1 #include <u.h>
2 #include <libc.h>
3 #include <ip.h>
4
5 enum
6 {
7 Isprefix= 16,
8 };
9
10 uchar prefixvals[256] =
11 {
12 [0x00] 0 | Isprefix,
13 [0x80] 1 | Isprefix,
14 [0xC0] 2 | Isprefix,
15 [0xE0] 3 | Isprefix,
16 [0xF0] 4 | Isprefix,
17 [0xF8] 5 | Isprefix,
18 [0xFC] 6 | Isprefix,
19 [0xFE] 7 | Isprefix,
20 [0xFF] 8 | Isprefix,
21 };
22
23 int
eipfmt(Fmt * f)24 eipfmt(Fmt *f)
25 {
26 char buf[5*8];
27 static char *efmt = "%.2ux%.2ux%.2ux%.2ux%.2ux%.2ux";
28 static char *ifmt = "%d.%d.%d.%d";
29 uchar *p, ip[16];
30 ulong *lp;
31 ushort s;
32 int i, j, n, eln, eli;
33
34 switch(f->r) {
35 case 'E': /* Ethernet address */
36 p = va_arg(f->args, uchar*);
37 snprint(buf, sizeof buf, efmt, p[0], p[1], p[2], p[3], p[4], p[5]);
38 return fmtstrcpy(f, buf);
39
40 case 'I': /* Ip address */
41 p = va_arg(f->args, uchar*);
42 common:
43 if(memcmp(p, v4prefix, 12) == 0){
44 snprint(buf, sizeof buf, ifmt, p[12], p[13], p[14], p[15]);
45 return fmtstrcpy(f, buf);
46 }
47
48 /* find longest elision */
49 eln = eli = -1;
50 for(i = 0; i < 16; i += 2){
51 for(j = i; j < 16; j += 2)
52 if(p[j] != 0 || p[j+1] != 0)
53 break;
54 if(j > i && j - i > eln){
55 eli = i;
56 eln = j - i;
57 }
58 }
59
60 /* print with possible elision */
61 n = 0;
62 for(i = 0; i < 16; i += 2){
63 if(i == eli){
64 n += sprint(buf+n, "::");
65 i += eln;
66 if(i >= 16)
67 break;
68 } else if(i != 0)
69 n += sprint(buf+n, ":");
70 s = (p[i]<<8) + p[i+1];
71 n += sprint(buf+n, "%ux", s);
72 }
73 return fmtstrcpy(f, buf);
74
75 case 'i': /* v6 address as 4 longs */
76 lp = va_arg(f->args, ulong*);
77 for(i = 0; i < 4; i++)
78 hnputl(ip+4*i, *lp++);
79 p = ip;
80 goto common;
81
82 case 'V': /* v4 ip address */
83 p = va_arg(f->args, uchar*);
84 snprint(buf, sizeof buf, ifmt, p[0], p[1], p[2], p[3]);
85 return fmtstrcpy(f, buf);
86
87 case 'M': /* ip mask */
88 p = va_arg(f->args, uchar*);
89
90 /* look for a prefix mask */
91 for(i = 0; i < 16; i++)
92 if(p[i] != 0xff)
93 break;
94 if(i < 16){
95 if((prefixvals[p[i]] & Isprefix) == 0)
96 goto common;
97 for(j = i+1; j < 16; j++)
98 if(p[j] != 0)
99 goto common;
100 n = 8*i + (prefixvals[p[i]] & ~Isprefix);
101 } else
102 n = 8*16;
103
104 /* got one, use /xx format */
105 snprint(buf, sizeof buf, "/%d", n);
106 return fmtstrcpy(f, buf);
107 }
108 return fmtstrcpy(f, "(eipfmt)");
109 }
110