1/*
2 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice,
9 *    this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 *    this list of conditions and the following disclaimer in the documentation
12 *    and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 *    derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
19 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
21 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
24 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
25 * OF SUCH DAMAGE.
26 *
27 * This file is part of the lwIP TCP/IP stack.
28 *
29 * Author: Adam Dunkels <adam@sics.se>
30 *
31 */
32
33/* Some ICMP messages should be passed to the transport protocols. This
34   is not implemented. */
35
36#include "lwip/opt.h"
37
38#if LWIP_ICMP                   /* don't build if not configured for use in lwipopts.h */
39
40#include "lwip/icmp.h"
41#include "lwip/inet.h"
42#include "lwip/ip.h"
43#include "lwip/def.h"
44#include "lwip/stats.h"
45
46void icmp_input(struct pbuf *p, struct netif *inp)
47{
48    u8_t type;
49    struct icmp_echo_hdr *iecho;
50    struct ip_hdr *iphdr;
51    struct ip_addr tmpaddr;
52
53    ICMP_STATS_INC(icmp.recv);
54
55    /* TODO: check length before accessing payload! */
56
57    type = ((u8_t *) p->payload)[0];
58
59    switch (type) {
60        case ICMP6_ECHO:
61            LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
62
63            if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
64                LWIP_DEBUGF(ICMP_DEBUG,
65                            ("icmp_input: bad ICMP echo received\n"));
66
67                pbuf_free(p);
68                ICMP_STATS_INC(icmp.lenerr);
69                return;
70            }
71            iecho = p->payload;
72            iphdr = (struct ip_hdr *) ((u8_t *) p->payload - IP_HLEN);
73            if (inet_chksum_pbuf(p) != 0) {
74                LWIP_DEBUGF(ICMP_DEBUG,
75                            ("icmp_input: checksum failed for received ICMP echo (%"
76                             X16_F ")\n", inet_chksum_pseudo(p, &(iphdr->src),
77                                                             &(iphdr->dest),
78                                                             IP_PROTO_ICMP,
79                                                             p->tot_len)));
80                ICMP_STATS_INC(icmp.chkerr);
81                /*      return; */
82            }
83            LWIP_DEBUGF(ICMP_DEBUG,
84                        ("icmp: p->len %" S16_F " p->tot_len %" S16_F "\n",
85                         p->len, p->tot_len));
86            ip_addr_set(&tmpaddr, &(iphdr->src));
87            ip_addr_set(&(iphdr->src), &(iphdr->dest));
88            ip_addr_set(&(iphdr->dest), &tmpaddr);
89            iecho->type = ICMP6_ER;
90            /* adjust the checksum */
91            if (iecho->chksum >= htons(0xffff - (ICMP6_ECHO << 8))) {
92                iecho->chksum += htons(ICMP6_ECHO << 8) + 1;
93            } else {
94                iecho->chksum += htons(ICMP6_ECHO << 8);
95            }
96            LWIP_DEBUGF(ICMP_DEBUG,
97                        ("icmp_input: checksum failed for received ICMP echo (%"
98                         X16_F ")\n", inet_chksum_pseudo(p, &(iphdr->src),
99                                                         &(iphdr->dest),
100                                                         IP_PROTO_ICMP,
101                                                         p->tot_len)));
102            ICMP_STATS_INC(icmp.xmit);
103
104            /*    LWIP_DEBUGF("icmp: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len); */
105            ip_output_if(p, &(iphdr->src), IP_HDRINCL,
106                         iphdr->hoplim, IP_PROTO_ICMP, inp);
107            break;
108        default:
109            LWIP_DEBUGF(ICMP_DEBUG,
110                        ("icmp_input: ICMP type %" S16_F " not supported.\n",
111                         (s16_t) type));
112            ICMP_STATS_INC(icmp.proterr);
113            ICMP_STATS_INC(icmp.drop);
114    }
115
116    pbuf_free(p);
117}
118
119void icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
120{
121    struct pbuf *q;
122    struct ip_hdr *iphdr;
123    struct icmp_dur_hdr *idur;
124
125    /* @todo: can this be PBUF_LINK instead of PBUF_IP? */
126    q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
127    /* ICMP header + IP header + 8 bytes of data */
128    if (q == NULL) {
129        LWIP_DEBUGF(ICMP_DEBUG,
130                    ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
131        pbuf_free(p);
132        return;
133    }
134    LWIP_ASSERT("check that first pbuf can hold icmp message",
135                (q->len >= (8 + IP_HLEN + 8)));
136
137    iphdr = p->payload;
138
139    idur = q->payload;
140    idur->type = (u8_t) ICMP6_DUR;
141    idur->icode = (u8_t) t;
142
143    SMEMCPY((u8_t *) q->payload + 8, p->payload, IP_HLEN + 8);
144
145    /* calculate checksum */
146    idur->chksum = 0;
147    idur->chksum = inet_chksum(idur, q->len);
148    ICMP_STATS_INC(icmp.xmit);
149
150    ip_output(q, NULL,
151              (struct ip_addr *) &(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
152    pbuf_free(q);
153}
154
155void icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
156{
157    struct pbuf *q;
158    struct ip_hdr *iphdr;
159    struct icmp_te_hdr *tehdr;
160
161    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded\n"));
162
163    /* @todo: can this be PBUF_LINK instead of PBUF_IP? */
164    q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
165    /* ICMP header + IP header + 8 bytes of data */
166    if (q == NULL) {
167        LWIP_DEBUGF(ICMP_DEBUG,
168                    ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
169        pbuf_free(p);
170        return;
171    }
172    LWIP_ASSERT("check that first pbuf can hold icmp message",
173                (q->len >= (8 + IP_HLEN + 8)));
174
175    iphdr = p->payload;
176
177    tehdr = q->payload;
178    tehdr->type = (u8_t) ICMP6_TE;
179    tehdr->icode = (u8_t) t;
180
181    /* copy fields from original packet */
182    SMEMCPY((u8_t *) q->payload + 8, (u8_t *) p->payload, IP_HLEN + 8);
183
184    /* calculate checksum */
185    tehdr->chksum = 0;
186    tehdr->chksum = inet_chksum(tehdr, q->len);
187    ICMP_STATS_INC(icmp.xmit);
188    ip_output(q, NULL,
189              (struct ip_addr *) &(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
190    pbuf_free(q);
191}
192
193#endif                          /* LWIP_ICMP */
194