30d7e724db
Replacing rtsock with netlink also means providing similar tracing facilities, rtsock provides `route -n monitor` interface, where each message can be traced to the originating PID. This diff closes the feature gap between rtsock and netlink in that regard. Netlink works slightly differently from rtsock, as it is a generic message "broker". It calls some kernel KPIs and returns the result to the caller. Other Netlink consumers gets notified on the changed kernel state using the relevant subsystem callbacks. Typically, it is close to impossible to pass some data through these KPIs to enhance the notification. This diff approaches the problem by using osd(9) to assign the relevant socket pointer (`'nlp`) to the per-socket taskqueue execution thread. This change allows to recover the pointer in the aforementioned notification callbacks and extract some additional data. Using `osd(9)` (and adding additional metadata) to the notification receiver comes with some additional cost attached, so this interface needs to be enabled explicitly by using a newly-created `NETLINK_MSG_INFO` `SOL_NETLINK` socket option. The actual medatadata (which includes the originator PID) is provided via control messages. To enable extensibility, the control message data is encoded in the standard netlink(TLV-based) fashion. The list of the currently-provided properties can be found in `nlmsginfo_attrs`. snl(3) is extended to enable decoding of netlink messages with metadata (`snl_read_message_dbg()` stores the parsed structure in the provided buffer). Differential Revision: https://reviews.freebsd.org/D39391
130 lines
4.6 KiB
C
130 lines
4.6 KiB
C
/*-
|
|
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
|
|
*
|
|
* Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef _NETLINK_NETLINK_CTL_H_
|
|
#define _NETLINK_NETLINK_CTL_H_
|
|
|
|
#ifdef _KERNEL
|
|
/*
|
|
* This file provides headers for the public KPI of the netlink
|
|
* subsystem
|
|
*/
|
|
#include <sys/_eventhandler.h>
|
|
|
|
MALLOC_DECLARE(M_NETLINK);
|
|
|
|
/*
|
|
* Macro for handling attribute TLVs
|
|
*/
|
|
#define _roundup2(x, y) (((x)+((y)-1))&(~((y)-1)))
|
|
|
|
#define NETLINK_ALIGN_SIZE sizeof(uint32_t)
|
|
#define NETLINK_ALIGN(_len) _roundup2(_len, NETLINK_ALIGN_SIZE)
|
|
|
|
#define NLA_ALIGN_SIZE sizeof(uint32_t)
|
|
#define NLA_ALIGN(_len) _roundup2(_len, NLA_ALIGN_SIZE)
|
|
#define NLA_HDRLEN ((int)sizeof(struct nlattr))
|
|
#define NLA_DATA_LEN(_nla) ((int)((_nla)->nla_len - NLA_HDRLEN))
|
|
#define NLA_DATA(_nla) NL_ITEM_DATA(_nla, NLA_HDRLEN)
|
|
#define NLA_DATA_CONST(_nla) NL_ITEM_DATA_CONST(_nla, NLA_HDRLEN)
|
|
#define NLA_TYPE(_nla) ((_nla)->nla_type & 0x3FFF)
|
|
|
|
#ifndef typeof
|
|
#define typeof __typeof
|
|
#endif
|
|
|
|
#define NLA_NEXT(_attr) (struct nlattr *)((char *)_attr + NLA_ALIGN(_attr->nla_len))
|
|
#define _NLA_END(_start, _len) ((char *)(_start) + (_len))
|
|
#define NLA_FOREACH(_attr, _start, _len) \
|
|
for (typeof(_attr) _end = (typeof(_attr))_NLA_END(_start, _len), _attr = (_start); \
|
|
((char *)_attr < (char *)_end) && \
|
|
((char *)NLA_NEXT(_attr) <= (char *)_end); \
|
|
_attr = (_len -= NLA_ALIGN(_attr->nla_len), NLA_NEXT(_attr)))
|
|
|
|
#define NL_ARRAY_LEN(_a) (sizeof(_a) / sizeof((_a)[0]))
|
|
|
|
#include <netlink/netlink_message_writer.h>
|
|
#include <netlink/netlink_message_parser.h>
|
|
|
|
|
|
/* Protocol handlers */
|
|
struct nl_pstate;
|
|
typedef int (*nl_handler_f)(struct nlmsghdr *hdr, struct nl_pstate *npt);
|
|
|
|
bool netlink_register_proto(int proto, const char *proto_name, nl_handler_f handler);
|
|
bool netlink_unregister_proto(int proto);
|
|
|
|
/* Common helpers */
|
|
bool nl_has_listeners(int netlink_family, uint32_t groups_mask);
|
|
bool nlp_has_priv(struct nlpcb *nlp, int priv);
|
|
struct ucred *nlp_get_cred(struct nlpcb *nlp);
|
|
uint32_t nlp_get_pid(const struct nlpcb *nlp);
|
|
bool nlp_unconstrained_vnet(const struct nlpcb *nlp);
|
|
|
|
/* netlink_generic.c */
|
|
struct genl_cmd {
|
|
const char *cmd_name;
|
|
nl_handler_f cmd_cb;
|
|
uint32_t cmd_flags;
|
|
uint32_t cmd_priv;
|
|
uint32_t cmd_num;
|
|
};
|
|
|
|
uint32_t genl_register_family(const char *family_name, size_t hdrsize,
|
|
int family_version, int max_attr_idx);
|
|
bool genl_unregister_family(const char *family_name);
|
|
bool genl_register_cmds(const char *family_name, const struct genl_cmd *cmds,
|
|
int count);
|
|
uint32_t genl_register_group(const char *family_name, const char *group_name);
|
|
|
|
struct genl_family;
|
|
const char *genl_get_family_name(const struct genl_family *gf);
|
|
uint32_t genl_get_family_id(const struct genl_family *gf);
|
|
|
|
typedef void (*genl_family_event_handler_t)(void *arg, const struct genl_family *gf, int action);
|
|
EVENTHANDLER_DECLARE(genl_family_event, genl_family_event_handler_t);
|
|
|
|
struct thread;
|
|
#if defined(NETLINK) || defined(NETLINK_MODULE)
|
|
/* Provide optimized calls to the functions inside the same linking unit */
|
|
struct nlpcb *_nl_get_thread_nlp(struct thread *td);
|
|
|
|
static inline struct nlpcb *
|
|
nl_get_thread_nlp(struct thread *td)
|
|
{
|
|
return (_nl_get_thread_nlp(td));
|
|
}
|
|
|
|
#else
|
|
/* Provide access to the functions via netlink_glue.c */
|
|
struct nlpcb *nl_get_thread_nlp(struct thread *td);
|
|
|
|
#endif /* defined(NETLINK) || defined(NETLINK_MODULE) */
|
|
|
|
#endif
|
|
#endif
|