[mirror_frr.git] / bgpd / bgp_io.c

/* BGP I/O.
 * Implements packet I/O in a consumer pthread.
 * Copyright (C) 2017  Cumulus Networks
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
 * MA 02110-1301 USA
 */

/* clang-format off */
#include <zebra.h>
#include <pthread.h>		// for pthread_mutex_unlock, pthread_mutex_lock

#include "frr_pthread.h"	// for frr_pthread_get, frr_pthread
#include "linklist.h"		// for list_delete, list_delete_all_node, lis...
#include "log.h"		// for zlog_debug, safe_strerror, zlog_err
#include "memory.h"		// for MTYPE_TMP, XCALLOC, XFREE
#include "network.h"		// for ERRNO_IO_RETRY
#include "stream.h"		// for stream_get_endp, stream_getw_from, str...
#include "thread.h"		// for THREAD_OFF, THREAD_ARG, thread, thread...
#include "zassert.h"		// for assert

#include "bgpd/bgp_io.h"
#include "bgpd/bgp_debug.h"	// for bgp_debug_neighbor_events, bgp_type_str
#include "bgpd/bgp_fsm.h"	// for BGP_EVENT_ADD, bgp_event
#include "bgpd/bgp_packet.h"	// for bgp_notify_send_with_data, bgp_notify...
#include "bgpd/bgpd.h"		// for peer, BGP_MARKER_SIZE, bgp_master, bm
/* clang-format on */

/* forward declarations */
static uint16_t bgp_write(struct peer *);
static uint16_t bgp_read(struct peer *);
static int bgp_process_writes(struct thread *);
static int bgp_process_reads(struct thread *);
static bool validate_header(struct peer *);

/* generic i/o status codes */
#define BGP_IO_TRANS_ERR (1 << 0) // EAGAIN or similar occurred
#define BGP_IO_FATAL_ERR (1 << 1) // some kind of fatal TCP error

/* Start and stop routines for I/O pthread + control variables
 * ------------------------------------------------------------------------ */
_Atomic bool bgp_io_thread_run;
_Atomic bool bgp_io_thread_started;

void bgp_io_init()
{
	bgp_io_thread_run = false;
	bgp_io_thread_started = false;
}

void *bgp_io_start(void *arg)
{
	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
	fpt->master->owner = pthread_self();

	// we definitely don't want to handle signals
	fpt->master->handle_signals = false;

	struct thread task;

	atomic_store_explicit(&bgp_io_thread_run, true, memory_order_relaxed);
	atomic_store_explicit(&bgp_io_thread_started, true,
			      memory_order_relaxed);

	while (bgp_io_thread_run) {
		if (thread_fetch(fpt->master, &task)) {
			thread_call(&task);
		}
	}

	return NULL;
}

int bgp_io_stop(void **result, struct frr_pthread *fpt)
{

	bgp_io_thread_run = false;
	/* let the loop break */
	fpt->master->spin = false;
	/* break poll */
	pthread_kill(fpt->thread, SIGINT);
	pthread_join(fpt->thread, result);

	return 0;
}
/* ------------------------------------------------------------------------ */

void bgp_writes_on(struct peer *peer)
{
	while (!atomic_load_explicit(&bgp_io_thread_started,
				     memory_order_relaxed))
		;

	assert(peer->status != Deleted);
	assert(peer->obuf);
	assert(peer->ibuf);
	assert(peer->ibuf_work);
	assert(!peer->t_connect_check);
	assert(peer->fd);

	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);

	thread_add_write(fpt->master, bgp_process_writes, peer, peer->fd,
			 &peer->t_write);
	SET_FLAG(peer->thread_flags, PEER_THREAD_WRITES_ON);
}

void bgp_writes_off(struct peer *peer)
{
	while (!atomic_load_explicit(&bgp_io_thread_started,
				     memory_order_relaxed))
		;

	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);

	thread_cancel_async(fpt->master, &peer->t_write, NULL);
	THREAD_OFF(peer->t_generate_updgrp_packets);

	UNSET_FLAG(peer->thread_flags, PEER_THREAD_WRITES_ON);
}

void bgp_reads_on(struct peer *peer)
{
	while (!atomic_load_explicit(&bgp_io_thread_started,
				     memory_order_relaxed))
		;

	assert(peer->status != Deleted);
	assert(peer->ibuf);
	assert(peer->fd);
	assert(peer->ibuf_work);
	assert(stream_get_endp(peer->ibuf_work) == 0);
	assert(peer->obuf);
	assert(!peer->t_connect_check);
	assert(peer->fd);

	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);

	thread_add_read(fpt->master, bgp_process_reads, peer, peer->fd,
			&peer->t_read);

	SET_FLAG(peer->thread_flags, PEER_THREAD_READS_ON);
}

void bgp_reads_off(struct peer *peer)
{
	while (!atomic_load_explicit(&bgp_io_thread_started,
				     memory_order_relaxed))
		;

	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);

	thread_cancel_async(fpt->master, &peer->t_read, NULL);
	THREAD_OFF(peer->t_process_packet);

	UNSET_FLAG(peer->thread_flags, PEER_THREAD_READS_ON);
}

/**
 * Called from PTHREAD_IO when select() or poll() determines that the file
 * descriptor is ready to be written to.
 */
static int bgp_process_writes(struct thread *thread)
{
	static struct peer *peer;
	peer = THREAD_ARG(thread);
	uint16_t status;
	bool reschedule;

	if (peer->fd < 0)
		return -1;

	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);

	pthread_mutex_lock(&peer->io_mtx);
	{
		status = bgp_write(peer);
		reschedule = (stream_fifo_head(peer->obuf) != NULL);
	}
	pthread_mutex_unlock(&peer->io_mtx);

	if (CHECK_FLAG(status, BGP_IO_TRANS_ERR)) { /* no problem */
	}

	if (CHECK_FLAG(status, BGP_IO_FATAL_ERR))
		reschedule = false; /* problem */

	if (reschedule) {
		thread_add_write(fpt->master, bgp_process_writes, peer,
				 peer->fd, &peer->t_write);
		thread_add_timer_msec(bm->master, bgp_generate_updgrp_packets,
				      peer, 0,
				      &peer->t_generate_updgrp_packets);
	}

	return 0;
}

/**
 * Called from PTHREAD_IO when select() or poll() determines that the file
 * descriptor is ready to be read from.
 *
 * We read as much data as possible, process as many packets as we can and
 * place them on peer->ibuf for secondary processing by the main thread.
 */
static int bgp_process_reads(struct thread *thread)
{
	static struct peer *peer; // peer to read from
	uint16_t status;	  // bgp_read status code
	bool more = true;	 // whether we got more data
	bool fatal = false;       // whether fatal error occurred
	bool added_pkt = false;   // whether we pushed onto ->ibuf
	bool header_valid = true; // whether header is valid

	peer = THREAD_ARG(thread);

	if (peer->fd < 0)
		return -1;

	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);

	pthread_mutex_lock(&peer->io_mtx);
	{
		status = bgp_read(peer);
	}
	pthread_mutex_unlock(&peer->io_mtx);

	/* error checking phase */
	if (CHECK_FLAG(status, BGP_IO_TRANS_ERR)) {
		/* no problem; just don't process packets */
		more = false;
	}

	if (CHECK_FLAG(status, BGP_IO_FATAL_ERR)) {
		/* problem; tear down session */
		more = false;
		fatal = true;
	}

	while (more) {
		/* static buffer for transferring packets */
		static unsigned char pktbuf[BGP_MAX_PACKET_SIZE];
		/* shorter alias to peer's input buffer */
		struct stream *ibw = peer->ibuf_work;
		/* offset of start of current packet */
		size_t offset = stream_get_getp(ibw);
		/* packet size as given by header */
		u_int16_t pktsize = 0;

		/* check that we have enough data for a header */
		if (STREAM_READABLE(ibw) < BGP_HEADER_SIZE)
			break;

		/* validate header */
		header_valid = validate_header(peer);

		if (!header_valid) {
			fatal = true;
			break;
		}

		/* header is valid; retrieve packet size */
		pktsize = stream_getw_from(ibw, offset + BGP_MARKER_SIZE);

		/* if this fails we are seriously screwed */
		assert(pktsize <= BGP_MAX_PACKET_SIZE);

		/* If we have that much data, chuck it into its own
		 * stream and append to input queue for processing. */
		if (STREAM_READABLE(ibw) >= pktsize) {
			struct stream *pkt = stream_new(pktsize);
			stream_get(pktbuf, ibw, pktsize);
			stream_put(pkt, pktbuf, pktsize);

			pthread_mutex_lock(&peer->io_mtx);
			{
				stream_fifo_push(peer->ibuf, pkt);
			}
			pthread_mutex_unlock(&peer->io_mtx);

			added_pkt = true;
		} else
			break;
	}

	/* After reading:
	 * 1. Move unread data to stream start to make room for more.
	 * 2. Reschedule and return when we have additional data.
	 *
	 * XXX: Heavy abuse of stream API. This needs a ring buffer.
	 */
	if (more && STREAM_WRITEABLE(peer->ibuf_work) < BGP_MAX_PACKET_SIZE) {
		void *from = stream_pnt(peer->ibuf_work);
		void *to = peer->ibuf_work->data;
		size_t siz = STREAM_READABLE(peer->ibuf_work);
		memmove(to, from, siz);
		stream_set_getp(peer->ibuf_work, 0);
		stream_set_endp(peer->ibuf_work, siz);
	}

	assert(STREAM_WRITEABLE(peer->ibuf_work) >= BGP_MAX_PACKET_SIZE);

	/* handle invalid header */
	if (fatal) {
		if (!header_valid) {
			bgp_size_t pktsize = BGP_HEADER_SIZE;
			stream_get(peer->last_reset_cause, peer->ibuf_work,
				   pktsize);
			peer->last_reset_cause_size = pktsize;
		}

		/* wipe buffer just in case someone screwed up */
		stream_reset(peer->ibuf_work);
	} else {
		thread_add_read(fpt->master, bgp_process_reads, peer, peer->fd,
				&peer->t_read);
		if (added_pkt)
			thread_add_event(bm->master, bgp_process_packet, peer,
					 0, NULL);
	}

	return 0;
}

/**
 * Flush peer output buffer.
 *
 * This function pops packets off of peer->obuf and writes them to peer->fd.
 * The amount of packets written is equal to the minimum of peer->wpkt_quanta
 * and the number of packets on the output buffer, unless an error occurs.
 *
 * If write() returns an error, the appropriate FSM event is generated.
 *
 * The return value is equal to the number of packets written
 * (which may be zero).
 */
static uint16_t bgp_write(struct peer *peer)
{
	u_char type;
	struct stream *s;
	int num;
	int update_last_write = 0;
	unsigned int count = 0;
	unsigned int oc = 0;
	uint16_t status = 0;
	uint32_t wpkt_quanta_old;

	// cache current write quanta
	wpkt_quanta_old = atomic_load_explicit(&peer->bgp->wpkt_quanta,
					       memory_order_relaxed);

	while (count < wpkt_quanta_old && (s = stream_fifo_head(peer->obuf))) {
		int writenum;
		do {
			writenum = stream_get_endp(s) - stream_get_getp(s);
			num = write(peer->fd, STREAM_PNT(s), writenum);

			if (num < 0) {
				if (!ERRNO_IO_RETRY(errno)) {
					BGP_EVENT_ADD(peer, TCP_fatal_error);
					SET_FLAG(status, BGP_IO_FATAL_ERR);
				} else {
					SET_FLAG(status, BGP_IO_TRANS_ERR);
				}

				goto done;
			} else if (num != writenum) // incomplete write
				stream_forward_getp(s, num);

		} while (num != writenum);

		/* Retrieve BGP packet type. */
		stream_set_getp(s, BGP_MARKER_SIZE + 2);
		type = stream_getc(s);

		switch (type) {
		case BGP_MSG_OPEN:
			peer->open_out++;
			break;
		case BGP_MSG_UPDATE:
			peer->update_out++;
			break;
		case BGP_MSG_NOTIFY:
			peer->notify_out++;
			/* Double start timer. */
			peer->v_start *= 2;

			/* Overflow check. */
			if (peer->v_start >= (60 * 2))
				peer->v_start = (60 * 2);

			/* Handle Graceful Restart case where the state changes
			   to
			   Connect instead of Idle */
			/* Flush any existing events */
			BGP_EVENT_ADD(peer, BGP_Stop);
			goto done;

		case BGP_MSG_KEEPALIVE:
			peer->keepalive_out++;
			break;
		case BGP_MSG_ROUTE_REFRESH_NEW:
		case BGP_MSG_ROUTE_REFRESH_OLD:
			peer->refresh_out++;
			break;
		case BGP_MSG_CAPABILITY:
			peer->dynamic_cap_out++;
			break;
		}

		count++;

		stream_free(stream_fifo_pop(peer->obuf));
		update_last_write = 1;
	}

done : {
	/* Update last_update if UPDATEs were written. */
	if (peer->update_out > oc)
		peer->last_update = bgp_clock();

	/* If we TXed any flavor of packet update last_write */
	if (update_last_write)
		peer->last_write = bgp_clock();
}

	return status;
}

/**
 * Reads <= 1 packet worth of data from peer->fd into peer->ibuf_work.
 *
 * @return whether a full packet was read
 */
static uint16_t bgp_read(struct peer *peer)
{
	size_t readsize; // how many bytes we want to read
	ssize_t nbytes;  // how many bytes we actually read
	uint16_t status = 0;

	readsize = STREAM_WRITEABLE(peer->ibuf_work);

	nbytes = stream_read_try(peer->ibuf_work, peer->fd, readsize);

	if (nbytes <= 0) // handle errors
	{
		switch (nbytes) {
		case -1: // fatal error; tear down the session
			zlog_err("%s [Error] bgp_read_packet error: %s",
				 peer->host, safe_strerror(errno));

			if (peer->status == Established) {
				if (CHECK_FLAG(peer->sflags,
					       PEER_STATUS_NSF_MODE)) {
					peer->last_reset =
						PEER_DOWN_NSF_CLOSE_SESSION;
					SET_FLAG(peer->sflags,
						 PEER_STATUS_NSF_WAIT);
				} else
					peer->last_reset =
						PEER_DOWN_CLOSE_SESSION;
			}

			BGP_EVENT_ADD(peer, TCP_fatal_error);
			SET_FLAG(status, BGP_IO_FATAL_ERR);
			break;

		case 0: // TCP session closed
			if (bgp_debug_neighbor_events(peer))
				zlog_debug(
					"%s [Event] BGP connection closed fd %d",
					peer->host, peer->fd);

			if (peer->status == Established) {
				if (CHECK_FLAG(peer->sflags,
					       PEER_STATUS_NSF_MODE)) {
					peer->last_reset =
						PEER_DOWN_NSF_CLOSE_SESSION;
					SET_FLAG(peer->sflags,
						 PEER_STATUS_NSF_WAIT);
				} else
					peer->last_reset =
						PEER_DOWN_CLOSE_SESSION;
			}

			BGP_EVENT_ADD(peer, TCP_connection_closed);
			SET_FLAG(status, BGP_IO_FATAL_ERR);
			break;

		case -2: // temporary error; come back later
			SET_FLAG(status, BGP_IO_TRANS_ERR);
			break;
		default:
			break;
		}

		return status;
	}

	return status;
}

/*
 * Called after we have read a BGP packet header. Validates marker, message
 * type and packet length. If any of these aren't correct, sends a notify.
 */
static bool validate_header(struct peer *peer)
{
	u_int16_t size, type;
	struct stream *pkt = peer->ibuf_work;
	size_t getp = stream_get_getp(pkt);

	static uint8_t marker[BGP_MARKER_SIZE] = {
		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

	if (memcmp(marker, stream_pnt(pkt), BGP_MARKER_SIZE) != 0) {
		bgp_notify_send(peer, BGP_NOTIFY_HEADER_ERR,
				BGP_NOTIFY_HEADER_NOT_SYNC);
		return false;
	}

	/* Get size and type. */
	size = stream_getw_from(pkt, getp + BGP_MARKER_SIZE);
	type = stream_getc_from(pkt, getp + BGP_MARKER_SIZE + 2);

	/* BGP type check. */
	if (type != BGP_MSG_OPEN && type != BGP_MSG_UPDATE
	    && type != BGP_MSG_NOTIFY && type != BGP_MSG_KEEPALIVE
	    && type != BGP_MSG_ROUTE_REFRESH_NEW
	    && type != BGP_MSG_ROUTE_REFRESH_OLD
	    && type != BGP_MSG_CAPABILITY) {
		if (bgp_debug_neighbor_events(peer))
			zlog_debug("%s unknown message type 0x%02x", peer->host,
				   type);

		bgp_notify_send_with_data(peer, BGP_NOTIFY_HEADER_ERR,
					  BGP_NOTIFY_HEADER_BAD_MESTYPE,
					  (u_char *)&type, 1);
		return false;
	}

	/* Mimimum packet length check. */
	if ((size < BGP_HEADER_SIZE) || (size > BGP_MAX_PACKET_SIZE)
	    || (type == BGP_MSG_OPEN && size < BGP_MSG_OPEN_MIN_SIZE)
	    || (type == BGP_MSG_UPDATE && size < BGP_MSG_UPDATE_MIN_SIZE)
	    || (type == BGP_MSG_NOTIFY && size < BGP_MSG_NOTIFY_MIN_SIZE)
	    || (type == BGP_MSG_KEEPALIVE && size != BGP_MSG_KEEPALIVE_MIN_SIZE)
	    || (type == BGP_MSG_ROUTE_REFRESH_NEW
		&& size < BGP_MSG_ROUTE_REFRESH_MIN_SIZE)
	    || (type == BGP_MSG_ROUTE_REFRESH_OLD
		&& size < BGP_MSG_ROUTE_REFRESH_MIN_SIZE)
	    || (type == BGP_MSG_CAPABILITY
		&& size < BGP_MSG_CAPABILITY_MIN_SIZE)) {
		if (bgp_debug_neighbor_events(peer))
			zlog_debug("%s bad message length - %d for %s",
				   peer->host, size,
				   type == 128 ? "ROUTE-REFRESH"
					       : bgp_type_str[(int)type]);

		bgp_notify_send_with_data(peer, BGP_NOTIFY_HEADER_ERR,
					  BGP_NOTIFY_HEADER_BAD_MESLEN,
					  (u_char *)&size, 2);
		return false;
	}

	return true;
}
Commit	Line	Data
958b450c QY	1	/* BGP I/O.
	2	* Implements packet I/O in a consumer pthread.
	3	* Copyright (C) 2017 Cumulus Networks
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; see the file COPYING; if not, write to the
	17	* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
	18	* MA 02110-1301 USA
56257a44 QY	19	*/
56257a44 QY	20
95158b0c	21	/* clang-format off */
42cf651e	22	#include <zebra.h>
95158b0c	23	#include <pthread.h> // for pthread_mutex_unlock, pthread_mutex_lock
56257a44	24
95158b0c QY	25	#include "frr_pthread.h" // for frr_pthread_get, frr_pthread
	26	#include "linklist.h" // for list_delete, list_delete_all_node, lis...
	27	#include "log.h" // for zlog_debug, safe_strerror, zlog_err
	28	#include "memory.h" // for MTYPE_TMP, XCALLOC, XFREE
	29	#include "network.h" // for ERRNO_IO_RETRY
	30	#include "stream.h" // for stream_get_endp, stream_getw_from, str...
	31	#include "thread.h" // for THREAD_OFF, THREAD_ARG, thread, thread...
	32	#include "zassert.h" // for assert
56257a44	33
42cf651e	34	#include "bgpd/bgp_io.h"
95158b0c QY	35	#include "bgpd/bgp_debug.h" // for bgp_debug_neighbor_events, bgp_type_str
	36	#include "bgpd/bgp_fsm.h" // for BGP_EVENT_ADD, bgp_event
	37	#include "bgpd/bgp_packet.h" // for bgp_notify_send_with_data, bgp_notify...
	38	#include "bgpd/bgpd.h" // for peer, BGP_MARKER_SIZE, bgp_master, bm
	39	/* clang-format on */
56257a44	40
424ab01d QY	41	/* forward declarations */
	42	static uint16_t bgp_write(struct peer *);
	43	static uint16_t bgp_read(struct peer *);
	44	static int bgp_process_writes(struct thread *);
	45	static int bgp_process_reads(struct thread *);
	46	static bool validate_header(struct peer *);
56257a44	47
424ab01d	48	/* generic i/o status codes */
95158b0c QY	49	#define BGP_IO_TRANS_ERR (1 << 0) // EAGAIN or similar occurred
95158b0c QY	50	#define BGP_IO_FATAL_ERR (1 << 1) // some kind of fatal TCP error
56257a44	51
424ab01d	52	/* Start and stop routines for I/O pthread + control variables
56257a44	53	* ------------------------------------------------------------------------ */
b750b0ba QY	54	_Atomic bool bgp_io_thread_run;
b750b0ba QY	55	_Atomic bool bgp_io_thread_started;
56257a44	56
424ab01d	57	void bgp_io_init()
56257a44	58	{
b750b0ba QY	59	bgp_io_thread_run = false;
b750b0ba QY	60	bgp_io_thread_started = false;
56257a44	61	}
56257a44	62
424ab01d	63	void bgp_io_start(void arg)
56257a44	64	{
424ab01d	65	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
72bb6e33	66	fpt->master->owner = pthread_self();
424ab01d QY	67
	68	// we definitely don't want to handle signals
	69	fpt->master->handle_signals = false;
	70
424ab01d QY	71	struct thread task;
424ab01d QY	72
b750b0ba QY	73	atomic_store_explicit(&bgp_io_thread_run, true, memory_order_relaxed);
	74	atomic_store_explicit(&bgp_io_thread_started, true,
	75	memory_order_relaxed);
	76
	77	while (bgp_io_thread_run) {
424ab01d	78	if (thread_fetch(fpt->master, &task)) {
b750b0ba	79	thread_call(&task);
424ab01d QY	80	}
424ab01d QY	81	}
56257a44	82
424ab01d	83	return NULL;
56257a44 QY	84	}
56257a44 QY	85
424ab01d	86	int bgp_io_stop(void *result, struct frr_pthread fpt)
56257a44	87	{
b750b0ba QY	88
	89	bgp_io_thread_run = false;
	90	/* let the loop break */
424ab01d	91	fpt->master->spin = false;
b750b0ba	92	/* break poll */
424ab01d QY	93	pthread_kill(fpt->thread, SIGINT);
424ab01d QY	94	pthread_join(fpt->thread, result);
56257a44	95
424ab01d	96	return 0;
56257a44	97	}
424ab01d	98	/* ------------------------------------------------------------------------ */
56257a44	99
424ab01d	100	void bgp_writes_on(struct peer *peer)
56257a44	101	{
b750b0ba QY	102	while (!atomic_load_explicit(&bgp_io_thread_started,
	103	memory_order_relaxed))
	104	;
	105
424ab01d QY	106	assert(peer->status != Deleted);
	107	assert(peer->obuf);
	108	assert(peer->ibuf);
	109	assert(peer->ibuf_work);
	110	assert(!peer->t_connect_check);
	111	assert(peer->fd);
56257a44	112
424ab01d	113	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
56257a44	114
b750b0ba QY	115	thread_add_write(fpt->master, bgp_process_writes, peer, peer->fd,
	116	&peer->t_write);
	117	SET_FLAG(peer->thread_flags, PEER_THREAD_WRITES_ON);
424ab01d	118	}
56257a44	119
424ab01d QY	120	void bgp_writes_off(struct peer *peer)
424ab01d QY	121	{
b750b0ba QY	122	while (!atomic_load_explicit(&bgp_io_thread_started,
	123	memory_order_relaxed))
	124	;
	125
151044ce QY	126	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
151044ce QY	127
b750b0ba QY	128	thread_cancel_async(fpt->master, &peer->t_write, NULL);
b750b0ba QY	129	THREAD_OFF(peer->t_generate_updgrp_packets);
56257a44	130
b750b0ba	131	UNSET_FLAG(peer->thread_flags, PEER_THREAD_WRITES_ON);
56257a44 QY	132	}
56257a44 QY	133
424ab01d	134	void bgp_reads_on(struct peer *peer)
56257a44	135	{
b750b0ba QY	136	while (!atomic_load_explicit(&bgp_io_thread_started,
	137	memory_order_relaxed))
	138	;
	139
424ab01d QY	140	assert(peer->status != Deleted);
	141	assert(peer->ibuf);
	142	assert(peer->fd);
	143	assert(peer->ibuf_work);
	144	assert(stream_get_endp(peer->ibuf_work) == 0);
	145	assert(peer->obuf);
	146	assert(!peer->t_connect_check);
	147	assert(peer->fd);
	148
	149	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
	150
b750b0ba QY	151	thread_add_read(fpt->master, bgp_process_reads, peer, peer->fd,
	152	&peer->t_read);
	153
	154	SET_FLAG(peer->thread_flags, PEER_THREAD_READS_ON);
56257a44 QY	155	}
56257a44 QY	156
424ab01d	157	void bgp_reads_off(struct peer *peer)
56257a44	158	{
b750b0ba QY	159	while (!atomic_load_explicit(&bgp_io_thread_started,
	160	memory_order_relaxed))
	161	;
	162
151044ce QY	163	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
151044ce QY	164
b750b0ba QY	165	thread_cancel_async(fpt->master, &peer->t_read, NULL);
b750b0ba QY	166	THREAD_OFF(peer->t_process_packet);
56257a44	167
b750b0ba	168	UNSET_FLAG(peer->thread_flags, PEER_THREAD_READS_ON);
56257a44 QY	169	}
56257a44 QY	170
424ab01d QY	171	/**
	172	* Called from PTHREAD_IO when select() or poll() determines that the file
	173	* descriptor is ready to be written to.
	174	*/
	175	static int bgp_process_writes(struct thread *thread)
56257a44	176	{
424ab01d QY	177	static struct peer *peer;
	178	peer = THREAD_ARG(thread);
	179	uint16_t status;
b750b0ba	180	bool reschedule;
424ab01d QY	181
	182	if (peer->fd < 0)
	183	return -1;
	184
	185	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
	186
424ab01d	187	pthread_mutex_lock(&peer->io_mtx);
56257a44	188	{
424ab01d QY	189	status = bgp_write(peer);
	190	reschedule = (stream_fifo_head(peer->obuf) != NULL);
	191	}
	192	pthread_mutex_unlock(&peer->io_mtx);
56257a44	193
424ab01d	194	if (CHECK_FLAG(status, BGP_IO_TRANS_ERR)) { /* no problem */
56257a44	195	}
56257a44	196
424ab01d	197	if (CHECK_FLAG(status, BGP_IO_FATAL_ERR))
b750b0ba	198	reschedule = false; /* problem */
424ab01d QY	199
	200	if (reschedule) {
	201	thread_add_write(fpt->master, bgp_process_writes, peer,
	202	peer->fd, &peer->t_write);
a9794991	203	thread_add_timer_msec(bm->master, bgp_generate_updgrp_packets,
424ab01d QY	204	peer, 0,
	205	&peer->t_generate_updgrp_packets);
	206	}
	207
	208	return 0;
56257a44 QY	209	}
	210
	211	/**
424ab01d QY	212	* Called from PTHREAD_IO when select() or poll() determines that the file
424ab01d QY	213	* descriptor is ready to be read from.
9eb217ff QY	214	*
	215	* We read as much data as possible, process as many packets as we can and
	216	* place them on peer->ibuf for secondary processing by the main thread.
56257a44	217	*/
424ab01d	218	static int bgp_process_reads(struct thread *thread)
56257a44	219	{
9eb217ff QY	220	static struct peer *peer; // peer to read from
	221	uint16_t status; // bgp_read status code
	222	bool more = true; // whether we got more data
	223	bool fatal = false; // whether fatal error occurred
	224	bool added_pkt = false; // whether we pushed onto ->ibuf
	225	bool header_valid = true; // whether header is valid
	226
424ab01d	227	peer = THREAD_ARG(thread);
424ab01d QY	228
	229	if (peer->fd < 0)
	230	return -1;
	231
	232	struct frr_pthread *fpt = frr_pthread_get(PTHREAD_IO);
	233
424ab01d	234	pthread_mutex_lock(&peer->io_mtx);
56257a44	235	{
424ab01d QY	236	status = bgp_read(peer);
	237	}
	238	pthread_mutex_unlock(&peer->io_mtx);
	239
9eb217ff QY	240	/* error checking phase */
	241	if (CHECK_FLAG(status, BGP_IO_TRANS_ERR)) {
	242	/* no problem; just don't process packets */
	243	more = false;
	244	}
424ab01d	245
9eb217ff QY	246	if (CHECK_FLAG(status, BGP_IO_FATAL_ERR)) {
	247	/* problem; tear down session */
	248	more = false;
	249	fatal = true;
56257a44	250	}
56257a44	251
9eb217ff QY	252	while (more) {
	253	/* static buffer for transferring packets */
	254	static unsigned char pktbuf[BGP_MAX_PACKET_SIZE];
	255	/* shorter alias to peer's input buffer */
	256	struct stream *ibw = peer->ibuf_work;
	257	/* offset of start of current packet */
	258	size_t offset = stream_get_getp(ibw);
	259	/* packet size as given by header */
	260	u_int16_t pktsize = 0;
	261
	262	/* check that we have enough data for a header */
	263	if (STREAM_READABLE(ibw) < BGP_HEADER_SIZE)
	264	break;
424ab01d	265
9eb217ff	266	/* validate header */
424ab01d	267	header_valid = validate_header(peer);
9eb217ff	268
424ab01d	269	if (!header_valid) {
9eb217ff QY	270	fatal = true;
9eb217ff QY	271	break;
424ab01d	272	}
424ab01d	273
9eb217ff QY	274	/* header is valid; retrieve packet size */
9eb217ff QY	275	pktsize = stream_getw_from(ibw, offset + BGP_MARKER_SIZE);
424ab01d	276
9eb217ff QY	277	/* if this fails we are seriously screwed */
	278	assert(pktsize <= BGP_MAX_PACKET_SIZE);
	279
	280	/* If we have that much data, chuck it into its own
	281	* stream and append to input queue for processing. */
	282	if (STREAM_READABLE(ibw) >= pktsize) {
	283	struct stream *pkt = stream_new(pktsize);
	284	stream_get(pktbuf, ibw, pktsize);
	285	stream_put(pkt, pktbuf, pktsize);
	286
	287	pthread_mutex_lock(&peer->io_mtx);
	288	{
	289	stream_fifo_push(peer->ibuf, pkt);
	290	}
	291	pthread_mutex_unlock(&peer->io_mtx);
	292
	293	added_pkt = true;
	294	} else
	295	break;
	296	}
	297
	298	/* After reading:
	299	* 1. Move unread data to stream start to make room for more.
	300	* 2. Reschedule and return when we have additional data.
	301	*
	302	* XXX: Heavy abuse of stream API. This needs a ring buffer.
	303	*/
	304	if (more && STREAM_WRITEABLE(peer->ibuf_work) < BGP_MAX_PACKET_SIZE) {
	305	void *from = stream_pnt(peer->ibuf_work);
	306	void *to = peer->ibuf_work->data;
	307	size_t siz = STREAM_READABLE(peer->ibuf_work);
	308	memmove(to, from, siz);
	309	stream_set_getp(peer->ibuf_work, 0);
	310	stream_set_endp(peer->ibuf_work, siz);
424ab01d QY	311	}
424ab01d QY	312
9eb217ff QY	313	assert(STREAM_WRITEABLE(peer->ibuf_work) >= BGP_MAX_PACKET_SIZE);
	314
	315	/* handle invalid header */
	316	if (fatal) {
	317	if (!header_valid) {
	318	bgp_size_t pktsize = BGP_HEADER_SIZE;
	319	stream_get(peer->last_reset_cause, peer->ibuf_work,
	320	pktsize);
	321	peer->last_reset_cause_size = pktsize;
	322	}
	323
	324	/* wipe buffer just in case someone screwed up */
	325	stream_reset(peer->ibuf_work);
	326	} else {
424ab01d QY	327	thread_add_read(fpt->master, bgp_process_reads, peer, peer->fd,
424ab01d QY	328	&peer->t_read);
9eb217ff QY	329	if (added_pkt)
	330	thread_add_event(bm->master, bgp_process_packet, peer,
	331	0, NULL);
9eb217ff	332	}
424ab01d QY	333
424ab01d QY	334	return 0;
56257a44 QY	335	}
	336
	337	/**
	338	* Flush peer output buffer.
	339	*
	340	* This function pops packets off of peer->obuf and writes them to peer->fd.
	341	* The amount of packets written is equal to the minimum of peer->wpkt_quanta
424ab01d	342	* and the number of packets on the output buffer, unless an error occurs.
56257a44 QY	343	*
	344	* If write() returns an error, the appropriate FSM event is generated.
	345	*
	346	* The return value is equal to the number of packets written
	347	* (which may be zero).
	348	*/
424ab01d	349	static uint16_t bgp_write(struct peer *peer)
56257a44 QY	350	{
	351	u_char type;
	352	struct stream *s;
	353	int num;
	354	int update_last_write = 0;
	355	unsigned int count = 0;
	356	unsigned int oc = 0;
424ab01d	357	uint16_t status = 0;
555e09d4	358	uint32_t wpkt_quanta_old;
56257a44	359
555e09d4 QY	360	// cache current write quanta
	361	wpkt_quanta_old = atomic_load_explicit(&peer->bgp->wpkt_quanta,
	362	memory_order_relaxed);
	363
	364	while (count < wpkt_quanta_old && (s = stream_fifo_head(peer->obuf))) {
56257a44 QY	365	int writenum;
	366	do {
	367	writenum = stream_get_endp(s) - stream_get_getp(s);
	368	num = write(peer->fd, STREAM_PNT(s), writenum);
	369
	370	if (num < 0) {
424ab01d	371	if (!ERRNO_IO_RETRY(errno)) {
56257a44	372	BGP_EVENT_ADD(peer, TCP_fatal_error);
424ab01d QY	373	SET_FLAG(status, BGP_IO_FATAL_ERR);
	374	} else {
	375	SET_FLAG(status, BGP_IO_TRANS_ERR);
	376	}
56257a44 QY	377
	378	goto done;
	379	} else if (num != writenum) // incomplete write
	380	stream_forward_getp(s, num);
	381
	382	} while (num != writenum);
	383
	384	/* Retrieve BGP packet type. */
	385	stream_set_getp(s, BGP_MARKER_SIZE + 2);
	386	type = stream_getc(s);
	387
	388	switch (type) {
	389	case BGP_MSG_OPEN:
	390	peer->open_out++;
	391	break;
	392	case BGP_MSG_UPDATE:
	393	peer->update_out++;
	394	break;
	395	case BGP_MSG_NOTIFY:
	396	peer->notify_out++;
	397	/* Double start timer. */
	398	peer->v_start *= 2;
	399
	400	/* Overflow check. */
	401	if (peer->v_start >= (60 * 2))
	402	peer->v_start = (60 * 2);
	403
	404	/* Handle Graceful Restart case where the state changes
	405	to
	406	Connect instead of Idle */
	407	/* Flush any existing events */
	408	BGP_EVENT_ADD(peer, BGP_Stop);
	409	goto done;
	410
	411	case BGP_MSG_KEEPALIVE:
	412	peer->keepalive_out++;
	413	break;
	414	case BGP_MSG_ROUTE_REFRESH_NEW:
	415	case BGP_MSG_ROUTE_REFRESH_OLD:
	416	peer->refresh_out++;
	417	break;
	418	case BGP_MSG_CAPABILITY:
	419	peer->dynamic_cap_out++;
	420	break;
	421	}
	422
	423	count++;
424ab01d	424
56257a44 QY	425	stream_free(stream_fifo_pop(peer->obuf));
	426	update_last_write = 1;
	427	}
	428
	429	done : {
	430	/* Update last_update if UPDATEs were written. */
	431	if (peer->update_out > oc)
	432	peer->last_update = bgp_clock();
	433
	434	/* If we TXed any flavor of packet update last_write */
	435	if (update_last_write)
	436	peer->last_write = bgp_clock();
	437	}
	438
424ab01d QY	439	return status;
	440	}
	441
	442	/**
	443	* Reads <= 1 packet worth of data from peer->fd into peer->ibuf_work.
	444	*
	445	* @return whether a full packet was read
	446	*/
	447	static uint16_t bgp_read(struct peer *peer)
	448	{
b750b0ba QY	449	size_t readsize; // how many bytes we want to read
b750b0ba QY	450	ssize_t nbytes; // how many bytes we actually read
424ab01d QY	451	uint16_t status = 0;
424ab01d QY	452
9eb217ff	453	readsize = STREAM_WRITEABLE(peer->ibuf_work);
424ab01d QY	454
	455	nbytes = stream_read_try(peer->ibuf_work, peer->fd, readsize);
	456
	457	if (nbytes <= 0) // handle errors
	458	{
	459	switch (nbytes) {
	460	case -1: // fatal error; tear down the session
	461	zlog_err("%s [Error] bgp_read_packet error: %s",
	462	peer->host, safe_strerror(errno));
	463
	464	if (peer->status == Established) {
	465	if (CHECK_FLAG(peer->sflags,
	466	PEER_STATUS_NSF_MODE)) {
	467	peer->last_reset =
	468	PEER_DOWN_NSF_CLOSE_SESSION;
	469	SET_FLAG(peer->sflags,
	470	PEER_STATUS_NSF_WAIT);
	471	} else
	472	peer->last_reset =
	473	PEER_DOWN_CLOSE_SESSION;
	474	}
	475
	476	BGP_EVENT_ADD(peer, TCP_fatal_error);
	477	SET_FLAG(status, BGP_IO_FATAL_ERR);
	478	break;
	479
	480	case 0: // TCP session closed
	481	if (bgp_debug_neighbor_events(peer))
	482	zlog_debug(
	483	"%s [Event] BGP connection closed fd %d",
	484	peer->host, peer->fd);
	485
	486	if (peer->status == Established) {
	487	if (CHECK_FLAG(peer->sflags,
	488	PEER_STATUS_NSF_MODE)) {
	489	peer->last_reset =
	490	PEER_DOWN_NSF_CLOSE_SESSION;
	491	SET_FLAG(peer->sflags,
	492	PEER_STATUS_NSF_WAIT);
	493	} else
	494	peer->last_reset =
	495	PEER_DOWN_CLOSE_SESSION;
	496	}
	497
	498	BGP_EVENT_ADD(peer, TCP_connection_closed);
	499	SET_FLAG(status, BGP_IO_FATAL_ERR);
	500	break;
	501
	502	case -2: // temporary error; come back later
	503	SET_FLAG(status, BGP_IO_TRANS_ERR);
	504	break;
	505	default:
	506	break;
	507	}
	508
	509	return status;
	510	}
	511
424ab01d QY	512	return status;
	513	}
	514
	515	/*
	516	* Called after we have read a BGP packet header. Validates marker, message
	517	* type and packet length. If any of these aren't correct, sends a notify.
	518	*/
	519	static bool validate_header(struct peer *peer)
	520	{
	521	u_int16_t size, type;
9eb217ff QY	522	struct stream *pkt = peer->ibuf_work;
9eb217ff QY	523	size_t getp = stream_get_getp(pkt);
424ab01d	524
442c9afb QY	525	static uint8_t marker[BGP_MARKER_SIZE] = {
	526	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	527	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
	528
9eb217ff	529	if (memcmp(marker, stream_pnt(pkt), BGP_MARKER_SIZE) != 0) {
442c9afb QY	530	bgp_notify_send(peer, BGP_NOTIFY_HEADER_ERR,
	531	BGP_NOTIFY_HEADER_NOT_SYNC);
	532	return false;
	533	}
424ab01d QY	534
424ab01d QY	535	/* Get size and type. */
9eb217ff QY	536	size = stream_getw_from(pkt, getp + BGP_MARKER_SIZE);
9eb217ff QY	537	type = stream_getc_from(pkt, getp + BGP_MARKER_SIZE + 2);
424ab01d QY	538
	539	/* BGP type check. */
	540	if (type != BGP_MSG_OPEN && type != BGP_MSG_UPDATE
	541	&& type != BGP_MSG_NOTIFY && type != BGP_MSG_KEEPALIVE
	542	&& type != BGP_MSG_ROUTE_REFRESH_NEW
	543	&& type != BGP_MSG_ROUTE_REFRESH_OLD
	544	&& type != BGP_MSG_CAPABILITY) {
	545	if (bgp_debug_neighbor_events(peer))
	546	zlog_debug("%s unknown message type 0x%02x", peer->host,
	547	type);
	548
	549	bgp_notify_send_with_data(peer, BGP_NOTIFY_HEADER_ERR,
	550	BGP_NOTIFY_HEADER_BAD_MESTYPE,
	551	(u_char *)&type, 1);
	552	return false;
	553	}
	554
	555	/* Mimimum packet length check. */
	556	if ((size < BGP_HEADER_SIZE) \|\| (size > BGP_MAX_PACKET_SIZE)
	557	\|\| (type == BGP_MSG_OPEN && size < BGP_MSG_OPEN_MIN_SIZE)
	558	\|\| (type == BGP_MSG_UPDATE && size < BGP_MSG_UPDATE_MIN_SIZE)
	559	\|\| (type == BGP_MSG_NOTIFY && size < BGP_MSG_NOTIFY_MIN_SIZE)
	560	\|\| (type == BGP_MSG_KEEPALIVE && size != BGP_MSG_KEEPALIVE_MIN_SIZE)
	561	\|\| (type == BGP_MSG_ROUTE_REFRESH_NEW
	562	&& size < BGP_MSG_ROUTE_REFRESH_MIN_SIZE)
	563	\|\| (type == BGP_MSG_ROUTE_REFRESH_OLD
	564	&& size < BGP_MSG_ROUTE_REFRESH_MIN_SIZE)
	565	\|\| (type == BGP_MSG_CAPABILITY
	566	&& size < BGP_MSG_CAPABILITY_MIN_SIZE)) {
	567	if (bgp_debug_neighbor_events(peer))
	568	zlog_debug("%s bad message length - %d for %s",
	569	peer->host, size,
	570	type == 128 ? "ROUTE-REFRESH"
	571	: bgp_type_str[(int)type]);
	572
	573	bgp_notify_send_with_data(peer, BGP_NOTIFY_HEADER_ERR,
	574	BGP_NOTIFY_HEADER_BAD_MESLEN,
	575	(u_char *)&size, 2);
	576	return false;
	577	}
	578
	579	return true;
56257a44	580	}