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 
46 void
icmp_input(struct pbuf * p,struct netif * inp)47 icmp_input(struct pbuf *p, struct netif *inp)
48 {
49   u8_t type;
50   struct icmp_echo_hdr *iecho;
51   struct ip_hdr *iphdr;
52   struct ip_addr tmpaddr;
53 
54   ICMP_STATS_INC(icmp.recv);
55 
56   /* TODO: check length before accessing payload! */
57 
58   type = ((u8_t *)p->payload)[0];
59 
60   switch (type) {
61   case ICMP6_ECHO:
62     LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
63 
64     if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
65       LWIP_DEBUGF(ICMP_DEBUG, ("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, ("icmp_input: checksum failed for received ICMP echo (%"X16_F")\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len)));
75       ICMP_STATS_INC(icmp.chkerr);
76     /*      return;*/
77     }
78     LWIP_DEBUGF(ICMP_DEBUG, ("icmp: p->len %"S16_F" p->tot_len %"S16_F"\n", p->len, p->tot_len));
79     ip_addr_set(&tmpaddr, &(iphdr->src));
80     ip_addr_set(&(iphdr->src), &(iphdr->dest));
81     ip_addr_set(&(iphdr->dest), &tmpaddr);
82     iecho->type = ICMP6_ER;
83     /* adjust the checksum */
84     if (iecho->chksum >= htons(0xffff - (ICMP6_ECHO << 8))) {
85       iecho->chksum += htons(ICMP6_ECHO << 8) + 1;
86     } else {
87       iecho->chksum += htons(ICMP6_ECHO << 8);
88     }
89     LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo (%"X16_F")\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len)));
90     ICMP_STATS_INC(icmp.xmit);
91 
92     /*    LWIP_DEBUGF("icmp: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len);*/
93     ip_output_if (p, &(iphdr->src), IP_HDRINCL,
94      iphdr->hoplim, IP_PROTO_ICMP, inp);
95     break;
96   default:
97     LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" not supported.\n", (s16_t)type));
98     ICMP_STATS_INC(icmp.proterr);
99     ICMP_STATS_INC(icmp.drop);
100   }
101 
102   pbuf_free(p);
103 }
104 
105 void
icmp_dest_unreach(struct pbuf * p,enum icmp_dur_type t)106 icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
107 {
108   struct pbuf *q;
109   struct ip_hdr *iphdr;
110   struct icmp_dur_hdr *idur;
111 
112   /* @todo: can this be PBUF_LINK instead of PBUF_IP? */
113   q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
114   /* ICMP header + IP header + 8 bytes of data */
115   if (q == NULL) {
116     LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
117     pbuf_free(p);
118     return;
119   }
120   LWIP_ASSERT("check that first pbuf can hold icmp message",
121              (q->len >= (8 + IP_HLEN + 8)));
122 
123   iphdr = p->payload;
124 
125   idur = q->payload;
126   idur->type = (u8_t)ICMP6_DUR;
127   idur->icode = (u8_t)t;
128 
129   SMEMCPY((u8_t *)q->payload + 8, p->payload, IP_HLEN + 8);
130 
131   /* calculate checksum */
132   idur->chksum = 0;
133   idur->chksum = inet_chksum(idur, q->len);
134   ICMP_STATS_INC(icmp.xmit);
135 
136   ip_output(q, NULL,
137       (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
138   pbuf_free(q);
139 }
140 
141 void
icmp_time_exceeded(struct pbuf * p,enum icmp_te_type t)142 icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
143 {
144   struct pbuf *q;
145   struct ip_hdr *iphdr;
146   struct icmp_te_hdr *tehdr;
147 
148   LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded\n"));
149 
150   /* @todo: can this be PBUF_LINK instead of PBUF_IP? */
151   q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
152   /* ICMP header + IP header + 8 bytes of data */
153   if (q == NULL) {
154     LWIP_DEBUGF(ICMP_DEBUG, ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
155     pbuf_free(p);
156     return;
157   }
158   LWIP_ASSERT("check that first pbuf can hold icmp message",
159              (q->len >= (8 + IP_HLEN + 8)));
160 
161   iphdr = p->payload;
162 
163   tehdr = q->payload;
164   tehdr->type = (u8_t)ICMP6_TE;
165   tehdr->icode = (u8_t)t;
166 
167   /* copy fields from original packet */
168   SMEMCPY((u8_t *)q->payload + 8, (u8_t *)p->payload, IP_HLEN + 8);
169 
170   /* calculate checksum */
171   tehdr->chksum = 0;
172   tehdr->chksum = inet_chksum(tehdr, q->len);
173   ICMP_STATS_INC(icmp.xmit);
174   ip_output(q, NULL,
175       (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
176   pbuf_free(q);
177 }
178 
179 #endif /* LWIP_ICMP */
180