This change does the following: Base Netlink KPIs (ability to register the family, parse and/or write a Netlink message) are always present in the kernel. Specifically, * Implementation of genetlink family/group registration/removal, some base accessors (netlink_generic_kpi.c, 260 LoC) are compiled in unconditionally. * Basic TLV parser functions (netlink_message_parser.c, 507 LoC) are compiled in unconditionally. * Glue functions (netlink<>rtsock), malloc/core sysctl definitions (netlink_glue.c, 259 LoC) are compiled in unconditionally. * The rest of the KPI _functions_ are defined in the netlink_glue.c, but their implementation calls a pointer to either the stub function or the actual function, depending on whether the module is loaded or not. This approach allows to have only 1k LoC out of ~3.7k LoC (current sys/netlink implementation) in the kernel, which will not grow further. It also allows for the generic netlink kernel customers to load successfully without requiring Netlink module and operate correctly once Netlink module is loaded. Reviewed by: imp MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D39269
280 lines
6.8 KiB
C
280 lines
6.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/ck.h>
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#include <sys/epoch.h>
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#include <sys/eventhandler.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/socket.h>
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#include <sys/sx.h>
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#include <netlink/netlink.h>
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#include <netlink/netlink_ctl.h>
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#include <netlink/netlink_generic.h>
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#include <netlink/netlink_var.h>
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#define DEBUG_MOD_NAME nl_generic_kpi
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#define DEBUG_MAX_LEVEL LOG_DEBUG3
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#include <netlink/netlink_debug.h>
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_DECLARE_DEBUG(LOG_DEBUG3);
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/*
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* NETLINK_GENERIC families/groups registration logic
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*/
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#define GENL_LOCK() sx_xlock(&sx_lock)
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#define GENL_UNLOCK() sx_xunlock(&sx_lock)
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static struct sx sx_lock;
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SX_SYSINIT(genl_lock, &sx_lock, "genetlink lock");
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static struct genl_family families[MAX_FAMILIES];
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static struct genl_group groups[MAX_GROUPS];
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static struct genl_family *
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find_family(const char *family_name)
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{
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for (int i = 0; i < MAX_FAMILIES; i++) {
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struct genl_family *gf = &families[i];
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if (gf->family_name != NULL && !strcmp(gf->family_name, family_name))
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return (gf);
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}
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return (NULL);
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}
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static struct genl_family *
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find_empty_family_id(const char *family_name)
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{
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struct genl_family *gf = NULL;
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if (!strcmp(family_name, CTRL_FAMILY_NAME)) {
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gf = &families[0];
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gf->family_id = GENL_MIN_ID;
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} else {
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/* Index 0 is reserved for the control family */
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for (int i = 1; i < MAX_FAMILIES; i++) {
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gf = &families[i];
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if (gf->family_name == NULL) {
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gf->family_id = GENL_MIN_ID + i;
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break;
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}
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}
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}
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return (gf);
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}
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uint32_t
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genl_register_family(const char *family_name, size_t hdrsize, int family_version,
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int max_attr_idx)
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{
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uint32_t family_id = 0;
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MPASS(family_name != NULL);
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if (find_family(family_name) != NULL)
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return (0);
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GENL_LOCK();
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struct genl_family *gf = find_empty_family_id(family_name);
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MPASS(gf != NULL);
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gf->family_name = family_name;
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gf->family_version = family_version;
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gf->family_hdrsize = hdrsize;
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gf->family_attr_max = max_attr_idx;
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NL_LOG(LOG_DEBUG2, "Registered family %s id %d", gf->family_name, gf->family_id);
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family_id = gf->family_id;
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EVENTHANDLER_INVOKE(genl_family_event, gf, CTRL_CMD_NEWFAMILY);
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GENL_UNLOCK();
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return (family_id);
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}
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static void
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free_family(struct genl_family *gf)
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{
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if (gf->family_cmds != NULL)
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free(gf->family_cmds, M_NETLINK);
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}
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/*
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* unregister groups of a given family
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*/
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static void
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unregister_groups(const struct genl_family *gf)
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{
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for (int i = 0; i < MAX_GROUPS; i++) {
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struct genl_group *gg = &groups[i];
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if (gg->group_family == gf && gg->group_name != NULL) {
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gg->group_family = NULL;
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gg->group_name = NULL;
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}
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}
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}
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/*
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* Can sleep, I guess
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*/
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bool
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genl_unregister_family(const char *family_name)
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{
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bool found = false;
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GENL_LOCK();
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struct genl_family *gf = find_family(family_name);
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if (gf != NULL) {
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EVENTHANDLER_INVOKE(genl_family_event, gf, CTRL_CMD_DELFAMILY);
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found = true;
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unregister_groups(gf);
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/* TODO: zero pointer first */
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free_family(gf);
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bzero(gf, sizeof(*gf));
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}
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GENL_UNLOCK();
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return (found);
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}
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bool
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genl_register_cmds(const char *family_name, const struct genl_cmd *cmds, int count)
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{
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GENL_LOCK();
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struct genl_family *gf = find_family(family_name);
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if (gf == NULL) {
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GENL_UNLOCK();
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return (false);
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}
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int cmd_size = gf->family_cmd_size;
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for (int i = 0; i < count; i++) {
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MPASS(cmds[i].cmd_cb != NULL);
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if (cmds[i].cmd_num >= cmd_size)
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cmd_size = cmds[i].cmd_num + 1;
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}
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if (cmd_size > gf->family_cmd_size) {
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/* need to realloc */
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size_t sz = cmd_size * sizeof(struct genl_cmd);
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void *data = malloc(sz, M_NETLINK, M_WAITOK | M_ZERO);
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memcpy(data, gf->family_cmds, gf->family_cmd_size * sizeof(struct genl_cmd));
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void *old_data = gf->family_cmds;
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gf->family_cmds = data;
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gf->family_cmd_size = cmd_size;
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free(old_data, M_NETLINK);
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}
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for (int i = 0; i < count; i++) {
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const struct genl_cmd *cmd = &cmds[i];
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MPASS(gf->family_cmds[cmd->cmd_num].cmd_cb == NULL);
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gf->family_cmds[cmd->cmd_num] = cmds[i];
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NL_LOG(LOG_DEBUG2, "Adding cmd %s(%d) to family %s",
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cmd->cmd_name, cmd->cmd_num, gf->family_name);
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}
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GENL_UNLOCK();
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return (true);
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}
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static struct genl_group *
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find_group(const struct genl_family *gf, const char *group_name)
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{
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for (int i = 0; i < MAX_GROUPS; i++) {
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struct genl_group *gg = &groups[i];
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if (gg->group_family == gf && !strcmp(gg->group_name, group_name))
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return (gg);
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}
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return (NULL);
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}
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uint32_t
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genl_register_group(const char *family_name, const char *group_name)
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{
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uint32_t group_id = 0;
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MPASS(family_name != NULL);
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MPASS(group_name != NULL);
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GENL_LOCK();
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struct genl_family *gf = find_family(family_name);
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if (gf == NULL || find_group(gf, group_name) != NULL) {
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GENL_UNLOCK();
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return (0);
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}
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for (int i = 0; i < MAX_GROUPS; i++) {
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struct genl_group *gg = &groups[i];
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if (gg->group_family == NULL) {
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gf->family_num_groups++;
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gg->group_family = gf;
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gg->group_name = group_name;
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group_id = i + MIN_GROUP_NUM;
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break;
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}
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}
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GENL_UNLOCK();
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return (group_id);
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}
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/* accessors */
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struct genl_family *
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genl_get_family(uint32_t family_id)
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{
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return ((family_id < MAX_FAMILIES) ? &families[family_id] : NULL);
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}
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const char *
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genl_get_family_name(const struct genl_family *gf)
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{
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return (gf->family_name);
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}
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uint32_t
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genl_get_family_id(const struct genl_family *gf)
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{
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return (gf->family_id);
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}
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struct genl_group *
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genl_get_group(uint32_t group_id)
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{
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return ((group_id < MAX_GROUPS) ? &groups[group_id] : NULL);
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}
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