From e0471ad3e2144d3f99437a624344f2760195d89c Mon Sep 17 00:00:00 2001
From: Stephen Hemminger <stephen.hemminger@vyatta.com>
Date: Mon, 28 Jul 2008 12:47:47 -0700
Subject: Add new program to check prefix boundary

Using perl to check prefix boundary, is slow because of the overhead
of compiling the same script many times. So convert this simple task
to a C program.
---
 src/check_prefix_boundary.c | 135 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 src/check_prefix_boundary.c

(limited to 'src')

diff --git a/src/check_prefix_boundary.c b/src/check_prefix_boundary.c
new file mode 100644
index 00000000..1c9ee30a
--- /dev/null
+++ b/src/check_prefix_boundary.c
@@ -0,0 +1,135 @@
+/*
+ * Check format of network prefix
+ */
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+typedef struct
+{
+	uint8_t family;
+	uint8_t bytelen;
+	unsigned int plen;
+	uint32_t data[4];
+} inet_prefix;
+
+static void err(const char *fmt, ...)
+{
+	va_list ap;
+	
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+
+	exit(1);
+}
+
+static void usage(void)
+{
+	fprintf(stderr, "Usage: check-prefix-boundary [-4|-6] address/prefix\n");
+	exit(1);
+}
+
+static void get_addr_1(inet_prefix *addr, const char *name, int family)
+{
+	memset(addr, 0, sizeof(*addr));
+
+	if (strchr(name, ':')) {
+		addr->family = AF_INET6;
+		addr->bytelen = 16;
+		if (family != AF_UNSPEC && family != AF_INET6)
+			err("IPV6 address not allowed\n");
+
+		if (inet_pton(AF_INET6, name, addr->data) <= 0)
+			err("Invalid IPV6 address: %s\n", name);
+
+		return;
+	}
+
+	addr->family = AF_INET;
+	addr->bytelen = 4;
+	if (family != AF_UNSPEC && family != AF_INET)
+		err("IPV4 address not allowed\n");
+
+	if (inet_pton(AF_INET, name, addr->data) <= 0)
+		err("Invalid IPV4 address: %s\n", name);
+	return;
+}
+
+static void get_prefix_1(inet_prefix *dst, char *arg, int family)
+{
+	char *slash, *endp;
+
+	memset(dst, 0, sizeof(*dst));
+
+	slash = strchr(arg, '/');
+	if (!slash || slash[1] == '\0')
+		err("Missing prefix length\n");
+	*slash = 0;
+
+	get_addr_1(dst, arg, family);
+
+	dst->plen = strtoul(slash+1, &endp, 0);
+	if (*endp != '\0')
+		err("Invalid character in prefix length\n");
+
+	if (dst->plen > 8 * dst->bytelen)
+		err("Prefix length is too large\n");
+
+	*slash = '/';
+}
+
+static void get_netmask(inet_prefix *msk, const inet_prefix *dst)
+{
+	int i, plen = dst->plen;
+
+	memset(msk, 0, sizeof(*msk));
+	msk->family = dst->family;
+	msk->bytelen = dst->bytelen;
+
+	for (i = 0; plen > 0 && i < dst->bytelen / sizeof(uint32_t); i++) {
+		uint32_t m = (plen > 32) ? ~0 : htonl(~0 << (32 - plen));
+		
+		msk->data[i] = dst->data[i] & m;
+		plen -= 32;
+	}
+}
+
+int main(int argc, char **argv)
+{
+	int family = AF_UNSPEC;
+
+	while (--argc) {
+		char *arg = *++argv;
+		inet_prefix dst, msk;
+
+		if (arg[0] == '-') 
+			switch(arg[1]) {
+			case '4':
+				family = AF_INET;
+				break;
+			case '6':
+				family = AF_INET6;
+				break;
+			default:
+				usage();
+			}
+
+		get_prefix_1(&dst, arg, family);
+		get_netmask(&msk, &dst);
+		
+		if (memcmp(msk.data, dst.data, dst.bytelen) != 0) {
+			char buf[INET_ADDRSTRLEN];
+			err("Prefix not on a natural network boundary."
+			    "Did you mean %s?\n", 
+			    inet_ntop(msk.family, msk.data, buf, sizeof buf));
+		}
+	}
+
+	return 0;
+}
-- 
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