Ben Pfaff
6b617bac12
This makes it easier to install the headers, or to use them directly from another software package with -I$(openflow)/include, without invading the top-level include file namespace.
258 lines
8.6 KiB
C
258 lines
8.6 KiB
C
/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
|
|
* Junior University
|
|
*
|
|
* We are making the OpenFlow specification and associated documentation
|
|
* (Software) available for public use and benefit with the expectation
|
|
* that others will use, modify and enhance the Software and contribute
|
|
* those enhancements back to the community. However, since we would
|
|
* like to make the Software available for broadest use, with as few
|
|
* restrictions as possible permission is hereby granted, free of
|
|
* charge, to any person obtaining a copy of this Software to deal in
|
|
* the Software under the copyrights without restriction, including
|
|
* without limitation the rights to use, copy, modify, merge, publish,
|
|
* distribute, sublicense, and/or sell copies of the Software, and to
|
|
* permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be
|
|
* included in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
|
|
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
|
|
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
|
|
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
* SOFTWARE.
|
|
*
|
|
* The name and trademarks of copyright holder(s) may NOT be used in
|
|
* advertising or publicity pertaining to the Software or any
|
|
* derivatives without specific, written prior permission.
|
|
*/
|
|
|
|
#include <config.h>
|
|
#include "ratelimit.h"
|
|
#include <arpa/inet.h>
|
|
#include <stdlib.h>
|
|
#include "ofpbuf.h"
|
|
#include "openflow/openflow.h"
|
|
#include "poll-loop.h"
|
|
#include "queue.h"
|
|
#include "rconn.h"
|
|
#include "secchan.h"
|
|
#include "status.h"
|
|
#include "timeval.h"
|
|
#include "vconn.h"
|
|
|
|
struct rate_limiter {
|
|
const struct settings *s;
|
|
struct rconn *remote_rconn;
|
|
|
|
/* One queue per physical port. */
|
|
struct ofp_queue queues[OFPP_MAX];
|
|
int n_queued; /* Sum over queues[*].n. */
|
|
int next_tx_port; /* Next port to check in round-robin. */
|
|
|
|
/* Token bucket.
|
|
*
|
|
* It costs 1000 tokens to send a single packet_in message. A single token
|
|
* per message would be more straightforward, but this choice lets us avoid
|
|
* round-off error in refill_bucket()'s calculation of how many tokens to
|
|
* add to the bucket, since no division step is needed. */
|
|
long long int last_fill; /* Time at which we last added tokens. */
|
|
int tokens; /* Current number of tokens. */
|
|
|
|
/* Transmission queue. */
|
|
int n_txq; /* No. of packets waiting in rconn for tx. */
|
|
|
|
/* Statistics reporting. */
|
|
unsigned long long n_normal; /* # txed w/o rate limit queuing. */
|
|
unsigned long long n_limited; /* # queued for rate limiting. */
|
|
unsigned long long n_queue_dropped; /* # dropped due to queue overflow. */
|
|
unsigned long long n_tx_dropped; /* # dropped due to tx overflow. */
|
|
};
|
|
|
|
/* Drop a packet from the longest queue in 'rl'. */
|
|
static void
|
|
drop_packet(struct rate_limiter *rl)
|
|
{
|
|
struct ofp_queue *longest; /* Queue currently selected as longest. */
|
|
int n_longest; /* # of queues of same length as 'longest'. */
|
|
struct ofp_queue *q;
|
|
|
|
longest = &rl->queues[0];
|
|
n_longest = 1;
|
|
for (q = &rl->queues[0]; q < &rl->queues[OFPP_MAX]; q++) {
|
|
if (longest->n < q->n) {
|
|
longest = q;
|
|
n_longest = 1;
|
|
} else if (longest->n == q->n) {
|
|
n_longest++;
|
|
|
|
/* Randomly select one of the longest queues, with a uniform
|
|
* distribution (Knuth algorithm 3.4.2R). */
|
|
if (!random_range(n_longest)) {
|
|
longest = q;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* FIXME: do we want to pop the tail instead? */
|
|
ofpbuf_delete(queue_pop_head(longest));
|
|
rl->n_queued--;
|
|
}
|
|
|
|
/* Remove and return the next packet to transmit (in round-robin order). */
|
|
static struct ofpbuf *
|
|
dequeue_packet(struct rate_limiter *rl)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < OFPP_MAX; i++) {
|
|
unsigned int port = (rl->next_tx_port + i) % OFPP_MAX;
|
|
struct ofp_queue *q = &rl->queues[port];
|
|
if (q->n) {
|
|
rl->next_tx_port = (port + 1) % OFPP_MAX;
|
|
rl->n_queued--;
|
|
return queue_pop_head(q);
|
|
}
|
|
}
|
|
NOT_REACHED();
|
|
}
|
|
|
|
/* Add tokens to the bucket based on elapsed time. */
|
|
static void
|
|
refill_bucket(struct rate_limiter *rl)
|
|
{
|
|
const struct settings *s = rl->s;
|
|
long long int now = time_msec();
|
|
long long int tokens = (now - rl->last_fill) * s->rate_limit + rl->tokens;
|
|
if (tokens >= 1000) {
|
|
rl->last_fill = now;
|
|
rl->tokens = MIN(tokens, s->burst_limit * 1000);
|
|
}
|
|
}
|
|
|
|
/* Attempts to remove enough tokens from 'rl' to transmit a packet. Returns
|
|
* true if successful, false otherwise. (In the latter case no tokens are
|
|
* removed.) */
|
|
static bool
|
|
get_token(struct rate_limiter *rl)
|
|
{
|
|
if (rl->tokens >= 1000) {
|
|
rl->tokens -= 1000;
|
|
return true;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static bool
|
|
rate_limit_local_packet_cb(struct relay *r, void *rl_)
|
|
{
|
|
struct rate_limiter *rl = rl_;
|
|
const struct settings *s = rl->s;
|
|
struct ofp_packet_in *opi;
|
|
|
|
opi = get_ofp_packet_in(r);
|
|
if (!opi) {
|
|
return false;
|
|
}
|
|
|
|
if (!rl->n_queued && get_token(rl)) {
|
|
/* In the common case where we are not constrained by the rate limit,
|
|
* let the packet take the normal path. */
|
|
rl->n_normal++;
|
|
return false;
|
|
} else {
|
|
/* Otherwise queue it up for the periodic callback to drain out. */
|
|
struct ofpbuf *msg = r->halves[HALF_LOCAL].rxbuf;
|
|
int port = ntohs(opi->in_port) % OFPP_MAX;
|
|
if (rl->n_queued >= s->burst_limit) {
|
|
drop_packet(rl);
|
|
}
|
|
queue_push_tail(&rl->queues[port], ofpbuf_clone(msg));
|
|
rl->n_queued++;
|
|
rl->n_limited++;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
static void
|
|
rate_limit_status_cb(struct status_reply *sr, void *rl_)
|
|
{
|
|
struct rate_limiter *rl = rl_;
|
|
|
|
status_reply_put(sr, "normal=%llu", rl->n_normal);
|
|
status_reply_put(sr, "limited=%llu", rl->n_limited);
|
|
status_reply_put(sr, "queue-dropped=%llu", rl->n_queue_dropped);
|
|
status_reply_put(sr, "tx-dropped=%llu", rl->n_tx_dropped);
|
|
}
|
|
|
|
static void
|
|
rate_limit_periodic_cb(void *rl_)
|
|
{
|
|
struct rate_limiter *rl = rl_;
|
|
int i;
|
|
|
|
/* Drain some packets out of the bucket if possible, but limit the number
|
|
* of iterations to allow other code to get work done too. */
|
|
refill_bucket(rl);
|
|
for (i = 0; rl->n_queued && get_token(rl) && i < 50; i++) {
|
|
/* Use a small, arbitrary limit for the amount of queuing to do here,
|
|
* because the TCP connection is responsible for buffering and there is
|
|
* no point in trying to transmit faster than the TCP connection can
|
|
* handle. */
|
|
struct ofpbuf *b = dequeue_packet(rl);
|
|
if (rconn_send_with_limit(rl->remote_rconn, b, &rl->n_txq, 10)) {
|
|
rl->n_tx_dropped++;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
rate_limit_wait_cb(void *rl_)
|
|
{
|
|
struct rate_limiter *rl = rl_;
|
|
if (rl->n_queued) {
|
|
if (rl->tokens >= 1000) {
|
|
/* We can transmit more packets as soon as we're called again. */
|
|
poll_immediate_wake();
|
|
} else {
|
|
/* We have to wait for the bucket to re-fill. We could calculate
|
|
* the exact amount of time here for increased smoothness. */
|
|
poll_timer_wait(TIME_UPDATE_INTERVAL / 2);
|
|
}
|
|
}
|
|
}
|
|
|
|
static struct hook_class rate_limit_hook_class = {
|
|
rate_limit_local_packet_cb, /* local_packet_cb */
|
|
NULL, /* remote_packet_cb */
|
|
rate_limit_periodic_cb, /* periodic_cb */
|
|
rate_limit_wait_cb, /* wait_cb */
|
|
NULL, /* closing_cb */
|
|
};
|
|
|
|
void
|
|
rate_limit_start(struct secchan *secchan, const struct settings *s,
|
|
struct switch_status *ss,
|
|
struct rconn *local, struct rconn *remote)
|
|
{
|
|
struct rate_limiter *rl;
|
|
size_t i;
|
|
|
|
rl = xcalloc(1, sizeof *rl);
|
|
rl->s = s;
|
|
rl->remote_rconn = remote;
|
|
for (i = 0; i < ARRAY_SIZE(rl->queues); i++) {
|
|
queue_init(&rl->queues[i]);
|
|
}
|
|
rl->last_fill = time_msec();
|
|
rl->tokens = s->rate_limit * 100;
|
|
switch_status_register_category(ss, "rate-limit",
|
|
rate_limit_status_cb, rl);
|
|
add_hook(secchan, &rate_limit_hook_class, rl);
|
|
}
|