genl: add new command to list genetlink(4)

This commands list genetlink protocols and its operations and
capabilities

Name: nlctrl
	ID: 0x10, Version: 00, header size: 2, max attributes: 10
	supported operations:
	 - ID: 0x3, Capabilities: 0xe (can modify; can get/dump;
has policy)
	multicast groups:
	 - ID: 0x30, Name: notify
Name: carp
	ID: 0x11, Version: 00, header size: 2, max attributes: 2
	supported operations:
	 - ID: 0x1, Capabilities: 0xe (can modify; can get/dump;
has policy)
	 - ID: 0x2, Capabilities: 0xb (requires admin permission;
can modify; has policy)

Reviewed by:		melifaro
Differential Revision:	https://reviews.freebsd.org/D40330
This commit is contained in:
Baptiste Daroussin 2023-05-30 13:31:04 +02:00
parent b71f278465
commit cb1fc924d2
8 changed files with 245 additions and 0 deletions

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@ -145,6 +145,7 @@ __DEFAULT_YES_OPTIONS = \
MLX5TOOL \
NETCAT \
NETGRAPH \
NETLINK \
NETLINK_SUPPORT \
NLS_CATALOGS \
NS_CACHING \

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@ -5639,6 +5639,11 @@ OLD_FILES+=var/yp/Makefile.dist
OLD_DIRS+=var/yp
.endif
.if ${MK_NETLINK} == no
OLD_FILES+=usr.bin/genl
OLD_FILES+=usr/share/man/man1/genl.1.gz
.endif
.if ${MK_NLS} == no
OLD_DIRS+=usr/share/nls/
OLD_DIRS+=usr/share/nls/C

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@ -0,0 +1,4 @@
.\" $FreeBSD$
Do not build
.Xr genl 1
utility.

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@ -0,0 +1,4 @@
.\" $FreeBSD$
Build the
.Xr genl 1
utility.

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@ -235,6 +235,7 @@ SUBDIR.${MK_MAIL}+= msgs
SUBDIR.${MK_MAKE}+= bmake
SUBDIR.${MK_MAN_UTILS}+= man
SUBDIR.${MK_NETCAT}+= nc
SUBDIR.${MK_NETLINK}+= genl
SUBDIR.${MK_NIS}+= ypcat
SUBDIR.${MK_NIS}+= ypmatch
SUBDIR.${MK_NIS}+= ypwhich

3
usr.bin/genl/Makefile Normal file
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@ -0,0 +1,3 @@
PROG= genl
.include <bsd.prog.mk>

46
usr.bin/genl/genl.1 Normal file
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@ -0,0 +1,46 @@
.\"
.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
.\"
.\" Copyright (c) 2023 Baptiste Daroussin <bapt@nours.eu>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd May 20, 2023
.Dt GENL 1
.Os
.Sh NAME
.Nm genl
.Nd "generic netlink list"
.Sh SYNOPSIS
.Nm
.Sh DESCRIPTION
.Nm
lists all available generic netlink protocols, and presents its details:
.Bl -tag -width "multicast groups"
.It operations
Id of the operation if any and associated capabilities
.It multicast groups
If of the available multicast group if any and it associated name
.El
.Sh SEE ALSO
.Xr genetlink 4 ,
.Xr netlink 4

181
usr.bin/genl/genl.c Normal file
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@ -0,0 +1,181 @@
/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright 2023 Baptiste Daroussin <bapt@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted providing that the following conditions~
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/module.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <stdio.h>
#include <netlink/netlink.h>
#include <netlink/netlink_generic.h>
#include <netlink/netlink_snl.h>
#include <netlink/netlink_snl_generic.h>
struct genl_ctrl_op {
uint32_t id;
uint32_t flags;
};
struct genl_ctrl_ops {
uint32_t num_ops;
struct genl_ctrl_op **ops;
};
#define _OUT(_field) offsetof(struct genl_ctrl_op, _field)
static struct snl_attr_parser _nla_p_getops[] = {
{ .type = CTRL_ATTR_OP_ID, .off = _OUT(id), .cb = snl_attr_get_uint32},
{ .type = CTRL_ATTR_OP_FLAGS, .off = _OUT(flags), .cb = snl_attr_get_uint32 },
};
#undef _OUT
SNL_DECLARE_ATTR_PARSER_EXT(genl_ctrl_op_parser,
sizeof(struct genl_ctrl_op),
_nla_p_getops, NULL);
struct genl_family {
uint16_t id;
char *name;
uint32_t version;
uint32_t hdrsize;
uint32_t max_attr;
struct snl_genl_ctrl_mcast_groups mcast_groups;
struct genl_ctrl_ops ops;
};
#define _OUT(_field) offsetof(struct genl_family, _field)
static struct snl_attr_parser _nla_p_getfamily[] = {
{ .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(id), .cb = snl_attr_get_uint16 },
{ .type = CTRL_ATTR_FAMILY_NAME, .off = _OUT(name), .cb = snl_attr_get_string },
{ .type = CTRL_ATTR_VERSION, .off = _OUT(version), .cb = snl_attr_get_uint32 },
{ .type = CTRL_ATTR_VERSION, .off = _OUT(hdrsize), .cb = snl_attr_get_uint32 },
{ .type = CTRL_ATTR_MAXATTR, .off = _OUT(max_attr), .cb = snl_attr_get_uint32 },
{
.type = CTRL_ATTR_OPS,
.off = _OUT(ops),
.cb = snl_attr_get_parray,
.arg = &genl_ctrl_op_parser,
},
{
.type = CTRL_ATTR_MCAST_GROUPS,
.off = _OUT(mcast_groups),
.cb = snl_attr_get_parray,
.arg = &_genl_ctrl_mc_parser,
},
};
#undef _OUT
SNL_DECLARE_GENL_PARSER(genl_family_parser, _nla_p_getfamily);
static struct op_capability {
uint32_t flag;
const char *str;
} op_caps[] = {
{ GENL_ADMIN_PERM, "requires admin permission" },
{ GENL_CMD_CAP_DO, "can modify" },
{ GENL_CMD_CAP_DUMP, "can get/dump" },
{ GENL_CMD_CAP_HASPOL, "has policy" },
};
static void
dump_operations(struct genl_ctrl_ops *ops)
{
if (ops->num_ops == 0)
return;
printf("\tsupported operations: \n");
for (uint32_t i = 0; i < ops->num_ops; i++) {
printf("\t - ID: %#02x, Capabilities: %#02x (",
ops->ops[i]->id,
ops->ops[i]->flags);
for (size_t j = 0; j < nitems(op_caps); j++)
if ((ops->ops[i]->flags & op_caps[j].flag) == op_caps[j].flag)
printf("%s; ", op_caps[j].str);
printf("\b\b)\n");
}
}
static void
dump_mcast_groups( struct snl_genl_ctrl_mcast_groups *mcast_groups)
{
if (mcast_groups->num_groups == 0)
return;
printf("\tmulticast groups: \n");
for (uint32_t i = 0; i < mcast_groups->num_groups; i++)
printf("\t - ID: %#02x, Name: %s\n",
mcast_groups->groups[i]->mcast_grp_id,
mcast_groups->groups[i]->mcast_grp_name);
}
static void
dump_family(struct genl_family *family)
{
printf("Name: %s\n\tID: %#02hx, Version: %#02x, "
"header size: %d, max attributes: %d\n",
family->name, family->id, family->version,
family->hdrsize, family->max_attr);
dump_operations(&family->ops);
dump_mcast_groups(&family->mcast_groups);
}
int
main(int argc, char **argv __unused)
{
struct snl_state ss;
struct snl_writer nw;
struct nlmsghdr *hdr;
struct snl_errmsg_data e = {};
uint32_t seq_id;
if (argc > 1)
errx(EXIT_FAILURE, "usage: genl does not accept any argument");
if (modfind("netlink") == -1)
err(EXIT_FAILURE, "require netlink module to be loaded");
if (!snl_init(&ss, NETLINK_GENERIC))
err(EXIT_FAILURE, "snl_init()");
snl_init_writer(&ss, &nw);
hdr = snl_create_genl_msg_request(&nw, GENL_ID_CTRL, CTRL_CMD_GETFAMILY);
if ((hdr = snl_finalize_msg(&nw)) == NULL)
err(EXIT_FAILURE, "snl_finalize_msg");
seq_id = hdr->nlmsg_seq;
if (!snl_send_message(&ss, hdr))
err(EXIT_FAILURE, "snl_send_message");
while ((hdr = snl_read_reply_multi(&ss, seq_id, &e)) != NULL) {
if (e.error != 0) {
err(EXIT_FAILURE, "Error reading generic netlink");
}
struct genl_family family = {};
if (snl_parse_nlmsg(&ss, hdr, &genl_family_parser, &family))
dump_family(&family);
}
return (EXIT_SUCCESS);
}