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Diffstat (limited to 'lib/learning-switch.c')
| -rw-r--r-- | lib/learning-switch.c | 644 |
1 files changed, 644 insertions, 0 deletions
diff --git a/lib/learning-switch.c b/lib/learning-switch.c new file mode 100644 index 000000000..efc583867 --- /dev/null +++ b/lib/learning-switch.c @@ -0,0 +1,644 @@ +/* + * Copyright (c) 2008, 2009 Nicira Networks. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include <config.h> +#include "learning-switch.h" + +#include <errno.h> +#include <inttypes.h> +#include <netinet/in.h> +#include <stdlib.h> +#include <time.h> + +#include "flow.h" +#include "mac-learning.h" +#include "ofpbuf.h" +#include "ofp-print.h" +#include "openflow/openflow.h" +#include "poll-loop.h" +#include "queue.h" +#include "rconn.h" +#include "stp.h" +#include "timeval.h" +#include "vconn.h" +#include "xtoxll.h" + +#define THIS_MODULE VLM_learning_switch +#include "vlog.h" + +enum port_state { + P_DISABLED = 1 << 0, + P_LISTENING = 1 << 1, + P_LEARNING = 1 << 2, + P_FORWARDING = 1 << 3, + P_BLOCKING = 1 << 4 +}; + +struct lswitch { + /* If nonnegative, the switch sets up flows that expire after the given + * number of seconds (or never expire, if the value is OFP_FLOW_PERMANENT). + * Otherwise, the switch processes every packet. */ + int max_idle; + + unsigned long long int datapath_id; + uint32_t capabilities; + time_t last_features_request; + struct mac_learning *ml; /* NULL to act as hub instead of switch. */ + + /* Number of outgoing queued packets on the rconn. */ + struct rconn_packet_counter *queued; + + /* Spanning tree protocol implementation. + * + * We implement STP states by, whenever a port's STP state changes, + * querying all the flows on the switch and then deleting any of them that + * are inappropriate for a port's STP state. */ + long long int next_query; /* Next time at which to query all flows. */ + long long int last_query; /* Last time we sent a query. */ + long long int last_reply; /* Last time we received a query reply. */ + unsigned int port_states[STP_MAX_PORTS]; + uint32_t query_xid; /* XID used for query. */ + int n_flows, n_no_recv, n_no_send; +}; + +/* The log messages here could actually be useful in debugging, so keep the + * rate limit relatively high. */ +static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(30, 300); + +static void queue_tx(struct lswitch *, struct rconn *, struct ofpbuf *); +static void send_features_request(struct lswitch *, struct rconn *); +static void schedule_query(struct lswitch *, long long int delay); +static bool may_learn(const struct lswitch *, uint16_t port_no); +static bool may_recv(const struct lswitch *, uint16_t port_no, + bool any_actions); +static bool may_send(const struct lswitch *, uint16_t port_no); + +typedef void packet_handler_func(struct lswitch *, struct rconn *, void *); +static packet_handler_func process_switch_features; +static packet_handler_func process_packet_in; +static packet_handler_func process_echo_request; +static packet_handler_func process_port_status; +static packet_handler_func process_phy_port; +static packet_handler_func process_stats_reply; + +/* Creates and returns a new learning switch. + * + * If 'learn_macs' is true, the new switch will learn the ports on which MAC + * addresses appear. Otherwise, the new switch will flood all packets. + * + * If 'max_idle' is nonnegative, the new switch will set up flows that expire + * after the given number of seconds (or never expire, if 'max_idle' is + * OFP_FLOW_PERMANENT). Otherwise, the new switch will process every packet. + * + * 'rconn' is used to send out an OpenFlow features request. */ +struct lswitch * +lswitch_create(struct rconn *rconn, bool learn_macs, int max_idle) +{ + struct lswitch *sw; + size_t i; + + sw = xcalloc(1, sizeof *sw); + sw->max_idle = max_idle; + sw->datapath_id = 0; + sw->last_features_request = time_now() - 1; + sw->ml = learn_macs ? mac_learning_create() : NULL; + sw->queued = rconn_packet_counter_create(); + sw->next_query = LLONG_MIN; + sw->last_query = LLONG_MIN; + sw->last_reply = LLONG_MIN; + for (i = 0; i < STP_MAX_PORTS; i++) { + sw->port_states[i] = P_DISABLED; + } + send_features_request(sw, rconn); + return sw; +} + +/* Destroys 'sw'. */ +void +lswitch_destroy(struct lswitch *sw) +{ + if (sw) { + mac_learning_destroy(sw->ml); + rconn_packet_counter_destroy(sw->queued); + free(sw); + } +} + +/* Takes care of necessary 'sw' activity, except for receiving packets (which + * the caller must do). */ +void +lswitch_run(struct lswitch *sw, struct rconn *rconn) +{ + long long int now = time_msec(); + + if (sw->ml) { + mac_learning_run(sw->ml, NULL); + } + + /* If we're waiting for more replies, keeping waiting for up to 10 s. */ + if (sw->last_reply != LLONG_MIN) { + if (now - sw->last_reply > 10000) { + VLOG_ERR_RL(&rl, "%012llx: No more flow stat replies last 10 s", + sw->datapath_id); + sw->last_reply = LLONG_MIN; + sw->last_query = LLONG_MIN; + schedule_query(sw, 0); + } else { + return; + } + } + + /* If we're waiting for any reply at all, keep waiting for up to 10 s. */ + if (sw->last_query != LLONG_MIN) { + if (now - sw->last_query > 10000) { + VLOG_ERR_RL(&rl, "%012llx: No flow stat replies in last 10 s", + sw->datapath_id); + sw->last_query = LLONG_MIN; + schedule_query(sw, 0); + } else { + return; + } + } + + /* If it's time to send another query, do so. */ + if (sw->next_query != LLONG_MIN && now >= sw->next_query) { + sw->next_query = LLONG_MIN; + if (!rconn_is_connected(rconn)) { + schedule_query(sw, 1000); + } else { + struct ofp_stats_request *osr; + struct ofp_flow_stats_request *ofsr; + struct ofpbuf *b; + int error; + + VLOG_DBG("%012llx: Sending flow stats request to implement STP", + sw->datapath_id); + + sw->last_query = now; + sw->query_xid = random_uint32(); + sw->n_flows = 0; + sw->n_no_recv = 0; + sw->n_no_send = 0; + osr = make_openflow_xid(sizeof *osr + sizeof *ofsr, + OFPT_STATS_REQUEST, sw->query_xid, &b); + osr->type = htons(OFPST_FLOW); + osr->flags = htons(0); + ofsr = (struct ofp_flow_stats_request *) osr->body; + ofsr->match.wildcards = htonl(OFPFW_ALL); + ofsr->table_id = 0xff; + ofsr->out_port = htons(OFPP_NONE); + + error = rconn_send(rconn, b, NULL); + if (error) { + VLOG_WARN_RL(&rl, "%012llx: sending flow stats request " + "failed: %s", sw->datapath_id, strerror(error)); + ofpbuf_delete(b); + schedule_query(sw, 1000); + } + } + } +} + +static void +wait_timeout(long long int started) +{ + long long int now = time_msec(); + long long int timeout = 10000 - (now - started); + if (timeout <= 0) { + poll_immediate_wake(); + } else { + poll_timer_wait(timeout); + } +} + +void +lswitch_wait(struct lswitch *sw) +{ + if (sw->ml) { + mac_learning_wait(sw->ml); + } + + if (sw->last_reply != LLONG_MIN) { + wait_timeout(sw->last_reply); + } else if (sw->last_query != LLONG_MIN) { + wait_timeout(sw->last_query); + } +} + +/* Processes 'msg', which should be an OpenFlow received on 'rconn', according + * to the learning switch state in 'sw'. The most likely result of processing + * is that flow-setup and packet-out OpenFlow messages will be sent out on + * 'rconn'. */ +void +lswitch_process_packet(struct lswitch *sw, struct rconn *rconn, + const struct ofpbuf *msg) +{ + struct processor { + uint8_t type; + size_t min_size; + packet_handler_func *handler; + }; + static const struct processor processors[] = { + { + OFPT_ECHO_REQUEST, + sizeof(struct ofp_header), + process_echo_request + }, + { + OFPT_FEATURES_REPLY, + sizeof(struct ofp_switch_features), + process_switch_features + }, + { + OFPT_PACKET_IN, + offsetof(struct ofp_packet_in, data), + process_packet_in + }, + { + OFPT_PORT_STATUS, + sizeof(struct ofp_port_status), + process_port_status + }, + { + OFPT_STATS_REPLY, + offsetof(struct ofp_stats_reply, body), + process_stats_reply + }, + { + OFPT_FLOW_EXPIRED, + sizeof(struct ofp_flow_expired), + NULL + }, + }; + const size_t n_processors = ARRAY_SIZE(processors); + const struct processor *p; + struct ofp_header *oh; + + oh = msg->data; + if (sw->datapath_id == 0 + && oh->type != OFPT_ECHO_REQUEST + && oh->type != OFPT_FEATURES_REPLY) { + send_features_request(sw, rconn); + return; + } + + for (p = processors; p < &processors[n_processors]; p++) { + if (oh->type == p->type) { + if (msg->size < p->min_size) { + VLOG_WARN_RL(&rl, "%012llx: %s: too short (%zu bytes) for " + "type %"PRIu8" (min %zu)", sw->datapath_id, + rconn_get_name(rconn), msg->size, oh->type, + p->min_size); + return; + } + if (p->handler) { + (p->handler)(sw, rconn, msg->data); + } + return; + } + } + if (VLOG_IS_DBG_ENABLED()) { + char *p = ofp_to_string(msg->data, msg->size, 2); + VLOG_DBG_RL(&rl, "%012llx: OpenFlow packet ignored: %s", + sw->datapath_id, p); + free(p); + } +} + +static void +send_features_request(struct lswitch *sw, struct rconn *rconn) +{ + time_t now = time_now(); + if (now >= sw->last_features_request + 1) { + struct ofpbuf *b; + struct ofp_switch_config *osc; + + /* Send OFPT_FEATURES_REQUEST. */ + make_openflow(sizeof(struct ofp_header), OFPT_FEATURES_REQUEST, &b); + queue_tx(sw, rconn, b); + + /* Send OFPT_SET_CONFIG. */ + osc = make_openflow(sizeof *osc, OFPT_SET_CONFIG, &b); + osc->flags = htons(OFPC_SEND_FLOW_EXP); + osc->miss_send_len = htons(OFP_DEFAULT_MISS_SEND_LEN); + queue_tx(sw, rconn, b); + + sw->last_features_request = now; + } +} + +static void +queue_tx(struct lswitch *sw, struct rconn *rconn, struct ofpbuf *b) +{ + int retval = rconn_send_with_limit(rconn, b, sw->queued, 10); + if (retval && retval != ENOTCONN) { + if (retval == EAGAIN) { + VLOG_INFO_RL(&rl, "%012llx: %s: tx queue overflow", + sw->datapath_id, rconn_get_name(rconn)); + } else { + VLOG_WARN_RL(&rl, "%012llx: %s: send: %s", + sw->datapath_id, rconn_get_name(rconn), + strerror(retval)); + } + } +} + +static void +schedule_query(struct lswitch *sw, long long int delay) +{ + long long int now = time_msec(); + if (sw->next_query == LLONG_MIN || sw->next_query > now + delay) { + sw->next_query = now + delay; + } +} + +static void +process_switch_features(struct lswitch *sw, struct rconn *rconn, void *osf_) +{ + struct ofp_switch_features *osf = osf_; + size_t n_ports = ((ntohs(osf->header.length) + - offsetof(struct ofp_switch_features, ports)) + / sizeof *osf->ports); + size_t i; + + sw->datapath_id = ntohll(osf->datapath_id); + sw->capabilities = ntohl(osf->capabilities); + for (i = 0; i < n_ports; i++) { + process_phy_port(sw, rconn, &osf->ports[i]); + } + if (sw->capabilities & OFPC_STP) { + schedule_query(sw, 1000); + } +} + +static void +process_packet_in(struct lswitch *sw, struct rconn *rconn, void *opi_) +{ + struct ofp_packet_in *opi = opi_; + uint16_t in_port = ntohs(opi->in_port); + uint16_t out_port = OFPP_FLOOD; + + size_t pkt_ofs, pkt_len; + struct ofpbuf pkt; + flow_t flow; + + /* Extract flow data from 'opi' into 'flow'. */ + pkt_ofs = offsetof(struct ofp_packet_in, data); + pkt_len = ntohs(opi->header.length) - pkt_ofs; + pkt.data = opi->data; + pkt.size = pkt_len; + flow_extract(&pkt, in_port, &flow); + + if (may_learn(sw, in_port) && sw->ml) { + if (mac_learning_learn(sw->ml, flow.dl_src, 0, in_port)) { + VLOG_DBG_RL(&rl, "%012llx: learned that "ETH_ADDR_FMT" is on " + "port %"PRIu16, sw->datapath_id, + ETH_ADDR_ARGS(flow.dl_src), in_port); + } + } + + if (eth_addr_is_reserved(flow.dl_src)) { + goto drop_it; + } + + if (!may_recv(sw, in_port, false)) { + /* STP prevents receiving anything on this port. */ + goto drop_it; + } + + if (sw->ml) { + int learned_port = mac_learning_lookup(sw->ml, flow.dl_dst, 0); + if (learned_port >= 0 && may_send(sw, learned_port)) { + out_port = learned_port; + } + } + + if (in_port == out_port) { + /* Don't send out packets on their input ports. */ + goto drop_it; + } else if (sw->max_idle >= 0 && (!sw->ml || out_port != OFPP_FLOOD)) { + /* The output port is known, or we always flood everything, so add a + * new flow. */ + queue_tx(sw, rconn, make_add_simple_flow(&flow, ntohl(opi->buffer_id), + out_port, sw->max_idle)); + + /* If the switch didn't buffer the packet, we need to send a copy. */ + if (ntohl(opi->buffer_id) == UINT32_MAX) { + queue_tx(sw, rconn, + make_unbuffered_packet_out(&pkt, in_port, out_port)); + } + } else { + /* We don't know that MAC, or we don't set up flows. Send along the + * packet without setting up a flow. */ + struct ofpbuf *b; + if (ntohl(opi->buffer_id) == UINT32_MAX) { + b = make_unbuffered_packet_out(&pkt, in_port, out_port); + } else { + b = make_buffered_packet_out(ntohl(opi->buffer_id), + in_port, out_port); + } + queue_tx(sw, rconn, b); + } + return; + +drop_it: + if (sw->max_idle >= 0) { + /* Set up a flow to drop packets. */ + queue_tx(sw, rconn, make_add_flow(&flow, ntohl(opi->buffer_id), + sw->max_idle, 0)); + } else { + /* Just drop the packet, since we don't set up flows at all. + * XXX we should send a packet_out with no actions if buffer_id != + * UINT32_MAX, to avoid clogging the kernel buffers. */ + } + return; +} + +static void +process_echo_request(struct lswitch *sw, struct rconn *rconn, void *rq_) +{ + struct ofp_header *rq = rq_; + queue_tx(sw, rconn, make_echo_reply(rq)); +} + +static void +process_port_status(struct lswitch *sw, struct rconn *rconn, void *ops_) +{ + struct ofp_port_status *ops = ops_; + process_phy_port(sw, rconn, &ops->desc); +} + +static void +process_phy_port(struct lswitch *sw, struct rconn *rconn UNUSED, void *opp_) +{ + const struct ofp_phy_port *opp = opp_; + uint16_t port_no = ntohs(opp->port_no); + if (sw->capabilities & OFPC_STP && port_no < STP_MAX_PORTS) { + uint32_t config = ntohl(opp->config); + uint32_t state = ntohl(opp->state); + unsigned int *port_state = &sw->port_states[port_no]; + unsigned int new_port_state; + + if (!(config & (OFPPC_NO_STP | OFPPC_PORT_DOWN)) + && !(state & OFPPS_LINK_DOWN)) + { + switch (state & OFPPS_STP_MASK) { + case OFPPS_STP_LISTEN: + new_port_state = P_LISTENING; + break; + case OFPPS_STP_LEARN: + new_port_state = P_LEARNING; + break; + case OFPPS_STP_FORWARD: + new_port_state = P_FORWARDING; + break; + case OFPPS_STP_BLOCK: + new_port_state = P_BLOCKING; + break; + default: + new_port_state = P_DISABLED; + break; + } + } else { + new_port_state = P_FORWARDING; + } + if (*port_state != new_port_state) { + *port_state = new_port_state; + schedule_query(sw, 1000); + } + } +} + +static unsigned int +get_port_state(const struct lswitch *sw, uint16_t port_no) +{ + return (port_no >= STP_MAX_PORTS || !(sw->capabilities & OFPC_STP) + ? P_FORWARDING + : sw->port_states[port_no]); +} + +static bool +may_learn(const struct lswitch *sw, uint16_t port_no) +{ + return get_port_state(sw, port_no) & (P_LEARNING | P_FORWARDING); +} + +static bool +may_recv(const struct lswitch *sw, uint16_t port_no, bool any_actions) +{ + unsigned int state = get_port_state(sw, port_no); + return !(any_actions + ? state & (P_DISABLED | P_LISTENING | P_BLOCKING) + : state & (P_DISABLED | P_LISTENING | P_BLOCKING | P_LEARNING)); +} + +static bool +may_send(const struct lswitch *sw, uint16_t port_no) +{ + return get_port_state(sw, port_no) & P_FORWARDING; +} + +static void +process_flow_stats(struct lswitch *sw, struct rconn *rconn, + const struct ofp_flow_stats *ofs) +{ + const char *end = (char *) ofs + ntohs(ofs->length); + bool delete = false; + + /* Decide to delete the flow if it matches on an STP-disabled physical + * port. But don't delete it if the flow just drops all received packets, + * because that's a perfectly reasonable thing to do for disabled physical + * ports. */ + if (!(ofs->match.wildcards & htonl(OFPFW_IN_PORT))) { + if (!may_recv(sw, ntohs(ofs->match.in_port), + end > (char *) ofs->actions)) { + delete = true; + sw->n_no_recv++; + } + } + + /* Decide to delete the flow if it forwards to an STP-disabled physical + * port. */ + if (!delete) { + const struct ofp_action_header *a; + size_t len; + + for (a = ofs->actions; (char *) a < end; a += len / 8) { + len = ntohs(a->len); + if (len > end - (char *) a) { + VLOG_DBG_RL(&rl, "%012llx: action exceeds available space " + "(%zu > %td)", + sw->datapath_id, len, end - (char *) a); + break; + } else if (len % 8) { + VLOG_DBG_RL(&rl, "%012llx: action length (%zu) not multiple " + "of 8 bytes", sw->datapath_id, len); + break; + } + + if (a->type == htons(OFPAT_OUTPUT)) { + struct ofp_action_output *oao = (struct ofp_action_output *) a; + if (!may_send(sw, ntohs(oao->port))) { + delete = true; + sw->n_no_send++; + break; + } + } + } + } + + /* Delete the flow. */ + if (delete) { + struct ofp_flow_mod *ofm; + struct ofpbuf *b; + + ofm = make_openflow(offsetof(struct ofp_flow_mod, actions), + OFPT_FLOW_MOD, &b); + ofm->match = ofs->match; + ofm->command = OFPFC_DELETE_STRICT; + rconn_send(rconn, b, NULL); + } +} + +static void +process_stats_reply(struct lswitch *sw, struct rconn *rconn, void *osr_) +{ + struct ofp_stats_reply *osr = osr_; + struct flow_stats_iterator i; + const struct ofp_flow_stats *fs; + + if (sw->last_query == LLONG_MIN + || osr->type != htons(OFPST_FLOW) + || osr->header.xid != sw->query_xid) { + return; + } + for (fs = flow_stats_first(&i, osr); fs; fs = flow_stats_next(&i)) { + sw->n_flows++; + process_flow_stats(sw, rconn, fs); + } + if (!(osr->flags & htons(OFPSF_REPLY_MORE))) { + VLOG_DBG("%012llx: Deleted %d of %d received flows to " + "implement STP, %d because of no-recv, %d because of " + "no-send", sw->datapath_id, + sw->n_no_recv + sw->n_no_send, sw->n_flows, + sw->n_no_recv, sw->n_no_send); + sw->last_query = LLONG_MIN; + sw->last_reply = LLONG_MIN; + } else { + sw->last_reply = time_msec(); + } +} + |