?? icmp.lst
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C51 COMPILER V7.50 ICMP 12/14/2006 13:34:44 PAGE 1
C51 COMPILER V7.50, COMPILATION OF MODULE ICMP
OBJECT MODULE PLACED IN ICMP.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE ICMP.C LARGE OPTIMIZE(9,SPEED) BROWSE DEBUG OBJECTEXTEND
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 "C8051f040.h"
13 #include "net.h"
14 #include "cksum.h"
15 #include "ip.h"
16 #include "icmp.h"
17
18 extern UCHAR idata debug;
19 extern char xdata outbuf1[];
20
21 //------------------------------------------------------------------------
22 // This builds a ping response message. It allocates memory for the
23 // entire outgoing message, including Eth and IP headers. See "TCP/IP
24 // Illustrated, Volume 1" Sect 7.2 for info on Ping messages
25 //------------------------------------------------------------------------
26 void ping_send(UCHAR xdata * inbuf, ULONG ipaddr, UINT len)
27 {
28 1 PING_HEADER xdata * ping_in;
29 1 PING_HEADER xdata * ping_out;
30 1 UCHAR xdata * outbuf;
31 1
32 1 ping_in = (PING_HEADER xdata *)(inbuf + 34);
33 1
34 1 // Allocate memory for entire outgoing message
35 1 // outbuf = (UCHAR xdata *)malloc(len + 34);
36 1 // if (outbuf == NULL)
37 1 //{
38 1 // return;
39 1 //}
40 1 outbuf = outbuf1;
41 1 // Ping response message payload starts at offset 34
42 1 ping_out = (PING_HEADER xdata *)(outbuf + 34);
43 1
44 1 ping_out->msg_type = 0;
45 1 ping_out->msg_code = 0;
46 1 ping_out->checksum = 0;
47 1 ping_out->identifier = ping_in->identifier;
48 1 ping_out->sequence = ping_in->sequence;
49 1
50 1 memcpy(&ping_out->echo_data, &ping_in->echo_data, len - 8);
51 1
52 1 // Compute checksum over the ICMP header plus
53 1 // optional data and insert complement
54 1 ping_out->checksum = ~cksum(outbuf + 34, len);
55 1
C51 COMPILER V7.50 ICMP 12/14/2006 13:34:44 PAGE 2
56 1
57 1 ip_send(outbuf, ipaddr, ICMP_TYPE, len);
58 1 }
59
60
61
62 //------------------------------------------------------------------------
63 // This builds an outgoing ICMP destination port unreachable response
64 // message. See See "TCP/IP Illustrated, Volume 1" Sect 6.5. This
65 // message is typically sent in response to a UDP message directed
66 // to a port that has no corresponding application running.
67 // Todo: The spec says we should return all options that were in
68 // the original incoming IP header. Right now we cut off everything
69 // after the first 20 bytes.
70 //------------------------------------------------------------------------
71 void dest_unreach_send(UCHAR xdata * inbuf, ULONG ipaddr)
72 {
73 1 UCHAR xdata * outbuf;
74 1 ICMP_ERR_HEADER xdata * icmp;
75 1
76 1 // Allocate memory for entire outgoing message
77 1 // including eth and IP haders. Always 70 bytes
78 1 // outbuf = (UCHAR xdata *)malloc(70);
79 1 //if (outbuf == NULL)
80 1 // {
81 1 // return;
82 1 //}
83 1 outbuf = outbuf1;
84 1
85 1 icmp = (ICMP_ERR_HEADER xdata *)(outbuf + 34);
86 1
87 1 // Fill in ICMP error message header
88 1 icmp->msg_type = 3; // destination unreachable
89 1 icmp->msg_code = 3; // port unreachable
90 1 icmp->checksum = 0;
91 1
92 1 // Fill in ICMP error message data
93 1 icmp->msg_data = 0;
94 1
95 1 // Copy in 20 byte original incoming IP header
96 1 // plus 8 bytes of data
97 1 memcpy(&icmp->echo_data, inbuf + 14, 28);
98 1
99 1 // Compute checksum over the 36 byte long ICMP
100 1 // header plus data and insert complement
101 1 icmp->checksum = ~cksum(outbuf + 34, 36);
102 1
103 1 // Forward message to the IP layer
104 1 ip_send(outbuf, ipaddr, ICMP_TYPE, 36);
105 1 }
106
107
108
109
110 //------------------------------------------------------------------------
111 // This handles incoming ICMP messages. See "TCP/IP Illustrated,
112 // Volume 1" Sect 6.2 for discussion of the various ICMP messages
113 //------------------------------------------------------------------------
114 void icmp_rcve(UCHAR xdata * inbuf, UINT len)
115 {
116 1 IP_HEADER * ip;
117 1 UCHAR idata msg_type;
C51 COMPILER V7.50 ICMP 12/14/2006 13:34:44 PAGE 3
118 1 UINT idata temp;
119 1
120 1 // Allow for 14 bytes eth header
121 1 ip = (IP_HEADER *)(inbuf + 14);
122 1
123 1 // IP header has been adjusted if necessary to always be
124 1 // 20 bytes so message starts at an offset of 34
125 1 // Validate checksum of entire ICMP message incl data
126 1 temp = cksum(inbuf + 34, len);
127 1
128 1 if (temp != 0xFFFF)
129 1 {
130 2 return;
131 2 }
132 1
133 1 // Switch on the message type
134 1 msg_type = *(inbuf + 34);
135 1 switch(msg_type)
136 1 {
137 2 case 3:
138 2 ;
139 2 break;
140 2
141 2 case 8:
142 2 ping_send(inbuf, ip->source_ipaddr, len);
143 2 break;
144 2
145 2 default:
146 2 ;
147 2 break;
148 2 }
149 1 }
150
151
MODULE INFORMATION: STATIC OVERLAYABLE
CODE SIZE = 595 ----
CONSTANT SIZE = ---- ----
XDATA SIZE = ---- 29
PDATA SIZE = ---- ----
DATA SIZE = ---- ----
IDATA SIZE = ---- 3
BIT SIZE = ---- ----
END OF MODULE INFORMATION.
C51 COMPILATION COMPLETE. 0 WARNING(S), 0 ERROR(S)
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