/*
* link_gre6.c gre driver module
*
* 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.
*
* Authors: Dmitry Kozlov <xeb@mail.ru>
*
*/
#include <string.h>
#include <net/if.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <linux/ip.h>
#include <linux/if_tunnel.h>
#include <linux/ip6_tunnel.h>
#include "rt_names.h"
#include "utils.h"
#include "ip_common.h"
#include "tunnel.h"
#define IP6_FLOWINFO_TCLASS htonl(0x0FF00000)
#define IP6_FLOWINFO_FLOWLABEL htonl(0x000FFFFF)
#define DEFAULT_TNL_HOP_LIMIT (64)
static void print_usage(FILE *f)
{
fprintf(f,
"Usage: ... { ip6gre | ip6gretap } [ remote ADDR ]\n"
" [ local ADDR ]\n"
" [ [i|o]seq ]\n"
" [ [i|o]key KEY ]\n"
" [ [i|o]csum ]\n"
" [ hoplimit TTL ]\n"
" [ encaplimit ELIM ]\n"
" [ tclass TCLASS ]\n"
" [ flowlabel FLOWLABEL ]\n"
" [ dscp inherit ]\n"
" [ fwmark MARK ]\n"
" [ dev PHYS_DEV ]\n"
" [ noencap ]\n"
" [ encap { fou | gue | none } ]\n"
" [ encap-sport PORT ]\n"
" [ encap-dport PORT ]\n"
" [ [no]encap-csum ]\n"
" [ [no]encap-csum6 ]\n"
" [ [no]encap-remcsum ]\n"
"\n"
"Where: ADDR := IPV6_ADDRESS\n"
" TTL := { 0..255 } (default=%d)\n"
" KEY := { DOTTED_QUAD | NUMBER }\n"
" ELIM := { none | 0..255 }(default=%d)\n"
" TCLASS := { 0x0..0xff | inherit }\n"
" FLOWLABEL := { 0x0..0xfffff | inherit }\n"
" MARK := { 0x0..0xffffffff | inherit }\n",
DEFAULT_TNL_HOP_LIMIT, IPV6_DEFAULT_TNL_ENCAP_LIMIT
);
}
static void usage(void) __attribute__((noreturn));
static void usage(void)
{
print_usage(stderr);
exit(-1);
}
static int gre_parse_opt(struct link_util *lu, int argc, char **argv,
struct nlmsghdr *n)
{
struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
struct {
struct nlmsghdr n;
struct ifinfomsg i;
char buf[1024];
} req = {
.n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi)),
.n.nlmsg_flags = NLM_F_REQUEST,
.n.nlmsg_type = RTM_GETLINK,
.i.ifi_family = preferred_family,
.i.ifi_index = ifi->ifi_index,
};
struct rtattr *tb[IFLA_MAX + 1];
struct rtattr *linkinfo[IFLA_INFO_MAX+1];
struct rtattr *greinfo[IFLA_GRE_MAX + 1];
__u16 iflags = 0;
__u16 oflags = 0;
unsigned int ikey = 0;
unsigned int okey = 0;
struct in6_addr raddr = IN6ADDR_ANY_INIT;
struct in6_addr laddr = IN6ADDR_ANY_INIT;
unsigned int link = 0;
unsigned int flowinfo = 0;
unsigned int flags = 0;
__u8 hop_limit = DEFAULT_TNL_HOP_LIMIT;
__u8 encap_limit = IPV6_DEFAULT_TNL_ENCAP_LIMIT;
__u16 encaptype = 0;
__u16 encapflags = TUNNEL_ENCAP_FLAG_CSUM6;
__u16 encapsport = 0;
__u16 encapdport = 0;
int len;
__u32 fwmark = 0;
if (!(n->nlmsg_flags & NLM_F_CREATE)) {
if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 0) {
get_failed:
fprintf(stderr,
"Failed to get existing tunnel info.\n");
return -1;
}
len = req.n.nlmsg_len;
len -= NLMSG_LENGTH(sizeof(*ifi));
if (len < 0)
goto get_failed;
parse_rtattr(tb, IFLA_MAX, IFLA_RTA(&req.i), len);
if (!tb[IFLA_LINKINFO])
goto get_failed;
parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
if (!linkinfo[IFLA_INFO_DATA])
goto get_failed;
parse_rtattr_nested(greinfo, IFLA_GRE_MAX,
linkinfo[IFLA_INFO_DATA]);
if (greinfo[IFLA_GRE_IKEY])
ikey = rta_getattr_u32(greinfo[IFLA_GRE_IKEY]);
if (greinfo[IFLA_GRE_OKEY])
okey = rta_getattr_u32(greinfo[IFLA_GRE_OKEY]);
if (greinfo[IFLA_GRE_IFLAGS])
iflags = rta_getattr_u16(greinfo[IFLA_GRE_IFLAGS]);
if (greinfo[IFLA_GRE_OFLAGS])
oflags = rta_getattr_u16(greinfo[IFLA_GRE_OFLAGS]);
if (greinfo[IFLA_GRE_LOCAL])
memcpy(&laddr, RTA_DATA(greinfo[IFLA_GRE_LOCAL]), sizeof(laddr));
if (greinfo[IFLA_GRE_REMOTE])
memcpy(&raddr, RTA_DATA(greinfo[IFLA_GRE_REMOTE]), sizeof(raddr));
if (greinfo[IFLA_GRE_TTL])
hop_limit = rta_getattr_u8(greinfo[IFLA_GRE_TTL]);
if (greinfo[IFLA_GRE_LINK])
link = rta_getattr_u32(greinfo[IFLA_GRE_LINK]);
if (greinfo[IFLA_GRE_ENCAP_LIMIT])
encap_limit = rta_getattr_u8(greinfo[IFLA_GRE_ENCAP_LIMIT]);
if (greinfo[IFLA_GRE_FLOWINFO])
flowinfo = rta_getattr_u32(greinfo[IFLA_GRE_FLOWINFO]);
if (greinfo[IFLA_GRE_FLAGS])
flags = rta_getattr_u32(greinfo[IFLA_GRE_FLAGS]);
if (greinfo[IFLA_GRE_ENCAP_TYPE])
encaptype = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_TYPE]);
if (greinfo[IFLA_GRE_ENCAP_FLAGS])
encapflags = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_FLAGS]);
if (greinfo[IFLA_GRE_ENCAP_SPORT])
encapsport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_SPORT]);
if (greinfo[IFLA_GRE_ENCAP_DPORT])
encapdport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_DPORT]);
if (greinfo[IFLA_GRE_FWMARK])
fwmark = rta_getattr_u32(greinfo[IFLA_GRE_FWMARK]);
}
while (argc > 0) {
if (!matches(*argv, "key")) {
unsigned int uval;
NEXT_ARG();
iflags |= GRE_KEY;
oflags |= GRE_KEY;
if (strchr(*argv, '.'))
uval = get_addr32(*argv);
else {
if (get_unsigned(&uval, *argv, 0) < 0) {
fprintf(stderr,
"Invalid value for \"key\"\n");
exit(-1);
}
uval = htonl(uval);
}
ikey = okey = uval;
} else if (!matches(*argv, "ikey")) {
unsigned int uval;
NEXT_ARG();
iflags |= GRE_KEY;
if (strchr(*argv, '.'))
uval = get_addr32(*argv);
else {
if (get_unsigned(&uval, *argv, 0) < 0) {
fprintf(stderr, "invalid value of \"ikey\"\n");
exit(-1);
}
uval = htonl(uval);
}
ikey = uval;
} else if (!matches(*argv, "okey")) {
unsigned int uval;
NEXT_ARG();
oflags |= GRE_KEY;
if (strchr(*argv, '.'))
uval = get_addr32(*argv);
else {
if (get_unsigned(&uval, *argv, 0) < 0) {
fprintf(stderr, "invalid value of \"okey\"\n");
exit(-1);
}
uval = htonl(uval);
}
okey = uval;
} else if (!matches(*argv, "seq")) {
iflags |= GRE_SEQ;
oflags |= GRE_SEQ;
} else if (!matches(*argv, "iseq")) {
iflags |= GRE_SEQ;
} else if (!matches(*argv, "oseq")) {
oflags |= GRE_SEQ;
} else if (!matches(*argv, "csum")) {
iflags |= GRE_CSUM;
oflags |= GRE_CSUM;
} else if (!matches(*argv, "icsum")) {
iflags |= GRE_CSUM;
} else if (!matches(*argv, "ocsum")) {
oflags |= GRE_CSUM;
} else if (!matches(*argv, "remote")) {
inet_prefix addr;
NEXT_ARG();
get_prefix(&addr, *argv, preferred_family);
if (addr.family == AF_UNSPEC)
invarg("\"remote\" address family is AF_UNSPEC", *argv);
memcpy(&raddr, &addr.data, sizeof(raddr));
} else if (!matches(*argv, "local")) {
inet_prefix addr;
NEXT_ARG();
get_prefix(&addr, *argv, preferred_family);
if (addr.family == AF_UNSPEC)
invarg("\"local\" address family is AF_UNSPEC", *argv);
memcpy(&laddr, &addr.data, sizeof(laddr));
} else if (!matches(*argv, "dev")) {
NEXT_ARG();
link = if_nametoindex(*argv);
if (link == 0) {
fprintf(stderr, "Cannot find device \"%s\"\n",
*argv);
exit(-1);
}
} else if (!matches(*argv, "ttl") ||
!matches(*argv, "hoplimit")) {
__u8 uval;
NEXT_ARG();
if (get_u8(&uval, *argv, 0))
invarg("invalid TTL", *argv);
hop_limit = uval;
} else if (!matches(*argv, "tos") ||
!matches(*argv, "tclass") ||
!matches(*argv, "dsfield")) {
__u8 uval;
NEXT_ARG();
if (strcmp(*argv, "inherit") == 0)
flags |= IP6_TNL_F_USE_ORIG_TCLASS;
else {
if (get_u8(&uval, *argv, 16))
invarg("invalid TClass", *argv);
flowinfo &= ~IP6_FLOWINFO_TCLASS;
flowinfo |= htonl((__u32)uval << 20) & IP6_FLOWINFO_TCLASS;
flags &= ~IP6_TNL_F_USE_ORIG_TCLASS;
}
} else if (strcmp(*argv, "flowlabel") == 0 ||
strcmp(*argv, "fl") == 0) {
__u32 uval;
NEXT_ARG();
if (strcmp(*argv, "inherit") == 0)
flags |= IP6_TNL_F_USE_ORIG_FLOWLABEL;
else {
if (get_u32(&uval, *argv, 16))
invarg("invalid Flowlabel", *argv);
if (uval > 0xFFFFF)
invarg("invalid Flowlabel", *argv);
flowinfo &= ~IP6_FLOWINFO_FLOWLABEL;
flowinfo |= htonl(uval) & IP6_FLOWINFO_FLOWLABEL;
flags &= ~IP6_TNL_F_USE_ORIG_FLOWLABEL;
}
} else if (strcmp(*argv, "dscp") == 0) {
NEXT_ARG();
if (strcmp(*argv, "inherit") != 0)
invarg("not inherit", *argv);
flags |= IP6_TNL_F_RCV_DSCP_COPY;
} else if (strcmp(*argv, "noencap") == 0) {
encaptype = TUNNEL_ENCAP_NONE;
} else if (strcmp(*argv, "encap") == 0) {
NEXT_ARG();
if (strcmp(*argv, "fou") == 0)
encaptype = TUNNEL_ENCAP_FOU;
else if (strcmp(*argv, "gue") == 0)
encaptype = TUNNEL_ENCAP_GUE;
else if (strcmp(*argv, "none") == 0)
encaptype = TUNNEL_ENCAP_NONE;
else
invarg("Invalid encap type.", *argv);
} else if (strcmp(*argv, "encap-sport") == 0) {
NEXT_ARG();
if (strcmp(*argv, "auto") == 0)
encapsport = 0;
else if (get_u16(&encapsport, *argv, 0))
invarg("Invalid source port.", *argv);
} else if (strcmp(*argv, "encap-dport") == 0) {
NEXT_ARG();
if (get_u16(&encapdport, *argv, 0))
invarg("Invalid destination port.", *argv);
} else if (strcmp(*argv, "encap-csum") == 0) {
encapflags |= TUNNEL_ENCAP_FLAG_CSUM;
} else if (strcmp(*argv, "noencap-csum") == 0) {
encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM;
} else if (strcmp(*argv, "encap-udp6-csum") == 0) {
encapflags |= TUNNEL_ENCAP_FLAG_CSUM6;
} else if (strcmp(*argv, "noencap-udp6-csum") == 0) {
encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM6;
} else if (strcmp(*argv, "encap-remcsum") == 0) {
encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
} else if (strcmp(*argv, "noencap-remcsum") == 0) {
encapflags &= ~TUNNEL_ENCAP_FLAG_REMCSUM;
} else if (strcmp(*argv, "fwmark") == 0) {
NEXT_ARG();
if (strcmp(*argv, "inherit") == 0) {
flags |= IP6_TNL_F_USE_ORIG_FWMARK;
fwmark = 0;
} else {
if (get_u32(&fwmark, *argv, 0))
invarg("invalid fwmark\n", *argv);
flags &= ~IP6_TNL_F_USE_ORIG_FWMARK;
}
} else if (strcmp(*argv, "encaplimit") == 0) {
NEXT_ARG();
if (strcmp(*argv, "none") == 0) {
flags |= IP6_TNL_F_IGN_ENCAP_LIMIT;
} else {
__u8 uval;
if (get_u8(&uval, *argv, 0) < -1)
invarg("invalid ELIM", *argv);
encap_limit = uval;
flags &= ~IP6_TNL_F_IGN_ENCAP_LIMIT;
}
} else
usage();
argc--; argv++;
}
addattr32(n, 1024, IFLA_GRE_IKEY, ikey);
addattr32(n, 1024, IFLA_GRE_OKEY, okey);
addattr_l(n, 1024, IFLA_GRE_IFLAGS, &iflags, 2);
addattr_l(n, 1024, IFLA_GRE_OFLAGS, &oflags, 2);
addattr_l(n, 1024, IFLA_GRE_LOCAL, &laddr, sizeof(laddr));
addattr_l(n, 1024, IFLA_GRE_REMOTE, &raddr, sizeof(raddr));
if (link)
addattr32(n, 1024, IFLA_GRE_LINK, link);
addattr_l(n, 1024, IFLA_GRE_TTL, &hop_limit, 1);
addattr_l(n, 1024, IFLA_GRE_ENCAP_LIMIT, &encap_limit, 1);
addattr_l(n, 1024, IFLA_GRE_FLOWINFO, &flowinfo, 4);
addattr32(n, 1024, IFLA_GRE_FLAGS, flags);
addattr32(n, 1024, IFLA_GRE_FWMARK, fwmark);
addattr16(n, 1024, IFLA_GRE_ENCAP_TYPE, encaptype);
addattr16(n, 1024, IFLA_GRE_ENCAP_FLAGS, encapflags);
addattr16(n, 1024, IFLA_GRE_ENCAP_SPORT, htons(encapsport));
addattr16(n, 1024, IFLA_GRE_ENCAP_DPORT, htons(encapdport));
return 0;
}
static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
{
char s2[64];
const char *local = "any";
const char *remote = "any";
unsigned int iflags = 0;
unsigned int oflags = 0;
unsigned int flags = 0;
unsigned int flowinfo = 0;
struct in6_addr in6_addr_any = IN6ADDR_ANY_INIT;
if (!tb)
return;
if (tb[IFLA_GRE_FLAGS])
flags = rta_getattr_u32(tb[IFLA_GRE_FLAGS]);
if (tb[IFLA_GRE_FLOWINFO])
flowinfo = rta_getattr_u32(tb[IFLA_GRE_FLOWINFO]);
if (tb[IFLA_GRE_REMOTE]) {
struct in6_addr addr;
memcpy(&addr, RTA_DATA(tb[IFLA_GRE_REMOTE]), sizeof(addr));
if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
remote = format_host(AF_INET6, sizeof(addr), &addr);
}
print_string(PRINT_ANY, "remote", "remote %s ", remote);
if (tb[IFLA_GRE_LOCAL]) {
struct in6_addr addr;
memcpy(&addr, RTA_DATA(tb[IFLA_GRE_LOCAL]), sizeof(addr));
if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
local = format_host(AF_INET6, sizeof(addr), &addr);
}
print_string(PRINT_ANY, "local", "local %s ", local);
if (tb[IFLA_GRE_LINK] && rta_getattr_u32(tb[IFLA_GRE_LINK])) {
unsigned int link = rta_getattr_u32(tb[IFLA_GRE_LINK]);
const char *n = if_indextoname(link, s2);
if (n)
print_string(PRINT_ANY, "link", "dev %s ", n);
else
print_uint(PRINT_ANY, "link_index", "dev %u ", link);
}
if (tb[IFLA_GRE_TTL]) {
__u8 ttl = rta_getattr_u8(tb[IFLA_GRE_TTL]);
if (ttl)
print_int(PRINT_ANY, "ttl", "hoplimit %d ", ttl);
else
print_int(PRINT_JSON, "ttl", NULL, ttl);
}
if (flags & IP6_TNL_F_IGN_ENCAP_LIMIT)
print_bool(PRINT_ANY,
"ip6_tnl_f_ign_encap_limit",
"encaplimit none ",
true);
else if (tb[IFLA_GRE_ENCAP_LIMIT]) {
int encap_limit = rta_getattr_u8(tb[IFLA_GRE_ENCAP_LIMIT]);
print_int(PRINT_ANY,
"encap_limit",
"encaplimit %d ",
encap_limit);
}
if (flags & IP6_TNL_F_USE_ORIG_FLOWLABEL) {
print_bool(PRINT_ANY,
"ip6_tnl_f_use_orig_flowlabel",
"flowlabel inherit ",
true);
} else {
if (is_json_context()) {
SPRINT_BUF(b1);
snprintf(b1, sizeof(b1), "0x%05x",
ntohl(flowinfo & IP6_FLOWINFO_FLOWLABEL));
print_string(PRINT_JSON, "flowlabel", NULL, b1);
} else {
fprintf(f, "flowlabel 0x%05x ",
ntohl(flowinfo & IP6_FLOWINFO_FLOWLABEL));
}
}
if (flags & IP6_TNL_F_USE_ORIG_TCLASS) {
print_bool(PRINT_ANY,
"ip6_tnl_f_use_orig_tclass",
"tclass inherit ",
true);
} else {
if (is_json_context()) {
SPRINT_BUF(b1);
snprintf(b1, sizeof(b1), "0x%05x",
ntohl(flowinfo & IP6_FLOWINFO_TCLASS) >> 20);
print_string(PRINT_JSON, "tclass", NULL, b1);
} else {
fprintf(f, "tclass 0x%02x ",
ntohl(flowinfo & IP6_FLOWINFO_TCLASS) >> 20);
}
}
if (flags & IP6_TNL_F_RCV_DSCP_COPY)
print_bool(PRINT_ANY,
"ip6_tnl_f_rcv_dscp_copy",
"dscp inherit ",
true);
if (tb[IFLA_GRE_IFLAGS])
iflags = rta_getattr_u16(tb[IFLA_GRE_IFLAGS]);
if (tb[IFLA_GRE_OFLAGS])
oflags = rta_getattr_u16(tb[IFLA_GRE_OFLAGS]);
if ((iflags & GRE_KEY) && tb[IFLA_GRE_IKEY]) {
inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_IKEY]), s2, sizeof(s2));
print_string(PRINT_ANY, "ikey", "ikey %s ", s2);
}
if ((oflags & GRE_KEY) && tb[IFLA_GRE_OKEY]) {
inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_OKEY]), s2, sizeof(s2));
print_string(PRINT_ANY, "okey", "okey %s ", s2);
}
if (iflags & GRE_SEQ)
print_bool(PRINT_ANY, "iseq", "iseq ", true);
if (oflags & GRE_SEQ)
print_bool(PRINT_ANY, "oseq", "oseq ", true);
if (iflags & GRE_CSUM)
print_bool(PRINT_ANY, "icsum", "icsum ", true);
if (oflags & GRE_CSUM)
print_bool(PRINT_ANY, "ocsum", "ocsum ", true);
if (flags & IP6_TNL_F_USE_ORIG_FWMARK)
print_bool(PRINT_ANY,
"ip6_tnl_f_use_orig_fwmark",
"fwmark inherit ",
true);
else if (tb[IFLA_GRE_FWMARK]) {
__u32 fwmark = rta_getattr_u32(tb[IFLA_GRE_FWMARK]);
if (fwmark) {
snprintf(s2, sizeof(s2), "0x%x", fwmark);
print_string(PRINT_ANY, "fwmark", "fwmark %s ", s2);
}
}
if (tb[IFLA_GRE_ENCAP_TYPE] &&
rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) {
__u16 type = rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]);
__u16 flags = rta_getattr_u16(tb[IFLA_GRE_ENCAP_FLAGS]);
__u16 sport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_SPORT]);
__u16 dport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_DPORT]);
open_json_object("encap");
print_string(PRINT_FP, NULL, "encap ", NULL);
switch (type) {
case TUNNEL_ENCAP_FOU:
print_string(PRINT_ANY, "type", "%s ", "fou");
break;
case TUNNEL_ENCAP_GUE:
print_string(PRINT_ANY, "type", "%s ", "gue");
break;
default:
print_null(PRINT_ANY, "type", "unknown ", NULL);
break;
}
if (is_json_context()) {
print_uint(PRINT_JSON,
"sport",
NULL,
sport ? ntohs(sport) : 0);
print_uint(PRINT_JSON, "dport", NULL, ntohs(dport));
print_bool(PRINT_JSON, "csum", NULL,
flags & TUNNEL_ENCAP_FLAG_CSUM);
print_bool(PRINT_JSON, "csum6", NULL,
flags & TUNNEL_ENCAP_FLAG_CSUM6);
print_bool(PRINT_JSON, "remcsum", NULL,
flags & TUNNEL_ENCAP_FLAG_REMCSUM);
close_json_object();
} else {
if (sport == 0)
fputs("encap-sport auto ", f);
else
fprintf(f, "encap-sport %u", ntohs(sport));
fprintf(f, "encap-dport %u ", ntohs(dport));
if (flags & TUNNEL_ENCAP_FLAG_CSUM)
fputs("encap-csum ", f);
else
fputs("noencap-csum ", f);
if (flags & TUNNEL_ENCAP_FLAG_CSUM6)
fputs("encap-csum6 ", f);
else
fputs("noencap-csum6 ", f);
if (flags & TUNNEL_ENCAP_FLAG_REMCSUM)
fputs("encap-remcsum ", f);
else
fputs("noencap-remcsum ", f);
}
}
}
static void gre_print_help(struct link_util *lu, int argc, char **argv,
FILE *f)
{
print_usage(f);
}
struct link_util ip6gre_link_util = {
.id = "ip6gre",
.maxattr = IFLA_GRE_MAX,
.parse_opt = gre_parse_opt,
.print_opt = gre_print_opt,
.print_help = gre_print_help,
};
struct link_util ip6gretap_link_util = {
.id = "ip6gretap",
.maxattr = IFLA_GRE_MAX,
.parse_opt = gre_parse_opt,
.print_opt = gre_print_opt,
.print_help = gre_print_help,
};