Diff: lwip/core/ipv4/icmp.c

Revision:

1:9d93f4dc2f46

Parent:

0:8b387bed54c2

--- a/lwip/core/ipv4/icmp.c	Mon Jan 10 21:03:11 2011 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,335 +0,0 @@
-/**
- * @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_chksum.h"
-#include "lwip/ip.h"
-#include "lwip/def.h"
-#include "lwip/stats.h"
-#include "lwip/snmp.h"
-
-#include <string.h>
-
-/** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be
- * used to modify and send a response packet (and to 1 if this is not the case,
- * e.g. when link header is stripped of when receiving) */
-#ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
-#define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
-#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
-
-/* The amount of data from the original packet to return in a dest-unreachable */
-#define ICMP_DEST_UNREACH_DATASIZE 8
-
-static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
-
-/**
- * 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;
-  s16_t hlen;
-
-  ICMP_STATS_INC(icmp.recv);
-  snmp_inc_icmpinmsgs();
-
-
-  iphdr = (struct ip_hdr *)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_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:
-#if !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING
-    {
-      int accepted = 1;
-#if !LWIP_MULTICAST_PING
-      /* multicast destination address? */
-      if (ip_addr_ismulticast(&current_iphdr_dest)) {
-        accepted = 0;
-      }
-#endif /* LWIP_MULTICAST_PING */
-#if !LWIP_BROADCAST_PING
-      /* broadcast destination address? */
-      if (ip_addr_isbroadcast(&current_iphdr_dest, inp)) {
-        accepted = 0;
-      }
-#endif /* LWIP_BROADCAST_PING */
-      /* broadcast or multicast destination address not acceptd? */
-      if (!accepted) {
-        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
-        ICMP_STATS_INC(icmp.err);
-        pbuf_free(p);
-        return;
-      }
-    }
-#endif /* !LWIP_MULTICAST_PING || !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 (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 LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
-    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 = (struct ip_hdr *)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;
-      }
-    }
-#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;
-    ip_addr_copy(iphdr->src, *ip_current_dest_addr());
-    ip_addr_copy(iphdr->dest, *ip_current_src_addr());
-    ICMPH_TYPE_SET(iecho, ICMP_ER);
-    /* adjust the checksum */
-    if (iecho->chksum >= PP_HTONS(0xffff - (ICMP_ECHO << 8))) {
-      iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
-    } else {
-      iecho->chksum += PP_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;
-      /* send an ICMP packet, src addr is the dest addr of the curren packet */
-      ret = ip_output_if(p, ip_current_dest_addr(), 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;
-#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
-memerr:
-  pbuf_free(p);
-  ICMP_STATS_INC(icmp.err);
-  snmp_inc_icmpinerrors();
-  return;
-#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
-}
-
-/**
- * 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)
-{
-  icmp_send_response(p, ICMP_DUR, t);
-}
-
-#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)
-{
-  icmp_send_response(p, ICMP_TE, t);
-}
-
-#endif /* IP_FORWARD || IP_REASSEMBLY */
-
-/**
- * Send an icmp packet in response to an incoming packet.
- *
- * @param p the input packet for which the 'unreachable' should be sent,
- *          p->payload pointing to the IP header
- * @param type Type of the ICMP header
- * @param code Code of the ICMP header
- */
-static void
-icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
-{
-  struct pbuf *q;
-  struct ip_hdr *iphdr;
-  /* we can use the echo header here */
-  struct icmp_echo_hdr *icmphdr;
-  ip_addr_t iphdr_src;
-
-  /* ICMP header + IP header + 8 bytes of data */
-  q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_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_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
-
-  iphdr = (struct ip_hdr *)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"));
-
-  icmphdr = (struct icmp_echo_hdr *)q->payload;
-  icmphdr->type = type;
-  icmphdr->code = code;
-  icmphdr->id = 0;
-  icmphdr->seqno = 0;
-
-  /* copy fields from original packet */
-  SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload,
-          IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
-
-  /* calculate checksum */
-  icmphdr->chksum = 0;
-  icmphdr->chksum = inet_chksum(icmphdr, 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_addr_copy(iphdr_src, iphdr->src);
-  ip_output(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP);
-  pbuf_free(q);
-}
-
-#endif /* LWIP_ICMP */