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bgpd: move bgp_connect_check() to bgp_fsm.c

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Prior to this change, after initiating a nonblocking connection to the
remote peer bgpd would call both BGP_READ_ON and BGP_WRITE_ON on the
peer's socket. This resulted in a call to select(), so that when some
event (either a connection success or failure) occurred on the socket,
one of bgp_read() or bgp_write() would run. At the beginning of each of
those functions was a hook into bgp_connect_check(), which checked the
socket status and issued the correct connection event onto the BGP FSM.

This code is better suited for bgp_fsm.c. Placing it there avoids
scheduling packet reads or writes when we don't know if the socket has
established a connection yet, and the specific functionality is a better
fit for the responsibility scope of this unit.

This change also helps isolate the responsibilities of the
packet-writing kernel thread.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
This commit is contained in:
Quentin Young 2017-03-24 19:05:56 +00:00
parent 80bd61c416
commit 07a1652682
No known key found for this signature in database
GPG Key ID: DAF48E0F57E0834F
2 changed files with 52 additions and 56 deletions
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48
bgpd/bgp_fsm.c
View File

@ -1176,6 +1176,48 @@ static int bgp_stop_with_notify(struct peer *peer, u_char code, u_char sub_code)
return (bgp_stop(peer));
}
/**
* Determines whether a TCP session has successfully established for a peer and
* events as appropriate.
*
* This function is called when setting up a new session. After connect() is
* called on the peer's socket (in bgp_start()), the fd is passed to select()
* to wait for connection success or failure. When select() returns, this
* function is called to evaluate the result.
*/
static int bgp_connect_check(struct thread *thread)
{
int status;
socklen_t slen;
int ret;
struct peer *peer;
peer = THREAD_ARG(thread);
/* Check file descriptor. */
slen = sizeof(status);
ret = getsockopt(peer->fd, SOL_SOCKET, SO_ERROR, (void *)&status,
&slen);
/* If getsockopt is fail, this is fatal error. */
if (ret < 0) {
zlog_info("can't get sockopt for nonblocking connect");
BGP_EVENT_ADD(peer, TCP_fatal_error);
return -1;
}
/* When status is 0 then TCP connection is established. */
if (status == 0) {
BGP_EVENT_ADD(peer, TCP_connection_open);
return 1;
} else {
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [Event] Connect failed (%s)", peer->host,
safe_strerror(errno));
BGP_EVENT_ADD(peer, TCP_connection_open_failed);
return 0;
}
}
/* TCP connection open. Next we send open message to remote peer. And
add read thread for reading open message. */
@ -1329,8 +1371,10 @@ int bgp_start(struct peer *peer)
peer->fd);
return -1;
}
BGP_READ_ON(peer->t_read, bgp_read, peer->fd);
peer_writes_on(peer);
// when the socket becomes ready (or fails to connect),
// bgp_connect_check
// will be called.
thread_add_read(bm->master, bgp_connect_check, peer, peer->fd);
break;
}
return 0;

60
bgpd/bgp_packet.c
View File

@ -129,43 +129,6 @@ static void bgp_packet_delete_unsafe(struct peer *peer)
stream_free(stream_fifo_pop(peer->obuf));
}
/* Check file descriptor whether connect is established. */
static int bgp_connect_check(struct peer *peer, int change_state)
{
int status;
socklen_t slen;
int ret;
/* Anyway I have to reset read and write thread. */
BGP_READ_OFF(peer->t_read);
/* Check file descriptor. */
slen = sizeof(status);
ret = getsockopt(peer->fd, SOL_SOCKET, SO_ERROR, (void *)&status,
&slen);
/* If getsockopt is fail, this is fatal error. */
if (ret < 0) {
zlog_info("can't get sockopt for nonblocking connect");
BGP_EVENT_ADD(peer, TCP_fatal_error);
return -1;
}
/* When status is 0 then TCP connection is established. */
if (status == 0) {
BGP_EVENT_ADD(peer, TCP_connection_open);
return 1;
} else {
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [Event] Connect failed (%s)", peer->host,
safe_strerror(errno));
if (change_state)
BGP_EVENT_ADD(peer, TCP_connection_open_failed);
return 0;
}
}
static struct stream *bgp_update_packet_eor(struct peer *peer, afi_t afi,
safi_t safi)
{
@ -2055,19 +2018,14 @@ int bgp_read(struct thread *thread)
*/
notify_out = peer->notify_out;
/* For non-blocking IO check. */
if (peer->status == Connect) {
bgp_connect_check(peer, 1);
goto done;
} else {
if (peer->fd < 0) {
zlog_err("bgp_read peer's fd is negative value %d",
peer->fd);
return -1;
}
BGP_READ_ON(peer->t_read, bgp_read, peer->fd);
if (peer->fd < 0) {
zlog_err("bgp_read(): peer's fd is negative value %d",
peer->fd);
return -1;
}
BGP_READ_ON(peer->t_read, bgp_read, peer->fd);
/* Read packet header to determine type of the packet */
if (peer->packet_size == 0)
peer->packet_size = BGP_HEADER_SIZE;
@ -2233,12 +2191,6 @@ static int bgp_write(struct peer *peer)
unsigned int count = 0;
unsigned int oc = 0;
/* For non-blocking IO check. */
if (peer->status == Connect) {
bgp_connect_check(peer, 1);
return 0;
}
/* Write packets. The number of packets written is the value of
* bgp->wpkt_quanta or the size of the output buffer, whichever is
* smaller.*/