ebtables library functions

1 files changed, 261 insertions, 0 deletions

diff --git a/useful_functions.c b/useful_functions.c
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+++ b/useful_functions.c
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+/*
+ * useful_functions.c, January 2004
+ *
+ * Random collection of functions that can be used by extensions.
+ *
+ * Author: Bart De Schuymer
+ *
+ *  This code is stongly inspired on the iptables code which is
+ *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include "include/ebtables_u.h"
+#include "include/ethernetdb.h"
+#include <stdio.h>
+#include <netinet/ether.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+
+const unsigned char mac_type_unicast[ETH_ALEN] =   {0,0,0,0,0,0};
+const unsigned char msk_type_unicast[ETH_ALEN] =   {1,0,0,0,0,0};
+const unsigned char mac_type_multicast[ETH_ALEN] = {1,0,0,0,0,0};
+const unsigned char msk_type_multicast[ETH_ALEN] = {1,0,0,0,0,0};
+const unsigned char mac_type_broadcast[ETH_ALEN] = {255,255,255,255,255,255};
+const unsigned char msk_type_broadcast[ETH_ALEN] = {255,255,255,255,255,255};
+const unsigned char mac_type_bridge_group[ETH_ALEN] = {0x01,0x80,0xc2,0,0,0};
+const unsigned char msk_type_bridge_group[ETH_ALEN] = {255,255,255,255,255,255};
+
+int ebt_printstyle_mac;
+/*
+ * flag = 2: byte always printed with 2 digits
+ */
+void ebt_print_mac(const char *mac)
+{
+	if (ebt_printstyle_mac == 2) {
+		int j;
+		for (j = 0; j < ETH_ALEN; j++)
+			printf("%02x%s", (unsigned char)mac[j],
+				(j==ETH_ALEN-1) ? "" : ":");
+	} else
+		printf("%s", ether_ntoa((struct ether_addr *) mac));
+}
+
+void ebt_print_mac_and_mask(const char *mac, const char *mask)
+{
+	char hlpmsk[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
+
+	if (!memcmp(mac, mac_type_unicast, 6) &&
+	    !memcmp(mask, msk_type_unicast, 6))
+		printf("Unicast");
+	else if (!memcmp(mac, mac_type_multicast, 6) &&
+	         !memcmp(mask, msk_type_multicast, 6))
+		printf("Multicast");
+	else if (!memcmp(mac, mac_type_broadcast, 6) &&
+	         !memcmp(mask, msk_type_broadcast, 6))
+		printf("Broadcast");
+	else if (!memcmp(mac, mac_type_bridge_group, 6) &&
+	         !memcmp(mask, msk_type_bridge_group, 6))
+		printf("BGA");
+	else {
+		ebt_print_mac(mac);
+		if (memcmp(mask, hlpmsk, 6)) {
+			printf("/");
+			ebt_print_mac(mask);
+		}
+	}
+}
+
+/*
+ * Checks the type for validity and calls getethertypebynumber()
+ */
+struct ethertypeent *parseethertypebynumber(int type)
+{
+	if (type < 1536)
+		print_error("Ethernet protocols have values >= 0x0600");
+	if (type > 0xffff)
+		print_error("Ethernet protocols have values <= 0xffff");
+	return getethertypebynumber(type);
+}
+
+/*
+ * put the mac address into 6 (ETH_ALEN) bytes
+ * returns 0 on success
+ */
+int ebt_get_mac_and_mask(char *from, char *to, char *mask)
+{
+	char *p;
+	int i;
+	struct ether_addr *addr;
+
+	if (strcasecmp(from, "Unicast") == 0) {
+		memcpy(to, mac_type_unicast, ETH_ALEN);
+		memcpy(mask, msk_type_unicast, ETH_ALEN);
+		return 0;
+	}
+	if (strcasecmp(from, "Multicast") == 0) {
+		memcpy(to, mac_type_multicast, ETH_ALEN);
+		memcpy(mask, msk_type_multicast, ETH_ALEN);
+		return 0;
+	}
+	if (strcasecmp(from, "Broadcast") == 0) {
+		memcpy(to, mac_type_broadcast, ETH_ALEN);
+		memcpy(mask, msk_type_broadcast, ETH_ALEN);
+		return 0;
+	}
+	if (strcasecmp(from, "BGA") == 0) {
+		memcpy(to, mac_type_bridge_group, ETH_ALEN);
+		memcpy(mask, msk_type_bridge_group, ETH_ALEN);
+		return 0;
+	}
+	if ( (p = strrchr(from, '/')) != NULL) {
+		*p = '\0';
+		if (!(addr = ether_aton(p + 1)))
+			return -1;
+		memcpy(mask, addr, ETH_ALEN);
+	} else
+		memset(mask, 0xff, ETH_ALEN);
+	if (!(addr = ether_aton(from)))
+		return -1;
+	memcpy(to, addr, ETH_ALEN);
+	for (i = 0; i < ETH_ALEN; i++)
+		to[i] &= mask[i];
+	return 0;
+}
+
+int ebt_invert = 0;
+int ebt_check_inverse(const char option[])
+{
+	if (strcmp(option, "!") == 0) {
+		if (ebt_invert == 1)
+			print_error("double use of '!' not allowed");
+		optind++;
+		ebt_invert = 1;
+		return 1;
+	}
+	return ebt_invert;
+}
+
+void ebt_check_option(unsigned int *flags, unsigned int mask)
+{
+	if (*flags & mask)
+		print_error("Multiple use of same option not allowed");
+	*flags |= mask;
+}
+
+/* put the ip string into 4 bytes */
+static int undot_ip(char *ip, unsigned char *ip2)
+{
+	char *p, *q, *end;
+	long int onebyte;
+	int i;
+	char buf[20];
+
+	strncpy(buf, ip, sizeof(buf) - 1);
+
+	p = buf;
+	for (i = 0; i < 3; i++) {
+		if ((q = strchr(p, '.')) == NULL)
+			return -1;
+		*q = '\0';
+		onebyte = strtol(p, &end, 10);
+		if (*end != '\0' || onebyte > 255 || onebyte < 0)   
+			return -1;
+		ip2[i] = (unsigned char)onebyte;
+		p = q + 1;
+	}
+
+	onebyte = strtol(p, &end, 10);
+	if (*end != '\0' || onebyte > 255 || onebyte < 0)
+		return -1;
+	ip2[3] = (unsigned char)onebyte;
+
+	return 0;
+}
+
+/* put the mask into 4 bytes */
+static int ip_mask(char *mask, unsigned char *mask2)
+{
+	char *end;
+	long int bits;
+	uint32_t mask22;
+
+	if (undot_ip(mask, mask2)) {
+		/* not the /a.b.c.e format, maybe the /x format */
+		bits = strtol(mask, &end, 10);
+		if (*end != '\0' || bits > 32 || bits < 0)
+			return -1;
+		if (bits != 0) {
+			mask22 = htonl(0xFFFFFFFF << (32 - bits));
+			memcpy(mask2, &mask22, 4);
+		} else {
+			mask22 = 0xFFFFFFFF;
+			memcpy(mask2, &mask22, 4);
+		}
+	}
+	return 0;
+}
+
+/* set the ip mask and ip address */
+void ebt_parse_ip_address(char *address, uint32_t *addr, uint32_t *msk)
+{
+	char *p;
+
+	/* first the mask */
+	if ((p = strrchr(address, '/')) != NULL) {
+		*p = '\0';
+		if (ip_mask(p + 1, (unsigned char *)msk))
+			print_error("Problem with the IP mask");
+	} else
+		*msk = 0xFFFFFFFF;
+
+	if (undot_ip(address, (unsigned char *)addr))
+		print_error("Problem with the IP address");
+	*addr = *addr & *msk;
+}
+
+/* transform the ip mask into a string ready for output */
+char *ebt_mask_to_dotted(uint32_t mask)
+{
+	int i;
+	static char buf[20];
+	uint32_t maskaddr, bits;
+
+	maskaddr = ntohl(mask);
+
+	/* don't print /32 */
+	if (mask == 0xFFFFFFFFL) {
+		*buf = '\0';
+		return buf;
+	}
+
+	i = 32;
+	bits = 0xFFFFFFFEL; /* case 0xFFFFFFFF has just been dealt with */
+	while (--i >= 0 && maskaddr != bits)
+		bits <<= 1;
+
+	if (i > 0)
+		sprintf(buf, "/%d", i);
+	else if (!i)
+		*buf = '\0';
+	else
+		/* mask was not a decent combination of 1's and 0's */
+		sprintf(buf, "/%d.%d.%d.%d", ((unsigned char *)&mask)[0], 
+		   ((unsigned char *)&mask)[1], ((unsigned char *)&mask)[2],
+		   ((unsigned char *)&mask)[3]);
+
+	return buf;
+}