/*
 * 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>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.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};

/* 0: default, print only 2 digits if necessary
 * 2: always print 2 digits, a printed mac address
 * then always has the same length */
int ebt_printstyle_mac;

void ebt_print_mac(const unsigned char *mac)
{
       if (ebt_printstyle_mac == 2) {
               int j;
               for (j = 0; j < ETH_ALEN; j++)
                       printf("%02x%s", mac[j],
                               (j==ETH_ALEN-1) ? "" : ":");
       } else
               printf("%s", ether_ntoa((struct ether_addr *) mac));
}

void ebt_print_mac_and_mask(const unsigned char *mac, const unsigned 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)
               ebt_print_error("Ethernet protocols have values >= 0x0600");
       if (type > 0xffff)
               ebt_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(const char *from, unsigned char *to,
  unsigned 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;
}

/* 0: default
 * 1: the inverse '!' of the option has already been specified */
int ebt_invert = 0;

/*
 * Check if the inverse of the option is specified. This is used
 * in the parse functions of the extensions and ebtables.c
 */
int _ebt_check_inverse(const char option[], int argc, char **argv)
{
       if (!option)
               return ebt_invert;
       if (strcmp(option, "!") == 0) {
               if (ebt_invert == 1)
                       ebt_print_error("Double use of '!' not allowed");
               if (optind >= argc)
                       optarg = NULL;
               else
                       optarg = argv[optind];
               optind++;
               ebt_invert = 1;
               return 1;
       }
       return ebt_invert;
}

/* Make sure the same option wasn't specified twice. This is used
 * in the parse functions of the extensions and ebtables.c */
void ebt_check_option(unsigned int *flags, unsigned int mask)
{
       if (*flags & mask)
               ebt_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. Callers should check ebt_errormsg[0].
 * The string pointed to by address can be altered. */
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)) {
                       ebt_print_error("Problem with the IP mask '%s'", p + 1);
                       return;
               }
       } else
               *msk = 0xFFFFFFFF;

       if (undot_ip(address, (unsigned char *)addr)) {
               ebt_print_error("Problem with the IP address '%s'", address);
               return;
       }
       *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;
}

/* Most of the following code is derived from iptables */
static void
in6addrcpy(struct in6_addr *dst, struct in6_addr *src)
{
       memcpy(dst, src, sizeof(struct in6_addr));
}

int string_to_number_ll(const char *s, unsigned long long min,
            unsigned long long max, unsigned long long *ret)
{
       unsigned long long number;
       char *end;

       /* Handle hex, octal, etc. */
       errno = 0;
       number = strtoull(s, &end, 0);
       if (*end == '\0' && end != s) {
               /* we parsed a number, let's see if we want this */
               if (errno != ERANGE && min <= number && (!max || number <= max)) {
                       *ret = number;
                       return 0;
               }
       }
       return -1;
}

int string_to_number_l(const char *s, unsigned long min, unsigned long max,
                       unsigned long *ret)
{
       int result;
       unsigned long long number;

       result = string_to_number_ll(s, min, max, &number);
       *ret = (unsigned long)number;

       return result;
}

int string_to_number(const char *s, unsigned int min, unsigned int max,
                     unsigned int *ret)
{
       int result;
       unsigned long number;

       result = string_to_number_l(s, min, max, &number);
       *ret = (unsigned int)number;

       return result;
}

static struct in6_addr *numeric_to_addr(const char *num)
{
       static struct in6_addr ap;
       int err;

       if ((err=inet_pton(AF_INET6, num, &ap)) == 1)
               return &ap;
       return (struct in6_addr *)NULL;
}

static struct in6_addr *parse_ip6_mask(char *mask)
{
       static struct in6_addr maskaddr;
       struct in6_addr *addrp;
       unsigned int bits;

       if (mask == NULL) {
               /* no mask at all defaults to 128 bits */
               memset(&maskaddr, 0xff, sizeof maskaddr);
               return &maskaddr;
       }
       if ((addrp = numeric_to_addr(mask)) != NULL)
               return addrp;
       if (string_to_number(mask, 0, 128, &bits) == -1)
               ebt_print_error("Invalid IPv6 Mask '%s' specified", mask);
       if (bits != 0) {
               char *p = (char *)&maskaddr;
               memset(p, 0xff, bits / 8);
               memset(p + (bits / 8) + 1, 0, (128 - bits) / 8);
               p[bits / 8] = 0xff << (8 - (bits & 7));
               return &maskaddr;
       }

       memset(&maskaddr, 0, sizeof maskaddr);
       return &maskaddr;
}

/* Set the ipv6 mask and address. Callers should check ebt_errormsg[0].
 * The string pointed to by address can be altered. */
void ebt_parse_ip6_address(char *address, struct in6_addr *addr,
                           struct in6_addr *msk)
{
       struct in6_addr *tmp_addr;
       char buf[256];
       char *p;
       int i;
       int err;

       strncpy(buf, address, sizeof(buf) - 1);
       /* first the mask */
       buf[sizeof(buf) - 1] = '\0';
       if ((p = strrchr(buf, '/')) != NULL) {
               *p = '\0';
               tmp_addr = parse_ip6_mask(p + 1);
       } else
               tmp_addr = parse_ip6_mask(NULL);
       in6addrcpy(msk, tmp_addr);

       /* if a null mask is given, the name is ignored, like in "any/0" */
       if (!memcmp(msk, &in6addr_any, sizeof(in6addr_any)))
               strcpy(buf, "::");

       if ((err=inet_pton(AF_INET6, buf, addr)) < 1) {
               ebt_print_error("Invalid IPv6 Address '%s' specified", buf);
               return;
       }

       for (i = 0; i < 4; i++)
               addr->s6_addr32[i] &= msk->s6_addr32[i];
}

/* Transform the ip6 addr into a string ready for output. */
char *ebt_ip6_to_numeric(const struct in6_addr *addrp)
{
       /* 0000:0000:0000:0000:0000:000.000.000.000
        * 0000:0000:0000:0000:0000:0000:0000:0000 */
       static char buf[50+1];
       return (char *)inet_ntop(AF_INET6, addrp, buf, sizeof(buf));
}
