📄 icmp.lst
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C51 COMPILER V8.08 ICMP 11/04/2008 18:45:34 PAGE 1
C51 COMPILER V8.08, COMPILATION OF MODULE ICMP
OBJECT MODULE PLACED IN Icmp.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.exe Icmp.c DB OE
line level source
1 //-----------------------------------------------------------------------------
2 // Copyright (c) 2002 Jim Brady
3 // Do not use commercially without author's permission
4 // Last revised August 2002
5 // Net ICMP.C
6 //
7 // This module handles ICMP messages
8 // Refer to RFC 792, 896, 950, 1122, and 1191
9 //-----------------------------------------------------------------------------
10 #include <string.h>
11 //#include <stdlib.h>
12 #include "C8051f340.h"
13 #include "global.h"
14 ///#include "net.h"
15 #include "cksum.h"
16 #include "ip.h"
17 #include "icmp.h"
18
19 extern UCHAR idata debug;
20 extern char xdata outbuf1[];
21
22 //------------------------------------------------------------------------
23 // This builds a ping response message. It allocates memory for the
24 // entire outgoing message, including Eth and IP headers. See "TCP/IP
25 // Illustrated, Volume 1" Sect 7.2 for info on Ping messages
26 //------------------------------------------------------------------------
27 void ping_send(UCHAR xdata * inbuf, ULONG ipaddr, UINT len)
28 {
29 1 PING_HEADER xdata * ping_in;
30 1 PING_HEADER xdata * ping_out;
31 1 UCHAR xdata * outbuf;
32 1
33 1 ping_in = (PING_HEADER xdata *)(inbuf + 34);
34 1
35 1 // Allocate memory for entire outgoing message
36 1 // outbuf = (UCHAR xdata *)malloc(len + 34);
37 1 // if (outbuf == NULL)
38 1 //{
39 1 // return;
40 1 //}
41 1 outbuf = outbuf1;
42 1 // Ping response message payload starts at offset 34
43 1 ping_out = (PING_HEADER xdata *)(outbuf + 34);
44 1
45 1 ping_out->msg_type = 0;
46 1 ping_out->msg_code = 0;
47 1 ping_out->checksum = 0;
48 1 ping_out->identifier = ping_in->identifier;
49 1 ping_out->sequence = ping_in->sequence;
50 1
51 1 memcpy(&ping_out->echo_data, &ping_in->echo_data, len - 8);
52 1
53 1 // Compute checksum over the ICMP header plus
54 1 // optional data and insert complement
55 1 ping_out->checksum = ~cksum(outbuf + 34, len);
C51 COMPILER V8.08 ICMP 11/04/2008 18:45:34 PAGE 2
56 1
57 1
58 1 ip_send(outbuf, ipaddr, ICMP_TYPE, len);
59 1 }
60
61
62
63 //------------------------------------------------------------------------
64 // This builds an outgoing ICMP destination port unreachable response
65 // message. See See "TCP/IP Illustrated, Volume 1" Sect 6.5. This
66 // message is typically sent in response to a UDP message directed
67 // to a port that has no corresponding application running.
68 // Todo: The spec says we should return all options that were in
69 // the original incoming IP header. Right now we cut off everything
70 // after the first 20 bytes.
71 //------------------------------------------------------------------------
72 void dest_unreach_send(UCHAR xdata * inbuf, ULONG ipaddr)
73 {
74 1 UCHAR xdata * outbuf;
75 1 ICMP_ERR_HEADER xdata * icmp;
76 1
77 1 // Allocate memory for entire outgoing message
78 1 // including eth and IP haders. Always 70 bytes
79 1 // outbuf = (UCHAR xdata *)malloc(70);
80 1 //if (outbuf == NULL)
81 1 // {
82 1 // return;
83 1 //}
84 1 outbuf = outbuf1;
85 1
86 1 icmp = (ICMP_ERR_HEADER xdata *)(outbuf + 34);
87 1
88 1 // Fill in ICMP error message header
89 1 icmp->msg_type = 3; // destination unreachable
90 1 icmp->msg_code = 3; // port unreachable
91 1 icmp->checksum = 0;
92 1
93 1 // Fill in ICMP error message data
94 1 icmp->msg_data = 0;
95 1
96 1 // Copy in 20 byte original incoming IP header
97 1 // plus 8 bytes of data
98 1 memcpy(&icmp->echo_data, inbuf + 14, 28);
99 1
100 1 // Compute checksum over the 36 byte long ICMP
101 1 // header plus data and insert complement
102 1 icmp->checksum = ~cksum(outbuf + 34, 36);
103 1
104 1 // Forward message to the IP layer
105 1 ip_send(outbuf, ipaddr, ICMP_TYPE, 36);
106 1 }
107
108
109
110
111 //------------------------------------------------------------------------
112 // This handles incoming ICMP messages. See "TCP/IP Illustrated,
113 // Volume 1" Sect 6.2 for discussion of the various ICMP messages
114 //------------------------------------------------------------------------
115 void icmp_rcve(UCHAR xdata * inbuf, UINT len)
116 {
117 1 IP_HEADER * ip;
C51 COMPILER V8.08 ICMP 11/04/2008 18:45:34 PAGE 3
118 1 UCHAR idata msg_type;
119 1 UINT idata temp;
120 1
121 1 // Allow for 14 bytes eth header
122 1 ip = (IP_HEADER *)(inbuf + 14);
123 1
124 1 // IP header has been adjusted if necessary to always be
125 1 // 20 bytes so message starts at an offset of 34
126 1 // Validate checksum of entire ICMP message incl data
127 1 temp = cksum(inbuf + 34, len);
128 1
129 1 if (temp != 0xFFFF)
130 1 {
131 2 return;
132 2 }
133 1
134 1 // Switch on the message type
135 1 msg_type = *(inbuf + 34);
136 1 switch(msg_type)
137 1 {
138 2 case 3:
139 2 ;
140 2 break;
141 2
142 2 case 8:
143 2 ping_send(inbuf, ip->source_ipaddr, len);
144 2 break;
145 2
146 2 default:
147 2 ;
148 2 break;
149 2 }
150 1 }
151
152
MODULE INFORMATION: STATIC OVERLAYABLE
CODE SIZE = 475 ----
CONSTANT SIZE = ---- ----
XDATA SIZE = ---- ----
PDATA SIZE = ---- ----
DATA SIZE = ---- 29
IDATA SIZE = ---- 3
BIT SIZE = ---- ----
END OF MODULE INFORMATION.
C51 COMPILATION COMPLETE. 0 WARNING(S), 0 ERROR(S)
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