Justin Pettit
0a3d4ba3a4
The learning switch functionality included in OpenFlow will send packets out the port they arrived on if the learned destination is from that port. This causes problems when newer switches flood packets for destinations they don't know and OpenFlow reinjects packets back into the network. The correct behavior is to just drop the packet.
261 lines
9.0 KiB
C
261 lines
9.0 KiB
C
/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
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* Junior University
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*
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* We are making the OpenFlow specification and associated documentation
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* (Software) available for public use and benefit with the expectation
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* that others will use, modify and enhance the Software and contribute
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* those enhancements back to the community. However, since we would
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* like to make the Software available for broadest use, with as few
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* restrictions as possible permission is hereby granted, free of
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* charge, to any person obtaining a copy of this Software to deal in
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* the Software under the copyrights without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* The name and trademarks of copyright holder(s) may NOT be used in
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* advertising or publicity pertaining to the Software or any
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* derivatives without specific, written prior permission.
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*/
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#include <config.h>
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#include "learning-switch.h"
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#include <errno.h>
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#include <inttypes.h>
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#include <netinet/in.h>
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#include <stdlib.h>
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#include <time.h>
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#include "buffer.h"
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#include "flow.h"
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#include "mac-learning.h"
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#include "ofp-print.h"
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#include "openflow.h"
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#include "queue.h"
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#include "rconn.h"
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#include "vconn.h"
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#include "xtoxll.h"
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#define THIS_MODULE VLM_learning_switch
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#include "vlog.h"
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struct lswitch {
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/* If nonnegative, the switch sets up flows that expire after the given
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* number of seconds (or never expire, if the value is OFP_FLOW_PERMANENT).
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* Otherwise, the switch processes every packet. */
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int max_idle;
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uint64_t datapath_id;
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time_t last_features_request;
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struct mac_learning *ml; /* NULL to act as hub instead of switch. */
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};
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static void queue_tx(struct lswitch *, struct rconn *, struct buffer *);
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static void send_features_request(struct lswitch *, struct rconn *);
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static void process_packet_in(struct lswitch *, struct rconn *,
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struct ofp_packet_in *);
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static void process_echo_request(struct lswitch *, struct rconn *,
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struct ofp_header *);
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/* Creates and returns a new learning switch.
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*
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* If 'learn_macs' is true, the new switch will learn the ports on which MAC
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* addresses appear. Otherwise, the new switch will flood all packets.
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*
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* If 'max_idle' is nonnegative, the new switch will set up flows that expire
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* after the given number of seconds (or never expire, if 'max_idle' is
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* OFP_FLOW_PERMANENT). Otherwise, the new switch will process every packet.
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*
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* 'rconn' is used to send out an OpenFlow features request. */
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struct lswitch *
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lswitch_create(struct rconn *rconn, bool learn_macs, int max_idle)
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{
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struct lswitch *sw = xmalloc(sizeof *sw);
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memset(sw, 0, sizeof *sw);
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sw->max_idle = max_idle;
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sw->datapath_id = 0;
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sw->last_features_request = time(0) - 1;
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sw->ml = learn_macs ? mac_learning_create() : NULL;
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send_features_request(sw, rconn);
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return sw;
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}
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/* Destroys 'sw'. */
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void
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lswitch_destroy(struct lswitch *sw)
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{
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if (sw) {
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mac_learning_destroy(sw->ml);
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free(sw);
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}
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}
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/* Processes 'msg', which should be an OpenFlow received on 'rconn', according
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* to the learning switch state in 'sw'. The most likely result of processing
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* is that flow-setup and packet-out OpenFlow messages will be sent out on
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* 'rconn'. */
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void
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lswitch_process_packet(struct lswitch *sw, struct rconn *rconn,
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const struct buffer *msg)
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{
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static const size_t min_size[UINT8_MAX + 1] = {
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[0 ... UINT8_MAX] = sizeof (struct ofp_header),
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[OFPT_FEATURES_REPLY] = sizeof (struct ofp_switch_features),
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[OFPT_PACKET_IN] = offsetof (struct ofp_packet_in, data),
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};
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struct ofp_header *oh;
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oh = msg->data;
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if (msg->size < min_size[oh->type]) {
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VLOG_WARN("%s: too short (%zu bytes) for type %"PRIu8" (min %zu)",
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rconn_get_name(rconn),
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msg->size, oh->type, min_size[oh->type]);
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return;
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}
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if (oh->type == OFPT_ECHO_REQUEST) {
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process_echo_request(sw, rconn, msg->data);
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} else if (oh->type == OFPT_FEATURES_REPLY) {
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struct ofp_switch_features *osf = msg->data;
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sw->datapath_id = osf->datapath_id;
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} else if (sw->datapath_id == 0) {
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send_features_request(sw, rconn);
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} else if (oh->type == OFPT_PACKET_IN) {
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process_packet_in(sw, rconn, msg->data);
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} else {
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if (VLOG_IS_DBG_ENABLED()) {
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char *p = ofp_to_string(msg->data, msg->size, 2);
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VLOG_DBG("OpenFlow packet ignored: %s", p);
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free(p);
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}
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}
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}
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static void
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send_features_request(struct lswitch *sw, struct rconn *rconn)
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{
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time_t now = time(0);
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if (now >= sw->last_features_request + 1) {
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struct buffer *b;
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struct ofp_header *ofr;
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struct ofp_switch_config *osc;
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/* Send OFPT_FEATURES_REQUEST. */
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b = buffer_new(0);
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ofr = buffer_put_uninit(b, sizeof *ofr);
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memset(ofr, 0, sizeof *ofr);
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ofr->type = OFPT_FEATURES_REQUEST;
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ofr->version = OFP_VERSION;
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ofr->length = htons(sizeof *ofr);
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queue_tx(sw, rconn, b);
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/* Send OFPT_SET_CONFIG. */
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b = buffer_new(0);
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osc = buffer_put_uninit(b, sizeof *osc);
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memset(osc, 0, sizeof *osc);
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osc->header.type = OFPT_SET_CONFIG;
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osc->header.version = OFP_VERSION;
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osc->header.length = htons(sizeof *osc);
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osc->flags = htons(OFPC_SEND_FLOW_EXP);
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osc->miss_send_len = htons(OFP_DEFAULT_MISS_SEND_LEN);
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queue_tx(sw, rconn, b);
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sw->last_features_request = now;
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}
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}
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static void
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queue_tx(struct lswitch *sw, struct rconn *rconn, struct buffer *b)
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{
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int retval = rconn_send(rconn, b);
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if (retval) {
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if (retval == EAGAIN) {
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/* FIXME: ratelimit. */
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VLOG_WARN("%s: tx queue overflow", rconn_get_name(rconn));
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} else if (retval == ENOTCONN) {
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/* Ignore. */
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} else {
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/* FIXME: ratelimit. */
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VLOG_WARN("%s: send: %s", rconn_get_name(rconn), strerror(retval));
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}
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buffer_delete(b);
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}
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}
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static void
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process_packet_in(struct lswitch *sw, struct rconn *rconn,
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struct ofp_packet_in *opi)
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{
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uint16_t in_port = ntohs(opi->in_port);
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uint16_t out_port = OFPP_FLOOD;
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size_t pkt_ofs, pkt_len;
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struct buffer pkt;
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struct flow flow;
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/* Extract flow data from 'opi' into 'flow'. */
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pkt_ofs = offsetof(struct ofp_packet_in, data);
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pkt_len = ntohs(opi->header.length) - pkt_ofs;
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pkt.data = opi->data;
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pkt.size = pkt_len;
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flow_extract(&pkt, in_port, &flow);
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if (sw->ml) {
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if (mac_learning_learn(sw->ml, flow.dl_src, in_port)) {
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VLOG_DBG("learned that "ETH_ADDR_FMT" is on datapath %"
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PRIx64" port %"PRIu16, ETH_ADDR_ARGS(flow.dl_src),
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ntohll(sw->datapath_id), in_port);
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}
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out_port = mac_learning_lookup(sw->ml, flow.dl_dst);
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}
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if (in_port == out_port) {
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/* The input port and output port match, so just drop the packet
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* by returning. */
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return;
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} else if (sw->max_idle >= 0 && (!sw->ml || out_port != OFPP_FLOOD)) {
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/* The output port is known, or we always flood everything, so add a
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* new flow. */
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queue_tx(sw, rconn, make_add_simple_flow(&flow, ntohl(opi->buffer_id),
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out_port, sw->max_idle));
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/* If the switch didn't buffer the packet, we need to send a copy. */
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if (ntohl(opi->buffer_id) == UINT32_MAX) {
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queue_tx(sw, rconn,
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make_unbuffered_packet_out(&pkt, in_port, out_port));
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}
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} else {
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/* We don't know that MAC, or we don't set up flows. Send along the
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* packet without setting up a flow. */
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struct buffer *b;
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if (ntohl(opi->buffer_id) == UINT32_MAX) {
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b = make_unbuffered_packet_out(&pkt, in_port, out_port);
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} else {
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b = make_buffered_packet_out(ntohl(opi->buffer_id),
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in_port, out_port);
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}
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queue_tx(sw, rconn, b);
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}
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}
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static void
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process_echo_request(struct lswitch *sw, struct rconn *rconn,
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struct ofp_header *rq)
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{
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queue_tx(sw, rconn, make_echo_reply(rq));
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}
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