?? udp.lst
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C51 COMPILER V7.09 UDP 07/31/2006 17:30:56 PAGE 1
C51 COMPILER V7.09, COMPILATION OF MODULE UDP
OBJECT MODULE PLACED IN UDP.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE UDP.C OPTIMIZE(9,SPEED) BROWSE DEBUG OBJECTEXTEND
line level source
1 //-----------------------------------------------------------------------------
2 // Net UDP.C
3 //
4 // This module handles UDP messages
5 // Refer to RFC 768, 1122
6 // Also RFC 862 echo, RFC 867 daytime, and RFC 868 time
7 //-----------------------------------------------------------------------------
8 #include <string.h>
9 #include <stdlib.h>
10 #include "C8051f.h"
11 #include "net.h"
12 #include "ip.h"
13 #include "cksum.h"
14 #include "serial.h"
15 #include "icmp.h"
16 #include "udp.h"
17
18 extern UCHAR idata debug;
19 extern ULONG code my_ipaddr;
20 UINT xdata sender_udpport;
21 static ULONG xdata sender_ipaddr;
22 extern char xdata text[];
23
24
25 //------------------------------------------------------------------------
26 // UDP Echo service - see RFC 862
27 // This simply echos what it received back to the sender
28 //------------------------------------------------------------------------
29 void udp_echo_service(UCHAR xdata * inbuf, UINT len)
30 {
31 1 if (debug)
32 1 {
33 2 serial_send("ECHO: Nr chars = ");
34 2 memset(text, 0, 10);
35 2 itoa(len, text, 10);
36 2 serial_send(text);
37 2 serial_send("\r");
38 2 }
39 1 udp_send(inbuf, ECHO_PORT, len);
40 1 }
41
42
43
44 //------------------------------------------------------------------------
45 // This handles outgoing UDP messages
46 // See "TCP/IP Illustrated, Volume 1" Sect 11.1 - 11.3
47 //------------------------------------------------------------------------
48 void udp_send(UCHAR xdata * inbuf, UINT port, UINT len)
49 {
50 1 ULONG idata sum;
51 1 UINT idata result;
52 1 UCHAR xdata * outbuf;
53 1 UDP_HEADER xdata * udp;
54 1 IP_HEADER xdata * ip;
55 1
C51 COMPILER V7.09 UDP 07/31/2006 17:30:56 PAGE 2
56 1 // Allocate memory for entire outgoing message including
57 1 // eth & IP headers. Total ethernet message length is:
58 1 // 14 byte eth header + 20 byte IP header + 8 byte UDP header
59 1 // + length of this data
60 1 outbuf = (UCHAR xdata *)malloc(42 + len);
61 1 if (outbuf == NULL)
62 1 {
63 2 if (debug) serial_send("UDP: Oops, out of memory\r");
64 2 return;
65 2 }
66 1
67 1 udp = (UDP_HEADER xdata *)(outbuf + 34);
68 1 ip = (IP_HEADER xdata *)(outbuf + 14);
69 1
70 1 // Direct message back to the senders port.
71 1 udp->dest_port = sender_udpport;
72 1 udp->source_port = port;
73 1 udp->length = 8 + len;
74 1 udp->checksum = 0;
75 1
76 1 // Fill in data
77 1 // Important do not free receive buffer prior to this
78 1 memcpy(&udp->msg_data, (inbuf + 42), len);
79 1
80 1
81 1 // Compute checksum including 12 bytes of pseudoheader
82 1 // Must pre-fill 2 items in outbuf to do this
83 1 // Direct message back to senders ip address
84 1 ip->dest_ipaddr = sender_ipaddr;
85 1 ip->source_ipaddr = my_ipaddr;
86 1
87 1
88 1 // Sum source_ipaddr, dest_ipaddr, and entire UDP message
89 1 sum = (ULONG)cksum(outbuf + 26, 8 + udp->length);
90 1
91 1 // Add in the rest of pseudoheader which is
92 1 // zero, protocol id, and UDP length
93 1 sum += (ULONG)0x0011;
94 1 sum += (ULONG)udp->length;
95 1
96 1 // In case there was a carry, add it back around
97 1 result = (UINT)(sum + (sum >> 16));
98 1 udp->checksum = ~result;
99 1 if (debug) serial_send("UDP: Sending msg to IP layer\r");
100 1 ip_send(outbuf, sender_ipaddr, UDP_TYPE, udp->length);
101 1 }
102
103
104
105 //------------------------------------------------------------------------
106 // This handles incoming UDP messages
107 // See "TCP/IP Illustrated, Volume 1" Sect 11.1 - 11.3
108 //------------------------------------------------------------------------
109 void udp_rcve(UCHAR xdata * inbuf, UINT len)
110 {
111 1 UINT idata result;
112 1 UDP_HEADER xdata * udp;
113 1 IP_HEADER xdata * ip;
114 1 ULONG idata sum;
115 1
116 1 // Total of eth & IP headers = 34 bytes
117 1 udp = (UDP_HEADER xdata *)(inbuf + 34);
C51 COMPILER V7.09 UDP 07/31/2006 17:30:56 PAGE 3
118 1 ip = (IP_HEADER xdata *)(inbuf + 14);
119 1
120 1 // The IP length "len" should be the same as the redundant length
121 1 // udp->length. TCP/IP Illustrated, Vol 2, Sect 23.7 says to use the
122 1 // UDP length, unless IP length < UDP length, in which case the frame
123 1 // should be discarded.
124 1 if (len < udp->length) return;
125 1
126 1 // If the checksum is zero it means that the sender did not compute
127 1 // it and we should not try to check it.
128 1 if (udp->checksum == 0)
129 1 {
130 2 if (debug) serial_send("UDP: Sender did not compute cksum\r");
131 2 }
132 1 else
133 1 {
134 2 // Compute UDP checksum including 12 byte pseudoheader
135 2 // Sum source_ipaddr, dest_ipaddr, and entire UDP message
136 2 sum = (ULONG)cksum(inbuf + 26, 8 + udp->length);
137 2
138 2 // Add in the rest of pseudoheader which is
139 2 // zero, protocol id, and UDP length
140 2 sum += (ULONG)0x0011;
141 2 sum += (ULONG)udp->length;
142 2
143 2 // In case there was a carry, add it back around
144 2 result = (UINT)(sum + (sum >> 16));
145 2
146 2 if (result != 0xFFFF)
147 2 {
148 3 if (debug) serial_send("UDP: Error, bad cksum\r");
149 3 return;
150 3 }
151 2
152 2 if (debug) serial_send("UDP: Msg rcvd with good cksum\r");
153 2 }
154 1
155 1 // Capture sender's port number and ip_addr
156 1 // to send return message to
157 1 sender_udpport = udp->source_port;
158 1 sender_ipaddr = ip->source_ipaddr;
159 1
160 1 // See if any applications are on any ports
161 1 switch (udp->dest_port)
162 1 {
163 2 case ECHO_PORT:
164 2 // Pass it the payload length
165 2 udp_echo_service(inbuf, udp->length - 8);
166 2 break;
167 2
168 2 default:
169 2 // If no application is registered to handle incoming
170 2 // UDP message then send ICMP destination unreachable
171 2 dest_unreach_send(inbuf, ip->source_ipaddr);
172 2 break;
173 2 }
174 1 }
175
MODULE INFORMATION: STATIC OVERLAYABLE
CODE SIZE = 789 ----
C51 COMPILER V7.09 UDP 07/31/2006 17:30:56 PAGE 4
CONSTANT SIZE = 165 ----
XDATA SIZE = 6 ----
PDATA SIZE = ---- ----
DATA SIZE = ---- 22
IDATA SIZE = ---- 12
BIT SIZE = ---- ----
END OF MODULE INFORMATION.
C51 COMPILATION COMPLETE. 0 WARNING(S), 0 ERROR(S)
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