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