freebsd-skq/sys/net/bpfdesc.h
ae 8de4ba103a Rework locking in BPF code to remove rwlock from fast path.
On high packets rate the contention on rwlock in bpf_*tap*() functions
can lead to packets dropping. To avoid this, migrate this code to use
epoch(9) KPI and ConcurrencyKit's lists.

* all lists changed to use CK_LIST;
* reference counting added to bpf_if and bpf_d;
* now bpf_if references ifnet and releases this reference on destroy;
* each bpf_d descriptor references bpf_if when it is attached;
* new struct bpf_program_buffer introduced to keep BPF filter programs;
* bpf_program_buffer, bpf_d and bpf_if structures are freed by
  epoch_call();
* bpf_freelist and ifnet_departure event are no longer needed, thus
  both are removed;

Reviewed by:	melifaro
Sponsored by:	Yandex LLC
Differential Revision:	https://reviews.freebsd.org/D20224
2019-05-13 13:45:28 +00:00

162 lines
6.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from the Stanford/CMU enet packet filter,
* (net/enet.c) distributed as part of 4.3BSD, and code contributed
* to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
* Berkeley Laboratory.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)bpfdesc.h 8.1 (Berkeley) 6/10/93
*
* $FreeBSD$
*/
#ifndef _NET_BPFDESC_H_
#define _NET_BPFDESC_H_
#include <sys/callout.h>
#include <sys/selinfo.h>
#include <sys/ck.h>
#include <sys/conf.h>
#include <sys/counter.h>
#include <sys/epoch.h>
#include <net/if.h>
/*
* Descriptor associated with each open bpf file.
*/
struct zbuf;
struct bpf_d {
CK_LIST_ENTRY(bpf_d) bd_next; /* Linked list of descriptors */
/*
* Buffer slots: two memory buffers store the incoming packets.
* The model has three slots. Sbuf is always occupied.
* sbuf (store) - Receive interrupt puts packets here.
* hbuf (hold) - When sbuf is full, put buffer here and
* wakeup read (replace sbuf with fbuf).
* fbuf (free) - When read is done, put buffer here.
* On receiving, if sbuf is full and fbuf is 0, packet is dropped.
*/
caddr_t bd_sbuf; /* store slot */
caddr_t bd_hbuf; /* hold slot */
caddr_t bd_fbuf; /* free slot */
int bd_hbuf_in_use; /* don't rotate buffers */
int bd_slen; /* current length of store buffer */
int bd_hlen; /* current length of hold buffer */
int bd_bufsize; /* absolute length of buffers */
struct bpf_if * bd_bif; /* interface descriptor */
u_long bd_rtout; /* Read timeout in 'ticks' */
struct bpf_insn *bd_rfilter; /* read filter code */
struct bpf_insn *bd_wfilter; /* write filter code */
void *bd_bfilter; /* binary filter code */
counter_u64_t bd_rcount; /* number of packets received */
counter_u64_t bd_dcount; /* number of packets dropped */
u_char bd_promisc; /* true if listening promiscuously */
u_char bd_state; /* idle, waiting, or timed out */
u_char bd_immediate; /* true to return on packet arrival */
u_char bd_writer; /* non-zero if d is writer-only */
int bd_hdrcmplt; /* false to fill in src lladdr automatically */
int bd_direction; /* select packet direction */
int bd_tstamp; /* select time stamping function */
int bd_feedback; /* true to feed back sent packets */
int bd_async; /* non-zero if packet reception should generate signal */
int bd_sig; /* signal to send upon packet reception */
struct sigio * bd_sigio; /* information for async I/O */
struct selinfo bd_sel; /* bsd select info */
struct mtx bd_lock; /* per-descriptor lock */
struct callout bd_callout; /* for BPF timeouts with select */
struct label *bd_label; /* MAC label for descriptor */
counter_u64_t bd_fcount; /* number of packets which matched filter */
pid_t bd_pid; /* PID which created descriptor */
int bd_locked; /* true if descriptor is locked */
u_int bd_bufmode; /* Current buffer mode. */
counter_u64_t bd_wcount; /* number of packets written */
counter_u64_t bd_wfcount; /* number of packets that matched write filter */
counter_u64_t bd_wdcount; /* number of packets dropped during a write */
counter_u64_t bd_zcopy; /* number of zero copy operations */
u_char bd_compat32; /* 32-bit stream on LP64 system */
volatile u_int bd_refcnt;
struct epoch_context epoch_ctx;
};
/* Values for bd_state */
#define BPF_IDLE 0 /* no select in progress */
#define BPF_WAITING 1 /* waiting for read timeout in select */
#define BPF_TIMED_OUT 2 /* read timeout has expired in select */
#define BPFD_LOCK(bd) mtx_lock(&(bd)->bd_lock)
#define BPFD_UNLOCK(bd) mtx_unlock(&(bd)->bd_lock)
#define BPFD_LOCK_ASSERT(bd) mtx_assert(&(bd)->bd_lock, MA_OWNED)
#define BPF_PID_REFRESH(bd, td) (bd)->bd_pid = (td)->td_proc->p_pid
#define BPF_PID_REFRESH_CUR(bd) (bd)->bd_pid = curthread->td_proc->p_pid
/*
* External representation of the bpf descriptor
*/
struct xbpf_d {
u_int bd_structsize; /* Size of this structure. */
u_char bd_promisc;
u_char bd_immediate;
u_char __bd_pad[6];
int bd_hdrcmplt;
int bd_direction;
int bd_feedback;
int bd_async;
u_int64_t bd_rcount;
u_int64_t bd_dcount;
u_int64_t bd_fcount;
int bd_sig;
int bd_slen;
int bd_hlen;
int bd_bufsize;
pid_t bd_pid;
char bd_ifname[IFNAMSIZ];
int bd_locked;
u_int64_t bd_wcount;
u_int64_t bd_wfcount;
u_int64_t bd_wdcount;
u_int64_t bd_zcopy;
int bd_bufmode;
/*
* Allocate 4 64 bit unsigned integers for future expansion so we do
* not have to worry about breaking the ABI.
*/
u_int64_t bd_spare[4];
};
#define BPFIF_FLAG_DYING 1 /* Reject new bpf consumers */
#endif