1 #include <u.h>
2 #include <libc.h>
3 #include <ip.h>
4 
5 enum
6 {
7 	Isprefix= 16
8 };
9 
10 /* XXX: manually initialize once to placate the Sun monster */
11 uchar prefixvals[256];
12 #ifdef NOTDEF
13 uchar prefixvals[256] =
14 {
15 [0x00] 0 | Isprefix,
16 [0x80] 1 | Isprefix,
17 [0xC0] 2 | Isprefix,
18 [0xE0] 3 | Isprefix,
19 [0xF0] 4 | Isprefix,
20 [0xF8] 5 | Isprefix,
21 [0xFC] 6 | Isprefix,
22 [0xFE] 7 | Isprefix,
23 [0xFF] 8 | Isprefix,
24 };
25 #endif
26 
27 int
28 eipfmt(Fmt *f)
29 {
30 	char buf[5*8];
31 	static char *efmt = "%.2ux%.2ux%.2ux%.2ux%.2ux%.2ux";
32 	static char *altefmt = "%.2ux:%.2ux:%.2ux:%.2ux:%.2ux:%.2ux";
33 	static char *ifmt = "%d.%d.%d.%d";
34 	char *fmt;
35 	uchar *p, ip[16];
36 	ulong *lp;
37 	ushort s;
38 	int i, j, n, eln, eli;
39 
40 	static int once = 0;	/* XXX: placate the Sun monster */
41 
42 	if(!once){
43 		once = 1;
44 		memset(prefixvals, 0, sizeof(prefixvals));
45 		prefixvals[0x00] = 0 | Isprefix;
46 		prefixvals[0x80] = 1 | Isprefix;
47 		prefixvals[0xC0] = 2 | Isprefix;
48 		prefixvals[0xE0] = 3 | Isprefix;
49 		prefixvals[0xF0] = 4 | Isprefix;
50 		prefixvals[0xF8] = 5 | Isprefix;
51 		prefixvals[0xFC] = 6 | Isprefix;
52 		prefixvals[0xFE] = 7 | Isprefix;
53 		prefixvals[0xFF] = 8 | Isprefix;
54 	}
55 
56 	switch(f->r) {
57 	case 'E':		/* Ethernet address */
58 		p = va_arg(f->args, uchar*);
59 		fmt = efmt;
60 		if(f->flags&FmtSharp)
61 			fmt = altefmt;
62 		snprint(buf, sizeof buf, fmt, p[0], p[1], p[2], p[3], p[4], p[5]);
63 		return fmtstrcpy(f, buf);
64 
65 	case 'I':		/* Ip address */
66 		p = va_arg(f->args, uchar*);
67 common:
68 		if(memcmp(p, v4prefix, 12) == 0){
69 			snprint(buf, sizeof buf, ifmt, p[12], p[13], p[14], p[15]);
70 			return fmtstrcpy(f, buf);
71 		}
72 
73 		/* find longest elision */
74 		eln = eli = -1;
75 		for(i = 0; i < 16; i += 2){
76 			for(j = i; j < 16; j += 2)
77 				if(p[j] != 0 || p[j+1] != 0)
78 					break;
79 			if(j > i && j - i > eln){
80 				eli = i;
81 				eln = j - i;
82 			}
83 		}
84 
85 		/* print with possible elision */
86 		n = 0;
87 		for(i = 0; i < 16; i += 2){
88 			if(i == eli){
89 				n += sprint(buf+n, "::");
90 				i += eln;
91 				if(i >= 16)
92 					break;
93 			} else if(i != 0)
94 				n += sprint(buf+n, ":");
95 			s = (p[i]<<8) + p[i+1];
96 			n += sprint(buf+n, "%ux", s);
97 		}
98 		return fmtstrcpy(f, buf);
99 
100 	case 'i':		/* v6 address as 4 longs */
101 		lp = va_arg(f->args, ulong*);
102 		for(i = 0; i < 4; i++)
103 			hnputl(ip+4*i, *lp++);
104 		p = ip;
105 		goto common;
106 
107 	case 'V':		/* v4 ip address */
108 		p = va_arg(f->args, uchar*);
109 		snprint(buf, sizeof buf, ifmt, p[0], p[1], p[2], p[3]);
110 		return fmtstrcpy(f, buf);
111 
112 	case 'M':		/* ip mask */
113 		p = va_arg(f->args, uchar*);
114 
115 		/* look for a prefix mask */
116 		for(i = 0; i < 16; i++)
117 			if(p[i] != 0xff)
118 				break;
119 		if(i < 16){
120 			if((prefixvals[p[i]] & Isprefix) == 0)
121 				goto common;
122 			for(j = i+1; j < 16; j++)
123 				if(p[j] != 0)
124 					goto common;
125 			n = 8*i + (prefixvals[p[i]] & ~Isprefix);
126 		} else
127 			n = 8*16;
128 
129 		/* got one, use /xx format */
130 		snprint(buf, sizeof buf, "/%d", n);
131 		return fmtstrcpy(f, buf);
132 	}
133 	return fmtstrcpy(f, "(eipfmt)");
134 }