.xmit);
+ /* increase number of messages attempted to send */
+ snmp_inc_icmpoutmsgs();
+ /* increase number of destination unreachable messages attempted to send */
+ snmp_inc_icmpoutdestunreachs();
+
+ ip_output(q, NULL, &(iphdr->src), ICMP_TTL, 0, IP_PROTO_ICMP);
+ pbuf_free(q);
+}
+
+#if IP_FORWARD || IP_REASSEMBLY
+/**
+ * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0.
+ *
+ * @param p the input packet for which the 'time exceeded' should be sent,
+ * p->payload pointing to the IP header
+ * @param t type of the 'time exceeded' packet
+ */
+void
+icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
+{
+ struct pbuf *q;
+ struct ip_hdr *iphdr;
+ struct icmp_te_hdr *tehdr;
+
+ /* ICMP header + IP header + 8 bytes of data */
+ q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
+ PBUF_RAM);
+ if (q == NULL) {
+ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
+ return;
+ }
+ LWIP_ASSERT("check that first pbuf can hold icmp message",
+ (q->len >= (sizeof(struct icmp_dur_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
+
+ iphdr = p->payload;
+ LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
+ ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
+ LWIP_DEBUGF(ICMP_DEBUG, (" to "));
+ ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
+ LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
+
+ tehdr = q->payload;
+ ICMPH_TYPE_SET(tehdr, ICMP_TE);
+ ICMPH_CODE_SET(tehdr, t);
+
+ /* copy fields from original packet */
+ SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_dur_hdr), (u8_t *)p->payload,
+ IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
+
+ /* calculate checksum */
+ tehdr->chksum = 0;
+ tehdr->chksum = inet_chksum(tehdr, q->len);
+ ICMP_STATS_INC(icmp.xmit);
+ /* increase number of messages attempted to send */
+ snmp_inc_icmpoutmsgs();
+ /* increase number of destination unreachable messages attempted to send */
+ snmp_inc_icmpouttimeexcds();
+ ip_output(q, NULL, &(iphdr->src), ICMP_TTL, 0, IP_PROTO_ICMP);
+ pbuf_free(q);
+}
+
+#endif /* IP_FORWARD */
+
+#endif /* LWIP_ICMP */
