blob: 235e2b2767d93d5b782fd4fd25b728083f91a029 [file] [log] [blame]
/*
* (C) 2000-2006 by the netfilter coreteam <coreteam@netfilter.org>:
*
* 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>
#include "iptables/internal.h"
#include "xshared.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 unused)
{
if (xt_params->opts != xt_params->orig_opts) {
free(xt_params->opts);
xt_params->opts = NULL;
}
}
struct option *xtables_merge_options(struct option *orig_opts,
struct option *oldopts,
const struct option *newopts,
unsigned int *option_offset)
{
unsigned int num_oold = 0, num_old = 0, num_new = 0, i;
struct option *merge, *mp;
if (newopts == NULL)
return oldopts;
for (num_oold = 0; orig_opts[num_oold].name; num_oold++) ;
if (oldopts != NULL)
for (num_old = 0; oldopts[num_old].name; num_old++) ;
for (num_new = 0; newopts[num_new].name; num_new++) ;
/*
* Since @oldopts also has @orig_opts already (and does so at the
* start), skip these entries.
*/
oldopts += num_oold;
num_old -= num_oold;
merge = malloc(sizeof(*mp) * (num_oold + num_old + num_new + 1));
if (merge == NULL)
return NULL;
/* Let the base options -[ADI...] have precedence over everything */
memcpy(merge, orig_opts, sizeof(*mp) * num_oold);
mp = merge + num_oold;
/* Second, the new options */
xt_params->option_offset += XT_OPTION_OFFSET_SCALE;
*option_offset = xt_params->option_offset;
memcpy(mp, newopts, sizeof(*mp) * num_new);
for (i = 0; i < num_new; ++i, ++mp)
mp->val += *option_offset;
/* Third, the old options */
memcpy(mp, oldopts, sizeof(*mp) * num_old);
mp += num_old;
xtables_free_opts(0);
/* Clear trailing entry */
memset(mp, 0, sizeof(*mp));
return merge;
}
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,
};
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;
if (fcntl(procfile, F_SETFD, FD_CLOEXEC) == -1) {
fprintf(stderr, "Could not set close on exec: %s\n",
strerror(errno));
exit(1);
}
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;
}
uint16_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 *af_prefix,
const char *name, bool is_target)
{
const char *all_prefixes[] = {"libxt_", af_prefix, NULL};
const char **prefix;
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);
for (prefix = all_prefixes; *prefix != NULL; ++prefix) {
snprintf(path, sizeof(path), "%.*s/%s%s.so",
(unsigned int)(next - dir), dir,
*prefix, name);
if (stat(path, &sb) != 0) {
if (errno == ENOENT)
continue;
fprintf(stderr, "%s: %s\n", path,
strerror(errno));
return NULL;
}
if (dlopen(path, RTLD_NOW) == NULL) {
fprintf(stderr, "%s: %s\n", path, dlerror());
break;
}
if (is_target)
ptr = xtables_find_target(name, XTF_DONT_LOAD);
else
ptr = xtables_find_match(name,
XTF_DONT_LOAD, NULL);
if (ptr != NULL)
return ptr;
fprintf(stderr, "%s: no \"%s\" extension found for "
"this protocol\n", path, name);
errno = ENOENT;
return NULL;
}
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, strerror(errno));
}
#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, strerror(errno));
}
#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, uint8_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);
}
if (fcntl(sockfd, F_SETFD, FD_CLOEXEC) == -1) {
fprintf(stderr, "Could not set close on exec: %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, uint8_t revision)
{
return compatible_revision(name, revision, afinfo->so_rev_match);
}
static int compatible_target_revision(const char *name, uint8_t revision)
{
return compatible_revision(name, revision, afinfo->so_rev_target);
}
static void xtables_check_options(const char *name, const struct option *opt)
{
for (; opt->name != NULL; ++opt)
if (opt->val < 0 || opt->val >= XT_OPTION_OFFSET_SCALE) {
fprintf(stderr, "%s: Extension %s uses invalid "
"option value %d\n",xt_params->program_name,
name, opt->val);
exit(1);
}
}
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: match `%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);
}
if (me->x6_options != NULL)
xtables_option_metavalidate(me->name, me->x6_options);
if (me->extra_opts != NULL)
xtables_check_options(me->name, me->extra_opts);
/* 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);
}
if (me->x6_options != NULL)
xtables_option_metavalidate(me->name, me->x6_options);
if (me->extra_opts != NULL)
xtables_check_options(me->name, me->extra_opts);
/* 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);
}
const char *xtables_ipmask_to_numeric(const struct in_addr *mask)
{
static char buf[20];
uint32_t maskaddr, bits;
int i;
maskaddr = ntohl(mask->s_addr);
if (maskaddr == 0xFFFFFFFFL)
/* we don't want to see "/32" */
return "";
i = 32;
bits = 0xFFFFFFFEL;
while (--i >= 0 && maskaddr != bits)
bits <<= 1;
if (i >= 0)
sprintf(buf, "/%d", i);
else
/* mask was not a decent combination of 1's and 0's */
sprintf(buf, "/%s", xtables_ipaddr_to_numeric(mask));
return buf;
}
static struct in_addr *__numeric_to_ipaddr(const char *dotted, bool is_mask)
{
static struct in_addr addr;
unsigned char *addrp;
unsigned int onebyte;
char buf[20], *p, *q;
int i;
/* copy dotted string, because we need to modify it */
strncpy(buf, dotted, sizeof(buf) - 1);
buf[sizeof(buf) - 1] = '\0';
addrp = (void *)&addr.s_addr;
p = buf;
for (i = 0; i < 3; ++i) {
if ((q = strchr(p, '.')) == NULL) {
if (is_mask)
return NULL;
/* autocomplete, this is a network address */
if (!xtables_strtoui(p, NULL, &onebyte, 0, UINT8_MAX))
return NULL;
addrp[i] = onebyte;
while (i < 3)
addrp[++i] = 0;
return &addr;
}
*q = '\0';
if (!xtables_strtoui(p, NULL, &onebyte, 0, UINT8_MAX))
return NULL;
addrp[i] = onebyte;
p = q + 1;
}
/* we have checked 3 bytes, now we check the last one */
if (!xtables_strtoui(p, NULL, &onebyte, 0, UINT8_MAX))
return NULL;
addrp[3] = onebyte;
return &addr;
}
struct in_addr *xtables_numeric_to_ipaddr(const char *dotted)
{
return __numeric_to_ipaddr(dotted, false);
}
struct in_addr *xtables_numeric_to_ipmask(const char *dotted)
{
return __numeric_to_ipaddr(dotted, true);
}
static struct in_addr *network_to_ipaddr(const char *name)
{
static struct in_addr addr;
struct netent *net;
if ((net = getnetbyname(name)) != NULL) {
if (net->n_addrtype != AF_INET)
return NULL;
addr.s_addr = htonl(net->n_net);
return &addr;
}
return NULL;
}
static struct in_addr *host_to_ipaddr(const char *name, unsigned int *naddr)
{
struct hostent *host;
struct in_addr *addr;
unsigned int i;
*naddr = 0;
if ((host = gethostbyname(name)) != NULL) {
if (host->h_addrtype != AF_INET ||
host->h_length != sizeof(struct in_addr))
return NULL;
while (host->h_addr_list[*naddr] != NULL)
++*naddr;
addr = xtables_calloc(*naddr, sizeof(struct in_addr));
for (i = 0; i < *naddr; i++)
memcpy(&addr[i], host->h_addr_list[i],
sizeof(struct in_addr));
return addr;
}
return NULL;
}
static struct in_addr *
ipparse_hostnetwork(const char *name, unsigned int *naddrs)
{
struct in_addr *addrptmp, *addrp;
if ((addrptmp = xtables_numeric_to_ipaddr(name)) != NULL ||
(addrptmp = network_to_ipaddr(name)) != NULL) {
addrp = xtables_malloc(sizeof(struct in_addr));
memcpy(addrp, addrptmp, sizeof(*addrp));
*naddrs = 1;
return addrp;
}
if ((addrptmp = host_to_ipaddr(name, naddrs)) != NULL)
return addrptmp;
xt_params->exit_err(PARAMETER_PROBLEM, "host/network `%s' not found", name);
}
static struct in_addr *parse_ipmask(const char *mask)
{
static struct in_addr maskaddr;
struct in_addr *addrp;
unsigned int bits;
if (mask == NULL) {
/* no mask at all defaults to 32 bits */
maskaddr.s_addr = 0xFFFFFFFF;
return &maskaddr;
}
if ((addrp = xtables_numeric_to_ipmask(mask)) != NULL)
/* dotted_to_addr already returns a network byte order addr */
return addrp;
if (!xtables_strtoui(mask, NULL, &bits, 0, 32))
xt_params->exit_err(PARAMETER_PROBLEM,
"invalid mask `%s' specified", mask);
if (bits != 0) {
maskaddr.s_addr = htonl(0xFFFFFFFF << (32 - bits));
return &maskaddr;
}
maskaddr.s_addr = 0U;
return &maskaddr;
}
void xtables_ipparse_multiple(const char *name, struct in_addr **addrpp,
struct in_addr **maskpp, unsigned int *naddrs)
{
struct in_addr *addrp;
char buf[256], *p;
unsigned int len, i, j, n, count = 1;
const char *loop = name;
while ((loop = strchr(loop, ',')) != NULL) {
++count;
++loop; /* skip ',' */
}
*addrpp = xtables_malloc(sizeof(struct in_addr) * count);
*maskpp = xtables_malloc(sizeof(struct in_addr) * count);
loop = name;
for (i = 0; i < count; ++i) {
if (loop == NULL)
break;
if (*loop == ',')
++loop;
if (*loop == '\0')
break;
p = strchr(loop, ',');
if (p != NULL)
len = p - loop;
else
len = strlen(loop);
if (len == 0 || sizeof(buf) - 1 < len)
break;
strncpy(buf, loop, len);
buf[len] = '\0';
loop += len;
if ((p = strrchr(buf, '/')) != NULL) {
*p = '\0';
addrp = parse_ipmask(p + 1);
} else {
addrp = parse_ipmask(NULL);
}
memcpy(*maskpp + i, addrp, sizeof(*addrp));
/* if a null mask is given, the name is ignored, like in "any/0" */
if ((*maskpp + i)->s_addr == 0)
/*
* A bit pointless to process multiple addresses
* in this case...
*/
strcpy(buf, "0.0.0.0");
addrp = ipparse_hostnetwork(buf, &n);
if (n > 1) {
count += n - 1;
*addrpp = xtables_realloc(*addrpp,
sizeof(struct in_addr) * count);
*maskpp = xtables_realloc(*maskpp,
sizeof(struct in_addr) * count);
for (j = 0; j < n; ++j)
/* for each new addr */
memcpy(*addrpp + i + j, addrp + j,
sizeof(*addrp));
for (j = 1; j < n; ++j)
/* for each new mask */
memcpy(*maskpp + i + j, *maskpp + i,
sizeof(*addrp));
i += n - 1;
} else {
memcpy(*addrpp + i, addrp, sizeof(*addrp));
}
/* free what ipparse_hostnetwork had allocated: */
free(addrp);
}
*naddrs = count;
for (i = 0; i < count; ++i)
(*addrpp+i)->s_addr &= (*maskpp+i)->s_addr;
}
/**
* xtables_ipparse_any - transform arbitrary name to in_addr
*
* Possible inputs (pseudo regex):
* m{^($hostname|$networkname|$ipaddr)(/$mask)?}
* "1.2.3.4/5", "1.2.3.4", "hostname", "networkname"
*/
void xtables_ipparse_any(const char *name, struct in_addr **addrpp,
struct in_addr *maskp, unsigned int *naddrs)
{
unsigned int i, j, k, n;
struct in_addr *addrp;
char buf[256], *p;
strncpy(buf, name, sizeof(buf) - 1);
buf[sizeof(buf) - 1] = '\0';
if ((p = strrchr(buf, '/')) != NULL) {
*p = '\0';
addrp = parse_ipmask(p + 1);
} else {
addrp = parse_ipmask(NULL);
}
memcpy(maskp, addrp, sizeof(*maskp));
/* if a null mask is given, the name is ignored, like in "any/0" */
if (maskp->s_addr == 0U)
strcpy(buf, "0.0.0.0");
addrp = *addrpp = ipparse_hostnetwork(buf, naddrs);
n = *naddrs;
for (i = 0, j = 0; i < n; ++i) {
addrp[j++].s_addr &= maskp->s_addr;
for (k = 0; k < j - 1; ++k)
if (addrp[k].s_addr == addrp[j-1].s_addr) {
/*
* Nuke the dup by copying an address from the
* tail here, and check the current position
* again (--j).
*/
memcpy(&addrp[--j], &addrp[--*naddrs],
sizeof(struct in_addr));
break;
}
}
}
const char *xtables_ip6addr_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 inet_ntop(AF_INET6, addrp, buf, sizeof(buf));
}
static const char *ip6addr_to_host(const struct in6_addr *addr)
{
static char hostname[NI_MAXHOST];
struct sockaddr_in6 saddr;
int err;
memset(&saddr, 0, sizeof(struct sockaddr_in6));
memcpy(&saddr.sin6_addr, addr, sizeof(*addr));
saddr.sin6_family = AF_INET6;
err = getnameinfo((const void *)&saddr, sizeof(struct sockaddr_in6),
hostname, sizeof(hostname) - 1, NULL, 0, 0);
if (err != 0) {
#ifdef DEBUG
fprintf(stderr,"IP2Name: %s\n",gai_strerror(err));
#endif
return NULL;
}
#ifdef DEBUG
fprintf (stderr, "\naddr2host: %s\n", hostname);
#endif
return hostname;
}
const char *xtables_ip6addr_to_anyname(const struct in6_addr *addr)
{
const char *name;
if ((name = ip6addr_to_host(addr)) != NULL)
return name;
return xtables_ip6addr_to_numeric(addr);
}
static int ip6addr_prefix_length(const struct in6_addr *k)
{
unsigned int bits = 0;
uint32_t a, b, c, d;
a = ntohl(k->s6_addr32[0]);
b = ntohl(k->s6_addr32[1]);
c = ntohl(k->s6_addr32[2]);
d = ntohl(k->s6_addr32[3]);
while (a & 0x80000000U) {
++bits;
a <<= 1;
a |= (b >> 31) & 1;
b <<= 1;
b |= (c >> 31) & 1;
c <<= 1;
c |= (d >> 31) & 1;
d <<= 1;
}
if (a != 0 || b != 0 || c != 0 || d != 0)
return -1;
return bits;
}
const char *xtables_ip6mask_to_numeric(const struct in6_addr *addrp)
{
static char buf[50+2];
int l = ip6addr_prefix_length(addrp);
if (l == -1) {
strcpy(buf, "/");
strcat(buf, xtables_ip6addr_to_numeric(addrp));
return buf;
}
sprintf(buf, "/%d", l);
return buf;
}
struct in6_addr *xtables_numeric_to_ip6addr(const char *num)
{
static struct in6_addr ap;
int err;
if ((err = inet_pton(AF_INET6, num, &ap)) == 1)
return &ap;
#ifdef DEBUG
fprintf(stderr, "\nnumeric2addr: %d\n", err);
#endif
return NULL;
}
static struct in6_addr *
host_to_ip6addr(const char *name, unsigned int *naddr)
{
struct in6_addr *addr;
struct addrinfo hints;
struct addrinfo *res, *p;
int err;
unsigned int i;
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_CANONNAME;
hints.ai_family = AF_INET6;
hints.ai_socktype = SOCK_RAW;
*naddr = 0;
if ((err = getaddrinfo(name, NULL, &hints, &res)) != 0) {
#ifdef DEBUG
fprintf(stderr,"Name2IP: %s\n",gai_strerror(err));
#endif
return NULL;
} else {
/* Find length of address chain */
for (p = res; p != NULL; p = p->ai_next)
++*naddr;
#ifdef DEBUG
fprintf(stderr, "resolved: len=%d %s ", res->ai_addrlen,
xtables_ip6addr_to_numeric(&((struct sockaddr_in6 *)res->ai_addr)->sin6_addr));
#endif
/* Copy each element of the address chain */
addr = xtables_calloc(*naddr, sizeof(struct in6_addr));
for (i = 0, p = res; p != NULL; p = p->ai_next)
memcpy(&addr[i++],
&((const struct sockaddr_in6 *)p->ai_addr)->sin6_addr,
sizeof(struct in6_addr));
freeaddrinfo(res);
return addr;
}
return NULL;
}
static struct in6_addr *network_to_ip6addr(const char *name)
{
/* abort();*/
/* TODO: not implemented yet, but the exception breaks the
* name resolvation */
return NULL;
}
static struct in6_addr *
ip6parse_hostnetwork(const char *name, unsigned int *naddrs)
{
struct in6_addr *addrp, *addrptmp;
if ((addrptmp = xtables_numeric_to_ip6addr(name)) != NULL ||
(addrptmp = network_to_ip6addr(name)) != NULL) {
addrp = xtables_malloc(sizeof(struct in6_addr));
memcpy(addrp, addrptmp, sizeof(*addrp));
*naddrs = 1;
return addrp;
}
if ((addrp = host_to_ip6addr(name, naddrs)) != NULL)
return addrp;
xt_params->exit_err(PARAMETER_PROBLEM, "host/network `%s' not found", name);
}
static struct in6_addr *parse_ip6mask(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 = xtables_numeric_to_ip6addr(mask)) != NULL)
return addrp;
if (!xtables_strtoui(mask, NULL, &bits, 0, 128))
xt_params->exit_err(PARAMETER_PROBLEM,
"invalid mask `%s' specified", mask);
if (bits != 0) {
char *p = (void *)&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;
}
void
xtables_ip6parse_multiple(const char *name, struct in6_addr **addrpp,
struct in6_addr **maskpp, unsigned int *naddrs)
{
static const struct in6_addr zero_addr;
struct in6_addr *addrp;
char buf[256], *p;
unsigned int len, i, j, n, count = 1;
const char *loop = name;
while ((loop = strchr(loop, ',')) != NULL) {
++count;
++loop; /* skip ',' */
}
*addrpp = xtables_malloc(sizeof(struct in6_addr) * count);
*maskpp = xtables_malloc(sizeof(struct in6_addr) * count);
loop = name;
for (i = 0; i < count /*NB: count can grow*/; ++i) {
if (loop == NULL)
break;
if (*loop == ',')
++loop;
if (*loop == '\0')
break;
p = strchr(loop, ',');
if (p != NULL)
len = p - loop;
else
len = strlen(loop);
if (len == 0 || sizeof(buf) - 1 < len)
break;
strncpy(buf, loop, len);
buf[len] = '\0';
loop += len;
if ((p = strrchr(buf, '/')) != NULL) {
*p = '\0';
addrp = parse_ip6mask(p + 1);
} else {
addrp = parse_ip6mask(NULL);
}
memcpy(*maskpp + i, addrp, sizeof(*addrp));
/* if a null mask is given, the name is ignored, like in "any/0" */
if (memcmp(*maskpp + i, &zero_addr, sizeof(zero_addr)) == 0)
strcpy(buf, "::");
addrp = ip6parse_hostnetwork(buf, &n);
if (n > 1) {
count += n - 1;
*addrpp = xtables_realloc(*addrpp,
sizeof(struct in6_addr) * count);
*maskpp = xtables_realloc(*maskpp,
sizeof(struct in6_addr) * count);
for (j = 0; j < n; ++j)
/* for each new addr */
memcpy(*addrpp + i + j, addrp + j,
sizeof(*addrp));
for (j = 1; j < n; ++j)
/* for each new mask */
memcpy(*maskpp + i + j, *maskpp + i,
sizeof(*addrp));
i += n - 1;
} else {
memcpy(*addrpp + i, addrp, sizeof(*addrp));
}
/* free what ip6parse_hostnetwork had allocated: */
free(addrp);
}
*naddrs = count;
for (i = 0; i < count; ++i)
for (j = 0; j < 4; ++j)
(*addrpp+i)->s6_addr32[j] &= (*maskpp+i)->s6_addr32[j];
}
void xtables_ip6parse_any(const char *name, struct in6_addr **addrpp,
struct in6_addr *maskp, unsigned int *naddrs)
{
static const struct in6_addr zero_addr;
struct in6_addr *addrp;
unsigned int i, j, k, n;
char buf[256], *p;
strncpy(buf, name, sizeof(buf) - 1);
buf[sizeof(buf)-1] = '\0';
if ((p = strrchr(buf, '/')) != NULL) {
*p = '\0';
addrp = parse_ip6mask(p + 1);
} else {
addrp = parse_ip6mask(NULL);
}
memcpy(maskp, addrp, sizeof(*maskp));
/* if a null mask is given, the name is ignored, like in "any/0" */
if (memcmp(maskp, &zero_addr, sizeof(zero_addr)) == 0)
strcpy(buf, "::");
addrp = *addrpp = ip6parse_hostnetwork(buf, naddrs);
n = *naddrs;
for (i = 0, j = 0; i < n; ++i) {
for (k = 0; k < 4; ++k)
addrp[j].s6_addr32[k] &= maskp->s6_addr32[k];
++j;
for (k = 0; k < j - 1; ++k)
if (IN6_ARE_ADDR_EQUAL(&addrp[k], &addrp[j - 1])) {
/*
* Nuke the dup by copying an address from the
* tail here, and check the current position
* again (--j).
*/
memcpy(&addrp[--j], &addrp[--*naddrs],
sizeof(struct in_addr));
break;
}
}
}
void xtables_save_string(const char *value)
{
static const char no_quote_chars[] = "_-0123456789"
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
static const char escape_chars[] = "\"\\'";
size_t length;
const char *p;
length = strspn(value, no_quote_chars);
if (length > 0 && value[length] == 0) {
/* no quoting required */
putchar(' ');
fputs(value, stdout);
} else {
/* there is at least one dangerous character in the
value, which we have to quote. Write double quotes
around the value and escape special characters with
a backslash */
printf(" \"");
for (p = strpbrk(value, escape_chars); p != NULL;
p = strpbrk(value, escape_chars)) {
if (p > value)
fwrite(value, 1, p - value, stdout);
putchar('\\');
putchar(*p);
value = p + 1;
}
/* print the rest and finish the double quoted
string */
fputs(value, stdout);
putchar('\"');
}
}
/**
* Check for option-intrapositional negation.
* Do not use in new code.
*/
int xtables_check_inverse(const char option[], int *invert,
int *my_optind, int argc, char **argv)
{
if (option == NULL || strcmp(option, "!") != 0)
return false;
fprintf(stderr, "Using intrapositioned negation "
"(`--option ! this`) is deprecated in favor of "
"extrapositioned (`! --option this`).\n");
if (*invert)
xt_params->exit_err(PARAMETER_PROBLEM,
"Multiple `!' flags not allowed");
*invert = true;
if (my_optind != NULL) {
optarg = argv[*my_optind];
++*my_optind;
if (argc && *my_optind > argc)
xt_params->exit_err(PARAMETER_PROBLEM,
"no argument following `!'");
}
return true;
}
const struct xtables_pprot xtables_chain_protos[] = {
{"tcp", IPPROTO_TCP},
{"sctp", IPPROTO_SCTP},
{"udp", IPPROTO_UDP},
{"udplite", IPPROTO_UDPLITE},
{"icmp", IPPROTO_ICMP},
{"icmpv6", IPPROTO_ICMPV6},
{"ipv6-icmp", IPPROTO_ICMPV6},
{"esp", IPPROTO_ESP},
{"ah", IPPROTO_AH},
{"ipv6-mh", IPPROTO_MH},
{"mh", IPPROTO_MH},
{"all", 0},
{NULL},
};
uint16_t
xtables_parse_protocol(const char *s)
{
unsigned int proto;
if (!xtables_strtoui(s, NULL, &proto, 0, UINT8_MAX)) {
struct protoent *pent;
/* first deal with the special case of 'all' to prevent
* people from being able to redefine 'all' in nsswitch
* and/or provoke expensive [not working] ldap/nis/...
* lookups */
if (!strcmp(s, "all"))
return 0;
if ((pent = getprotobyname(s)))
proto = pent->p_proto;
else {
unsigned int i;
for (i = 0; i < ARRAY_SIZE(xtables_chain_protos); ++i) {
if (xtables_chain_protos[i].name == NULL)
continue;
if (strcmp(s, xtables_chain_protos[i].name) == 0) {
proto = xtables_chain_protos[i].num;
break;
}
}
if (i == ARRAY_SIZE(xtables_chain_protos))
xt_params->exit_err(PARAMETER_PROBLEM,
"unknown protocol `%s' specified",
s);
}
}
return proto;
}