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-rw-r--r--bgpd/bgp_io.c583
1 files changed, 583 insertions, 0 deletions
diff --git a/bgpd/bgp_io.c b/bgpd/bgp_io.c
new file mode 100644
index 0000000..f9bb8d5
--- /dev/null
+++ b/bgpd/bgp_io.c
@@ -0,0 +1,583 @@
+/* BGP I/O.
+ * Implements packet I/O in a pthread.
+ * Copyright (C) 2017 Cumulus Networks
+ * Quentin Young
+ *
+ * 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 <sys/uio.h> // for writev
+
+#include "frr_pthread.h"
+#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 "ringbuf.h" // for ringbuf_remain, ringbuf_peek, ringbuf_...
+#include "thread.h" // for THREAD_OFF, THREAD_ARG, thread...
+
+#include "bgpd/bgp_io.h"
+#include "bgpd/bgp_debug.h" // for bgp_debug_neighbor_events, bgp_type_str
+#include "bgpd/bgp_errors.h" // for expanded error reference information
+#include "bgpd/bgp_fsm.h" // for BGP_EVENT_ADD, bgp_event
+#include "bgpd/bgp_packet.h" // for bgp_notify_io_invalid...
+#include "bgpd/bgp_trace.h" // for frrtraces
+#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 *peer, int *code_p);
+static void bgp_process_writes(struct thread *);
+static void 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
+
+/* Thread external API ----------------------------------------------------- */
+
+void bgp_writes_on(struct peer *peer)
+{
+ struct frr_pthread *fpt = bgp_pth_io;
+ assert(fpt->running);
+
+ assert(peer->status != Deleted);
+ assert(peer->obuf);
+ assert(peer->ibuf);
+ assert(peer->ibuf_work);
+ assert(!peer->t_connect_check_r);
+ assert(!peer->t_connect_check_w);
+ assert(peer->fd);
+
+ 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)
+{
+ struct frr_pthread *fpt = bgp_pth_io;
+ assert(fpt->running);
+
+ 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)
+{
+ struct frr_pthread *fpt = bgp_pth_io;
+ assert(fpt->running);
+
+ assert(peer->status != Deleted);
+ assert(peer->ibuf);
+ assert(peer->fd);
+ assert(peer->ibuf_work);
+ assert(peer->obuf);
+ assert(!peer->t_connect_check_r);
+ assert(!peer->t_connect_check_w);
+ assert(peer->fd);
+
+ 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)
+{
+ struct frr_pthread *fpt = bgp_pth_io;
+ assert(fpt->running);
+
+ thread_cancel_async(fpt->master, &peer->t_read, NULL);
+ THREAD_OFF(peer->t_process_packet);
+ THREAD_OFF(peer->t_process_packet_error);
+
+ UNSET_FLAG(peer->thread_flags, PEER_THREAD_READS_ON);
+}
+
+/* Thread internal functions ----------------------------------------------- */
+
+/*
+ * Called from I/O pthread when a file descriptor has become ready for writing.
+ */
+static void bgp_process_writes(struct thread *thread)
+{
+ static struct peer *peer;
+ peer = THREAD_ARG(thread);
+ uint16_t status;
+ bool reschedule;
+ bool fatal = false;
+
+ if (peer->fd < 0)
+ return;
+
+ struct frr_pthread *fpt = bgp_pth_io;
+
+ frr_with_mutex (&peer->io_mtx) {
+ status = bgp_write(peer);
+ reschedule = (stream_fifo_head(peer->obuf) != NULL);
+ }
+
+ /* no problem */
+ if (CHECK_FLAG(status, BGP_IO_TRANS_ERR)) {
+ }
+
+ /* problem */
+ if (CHECK_FLAG(status, BGP_IO_FATAL_ERR)) {
+ reschedule = false;
+ fatal = true;
+ }
+
+ /* If suppress fib pending is enabled, route is advertised to peers when
+ * the status is received from the FIB. The delay is added
+ * to update group packet generate which will allow more routes to be
+ * sent in the update message
+ */
+ if (reschedule) {
+ thread_add_write(fpt->master, bgp_process_writes, peer,
+ peer->fd, &peer->t_write);
+ } else if (!fatal) {
+ BGP_UPDATE_GROUP_TIMER_ON(&peer->t_generate_updgrp_packets,
+ bgp_generate_updgrp_packets);
+ }
+}
+
+/*
+ * Called from I/O pthread when a file descriptor has become ready for reading,
+ * or has hung up.
+ *
+ * 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 void bgp_process_reads(struct thread *thread)
+{
+ /* clang-format off */
+ 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
+ int code = 0; // FSM code if error occurred
+ /* clang-format on */
+
+ peer = THREAD_ARG(thread);
+
+ if (peer->fd < 0 || bm->terminating)
+ return;
+
+ struct frr_pthread *fpt = bgp_pth_io;
+
+ frr_with_mutex (&peer->io_mtx) {
+ status = bgp_read(peer, &code);
+ }
+
+ /* 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;
+
+ /* Handle the error in the main pthread, include the
+ * specific state change from 'bgp_read'.
+ */
+ thread_add_event(bm->master, bgp_packet_process_error,
+ peer, code, &peer->t_process_packet_error);
+ }
+
+ while (more) {
+ /* static buffer for transferring packets */
+ /* shorter alias to peer's input buffer */
+ struct ringbuf *ibw = peer->ibuf_work;
+ /* packet size as given by header */
+ uint16_t pktsize = 0;
+
+ /* check that we have enough data for a header */
+ if (ringbuf_remain(ibw) < BGP_HEADER_SIZE)
+ break;
+
+ /* check that header is valid */
+ if (!validate_header(peer)) {
+ fatal = true;
+ break;
+ }
+
+ /* header is valid; retrieve packet size */
+ ringbuf_peek(ibw, BGP_MARKER_SIZE, &pktsize, sizeof(pktsize));
+
+ pktsize = ntohs(pktsize);
+
+ /* if this fails we are seriously screwed */
+ assert(pktsize <= peer->max_packet_size);
+
+ /*
+ * If we have that much data, chuck it into its own
+ * stream and append to input queue for processing.
+ */
+ if (ringbuf_remain(ibw) >= pktsize) {
+ struct stream *pkt = stream_new(pktsize);
+
+ assert(STREAM_WRITEABLE(pkt) == pktsize);
+ assert(ringbuf_get(ibw, pkt->data, pktsize) == pktsize);
+ stream_set_endp(pkt, pktsize);
+
+ frrtrace(2, frr_bgp, packet_read, peer, pkt);
+ frr_with_mutex (&peer->io_mtx) {
+ stream_fifo_push(peer->ibuf, pkt);
+ }
+
+ added_pkt = true;
+ } else
+ break;
+ }
+
+ /* handle invalid header */
+ if (fatal) {
+ /* wipe buffer just in case someone screwed up */
+ ringbuf_wipe(peer->ibuf_work);
+ } else {
+ assert(ringbuf_space(peer->ibuf_work) >= peer->max_packet_size);
+
+ 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, &peer->t_process_packet);
+ }
+}
+
+/*
+ * 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)
+{
+ uint8_t type;
+ struct stream *s;
+ int update_last_write = 0;
+ unsigned int count;
+ uint32_t uo = 0;
+ uint16_t status = 0;
+ uint32_t wpkt_quanta_old;
+
+ int writenum = 0;
+ int num;
+ unsigned int iovsz;
+ unsigned int strmsz;
+ unsigned int total_written;
+ time_t now;
+
+ wpkt_quanta_old = atomic_load_explicit(&peer->bgp->wpkt_quanta,
+ memory_order_relaxed);
+ struct stream *ostreams[wpkt_quanta_old];
+ struct stream **streams = ostreams;
+ struct iovec iov[wpkt_quanta_old];
+
+ s = stream_fifo_head(peer->obuf);
+
+ if (!s)
+ goto done;
+
+ count = iovsz = 0;
+ while (count < wpkt_quanta_old && iovsz < array_size(iov) && s) {
+ ostreams[iovsz] = s;
+ iov[iovsz].iov_base = stream_pnt(s);
+ iov[iovsz].iov_len = STREAM_READABLE(s);
+ writenum += STREAM_READABLE(s);
+ s = s->next;
+ ++iovsz;
+ ++count;
+ }
+
+ strmsz = iovsz;
+ total_written = 0;
+
+ do {
+ num = writev(peer->fd, iov, iovsz);
+
+ 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);
+ }
+
+ break;
+ } else if (num != writenum) {
+ unsigned int msg_written = 0;
+ unsigned int ic = iovsz;
+
+ for (unsigned int i = 0; i < ic; i++) {
+ size_t ss = iov[i].iov_len;
+
+ if (ss > (unsigned int) num)
+ break;
+
+ msg_written++;
+ iovsz--;
+ writenum -= ss;
+ num -= ss;
+ }
+
+ total_written += msg_written;
+
+ assert(total_written < count);
+
+ memmove(&iov, &iov[msg_written],
+ sizeof(iov[0]) * iovsz);
+ streams = &streams[msg_written];
+ stream_forward_getp(streams[0], num);
+ iov[0].iov_base = stream_pnt(streams[0]);
+ iov[0].iov_len = STREAM_READABLE(streams[0]);
+
+ writenum -= num;
+ num = 0;
+ assert(writenum > 0);
+ } else {
+ total_written = strmsz;
+ }
+
+ } while (num != writenum);
+
+ /* Handle statistics */
+ for (unsigned int i = 0; i < total_written; i++) {
+ s = stream_fifo_pop(peer->obuf);
+
+ assert(s == ostreams[i]);
+
+ /* Retrieve BGP packet type. */
+ stream_set_getp(s, BGP_MARKER_SIZE + 2);
+ type = stream_getc(s);
+
+ switch (type) {
+ case BGP_MSG_OPEN:
+ atomic_fetch_add_explicit(&peer->open_out, 1,
+ memory_order_relaxed);
+ break;
+ case BGP_MSG_UPDATE:
+ atomic_fetch_add_explicit(&peer->update_out, 1,
+ memory_order_relaxed);
+ uo++;
+ break;
+ case BGP_MSG_NOTIFY:
+ atomic_fetch_add_explicit(&peer->notify_out, 1,
+ memory_order_relaxed);
+ /* 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.
+ */
+ BGP_EVENT_ADD(peer, BGP_Stop);
+ goto done;
+
+ case BGP_MSG_KEEPALIVE:
+ atomic_fetch_add_explicit(&peer->keepalive_out, 1,
+ memory_order_relaxed);
+ break;
+ case BGP_MSG_ROUTE_REFRESH_NEW:
+ case BGP_MSG_ROUTE_REFRESH_OLD:
+ atomic_fetch_add_explicit(&peer->refresh_out, 1,
+ memory_order_relaxed);
+ break;
+ case BGP_MSG_CAPABILITY:
+ atomic_fetch_add_explicit(&peer->dynamic_cap_out, 1,
+ memory_order_relaxed);
+ break;
+ }
+
+ stream_free(s);
+ ostreams[i] = NULL;
+ update_last_write = 1;
+ }
+
+done : {
+ now = monotime(NULL);
+ /*
+ * Update last_update if UPDATEs were written.
+ * Note: that these are only updated at end,
+ * not per message (i.e., per loop)
+ */
+ if (uo)
+ atomic_store_explicit(&peer->last_update, now,
+ memory_order_relaxed);
+
+ /* If we TXed any flavor of packet */
+ if (update_last_write) {
+ atomic_store_explicit(&peer->last_write, now,
+ memory_order_relaxed);
+ peer->last_sendq_ok = now;
+ }
+}
+
+ return status;
+}
+
+/*
+ * Reads a chunk of data from peer->fd into peer->ibuf_work.
+ *
+ * code_p
+ * Pointer to location to store FSM event code in case of fatal error.
+ *
+ * @return status flag (see top-of-file)
+ */
+static uint16_t bgp_read(struct peer *peer, int *code_p)
+{
+ size_t readsize; // how many bytes we want to read
+ ssize_t nbytes; // how many bytes we actually read
+ uint16_t status = 0;
+
+ readsize =
+ MIN(ringbuf_space(peer->ibuf_work), sizeof(peer->ibuf_scratch));
+ nbytes = read(peer->fd, peer->ibuf_scratch, readsize);
+
+ /* EAGAIN or EWOULDBLOCK; come back later */
+ if (nbytes < 0 && ERRNO_IO_RETRY(errno)) {
+ SET_FLAG(status, BGP_IO_TRANS_ERR);
+ } else if (nbytes < 0) {
+ /* Fatal error; tear down session */
+ flog_err(EC_BGP_UPDATE_RCV,
+ "%s [Error] bgp_read_packet error: %s", peer->host,
+ safe_strerror(errno));
+
+ /* Handle the error in the main pthread. */
+ if (code_p)
+ *code_p = TCP_fatal_error;
+
+ SET_FLAG(status, BGP_IO_FATAL_ERR);
+
+ } else if (nbytes == 0) {
+ /* Received EOF / TCP session closed */
+ if (bgp_debug_neighbor_events(peer))
+ zlog_debug("%s [Event] BGP connection closed fd %d",
+ peer->host, peer->fd);
+
+ /* Handle the error in the main pthread. */
+ if (code_p)
+ *code_p = TCP_connection_closed;
+
+ SET_FLAG(status, BGP_IO_FATAL_ERR);
+ } else {
+ assert(ringbuf_put(peer->ibuf_work, peer->ibuf_scratch, nbytes)
+ == (size_t)nbytes);
+ }
+
+ 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.
+ *
+ * Assumes that there are at least BGP_HEADER_SIZE readable bytes in the input
+ * buffer.
+ */
+static bool validate_header(struct peer *peer)
+{
+ uint16_t size;
+ uint8_t type;
+ struct ringbuf *pkt = peer->ibuf_work;
+
+ static const uint8_t m_correct[BGP_MARKER_SIZE] = {
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
+ uint8_t m_rx[BGP_MARKER_SIZE] = {0x00};
+
+ if (ringbuf_peek(pkt, 0, m_rx, BGP_MARKER_SIZE) != BGP_MARKER_SIZE)
+ return false;
+
+ if (memcmp(m_correct, m_rx, BGP_MARKER_SIZE) != 0) {
+ bgp_notify_io_invalid(peer, BGP_NOTIFY_HEADER_ERR,
+ BGP_NOTIFY_HEADER_NOT_SYNC, NULL, 0);
+ return false;
+ }
+
+ /* Get size and type in network byte order. */
+ ringbuf_peek(pkt, BGP_MARKER_SIZE, &size, sizeof(size));
+ ringbuf_peek(pkt, BGP_MARKER_SIZE + 2, &type, sizeof(type));
+
+ size = ntohs(size);
+
+ /* 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_io_invalid(peer, BGP_NOTIFY_HEADER_ERR,
+ BGP_NOTIFY_HEADER_BAD_MESTYPE, &type, 1);
+ return false;
+ }
+
+ /* Minimum packet length check. */
+ if ((size < BGP_HEADER_SIZE) || (size > peer->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]);
+ }
+
+ uint16_t nsize = htons(size);
+
+ bgp_notify_io_invalid(peer, BGP_NOTIFY_HEADER_ERR,
+ BGP_NOTIFY_HEADER_BAD_MESLEN,
+ (unsigned char *)&nsize, 2);
+ return false;
+ }
+
+ return true;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-07 23:08:30 +0000