1 #include <u.h>
2 #include <libc.h>
3 #include <ip.h>
4 
5 /*
6  *  well known IP addresses
7  */
8 uchar IPv4bcast[IPaddrlen] = {
9 	0, 0, 0, 0,
10 	0, 0, 0, 0,
11 	0, 0, 0xff, 0xff,
12 	0xff, 0xff, 0xff, 0xff
13 };
14 uchar IPv4allsys[IPaddrlen] = {
15 	0, 0, 0, 0,
16 	0, 0, 0, 0,
17 	0, 0, 0xff, 0xff,
18 	0xe0, 0, 0, 0x01
19 };
20 uchar IPv4allrouter[IPaddrlen] = {
21 	0, 0, 0, 0,
22 	0, 0, 0, 0,
23 	0, 0, 0xff, 0xff,
24 	0xe0, 0, 0, 0x02
25 };
26 uchar IPallbits[IPaddrlen] = {
27 	0xff, 0xff, 0xff, 0xff,
28 	0xff, 0xff, 0xff, 0xff,
29 	0xff, 0xff, 0xff, 0xff,
30 	0xff, 0xff, 0xff, 0xff
31 };
32 uchar IPnoaddr[IPaddrlen];
33 
34 /*
35  *  prefix of all v4 addresses
36  */
37 uchar v4prefix[IPaddrlen] = {
38 	0, 0, 0, 0,
39 	0, 0, 0, 0,
40 	0, 0, 0xff, 0xff,
41 	0, 0, 0, 0
42 };
43 
44 int
45 isv4(uchar *ip)
46 {
47 	return memcmp(ip, v4prefix, IPv4off) == 0;
48 }
49 
50 /*
51  *  the following routines are unrolled with no memset's to speed
52  *  up the usual case
53  */
54 void
55 v4tov6(uchar *v6, uchar *v4)
56 {
57 	v6[0] = 0;
58 	v6[1] = 0;
59 	v6[2] = 0;
60 	v6[3] = 0;
61 	v6[4] = 0;
62 	v6[5] = 0;
63 	v6[6] = 0;
64 	v6[7] = 0;
65 	v6[8] = 0;
66 	v6[9] = 0;
67 	v6[10] = 0xff;
68 	v6[11] = 0xff;
69 	v6[12] = v4[0];
70 	v6[13] = v4[1];
71 	v6[14] = v4[2];
72 	v6[15] = v4[3];
73 }
74 
75 int
76 v6tov4(uchar *v4, uchar *v6)
77 {
78 	if(v6[0] == 0
79 	&& v6[1] == 0
80 	&& v6[2] == 0
81 	&& v6[3] == 0
82 	&& v6[4] == 0
83 	&& v6[5] == 0
84 	&& v6[6] == 0
85 	&& v6[7] == 0
86 	&& v6[8] == 0
87 	&& v6[9] == 0
88 	&& v6[10] == 0xff
89 	&& v6[11] == 0xff)
90 	{
91 		v4[0] = v6[12];
92 		v4[1] = v6[13];
93 		v4[2] = v6[14];
94 		v4[3] = v6[15];
95 		return 0;
96 	} else {
97 		memset(v4, 0, 4);
98 		if(memcmp(v6, IPnoaddr, IPaddrlen) == 0)
99 			return 0;
100 		return -1;
101 	}
102 }