From 80c82bbb27681dc261b8615b8abd3e94c95c72b4 Mon Sep 17 00:00:00 2001 From: Bart De Schuymer Date: Wed, 14 Jan 2004 20:06:44 +0000 Subject: ebtables library functions --- useful_functions.c | 261 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 261 insertions(+) create mode 100644 useful_functions.c (limited to 'useful_functions.c') diff --git a/useful_functions.c b/useful_functions.c new file mode 100644 index 0000000..cec0cc4 --- /dev/null +++ b/useful_functions.c @@ -0,0 +1,261 @@ +/* + * 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 +#include +#include +#include +#include + +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; +} -- cgit v1.2.3