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|
/*
* Zebra opaque message handler module
* Copyright (c) 2020 Volta Networks, Inc.
*
* 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
*/
#include <zebra.h>
#include "lib/debug.h"
#include "lib/frr_pthread.h"
#include "lib/stream.h"
#include "zebra/debug.h"
#include "zebra/zserv.h"
#include "zebra/zebra_opaque.h"
#include "zebra/rib.h"
/* Mem type */
DEFINE_MTYPE_STATIC(ZEBRA, OPQ, "ZAPI Opaque Information");
/* Hash to hold message registration info from zapi clients */
PREDECL_HASH(opq_regh);
/* Registered client info */
struct opq_client_reg {
int proto;
int instance;
uint32_t session_id;
struct opq_client_reg *next;
struct opq_client_reg *prev;
};
/* Opaque message registration info */
struct opq_msg_reg {
struct opq_regh_item item;
/* Message type */
uint32_t type;
struct opq_client_reg *clients;
};
/* Registration helper prototypes */
static uint32_t registration_hash(const struct opq_msg_reg *reg);
static int registration_compare(const struct opq_msg_reg *reg1,
const struct opq_msg_reg *reg2);
DECLARE_HASH(opq_regh, struct opq_msg_reg, item, registration_compare,
registration_hash);
static struct opq_regh_head opq_reg_hash;
/*
* Globals
*/
static struct zebra_opaque_globals {
/* Sentinel for run or start of shutdown */
_Atomic uint32_t run;
/* Limit number of pending, unprocessed updates */
_Atomic uint32_t max_queued_updates;
/* Limit number of new messages dequeued at once, to pace an
* incoming burst.
*/
uint32_t msgs_per_cycle;
/* Stats: counters of incoming messages, errors, and yields (when
* the limit has been reached.)
*/
_Atomic uint32_t msgs_in;
_Atomic uint32_t msg_errors;
_Atomic uint32_t yields;
/* pthread */
struct frr_pthread *pthread;
/* Event-delivery context 'master' for the module */
struct thread_master *master;
/* Event/'thread' pointer for queued zapi messages */
struct thread *t_msgs;
/* Input fifo queue to the module, and lock to protect it. */
pthread_mutex_t mutex;
struct stream_fifo in_fifo;
} zo_info;
/* Name string for debugs/logs */
static const char LOG_NAME[] = "Zebra Opaque";
/* Prototypes */
/* Main event loop, processing incoming message queue */
static void process_messages(struct thread *event);
static int handle_opq_registration(const struct zmsghdr *hdr,
struct stream *msg);
static int handle_opq_unregistration(const struct zmsghdr *hdr,
struct stream *msg);
static int dispatch_opq_messages(struct stream_fifo *msg_fifo);
static struct opq_msg_reg *opq_reg_lookup(uint32_t type);
static bool opq_client_match(const struct opq_client_reg *client,
const struct zapi_opaque_reg_info *info);
static struct opq_msg_reg *opq_reg_alloc(uint32_t type);
static void opq_reg_free(struct opq_msg_reg **reg);
static struct opq_client_reg *opq_client_alloc(
const struct zapi_opaque_reg_info *info);
static void opq_client_free(struct opq_client_reg **client);
static const char *opq_client2str(char *buf, size_t buflen,
const struct opq_client_reg *client);
/*
* Initialize the module at startup
*/
void zebra_opaque_init(void)
{
memset(&zo_info, 0, sizeof(zo_info));
pthread_mutex_init(&zo_info.mutex, NULL);
stream_fifo_init(&zo_info.in_fifo);
zo_info.msgs_per_cycle = ZEBRA_OPAQUE_MSG_LIMIT;
}
/*
* Start the module pthread. This step is run later than the
* 'init' step, in case zebra has fork-ed.
*/
void zebra_opaque_start(void)
{
struct frr_pthread_attr pattr = {
.start = frr_pthread_attr_default.start,
.stop = frr_pthread_attr_default.stop
};
if (IS_ZEBRA_DEBUG_EVENT)
zlog_debug("%s module starting", LOG_NAME);
/* Start pthread */
zo_info.pthread = frr_pthread_new(&pattr, "Zebra Opaque thread",
"zebra_opaque");
/* Associate event 'master' */
zo_info.master = zo_info.pthread->master;
atomic_store_explicit(&zo_info.run, 1, memory_order_relaxed);
/* Enqueue an initial event for the pthread */
thread_add_event(zo_info.master, process_messages, NULL, 0,
&zo_info.t_msgs);
/* And start the pthread */
frr_pthread_run(zo_info.pthread, NULL);
}
/*
* Module stop, halting the dedicated pthread; called from the main pthread.
*/
void zebra_opaque_stop(void)
{
if (IS_ZEBRA_DEBUG_EVENT)
zlog_debug("%s module stop", LOG_NAME);
atomic_store_explicit(&zo_info.run, 0, memory_order_relaxed);
frr_pthread_stop(zo_info.pthread, NULL);
frr_pthread_destroy(zo_info.pthread);
if (IS_ZEBRA_DEBUG_EVENT)
zlog_debug("%s module stop complete", LOG_NAME);
}
/*
* Module final cleanup, called from the zebra main pthread.
*/
void zebra_opaque_finish(void)
{
struct opq_msg_reg *reg;
struct opq_client_reg *client;
if (IS_ZEBRA_DEBUG_EVENT)
zlog_debug("%s module shutdown", LOG_NAME);
/* Clear out registration info */
while ((reg = opq_regh_pop(&opq_reg_hash)) != NULL) {
client = reg->clients;
while (client) {
reg->clients = client->next;
opq_client_free(&client);
client = reg->clients;
}
opq_reg_free(®);
}
opq_regh_fini(&opq_reg_hash);
pthread_mutex_destroy(&zo_info.mutex);
stream_fifo_deinit(&zo_info.in_fifo);
}
/*
* Does this module handle (intercept) the specified zapi message type?
*/
bool zebra_opaque_handles_msgid(uint16_t id)
{
bool ret = false;
switch (id) {
case ZEBRA_OPAQUE_MESSAGE:
case ZEBRA_OPAQUE_REGISTER:
case ZEBRA_OPAQUE_UNREGISTER:
ret = true;
break;
default:
break;
}
return ret;
}
/*
* Enqueue a batch of messages for processing - this is the public api
* used from the zapi processing threads.
*/
uint32_t zebra_opaque_enqueue_batch(struct stream_fifo *batch)
{
uint32_t counter = 0;
struct stream *msg;
/* Dequeue messages from the incoming batch, and save them
* on the module fifo.
*/
frr_with_mutex (&zo_info.mutex) {
msg = stream_fifo_pop(batch);
while (msg) {
stream_fifo_push(&zo_info.in_fifo, msg);
counter++;
msg = stream_fifo_pop(batch);
}
}
/* Schedule module pthread to process the batch */
if (counter > 0) {
if (IS_ZEBRA_DEBUG_RECV && IS_ZEBRA_DEBUG_DETAIL)
zlog_debug("%s: received %u messages",
__func__, counter);
thread_add_event(zo_info.master, process_messages, NULL, 0,
&zo_info.t_msgs);
}
return counter;
}
/*
* Pthread event loop, process the incoming message queue.
*/
static void process_messages(struct thread *event)
{
struct stream_fifo fifo;
struct stream *msg;
uint32_t i;
bool need_resched = false;
stream_fifo_init(&fifo);
/* Check for zebra shutdown */
if (atomic_load_explicit(&zo_info.run, memory_order_relaxed) == 0)
goto done;
/*
* Dequeue some messages from the incoming queue, temporarily
* save them on the local fifo
*/
frr_with_mutex (&zo_info.mutex) {
for (i = 0; i < zo_info.msgs_per_cycle; i++) {
msg = stream_fifo_pop(&zo_info.in_fifo);
if (msg == NULL)
break;
stream_fifo_push(&fifo, msg);
}
/*
* We may need to reschedule, if there are still
* queued messages
*/
if (stream_fifo_head(&zo_info.in_fifo) != NULL)
need_resched = true;
}
/* Update stats */
atomic_fetch_add_explicit(&zo_info.msgs_in, i, memory_order_relaxed);
/* Check for zebra shutdown */
if (atomic_load_explicit(&zo_info.run, memory_order_relaxed) == 0) {
need_resched = false;
goto done;
}
if (IS_ZEBRA_DEBUG_RECV && IS_ZEBRA_DEBUG_DETAIL)
zlog_debug("%s: processing %u messages", __func__, i);
/*
* Process the messages from the temporary fifo. We send the whole
* fifo so that we can take advantage of batching internally. Note
* that registration/deregistration messages are handled here also.
*/
dispatch_opq_messages(&fifo);
done:
if (need_resched) {
atomic_fetch_add_explicit(&zo_info.yields, 1,
memory_order_relaxed);
thread_add_event(zo_info.master, process_messages, NULL, 0,
&zo_info.t_msgs);
}
/* This will also free any leftover messages, in the shutdown case */
stream_fifo_deinit(&fifo);
}
/*
* Process (dispatch) or drop opaque messages.
*/
static int dispatch_opq_messages(struct stream_fifo *msg_fifo)
{
struct stream *msg, *dup;
struct zmsghdr hdr;
struct zapi_opaque_msg info;
struct opq_msg_reg *reg;
int ret;
struct opq_client_reg *client;
struct zserv *zclient;
char buf[50];
while ((msg = stream_fifo_pop(msg_fifo)) != NULL) {
zapi_parse_header(msg, &hdr);
hdr.length -= ZEBRA_HEADER_SIZE;
/* Handle client registration messages */
if (hdr.command == ZEBRA_OPAQUE_REGISTER) {
handle_opq_registration(&hdr, msg);
continue;
} else if (hdr.command == ZEBRA_OPAQUE_UNREGISTER) {
handle_opq_unregistration(&hdr, msg);
continue;
}
/* We only process OPAQUE messages - drop anything else */
if (hdr.command != ZEBRA_OPAQUE_MESSAGE)
goto drop_it;
/* Dispatch to any registered ZAPI client(s) */
/* Extract subtype and flags */
ret = zclient_opaque_decode(msg, &info);
if (ret != 0)
goto drop_it;
/* Look up registered ZAPI client(s) */
reg = opq_reg_lookup(info.type);
if (reg == NULL) {
if (IS_ZEBRA_DEBUG_RECV && IS_ZEBRA_DEBUG_DETAIL)
zlog_debug("%s: no registrations for opaque type %u, flags %#x",
__func__, info.type, info.flags);
goto drop_it;
}
/* Reset read pointer, since we'll be re-sending message */
stream_set_getp(msg, 0);
/* Send a copy of the message to all registered clients */
for (client = reg->clients; client; client = client->next) {
dup = NULL;
if (CHECK_FLAG(info.flags, ZAPI_OPAQUE_FLAG_UNICAST)) {
if (client->proto != info.proto ||
client->instance != info.instance ||
client->session_id != info.session_id)
continue;
if (IS_ZEBRA_DEBUG_RECV &&
IS_ZEBRA_DEBUG_DETAIL)
zlog_debug("%s: found matching unicast client %s",
__func__,
opq_client2str(buf,
sizeof(buf),
client));
} else {
/* Copy message if more clients */
if (client->next)
dup = stream_dup(msg);
}
/*
* TODO -- this isn't ideal: we're going through an
* acquire/release cycle for each client for each
* message. Replace this with a batching version.
*/
zclient = zserv_acquire_client(client->proto,
client->instance,
client->session_id);
if (zclient) {
if (IS_ZEBRA_DEBUG_SEND &&
IS_ZEBRA_DEBUG_DETAIL)
zlog_debug("%s: sending %s to client %s",
__func__,
(dup ? "dup" : "msg"),
opq_client2str(buf,
sizeof(buf),
client));
/*
* Sending a message actually means enqueuing
* it for a zapi io pthread to send - so we
* don't touch the message after this call.
*/
zserv_send_message(zclient, dup ? dup : msg);
if (dup)
dup = NULL;
else
msg = NULL;
zserv_release_client(zclient);
} else {
if (IS_ZEBRA_DEBUG_RECV &&
IS_ZEBRA_DEBUG_DETAIL)
zlog_debug("%s: type %u: no zclient for %s",
__func__, info.type,
opq_client2str(buf,
sizeof(buf),
client));
/* Registered but gone? */
if (dup)
stream_free(dup);
}
/* If unicast, we're done */
if (CHECK_FLAG(info.flags, ZAPI_OPAQUE_FLAG_UNICAST))
break;
}
drop_it:
if (msg)
stream_free(msg);
}
return 0;
}
/*
* Process a register/unregister message
*/
static int handle_opq_registration(const struct zmsghdr *hdr,
struct stream *msg)
{
int ret = 0;
struct zapi_opaque_reg_info info;
struct opq_client_reg *client;
struct opq_msg_reg key, *reg;
char buf[50];
memset(&info, 0, sizeof(info));
if (zapi_opaque_reg_decode(msg, &info) < 0) {
ret = -1;
goto done;
}
memset(&key, 0, sizeof(key));
key.type = info.type;
reg = opq_regh_find(&opq_reg_hash, &key);
if (reg) {
/* Look for dup client */
for (client = reg->clients; client != NULL;
client = client->next) {
if (opq_client_match(client, &info))
break;
}
if (client) {
/* Oops - duplicate registration? */
if (IS_ZEBRA_DEBUG_RECV)
zlog_debug("%s: duplicate opq reg for client %s",
__func__,
opq_client2str(buf, sizeof(buf),
client));
goto done;
}
client = opq_client_alloc(&info);
if (IS_ZEBRA_DEBUG_RECV)
zlog_debug("%s: client %s registers for %u",
__func__,
opq_client2str(buf, sizeof(buf), client),
info.type);
/* Link client into registration */
client->next = reg->clients;
if (reg->clients)
reg->clients->prev = client;
reg->clients = client;
} else {
/*
* No existing registrations - create one, add the
* client, and add registration to hash.
*/
reg = opq_reg_alloc(info.type);
client = opq_client_alloc(&info);
if (IS_ZEBRA_DEBUG_RECV)
zlog_debug("%s: client %s registers for new reg %u",
__func__,
opq_client2str(buf, sizeof(buf), client),
info.type);
reg->clients = client;
opq_regh_add(&opq_reg_hash, reg);
}
done:
stream_free(msg);
return ret;
}
/*
* Process a register/unregister message
*/
static int handle_opq_unregistration(const struct zmsghdr *hdr,
struct stream *msg)
{
int ret = 0;
struct zapi_opaque_reg_info info;
struct opq_client_reg *client;
struct opq_msg_reg key, *reg;
char buf[50];
memset(&info, 0, sizeof(info));
if (zapi_opaque_reg_decode(msg, &info) < 0) {
ret = -1;
goto done;
}
memset(&key, 0, sizeof(key));
key.type = info.type;
reg = opq_regh_find(&opq_reg_hash, &key);
if (reg == NULL) {
/* Weird: unregister for unknown message? */
if (IS_ZEBRA_DEBUG_RECV)
zlog_debug("%s: unknown client %s/%u/%u unregisters for unknown type %u",
__func__,
zebra_route_string(info.proto),
info.instance, info.session_id, info.type);
goto done;
}
/* Look for client */
for (client = reg->clients; client != NULL;
client = client->next) {
if (opq_client_match(client, &info))
break;
}
if (client == NULL) {
/* Oops - unregister for unknown client? */
if (IS_ZEBRA_DEBUG_RECV)
zlog_debug("%s: unknown client %s/%u/%u unregisters for %u",
__func__, zebra_route_string(info.proto),
info.instance, info.session_id, info.type);
goto done;
}
if (IS_ZEBRA_DEBUG_RECV)
zlog_debug("%s: client %s unregisters for %u",
__func__, opq_client2str(buf, sizeof(buf), client),
info.type);
if (client->prev)
client->prev->next = client->next;
if (client->next)
client->next->prev = client->prev;
if (reg->clients == client)
reg->clients = client->next;
opq_client_free(&client);
/* Is registration empty now? */
if (reg->clients == NULL) {
opq_regh_del(&opq_reg_hash, reg);
opq_reg_free(®);
}
done:
stream_free(msg);
return ret;
}
/* Compare utility for registered clients */
static bool opq_client_match(const struct opq_client_reg *client,
const struct zapi_opaque_reg_info *info)
{
if (client->proto == info->proto &&
client->instance == info->instance &&
client->session_id == info->session_id)
return true;
else
return false;
}
static struct opq_msg_reg *opq_reg_lookup(uint32_t type)
{
struct opq_msg_reg key, *reg;
memset(&key, 0, sizeof(key));
key.type = type;
reg = opq_regh_find(&opq_reg_hash, &key);
return reg;
}
static struct opq_msg_reg *opq_reg_alloc(uint32_t type)
{
struct opq_msg_reg *reg;
reg = XCALLOC(MTYPE_OPQ, sizeof(struct opq_msg_reg));
reg->type = type;
INIT_HASH(®->item);
return reg;
}
static void opq_reg_free(struct opq_msg_reg **reg)
{
XFREE(MTYPE_OPQ, (*reg));
}
static struct opq_client_reg *opq_client_alloc(
const struct zapi_opaque_reg_info *info)
{
struct opq_client_reg *client;
client = XCALLOC(MTYPE_OPQ, sizeof(struct opq_client_reg));
client->proto = info->proto;
client->instance = info->instance;
client->session_id = info->session_id;
return client;
}
static void opq_client_free(struct opq_client_reg **client)
{
XFREE(MTYPE_OPQ, (*client));
}
static const char *opq_client2str(char *buf, size_t buflen,
const struct opq_client_reg *client)
{
char sbuf[20];
snprintf(buf, buflen, "%s/%u", zebra_route_string(client->proto),
client->instance);
if (client->session_id > 0) {
snprintf(sbuf, sizeof(sbuf), "/%u", client->session_id);
strlcat(buf, sbuf, buflen);
}
return buf;
}
/* Hash function for clients registered for messages */
static uint32_t registration_hash(const struct opq_msg_reg *reg)
{
return reg->type;
}
/* Comparison function for client registrations */
static int registration_compare(const struct opq_msg_reg *reg1,
const struct opq_msg_reg *reg2)
{
if (reg1->type == reg2->type)
return 0;
else
return -1;
}
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