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/* Shared library add-on to ip6tables to add Hop-by-Hop and Dst headers support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <errno.h>
#include <ip6tables.h>
/*#include <linux/in6.h>*/
#include <linux/netfilter_ipv6/ip6t_opts.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#define DEBUG 0
#define HOPBYHOP 1
#define UNAME (HOPBYHOP ? "HBH" : "DST")
#define LNAME (HOPBYHOP ? "hbh" : "dst")
/* Function which prints out usage message. */
static void
help(void)
{
printf(
"%s v%s options:\n"
" --%s-len [!] length total length of this header\n"
" --%s-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
" Options and its length (list, max: %d)\n",
UNAME , IPTABLES_VERSION, LNAME, LNAME, IP6T_OPTS_OPTSNR);
}
#if HOPBYHOP
static const struct option opts[] = {
{ "hbh-len", 1, NULL, '1' },
{ "hbh-opts", 1, NULL, '2' },
{ "hbh-not-strict", 1, NULL, '3' },
{ }
};
#else
static const struct option opts[] = {
{ "dst-len", 1, NULL, '1' },
{ "dst-opts", 1, NULL, '2' },
{ "dst-not-strict", 1, NULL, '3' },
{ }
};
#endif
static u_int32_t
parse_opts_num(const char *idstr, const char *typestr)
{
unsigned long int id;
char* ep;
id = strtoul(idstr,&ep,0) ;
if ( idstr == ep ) {
exit_error(PARAMETER_PROBLEM,
"%s no valid digits in %s `%s'", UNAME, typestr, idstr);
}
if ( id == ULONG_MAX && errno == ERANGE ) {
exit_error(PARAMETER_PROBLEM,
"%s `%s' specified too big: would overflow",
typestr, idstr);
}
if ( *idstr != '\0' && *ep != '\0' ) {
exit_error(PARAMETER_PROBLEM,
"%s error parsing %s `%s'", UNAME, typestr, idstr);
}
return (u_int32_t) id;
}
static int
parse_options(const char *optsstr, u_int16_t *opts)
{
char *buffer, *cp, *next, *range;
unsigned int i;
buffer = strdup(optsstr);
if (!buffer) exit_error(OTHER_PROBLEM, "strdup failed");
for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
{
next=strchr(cp, ',');
if (next) *next++='\0';
range = strchr(cp, ':');
if (range) {
if (i == IP6T_OPTS_OPTSNR-1)
exit_error(PARAMETER_PROBLEM,
"too many ports specified");
*range++ = '\0';
}
opts[i] = (u_int16_t)((parse_opts_num(cp,"opt") & 0x000000FF)<<8);
if (range) {
if (opts[i] == 0)
exit_error(PARAMETER_PROBLEM, "PAD0 hasn't got length");
opts[i] |= (u_int16_t)(parse_opts_num(range,"length") &
0x000000FF);
} else {
opts[i] |= (0x00FF);
}
#if DEBUG
printf("opts str: %s %s\n", cp, range);
printf("opts opt: %04X\n", opts[i]);
#endif
}
if (cp) exit_error(PARAMETER_PROBLEM, "too many addresses specified");
free(buffer);
#if DEBUG
printf("addr nr: %d\n", i);
#endif
return i;
}
/* Initialize the match. */
static void
init(struct xt_entry_match *m)
{
struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
optinfo->hdrlen = 0;
optinfo->flags = 0;
optinfo->invflags = 0;
optinfo->optsnr = 0;
}
/* Function which parses command options; returns true if it
ate an option */
static int
parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry,
struct xt_entry_match **match)
{
struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
switch (c) {
case '1':
if (*flags & IP6T_OPTS_LEN)
exit_error(PARAMETER_PROBLEM,
"Only one `--%s-len' allowed", LNAME);
check_inverse(optarg, &invert, &optind, 0);
optinfo->hdrlen = parse_opts_num(argv[optind-1], "length");
if (invert)
optinfo->invflags |= IP6T_OPTS_INV_LEN;
optinfo->flags |= IP6T_OPTS_LEN;
*flags |= IP6T_OPTS_LEN;
break;
case '2':
if (*flags & IP6T_OPTS_OPTS)
exit_error(PARAMETER_PROBLEM,
"Only one `--%s-opts' allowed", LNAME);
check_inverse(optarg, &invert, &optind, 0);
if (invert)
exit_error(PARAMETER_PROBLEM,
" '!' not allowed with `--%s-opts'", LNAME);
optinfo->optsnr = parse_options(argv[optind-1], optinfo->opts);
optinfo->flags |= IP6T_OPTS_OPTS;
*flags |= IP6T_OPTS_OPTS;
break;
case '3':
if (*flags & IP6T_OPTS_NSTRICT)
exit_error(PARAMETER_PROBLEM,
"Only one `--%s-not-strict' allowed", LNAME);
if ( !(*flags & IP6T_OPTS_OPTS) )
exit_error(PARAMETER_PROBLEM,
"`--%s-opts ...' required before `--%s-not-strict'", LNAME, LNAME);
optinfo->flags |= IP6T_OPTS_NSTRICT;
*flags |= IP6T_OPTS_NSTRICT;
break;
default:
return 0;
}
return 1;
}
/* Final check; we don't care. */
static void
final_check(unsigned int flags)
{
}
static void
print_options(int optsnr, u_int16_t *optsp)
{
unsigned int i;
for(i=0; i<optsnr; i++){
printf("%d", (optsp[i] & 0xFF00)>>8);
if ((optsp[i] & 0x00FF) != 0x00FF){
printf(":%d", (optsp[i] & 0x00FF));
}
printf("%c", (i!=optsnr-1)?',':' ');
}
}
/* Prints out the union ip6t_matchinfo. */
static void
print(const void *ip,
const struct xt_entry_match *match, int numeric)
{
const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
printf("%s ", LNAME);
if (optinfo->flags & IP6T_OPTS_LEN) {
printf("length");
printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
printf("%u", optinfo->hdrlen);
printf(" ");
}
if (optinfo->flags & IP6T_OPTS_OPTS) printf("opts ");
print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("not-strict ");
if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
printf("Unknown invflags: 0x%X ",
optinfo->invflags & ~IP6T_OPTS_INV_MASK);
}
/* Saves the union ip6t_matchinfo in parsable form to stdout. */
static void save(const void *ip, const struct xt_entry_match *match)
{
const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
if (optinfo->flags & IP6T_OPTS_LEN) {
printf("--%s-len %s%u ", LNAME,
(optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "",
optinfo->hdrlen);
}
if (optinfo->flags & IP6T_OPTS_OPTS) printf("--%s-opts ", LNAME);
print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("--%s-not-strict ", LNAME);
}
static struct ip6tables_match optstruct = {
#if HOPBYHOP
.name = "hbh",
#else
.name = "dst",
#endif
.version = IPTABLES_VERSION,
.size = IP6T_ALIGN(sizeof(struct ip6t_opts)),
.userspacesize = IP6T_ALIGN(sizeof(struct ip6t_opts)),
.help = &help,
.init = &init,
.parse = &parse,
.final_check = &final_check,
.print = &print,
.save = &save,
.extra_opts = opts,
};
void
_init(void)
{
register_match6(&optstruct);
}
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