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
305 lines
9.2 KiB
C
305 lines
9.2 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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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 "opt_netlink.h"
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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/jail.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/priv.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
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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_DEBUG);
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static int dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr,
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const struct genl_family *gf, struct nl_writer *nw);
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/*
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* Handler called by netlink subsystem when matching netlink message is received
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*/
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static int
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genl_handle_message(struct nlmsghdr *hdr, struct nl_pstate *npt)
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{
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struct nlpcb *nlp = npt->nlp;
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struct genl_family *gf = NULL;
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int error = 0;
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int family_id = (int)hdr->nlmsg_type - GENL_MIN_ID;
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if (__predict_false(family_id < 0 || (gf = genl_get_family(family_id)) == NULL)) {
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NLP_LOG(LOG_DEBUG, nlp, "invalid message type: %d", hdr->nlmsg_type);
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return (ENOTSUP);
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}
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if (__predict_false(hdr->nlmsg_len < sizeof(hdr) + GENL_HDRLEN)) {
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NLP_LOG(LOG_DEBUG, nlp, "invalid message size: %d", hdr->nlmsg_len);
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return (EINVAL);
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}
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struct genlmsghdr *ghdr = (struct genlmsghdr *)(hdr + 1);
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if (ghdr->cmd >= gf->family_cmd_size || gf->family_cmds[ghdr->cmd].cmd_cb == NULL) {
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NLP_LOG(LOG_DEBUG, nlp, "family %s: invalid cmd %d",
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gf->family_name, ghdr->cmd);
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return (ENOTSUP);
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}
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struct genl_cmd *cmd = &gf->family_cmds[ghdr->cmd];
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if (cmd->cmd_priv != 0 && !nlp_has_priv(nlp, cmd->cmd_priv)) {
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NLP_LOG(LOG_DEBUG, nlp, "family %s: cmd %d priv_check() failed",
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gf->family_name, ghdr->cmd);
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return (EPERM);
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}
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NLP_LOG(LOG_DEBUG2, nlp, "received family %s cmd %s(%d) len %d",
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gf->family_name, cmd->cmd_name, ghdr->cmd, hdr->nlmsg_len);
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error = cmd->cmd_cb(hdr, npt);
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return (error);
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}
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static uint32_t
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get_cmd_flags(const struct genl_cmd *cmd)
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{
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uint32_t flags = cmd->cmd_flags;
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if (cmd->cmd_priv != 0)
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flags |= GENL_ADMIN_PERM;
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return (flags);
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}
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static int
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dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr,
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const struct genl_family *gf, struct nl_writer *nw)
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{
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if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr)))
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goto enomem;
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struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
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ghdr_new->cmd = ghdr->cmd;
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ghdr_new->version = gf->family_version;
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ghdr_new->reserved = 0;
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nlattr_add_string(nw, CTRL_ATTR_FAMILY_NAME, gf->family_name);
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nlattr_add_u16(nw, CTRL_ATTR_FAMILY_ID, gf->family_id);
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nlattr_add_u32(nw, CTRL_ATTR_VERSION, gf->family_version);
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nlattr_add_u32(nw, CTRL_ATTR_HDRSIZE, gf->family_hdrsize);
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nlattr_add_u32(nw, CTRL_ATTR_MAXATTR, gf->family_attr_max);
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if (gf->family_cmd_size > 0) {
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int off = nlattr_add_nested(nw, CTRL_ATTR_OPS);
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if (off == 0)
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goto enomem;
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for (int i = 0, cnt=0; i < gf->family_cmd_size; i++) {
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struct genl_cmd *cmd = &gf->family_cmds[i];
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if (cmd->cmd_cb == NULL)
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continue;
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int cmd_off = nlattr_add_nested(nw, ++cnt);
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if (cmd_off == 0)
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goto enomem;
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nlattr_add_u32(nw, CTRL_ATTR_OP_ID, cmd->cmd_num);
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nlattr_add_u32(nw, CTRL_ATTR_OP_FLAGS, get_cmd_flags(cmd));
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nlattr_set_len(nw, cmd_off);
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}
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nlattr_set_len(nw, off);
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}
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if (gf->family_num_groups > 0) {
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int off = nlattr_add_nested(nw, CTRL_ATTR_MCAST_GROUPS);
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if (off == 0)
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goto enomem;
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for (int i = 0, cnt = 0; i < MAX_GROUPS; i++) {
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struct genl_group *gg = genl_get_group(i);
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if (gg == NULL || gg->group_family != gf)
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continue;
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int cmd_off = nlattr_add_nested(nw, ++cnt);
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if (cmd_off == 0)
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goto enomem;
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nlattr_add_u32(nw, CTRL_ATTR_MCAST_GRP_ID, i + MIN_GROUP_NUM);
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nlattr_add_string(nw, CTRL_ATTR_MCAST_GRP_NAME, gg->group_name);
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nlattr_set_len(nw, cmd_off);
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}
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nlattr_set_len(nw, off);
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}
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if (nlmsg_end(nw))
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return (0);
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enomem:
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NL_LOG(LOG_DEBUG, "unable to dump family %s state (ENOMEM)", gf->family_name);
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nlmsg_abort(nw);
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return (ENOMEM);
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}
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/* Declare ourself as a user */
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static void nlctrl_notify(void *arg, const struct genl_family *gf, int action);
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static eventhandler_tag family_event_tag;
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static uint32_t ctrl_family_id;
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static uint32_t ctrl_group_id;
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struct nl_parsed_family {
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uint32_t family_id;
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char *family_name;
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uint8_t version;
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};
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#define _IN(_field) offsetof(struct genlmsghdr, _field)
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#define _OUT(_field) offsetof(struct nl_parsed_family, _field)
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static const struct nlfield_parser nlf_p_generic[] = {
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{ .off_in = _IN(version), .off_out = _OUT(version), .cb = nlf_get_u8 },
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};
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static struct nlattr_parser nla_p_generic[] = {
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{ .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(family_id), .cb = nlattr_get_uint16 },
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{ .type = CTRL_ATTR_FAMILY_NAME , .off = _OUT(family_name), .cb = nlattr_get_string },
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};
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#undef _IN
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#undef _OUT
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NL_DECLARE_PARSER(genl_parser, struct genlmsghdr, nlf_p_generic, nla_p_generic);
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static bool
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match_family(const struct genl_family *gf, const struct nl_parsed_family *attrs)
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{
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if (gf->family_name == NULL)
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return (false);
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if (attrs->family_id != 0 && attrs->family_id != gf->family_id)
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return (false);
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if (attrs->family_name != NULL && strcmp(attrs->family_name, gf->family_name))
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return (false);
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return (true);
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}
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static int
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nlctrl_handle_getfamily(struct nlmsghdr *hdr, struct nl_pstate *npt)
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{
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int error = 0;
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struct nl_parsed_family attrs = {};
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error = nl_parse_nlmsg(hdr, &genl_parser, npt, &attrs);
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if (error != 0)
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return (error);
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struct genlmsghdr ghdr = {
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.cmd = CTRL_CMD_NEWFAMILY,
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};
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if (attrs.family_id != 0 || attrs.family_name != NULL) {
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/* Resolve request */
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for (int i = 0; i < MAX_FAMILIES; i++) {
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struct genl_family *gf = genl_get_family(i);
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if (gf != NULL && match_family(gf, &attrs)) {
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error = dump_family(hdr, &ghdr, gf, npt->nw);
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return (error);
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}
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}
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return (ENOENT);
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}
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hdr->nlmsg_flags = hdr->nlmsg_flags | NLM_F_MULTI;
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for (int i = 0; i < MAX_FAMILIES; i++) {
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struct genl_family *gf = genl_get_family(i);
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if (gf != NULL && match_family(gf, &attrs)) {
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error = dump_family(hdr, &ghdr, gf, npt->nw);
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if (error != 0)
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break;
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}
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}
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if (!nlmsg_end_dump(npt->nw, error, hdr)) {
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NL_LOG(LOG_DEBUG, "Unable to finalize the dump");
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return (ENOMEM);
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}
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return (error);
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}
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static void
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nlctrl_notify(void *arg __unused, const struct genl_family *gf, int cmd)
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{
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struct nlmsghdr hdr = {.nlmsg_type = NETLINK_GENERIC };
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struct genlmsghdr ghdr = { .cmd = cmd };
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struct nl_writer nw = {};
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if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_GENERIC, ctrl_group_id)) {
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dump_family(&hdr, &ghdr, gf, &nw);
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nlmsg_flush(&nw);
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return;
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}
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NL_LOG(LOG_DEBUG, "error allocating group writer");
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}
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static const struct genl_cmd nlctrl_cmds[] = {
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{
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.cmd_num = CTRL_CMD_GETFAMILY,
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.cmd_name = "GETFAMILY",
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.cmd_cb = nlctrl_handle_getfamily,
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.cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL,
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},
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};
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static const struct nlhdr_parser *all_parsers[] = { &genl_parser };
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static void
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genl_load_all(void *u __unused)
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{
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NL_VERIFY_PARSERS(all_parsers);
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ctrl_family_id = genl_register_family(CTRL_FAMILY_NAME, 0, 2, CTRL_ATTR_MAX);
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genl_register_cmds(CTRL_FAMILY_NAME, nlctrl_cmds, NL_ARRAY_LEN(nlctrl_cmds));
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ctrl_group_id = genl_register_group(CTRL_FAMILY_NAME, "notify");
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family_event_tag = EVENTHANDLER_REGISTER(genl_family_event, nlctrl_notify, NULL,
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EVENTHANDLER_PRI_ANY);
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netlink_register_proto(NETLINK_GENERIC, "NETLINK_GENERIC", genl_handle_message);
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}
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SYSINIT(genl_load_all, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_load_all, NULL);
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static void
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genl_unload(void *u __unused)
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{
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EVENTHANDLER_DEREGISTER(genl_family_event, family_event_tag);
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genl_unregister_family(CTRL_FAMILY_NAME);
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NET_EPOCH_WAIT();
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}
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SYSUNINIT(genl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_unload, NULL);
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