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xtables.c
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xtables.c
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/*
* (C) 2000-2006 by the netfilter coreteam <[email protected]>:
*
* 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 <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include <xtables.h>
#include <limits.h> /* INT_MAX in ip_tables.h/ip6_tables.h */
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <libiptc/libxtc.h>
#ifndef NO_SHARED_LIBS
#include <dlfcn.h>
#endif
#ifndef IPT_SO_GET_REVISION_MATCH /* Old kernel source. */
# define IPT_SO_GET_REVISION_MATCH (IPT_BASE_CTL + 2)
# define IPT_SO_GET_REVISION_TARGET (IPT_BASE_CTL + 3)
#endif
#ifndef IP6T_SO_GET_REVISION_MATCH /* Old kernel source. */
# define IP6T_SO_GET_REVISION_MATCH 68
# define IP6T_SO_GET_REVISION_TARGET 69
#endif
#include <getopt.h>
#define NPROTO 255
#ifndef PROC_SYS_MODPROBE
#define PROC_SYS_MODPROBE "/proc/sys/kernel/modprobe"
#endif
void basic_exit_err(enum xtables_exittype status, const char *msg, ...) __attribute__((noreturn, format(printf,2,3)));
struct xtables_globals *xt_params = NULL;
void basic_exit_err(enum xtables_exittype status, const char *msg, ...)
{
va_list args;
va_start(args, msg);
fprintf(stderr, "%s v%s: ", xt_params->program_name, xt_params->program_version);
vfprintf(stderr, msg, args);
va_end(args);
fprintf(stderr, "\n");
exit(status);
}
void xtables_free_opts(int reset_offset)
{
if (xt_params->opts != xt_params->orig_opts) {
free(xt_params->opts);
xt_params->opts = xt_params->orig_opts;
if (reset_offset)
xt_params->option_offset = 0;
}
}
struct option *xtables_merge_options(struct option *oldopts,
const struct option *newopts,
unsigned int *option_offset)
{
unsigned int num_old, num_new, i;
struct option *merge;
if (newopts == NULL)
return oldopts;
for (num_old = 0; oldopts[num_old].name; num_old++) ;
for (num_new = 0; newopts[num_new].name; num_new++) ;
xt_params->option_offset += 256;
*option_offset = xt_params->option_offset;
merge = malloc(sizeof(struct option) * (num_new + num_old + 1));
if (merge == NULL)
return NULL;
memcpy(merge, oldopts, num_old * sizeof(struct option));
xtables_free_opts(0); /* Release any old options merged */
for (i = 0; i < num_new; i++) {
merge[num_old + i] = newopts[i];
merge[num_old + i].val += *option_offset;
}
memset(merge + num_old + num_new, 0, sizeof(struct option));
return merge;
}
/**
* xtables_afinfo - protocol family dependent information
* @kmod: kernel module basename (e.g. "ip_tables")
* @libprefix: prefix of .so library name (e.g. "libipt_")
* @family: nfproto family
* @ipproto: used by setsockopt (e.g. IPPROTO_IP)
* @so_rev_match: optname to check revision support of match
* @so_rev_target: optname to check revision support of target
*/
struct xtables_afinfo {
const char *kmod;
const char *libprefix;
uint8_t family;
uint8_t ipproto;
int so_rev_match;
int so_rev_target;
};
static const struct xtables_afinfo afinfo_ipv4 = {
.kmod = "ip_tables",
.libprefix = "libipt_",
.family = NFPROTO_IPV4,
.ipproto = IPPROTO_IP,
.so_rev_match = IPT_SO_GET_REVISION_MATCH,
.so_rev_target = IPT_SO_GET_REVISION_TARGET,
};
static const struct xtables_afinfo afinfo_ipv6 = {
.kmod = "ip6_tables",
.libprefix = "libip6t_",
.family = NFPROTO_IPV6,
.ipproto = IPPROTO_IPV6,
.so_rev_match = IP6T_SO_GET_REVISION_MATCH,
.so_rev_target = IP6T_SO_GET_REVISION_TARGET,
};
static const struct xtables_afinfo *afinfo;
/* Search path for Xtables .so files */
static const char *xtables_libdir;
/* the path to command to load kernel module */
const char *xtables_modprobe_program;
/* Keeping track of external matches and targets: linked lists. */
struct xtables_match *xtables_matches;
struct xtables_target *xtables_targets;
void xtables_init(void)
{
xtables_libdir = getenv("XTABLES_LIBDIR");
if (xtables_libdir != NULL)
return;
xtables_libdir = getenv("IPTABLES_LIB_DIR");
if (xtables_libdir != NULL) {
fprintf(stderr, "IPTABLES_LIB_DIR is deprecated, "
"use XTABLES_LIBDIR.\n");
return;
}
/*
* Well yes, IP6TABLES_LIB_DIR is of lower priority over
* IPTABLES_LIB_DIR since this moved to libxtables; I think that is ok
* for these env vars are deprecated anyhow, and in light of the
* (shared) libxt_*.so files, makes less sense to have
* IPTABLES_LIB_DIR != IP6TABLES_LIB_DIR.
*/
xtables_libdir = getenv("IP6TABLES_LIB_DIR");
if (xtables_libdir != NULL) {
fprintf(stderr, "IP6TABLES_LIB_DIR is deprecated, "
"use XTABLES_LIBDIR.\n");
return;
}
xtables_libdir = XTABLES_LIBDIR;
}
void xtables_set_nfproto(uint8_t nfproto)
{
switch (nfproto) {
case NFPROTO_IPV4:
afinfo = &afinfo_ipv4;
break;
case NFPROTO_IPV6:
afinfo = &afinfo_ipv6;
break;
default:
fprintf(stderr, "libxtables: unhandled NFPROTO in %s\n",
__func__);
}
}
/**
* xtables_set_params - set the global parameters used by xtables
* @xtp: input xtables_globals structure
*
* The app is expected to pass a valid xtables_globals data-filled
* with proper values
* @xtp cannot be NULL
*
* Returns -1 on failure to set and 0 on success
*/
int xtables_set_params(struct xtables_globals *xtp)
{
if (!xtp) {
fprintf(stderr, "%s: Illegal global params\n",__func__);
return -1;
}
xt_params = xtp;
if (!xt_params->exit_err)
xt_params->exit_err = basic_exit_err;
return 0;
}
int xtables_init_all(struct xtables_globals *xtp, uint8_t nfproto)
{
xtables_init();
xtables_set_nfproto(nfproto);
return xtables_set_params(xtp);
}
/**
* xtables_*alloc - wrappers that exit on failure
*/
void *xtables_calloc(size_t count, size_t size)
{
void *p;
if ((p = calloc(count, size)) == NULL) {
perror("ip[6]tables: calloc failed");
exit(1);
}
return p;
}
void *xtables_malloc(size_t size)
{
void *p;
if ((p = malloc(size)) == NULL) {
perror("ip[6]tables: malloc failed");
exit(1);
}
return p;
}
void *xtables_realloc(void *ptr, size_t size)
{
void *p;
if ((p = realloc(ptr, size)) == NULL) {
perror("ip[6]tables: realloc failed");
exit(1);
}
return p;
}
static char *get_modprobe(void)
{
int procfile;
char *ret;
#define PROCFILE_BUFSIZ 1024
procfile = open(PROC_SYS_MODPROBE, O_RDONLY);
if (procfile < 0)
return NULL;
ret = malloc(PROCFILE_BUFSIZ);
if (ret) {
memset(ret, 0, PROCFILE_BUFSIZ);
switch (read(procfile, ret, PROCFILE_BUFSIZ)) {
case -1: goto fail;
case PROCFILE_BUFSIZ: goto fail; /* Partial read. Wierd */
}
if (ret[strlen(ret)-1]=='\n')
ret[strlen(ret)-1]=0;
close(procfile);
return ret;
}
fail:
free(ret);
close(procfile);
return NULL;
}
int xtables_insmod(const char *modname, const char *modprobe, bool quiet)
{
char *buf = NULL;
char *argv[4];
int status;
/* If they don't explicitly set it, read out of kernel */
if (!modprobe) {
buf = get_modprobe();
if (!buf)
return -1;
modprobe = buf;
}
/*
* Need to flush the buffer, or the child may output it again
* when switching the program thru execv.
*/
fflush(stdout);
switch (vfork()) {
case 0:
argv[0] = (char *)modprobe;
argv[1] = (char *)modname;
if (quiet) {
argv[2] = "-q";
argv[3] = NULL;
} else {
argv[2] = NULL;
argv[3] = NULL;
}
execv(argv[0], argv);
/* not usually reached */
exit(1);
case -1:
return -1;
default: /* parent */
wait(&status);
}
free(buf);
if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
return 0;
return -1;
}
int xtables_load_ko(const char *modprobe, bool quiet)
{
static bool loaded = false;
static int ret = -1;
if (!loaded) {
ret = xtables_insmod(afinfo->kmod, modprobe, quiet);
loaded = (ret == 0);
}
return ret;
}
/**
* xtables_strtou{i,l} - string to number conversion
* @s: input string
* @end: like strtoul's "end" pointer
* @value: pointer for result
* @min: minimum accepted value
* @max: maximum accepted value
*
* If @end is NULL, we assume the caller wants a "strict strtoul", and hence
* "15a" is rejected.
* In either case, the value obtained is compared for min-max compliance.
* Base is always 0, i.e. autodetect depending on @s.
*
* Returns true/false whether number was accepted. On failure, *value has
* undefined contents.
*/
bool xtables_strtoul(const char *s, char **end, unsigned long *value,
unsigned long min, unsigned long max)
{
unsigned long v;
char *my_end;
errno = 0;
v = strtoul(s, &my_end, 0);
if (my_end == s)
return false;
if (end != NULL)
*end = my_end;
if (errno != ERANGE && min <= v && (max == 0 || v <= max)) {
if (value != NULL)
*value = v;
if (end == NULL)
return *my_end == '\0';
return true;
}
return false;
}
bool xtables_strtoui(const char *s, char **end, unsigned int *value,
unsigned int min, unsigned int max)
{
unsigned long v;
bool ret;
ret = xtables_strtoul(s, end, &v, min, max);
if (value != NULL)
*value = v;
return ret;
}
int xtables_service_to_port(const char *name, const char *proto)
{
struct servent *service;
if ((service = getservbyname(name, proto)) != NULL)
return ntohs((unsigned short) service->s_port);
return -1;
}
u_int16_t xtables_parse_port(const char *port, const char *proto)
{
unsigned int portnum;
if (xtables_strtoui(port, NULL, &portnum, 0, UINT16_MAX) ||
(portnum = xtables_service_to_port(port, proto)) != (unsigned)-1)
return portnum;
xt_params->exit_err(PARAMETER_PROBLEM,
"invalid port/service `%s' specified", port);
}
void xtables_parse_interface(const char *arg, char *vianame,
unsigned char *mask)
{
unsigned int vialen = strlen(arg);
unsigned int i;
memset(mask, 0, IFNAMSIZ);
memset(vianame, 0, IFNAMSIZ);
if (vialen + 1 > IFNAMSIZ)
xt_params->exit_err(PARAMETER_PROBLEM,
"interface name `%s' must be shorter than IFNAMSIZ"
" (%i)", arg, IFNAMSIZ-1);
strcpy(vianame, arg);
if (vialen == 0)
memset(mask, 0, IFNAMSIZ);
else if (vianame[vialen - 1] == '+') {
memset(mask, 0xFF, vialen - 1);
memset(mask + vialen - 1, 0, IFNAMSIZ - vialen + 1);
/* Don't remove `+' here! -HW */
} else {
/* Include nul-terminator in match */
memset(mask, 0xFF, vialen + 1);
memset(mask + vialen + 1, 0, IFNAMSIZ - vialen - 1);
for (i = 0; vianame[i]; i++) {
if (vianame[i] == '/' ||
vianame[i] == ' ') {
fprintf(stderr,
"Warning: weird character in interface"
" `%s' ('/' and ' ' are not allowed by the kernel).\n",
vianame);
break;
}
}
}
}
#ifndef NO_SHARED_LIBS
static void *load_extension(const char *search_path, const char *prefix,
const char *name, bool is_target)
{
const char *dir = search_path, *next;
void *ptr = NULL;
struct stat sb;
char path[256];
do {
next = strchr(dir, ':');
if (next == NULL)
next = dir + strlen(dir);
snprintf(path, sizeof(path), "%.*s/libxt_%s.so",
(unsigned int)(next - dir), dir, name);
if (dlopen(path, RTLD_NOW) != NULL) {
/* Found library. If it didn't register itself,
maybe they specified target as match. */
if (is_target)
ptr = xtables_find_target(name, XTF_DONT_LOAD);
else
ptr = xtables_find_match(name,
XTF_DONT_LOAD, NULL);
} else if (stat(path, &sb) == 0) {
fprintf(stderr, "%s: %s\n", path, dlerror());
}
if (ptr != NULL)
return ptr;
snprintf(path, sizeof(path), "%.*s/%s%s.so",
(unsigned int)(next - dir), dir, prefix, name);
if (dlopen(path, RTLD_NOW) != NULL) {
if (is_target)
ptr = xtables_find_target(name, XTF_DONT_LOAD);
else
ptr = xtables_find_match(name,
XTF_DONT_LOAD, NULL);
} else if (stat(path, &sb) == 0) {
fprintf(stderr, "%s: %s\n", path, dlerror());
}
if (ptr != NULL)
return ptr;
dir = next + 1;
} while (*next != '\0');
return NULL;
}
#endif
struct xtables_match *
xtables_find_match(const char *name, enum xtables_tryload tryload,
struct xtables_rule_match **matches)
{
struct xtables_match *ptr;
const char *icmp6 = "icmp6";
if (strlen(name) >= XT_EXTENSION_MAXNAMELEN)
xtables_error(PARAMETER_PROBLEM,
"Invalid match name \"%s\" (%u chars max)",
name, XT_EXTENSION_MAXNAMELEN - 1);
/* This is ugly as hell. Nonetheless, there is no way of changing
* this without hurting backwards compatibility */
if ( (strcmp(name,"icmpv6") == 0) ||
(strcmp(name,"ipv6-icmp") == 0) ||
(strcmp(name,"icmp6") == 0) )
name = icmp6;
for (ptr = xtables_matches; ptr; ptr = ptr->next) {
if (strcmp(name, ptr->name) == 0) {
struct xtables_match *clone;
/* First match of this type: */
if (ptr->m == NULL)
break;
/* Second and subsequent clones */
clone = xtables_malloc(sizeof(struct xtables_match));
memcpy(clone, ptr, sizeof(struct xtables_match));
clone->mflags = 0;
/* This is a clone: */
clone->next = clone;
ptr = clone;
break;
}
}
#ifndef NO_SHARED_LIBS
if (!ptr && tryload != XTF_DONT_LOAD && tryload != XTF_DURING_LOAD) {
ptr = load_extension(xtables_libdir, afinfo->libprefix,
name, false);
if (ptr == NULL && tryload == XTF_LOAD_MUST_SUCCEED)
xt_params->exit_err(PARAMETER_PROBLEM,
"Couldn't load match `%s':%s\n",
name, dlerror());
}
#else
if (ptr && !ptr->loaded) {
if (tryload != XTF_DONT_LOAD)
ptr->loaded = 1;
else
ptr = NULL;
}
if(!ptr && (tryload == XTF_LOAD_MUST_SUCCEED)) {
xt_params->exit_err(PARAMETER_PROBLEM,
"Couldn't find match `%s'\n", name);
}
#endif
if (ptr && matches) {
struct xtables_rule_match **i;
struct xtables_rule_match *newentry;
newentry = xtables_malloc(sizeof(struct xtables_rule_match));
for (i = matches; *i; i = &(*i)->next) {
if (strcmp(name, (*i)->match->name) == 0)
(*i)->completed = true;
}
newentry->match = ptr;
newentry->completed = false;
newentry->next = NULL;
*i = newentry;
}
return ptr;
}
struct xtables_target *
xtables_find_target(const char *name, enum xtables_tryload tryload)
{
struct xtables_target *ptr;
/* Standard target? */
if (strcmp(name, "") == 0
|| strcmp(name, XTC_LABEL_ACCEPT) == 0
|| strcmp(name, XTC_LABEL_DROP) == 0
|| strcmp(name, XTC_LABEL_QUEUE) == 0
|| strcmp(name, XTC_LABEL_RETURN) == 0)
name = "standard";
for (ptr = xtables_targets; ptr; ptr = ptr->next) {
if (strcmp(name, ptr->name) == 0)
break;
}
#ifndef NO_SHARED_LIBS
if (!ptr && tryload != XTF_DONT_LOAD && tryload != XTF_DURING_LOAD) {
ptr = load_extension(xtables_libdir, afinfo->libprefix,
name, true);
if (ptr == NULL && tryload == XTF_LOAD_MUST_SUCCEED)
xt_params->exit_err(PARAMETER_PROBLEM,
"Couldn't load target `%s':%s\n",
name, dlerror());
}
#else
if (ptr && !ptr->loaded) {
if (tryload != XTF_DONT_LOAD)
ptr->loaded = 1;
else
ptr = NULL;
}
if (ptr == NULL && tryload == XTF_LOAD_MUST_SUCCEED) {
xt_params->exit_err(PARAMETER_PROBLEM,
"Couldn't find target `%s'\n", name);
}
#endif
if (ptr)
ptr->used = 1;
return ptr;
}
static int compatible_revision(const char *name, u_int8_t revision, int opt)
{
struct xt_get_revision rev;
socklen_t s = sizeof(rev);
int max_rev, sockfd;
sockfd = socket(afinfo->family, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
if (errno == EPERM) {
/* revision 0 is always supported. */
if (revision != 0)
fprintf(stderr, "Could not determine whether "
"revision %u is supported, "
"assuming it is.\n",
revision);
return 1;
}
fprintf(stderr, "Could not open socket to kernel: %s\n",
strerror(errno));
exit(1);
}
xtables_load_ko(xtables_modprobe_program, true);
strcpy(rev.name, name);
rev.revision = revision;
max_rev = getsockopt(sockfd, afinfo->ipproto, opt, &rev, &s);
if (max_rev < 0) {
/* Definitely don't support this? */
if (errno == ENOENT || errno == EPROTONOSUPPORT) {
close(sockfd);
return 0;
} else if (errno == ENOPROTOOPT) {
close(sockfd);
/* Assume only revision 0 support (old kernel) */
return (revision == 0);
} else {
fprintf(stderr, "getsockopt failed strangely: %s\n",
strerror(errno));
exit(1);
}
}
close(sockfd);
return 1;
}
static int compatible_match_revision(const char *name, u_int8_t revision)
{
return compatible_revision(name, revision, afinfo->so_rev_match);
}
static int compatible_target_revision(const char *name, u_int8_t revision)
{
return compatible_revision(name, revision, afinfo->so_rev_target);
}
void xtables_register_match(struct xtables_match *me)
{
struct xtables_match **i, *old;
if (me->version == NULL) {
fprintf(stderr, "%s: match %s<%u> is missing a version\n",
xt_params->program_name, me->name, me->revision);
exit(1);
}
if (strcmp(me->version, XTABLES_VERSION) != 0) {
fprintf(stderr, "%s: match \"%s\" has version \"%s\", "
"but \"%s\" is required.\n",
xt_params->program_name, me->name,
me->version, XTABLES_VERSION);
exit(1);
}
if (strlen(me->name) >= XT_EXTENSION_MAXNAMELEN) {
fprintf(stderr, "%s: target `%s' has invalid name\n",
xt_params->program_name, me->name);
exit(1);
}
if (me->family >= NPROTO) {
fprintf(stderr,
"%s: BUG: match %s has invalid protocol family\n",
xt_params->program_name, me->name);
exit(1);
}
/* ignore not interested match */
if (me->family != afinfo->family && me->family != AF_UNSPEC)
return;
old = xtables_find_match(me->name, XTF_DURING_LOAD, NULL);
if (old) {
if (old->revision == me->revision &&
old->family == me->family) {
fprintf(stderr,
"%s: match `%s' already registered.\n",
xt_params->program_name, me->name);
exit(1);
}
/* Now we have two (or more) options, check compatibility. */
if (compatible_match_revision(old->name, old->revision)
&& old->revision > me->revision)
return;
/* See if new match can be used. */
if (!compatible_match_revision(me->name, me->revision))
return;
/* Prefer !AF_UNSPEC over AF_UNSPEC for same revision. */
if (old->revision == me->revision && me->family == AF_UNSPEC)
return;
/* Delete old one. */
for (i = &xtables_matches; *i!=old; i = &(*i)->next);
*i = old->next;
}
if (me->size != XT_ALIGN(me->size)) {
fprintf(stderr, "%s: match `%s' has invalid size %u.\n",
xt_params->program_name, me->name,
(unsigned int)me->size);
exit(1);
}
/* Append to list. */
for (i = &xtables_matches; *i; i = &(*i)->next);
me->next = NULL;
*i = me;
me->m = NULL;
me->mflags = 0;
}
void xtables_register_matches(struct xtables_match *match, unsigned int n)
{
do {
xtables_register_match(&match[--n]);
} while (n > 0);
}
void xtables_register_target(struct xtables_target *me)
{
struct xtables_target *old;
if (me->version == NULL) {
fprintf(stderr, "%s: target %s<%u> is missing a version\n",
xt_params->program_name, me->name, me->revision);
exit(1);
}
if (strcmp(me->version, XTABLES_VERSION) != 0) {
fprintf(stderr, "%s: target \"%s\" has version \"%s\", "
"but \"%s\" is required.\n",
xt_params->program_name, me->name,
me->version, XTABLES_VERSION);
exit(1);
}
if (strlen(me->name) >= XT_EXTENSION_MAXNAMELEN) {
fprintf(stderr, "%s: target `%s' has invalid name\n",
xt_params->program_name, me->name);
exit(1);
}
if (me->family >= NPROTO) {
fprintf(stderr,
"%s: BUG: target %s has invalid protocol family\n",
xt_params->program_name, me->name);
exit(1);
}
/* ignore not interested target */
if (me->family != afinfo->family && me->family != AF_UNSPEC)
return;
old = xtables_find_target(me->name, XTF_DURING_LOAD);
if (old) {
struct xtables_target **i;
if (old->revision == me->revision &&
old->family == me->family) {
fprintf(stderr,
"%s: target `%s' already registered.\n",
xt_params->program_name, me->name);
exit(1);
}
/* Now we have two (or more) options, check compatibility. */
if (compatible_target_revision(old->name, old->revision)
&& old->revision > me->revision)
return;
/* See if new target can be used. */
if (!compatible_target_revision(me->name, me->revision))
return;
/* Prefer !AF_UNSPEC over AF_UNSPEC for same revision. */
if (old->revision == me->revision && me->family == AF_UNSPEC)
return;
/* Delete old one. */
for (i = &xtables_targets; *i!=old; i = &(*i)->next);
*i = old->next;
}
if (me->size != XT_ALIGN(me->size)) {
fprintf(stderr, "%s: target `%s' has invalid size %u.\n",
xt_params->program_name, me->name,
(unsigned int)me->size);
exit(1);
}
/* Prepend to list. */
me->next = xtables_targets;
xtables_targets = me;
me->t = NULL;
me->tflags = 0;
}
void xtables_register_targets(struct xtables_target *target, unsigned int n)
{
do {
xtables_register_target(&target[--n]);
} while (n > 0);
}
/**
* xtables_param_act - act on condition
* @status: a constant from enum xtables_exittype
*
* %XTF_ONLY_ONCE: print error message that option may only be used once.
* @p1: module name (e.g. "mark")
* @p2(...): option in conflict (e.g. "--mark")
* @p3(...): condition to match on (see extensions/ for examples)
*
* %XTF_NO_INVERT: option does not support inversion
* @p1: module name
* @p2: option in conflict
* @p3: condition to match on
*
* %XTF_BAD_VALUE: bad value for option
* @p1: module name
* @p2: option with which the problem occured (e.g. "--mark")
* @p3: string the user passed in (e.g. "99999999999999")
*
* %XTF_ONE_ACTION: two mutually exclusive actions have been specified
* @p1: module name
*
* Displays an error message and exits the program.
*/
void xtables_param_act(unsigned int status, const char *p1, ...)
{
const char *p2, *p3;
va_list args;
bool b;
va_start(args, p1);
switch (status) {
case XTF_ONLY_ONCE:
p2 = va_arg(args, const char *);
b = va_arg(args, unsigned int);
if (!b)
return;
xt_params->exit_err(PARAMETER_PROBLEM,
"%s: \"%s\" option may only be specified once",
p1, p2);
break;
case XTF_NO_INVERT:
p2 = va_arg(args, const char *);
b = va_arg(args, unsigned int);
if (!b)
return;
xt_params->exit_err(PARAMETER_PROBLEM,
"%s: \"%s\" option cannot be inverted", p1, p2);
break;
case XTF_BAD_VALUE:
p2 = va_arg(args, const char *);
p3 = va_arg(args, const char *);
xt_params->exit_err(PARAMETER_PROBLEM,
"%s: Bad value for \"%s\" option: \"%s\"",
p1, p2, p3);
break;
case XTF_ONE_ACTION:
b = va_arg(args, unsigned int);
if (!b)
return;
xt_params->exit_err(PARAMETER_PROBLEM,
"%s: At most one action is possible", p1);
break;
default:
xt_params->exit_err(status, p1, args);
break;
}
va_end(args);
}
const char *xtables_ipaddr_to_numeric(const struct in_addr *addrp)
{
static char buf[20];
const unsigned char *bytep = (const void *)&addrp->s_addr;
sprintf(buf, "%u.%u.%u.%u", bytep[0], bytep[1], bytep[2], bytep[3]);
return buf;
}
static const char *ipaddr_to_host(const struct in_addr *addr)
{
struct hostent *host;
host = gethostbyaddr(addr, sizeof(struct in_addr), AF_INET);
if (host == NULL)
return NULL;
return host->h_name;
}
static const char *ipaddr_to_network(const struct in_addr *addr)
{
struct netent *net;
if ((net = getnetbyaddr(ntohl(addr->s_addr), AF_INET)) != NULL)
return net->n_name;
return NULL;
}
const char *xtables_ipaddr_to_anyname(const struct in_addr *addr)
{
const char *name;
if ((name = ipaddr_to_host(addr)) != NULL ||
(name = ipaddr_to_network(addr)) != NULL)
return name;
return xtables_ipaddr_to_numeric(addr);
}