?? ip.lst
字號:
C51 COMPILER V7.50 IP 12/14/2006 13:34:44 PAGE 1
C51 COMPILER V7.50, COMPILATION OF MODULE IP
OBJECT MODULE PLACED IN IP.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE IP.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 IP.C
6 //
7 // This module is the IP layer
8 // Refer to RFC 791, 1122, and RFC 815 (fragmentation)
9 //-----------------------------------------------------------------------------
10 #include <string.h>
11 #include "C8051f040.h"
12 #include "net.h"
13 #include "cksum.h"
14 #include "arp.h"
15 #include "icmp.h"
16 #include "udp.h"
17 #include "tcp.h"
18 #include "ip.h"
19
20 extern UCHAR idata debug;
21 extern ULONG code my_ipaddr;
22 WAIT xdata wait;
23
24
25 //------------------------------------------------------------------------
26 // This handles outgoing IP datagrams. It adds the 20 byte IP header
27 // and checksum then forwards the IP datagram to the Ethernet layer
28 // for sending. See "TCP/IP Illustrated, Volume 1" Sect 3.2
29 //------------------------------------------------------------------------
30 void ip_send(UCHAR xdata * outbuf, ULONG ipaddr, UCHAR proto_id, UINT len)
31 {
32 1 IP_HEADER xdata * ip;
33 1 UCHAR xdata * hwaddr;
34 1 static UINT ip_ident = 0;
35 1
36 1 ip = (IP_HEADER xdata *)(outbuf + 14);
37 1 ip->ver_len = 0x45; // IPv4 with 20 byte header
38 1 ip->type_of_service = 0;
39 1 ip->total_length = 20 + len;
40 1 ip->identifier = ip_ident++; // sequential identifier
41 1 ip->fragment_info = 0; // not fragmented
42 1 ip->time_to_live = 32; // max hops
43 1 ip->protocol_id = proto_id; // type of payload
44 1 ip->header_cksum = 0;
45 1 ip->source_ipaddr = my_ipaddr;
46 1
47 1 // Outgoing IP address
48 1 ip->dest_ipaddr = ipaddr;
49 1
50 1 // Compute and insert complement of checksum of ip header
51 1 // Outgoing ip header length is always 20 bytes
52 1 ip->header_cksum = ~cksum(outbuf + 14, 20);
53 1
54 1 // Use ARP to get hardware address to send this to
55 1 hwaddr = arp_resolve(ip->dest_ipaddr);
C51 COMPILER V7.50 IP 12/14/2006 13:34:44 PAGE 2
56 1
57 1 // Null means that the ARP resolver did not find the IP address
58 1 // in its cache so had to send an ARP request
59 1 if (hwaddr == NULL)
60 1 {
61 2 // Fill in the destination information so ehrn the ARP response
62 2 // arrives we can identify it and know what to do when we get it
63 2 wait.buf = outbuf;
64 2 wait.ipaddr = ip->dest_ipaddr;
65 2 wait.proto_id = proto_id;
66 2 wait.len = len;
67 2 wait.timer = ARP_TIMEOUT;
68 2 return;
69 2 }
70 1
71 1 eth_send(outbuf, hwaddr, IP_PACKET, 20 + len);
72 1 }
73
74
75
76 //------------------------------------------------------------------------
77 // This handles incoming IP datagrams from the Ethernet layer
78 // See "TCP/IP Illustrated, Volume 1" Sect 3.2
79 //------------------------------------------------------------------------
80 void ip_rcve(UCHAR xdata * inbuf)
81 {
82 1 IP_HEADER xdata * ip;
83 1 UINT idata header_len, payload_len;
84 1
85 1 ip = (IP_HEADER xdata *)(inbuf + 14);
86 1
87 1 // Make sure it is addressed to my IP address
88 1 if (ip->dest_ipaddr != my_ipaddr) return;
89 1
90 1 // Validate checksum of ip header
91 1 header_len = 4 * (0x0F & ip->ver_len);
92 1 payload_len = ip->total_length - header_len;
93 1 if (cksum(inbuf + 14, header_len) != 0xFFFF)
94 1 {
95 2 return;
96 2 }
97 1
98 1 // Make sure incoming message is IP version 4
99 1 if ((ip->ver_len >> 4) != 0x04)
100 1 {
101 2 return;
102 2 }
103 1
104 1 // Make sure incoming message is not fragmented because
105 1 // we cannot handle fragmented messages
106 1 if ((ip->fragment_info & 0x3FFF) != 0)
107 1 {
108 2 return;
109 2 }
110 1
111 1 // At this point we have received a valid IP datagram addressed
112 1 // to me. We do not use header options, and do not forward
113 1 // messages, so in the unlikely event there are header options,
114 1 // delete them and shift the data down. The advantage is that
115 1 // layers such as UDP and TCP know where their data starts
116 1 if (header_len > 20)
117 1 {
C51 COMPILER V7.50 IP 12/14/2006 13:34:44 PAGE 3
118 2
119 2 // Use memmove because of overlap
120 2 memmove(inbuf + 34, inbuf + 14 + header_len, payload_len);
121 2
122 2 // Adjust info to reflect the move
123 2 header_len = 20;
124 2 ip->ver_len = 0x45;
125 2 ip->total_length = 20 + payload_len;
126 2 }
127 1
128 1
129 1 // Look at protocol ID byte and call the appropriate
130 1 // function to handle the received message. See
131 1 // "TCP/IP Illustrated, Volume 1" Sect 1.7 and RFC 791
132 1 // for values for various protocols
133 1 switch (ip->protocol_id)
134 1 {
135 2 case ICMP_TYPE:
136 2 icmp_rcve(inbuf, payload_len);
137 2 break;
138 2
139 2 case IGMP_TYPE:
140 2 ;
141 2 // We cannot handle IGMP messages
142 2 break;
143 2
144 2 case UDP_TYPE:
145 2 udp_rcve(inbuf, payload_len);
146 2 break;
147 2
148 2 case TCP_TYPE:
149 2 tcp_rcve(inbuf, payload_len);
150 2 break;
151 2
152 2 default:
153 2 ;
154 2 break;
155 2 }
156 1 }
157
158
159
MODULE INFORMATION: STATIC OVERLAYABLE
CODE SIZE = 708 ----
CONSTANT SIZE = ---- ----
XDATA SIZE = 12 15
PDATA SIZE = ---- ----
DATA SIZE = ---- ----
IDATA SIZE = ---- 4
BIT SIZE = ---- ----
END OF MODULE INFORMATION.
C51 COMPILATION COMPLETE. 0 WARNING(S), 0 ERROR(S)
?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -