add libip

1 files changed, 109 insertions, 0 deletions

diff --git a/src/libip/eipfmt.c b/src/libip/eipfmt.c
new file mode 100644
index 00000000..8333225a
--- /dev/null
+++ b/src/libip/eipfmt.c
@@ -0,0 +1,109 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+
+enum
+{
+	Isprefix= 16,
+};
+
+uchar prefixvals[256] =
+{
+[0x00] 0 | Isprefix,
+[0x80] 1 | Isprefix,
+[0xC0] 2 | Isprefix,
+[0xE0] 3 | Isprefix,
+[0xF0] 4 | Isprefix,
+[0xF8] 5 | Isprefix,
+[0xFC] 6 | Isprefix,
+[0xFE] 7 | Isprefix,
+[0xFF] 8 | Isprefix,
+};
+
+int
+eipfmt(Fmt *f)
+{
+	char buf[5*8];
+	static char *efmt = "%.2lux%.2lux%.2lux%.2lux%.2lux%.2lux";
+	static char *ifmt = "%d.%d.%d.%d";
+	uchar *p, ip[16];
+	ulong *lp;
+	ushort s;
+	int i, j, n, eln, eli;
+
+	switch(f->r) {
+	case 'E':		/* Ethernet address */
+		p = va_arg(f->args, uchar*);
+		snprint(buf, sizeof buf, efmt, p[0], p[1], p[2], p[3], p[4], p[5]);
+		return fmtstrcpy(f, buf);
+
+	case 'I':		/* Ip address */
+		p = va_arg(f->args, uchar*);
+common:
+		if(memcmp(p, v4prefix, 12) == 0){
+			snprint(buf, sizeof buf, ifmt, p[12], p[13], p[14], p[15]);
+			return fmtstrcpy(f, buf);
+		}
+
+		/* find longest elision */
+		eln = eli = -1;
+		for(i = 0; i < 16; i += 2){
+			for(j = i; j < 16; j += 2)
+				if(p[j] != 0 || p[j+1] != 0)
+					break;
+			if(j > i && j - i > eln){
+				eli = i;
+				eln = j - i;
+			}
+		}
+
+		/* print with possible elision */
+		n = 0;
+		for(i = 0; i < 16; i += 2){
+			if(i == eli){
+				n += sprint(buf+n, "::");
+				i += eln;
+				if(i >= 16)
+					break;
+			} else if(i != 0)
+				n += sprint(buf+n, ":");
+			s = (p[i]<<8) + p[i+1];
+			n += sprint(buf+n, "%ux", s);
+		}
+		return fmtstrcpy(f, buf);
+
+	case 'i':		/* v6 address as 4 longs */
+		lp = va_arg(f->args, ulong*);
+		for(i = 0; i < 4; i++)
+			hnputl(ip+4*i, *lp++);
+		p = ip;
+		goto common;
+
+	case 'V':		/* v4 ip address */
+		p = va_arg(f->args, uchar*);
+		snprint(buf, sizeof buf, ifmt, p[0], p[1], p[2], p[3]);
+		return fmtstrcpy(f, buf);
+
+	case 'M':		/* ip mask */
+		p = va_arg(f->args, uchar*);
+
+		/* look for a prefix mask */
+		for(i = 0; i < 16; i++)
+			if(p[i] != 0xff)
+				break;
+		if(i < 16){
+			if((prefixvals[p[i]] & Isprefix) == 0)
+				goto common;
+			for(j = i+1; j < 16; j++)
+				if(p[j] != 0)
+					goto common;
+			n = 8*i + (prefixvals[p[i]] & ~Isprefix);
+		} else
+			n = 8*16;
+
+		/* got one, use /xx format */
+		snprint(buf, sizeof buf, "/%d", n);
+		return fmtstrcpy(f, buf);
+	}
+	return fmtstrcpy(f, "(eipfmt)");
+}