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/*
* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2016 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "pktbuf.h"
#include <inttypes.h>
#include <stdlib.h>
#include "coverage.h"
#include "openvswitch/ofp-util.h"
#include "dp-packet.h"
#include "timeval.h"
#include "util.h"
#include "openvswitch/vconn.h"
#include "openvswitch/vlog.h"
VLOG_DEFINE_THIS_MODULE(pktbuf);
COVERAGE_DEFINE(pktbuf_buffer_unknown);
COVERAGE_DEFINE(pktbuf_retrieved);
COVERAGE_DEFINE(pktbuf_reuse_error);
/* Buffers are identified by a 32-bit opaque ID. We divide the ID
* into a buffer number (low bits) and a cookie (high bits). The buffer number
* is an index into an array of buffers. The cookie distinguishes between
* different packets that have occupied a single buffer. Thus, the more
* buffers we have, the lower-quality the cookie... */
#define PKTBUF_BITS 8
#define PKTBUF_MASK (PKTBUF_CNT - 1)
#define PKTBUF_CNT (1u << PKTBUF_BITS)
#define COOKIE_BITS (32 - PKTBUF_BITS)
#define COOKIE_MAX ((1u << COOKIE_BITS) - 1)
#define OVERWRITE_MSECS 5000
struct packet {
struct dp_packet *buffer;
uint32_t cookie;
long long int timeout;
ofp_port_t in_port;
};
struct pktbuf {
struct packet packets[PKTBUF_CNT];
unsigned int buffer_idx;
unsigned int null_idx;
};
int
pktbuf_capacity(void)
{
return PKTBUF_CNT;
}
struct pktbuf *
pktbuf_create(void)
{
return xzalloc(sizeof *pktbuf_create());
}
void
pktbuf_destroy(struct pktbuf *pb)
{
if (pb) {
size_t i;
for (i = 0; i < PKTBUF_CNT; i++) {
dp_packet_delete(pb->packets[i].buffer);
}
free(pb);
}
}
static unsigned int
make_id(unsigned int buffer_idx, unsigned int cookie)
{
return buffer_idx | (cookie << PKTBUF_BITS);
}
/* Attempts to allocate an OpenFlow packet buffer id within 'pb'. The packet
* buffer will store a copy of 'buffer_size' bytes in 'buffer' and the port
* number 'in_port', which should be the OpenFlow port number on which 'buffer'
* was received.
*
* If successful, returns the packet buffer id (a number other than
* UINT32_MAX). pktbuf_retrieve() can later be used to retrieve the buffer and
* its input port number (buffers do expire after a time, so this is not
* guaranteed to be true forever). On failure, returns UINT32_MAX.
*
* The caller retains ownership of 'buffer'. */
uint32_t
pktbuf_save(struct pktbuf *pb, const void *buffer, size_t buffer_size,
ofp_port_t in_port)
{
struct packet *p = &pb->packets[pb->buffer_idx];
pb->buffer_idx = (pb->buffer_idx + 1) & PKTBUF_MASK;
if (p->buffer) {
if (time_msec() < p->timeout) {
return UINT32_MAX;
}
dp_packet_delete(p->buffer);
}
/* Don't use maximum cookie value since all-1-bits ID is special. */
if (++p->cookie >= COOKIE_MAX) {
p->cookie = 0;
}
/* Use 2 bytes of headroom to 32-bit align the L3 header. */
p->buffer = dp_packet_clone_data_with_headroom(buffer, buffer_size, 2);
p->timeout = time_msec() + OVERWRITE_MSECS;
p->in_port = in_port;
return make_id(p - pb->packets, p->cookie);
}
/* Attempts to retrieve a saved packet with the given 'id' from 'pb'. Returns
* 0 if successful, otherwise an OpenFlow error code.
*
* On success, stores the buffered packet in '*bufferp' and the OpenFlow port
* number on which the packet was received in '*in_port'. The caller becomes
* responsible for freeing the buffer.
*
* 'in_port' may be NULL if the input port is not of interest.
*
* The L3 header of a returned packet will be 32-bit aligned.
*
* On failure, stores NULL in in '*bufferp' and UINT16_MAX in '*in_port'. */
enum ofperr
pktbuf_retrieve(struct pktbuf *pb, uint32_t id, struct dp_packet **bufferp,
ofp_port_t *in_port)
{
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 20);
struct packet *p;
enum ofperr error;
if (id == UINT32_MAX) {
error = 0;
goto error;
}
if (!pb) {
VLOG_WARN_RL(&rl, "attempt to send buffered packet via connection "
"without buffers");
error = OFPERR_OFPBRC_BUFFER_UNKNOWN;
goto error;
}
p = &pb->packets[id & PKTBUF_MASK];
if (p->cookie == id >> PKTBUF_BITS) {
struct dp_packet *buffer = p->buffer;
if (buffer) {
*bufferp = buffer;
if (in_port) {
*in_port = p->in_port;
}
p->buffer = NULL;
COVERAGE_INC(pktbuf_retrieved);
return 0;
} else {
COVERAGE_INC(pktbuf_reuse_error);
VLOG_WARN_RL(&rl, "attempt to reuse buffer %08"PRIx32, id);
error = OFPERR_OFPBRC_BUFFER_EMPTY;
}
} else {
COVERAGE_INC(pktbuf_buffer_unknown);
VLOG_WARN_RL(&rl, "cookie mismatch: %08"PRIx32" != %08"PRIx32,
id, (id & PKTBUF_MASK) | (p->cookie << PKTBUF_BITS));
error = OFPERR_OFPBRC_BUFFER_UNKNOWN;
}
error:
*bufferp = NULL;
if (in_port) {
*in_port = OFPP_NONE;
}
return error;
}
void
pktbuf_discard(struct pktbuf *pb, uint32_t id)
{
struct packet *p = &pb->packets[id & PKTBUF_MASK];
if (p->cookie == id >> PKTBUF_BITS) {
dp_packet_delete(p->buffer);
p->buffer = NULL;
}
}
/* Returns the number of packets buffered in 'pb'. Returns 0 if 'pb' is
* null. */
unsigned int
pktbuf_count_packets(const struct pktbuf *pb)
{
int n = 0;
if (pb) {
int i;
for (i = 0; i < PKTBUF_CNT; i++) {
if (pb->packets[i].buffer) {
n++;
}
}
}
return n;
}
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