/usr/src/openvswitch-1.4.0/lib/cfm.c is in openvswitch-datapath-dkms 1.4.0-1ubuntu1.
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* Copyright (c) 2010, 2011 Nicira Networks.
*
* 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 "cfm.h"
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "byte-order.h"
#include "dynamic-string.h"
#include "flow.h"
#include "hash.h"
#include "hmap.h"
#include "ofpbuf.h"
#include "packets.h"
#include "poll-loop.h"
#include "timer.h"
#include "timeval.h"
#include "unixctl.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(cfm);
#define CFM_MAX_RMPS 256
/* Ethernet destination address of CCM packets. */
static const uint8_t eth_addr_ccm[6] = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x30 };
static const uint8_t eth_addr_ccm_x[6] = {
0x01, 0x23, 0x20, 0x00, 0x00, 0x30
};
#define ETH_TYPE_CFM 0x8902
/* A 'ccm' represents a Continuity Check Message from the 802.1ag
* specification. Continuity Check Messages are broadcast periodically so that
* hosts can determine whom they have connectivity to.
*
* The minimum length of a CCM as specified by IEEE 802.1ag is 75 bytes.
* Previous versions of Open vSwitch generated 74-byte CCM messages, so we
* accept such messages too. */
#define CCM_LEN 75
#define CCM_ACCEPT_LEN 74
#define CCM_MAID_LEN 48
#define CCM_OPCODE 1 /* CFM message opcode meaning CCM. */
#define CCM_RDI_MASK 0x80
struct ccm {
uint8_t mdlevel_version; /* MD Level and Version */
uint8_t opcode;
uint8_t flags;
uint8_t tlv_offset;
ovs_be32 seq;
ovs_be16 mpid;
uint8_t maid[CCM_MAID_LEN];
/* Defined by ITU-T Y.1731 should be zero */
ovs_be16 interval_ms_x; /* Transmission interval in ms. */
ovs_be64 mpid64; /* MPID in extended mode. */
uint8_t opdown; /* Operationally down. */
uint8_t zero[5];
/* TLV space. */
uint8_t end_tlv;
} __attribute__((packed));
BUILD_ASSERT_DECL(CCM_LEN == sizeof(struct ccm));
struct cfm {
char *name; /* Name of this CFM object. */
struct hmap_node hmap_node; /* Node in all_cfms list. */
uint64_t mpid;
bool extended; /* Extended mode. */
bool fault; /* Indicates connectivity fault. */
bool unexpected_recv; /* Received an unexpected CCM. */
bool opup; /* Operational State. */
bool remote_opup; /* Remote Operational State. */
uint32_t seq; /* The sequence number of our last CCM. */
uint8_t ccm_interval; /* The CCM transmission interval. */
int ccm_interval_ms; /* 'ccm_interval' in milliseconds. */
uint16_t ccm_vlan; /* Vlan tag of CCM PDUs. */
uint8_t maid[CCM_MAID_LEN]; /* The MAID of this CFM. */
struct timer tx_timer; /* Send CCM when expired. */
struct timer fault_timer; /* Check for faults when expired. */
struct hmap remote_mps; /* Remote MPs. */
/* Result of cfm_get_remote_mpids(). Updated only during fault check to
* avoid flapping. */
uint64_t *rmps_array; /* Cache of remote_mps. */
size_t rmps_array_len; /* Number of rmps in 'rmps_array'. */
};
/* Remote MPs represent foreign network entities that are configured to have
* the same MAID as this CFM instance. */
struct remote_mp {
uint64_t mpid; /* The Maintenance Point ID of this 'remote_mp'. */
struct hmap_node node; /* Node in 'remote_mps' map. */
bool recv; /* CCM was received since last fault check. */
bool rdi; /* Remote Defect Indicator. Indicates remote_mp isn't
receiving CCMs that it's expecting to. */
bool opup; /* Operational State. */
};
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
static struct hmap all_cfms = HMAP_INITIALIZER(&all_cfms);
static void cfm_unixctl_show(struct unixctl_conn *, const char *args,
void *aux);
static const uint8_t *
cfm_ccm_addr(const struct cfm *cfm)
{
return cfm->extended ? eth_addr_ccm_x : eth_addr_ccm;
}
static void
cfm_generate_maid(struct cfm *cfm)
{
const char *ovs_md_name = "ovs";
const char *ovs_ma_name = "ovs";
uint8_t *ma_p;
size_t md_len, ma_len;
memset(cfm->maid, 0, CCM_MAID_LEN);
md_len = strlen(ovs_md_name);
ma_len = strlen(ovs_ma_name);
assert(md_len && ma_len && md_len + ma_len + 4 <= CCM_MAID_LEN);
cfm->maid[0] = 4; /* MD name string format. */
cfm->maid[1] = md_len; /* MD name size. */
memcpy(&cfm->maid[2], ovs_md_name, md_len); /* MD name. */
ma_p = cfm->maid + 2 + md_len;
ma_p[0] = 2; /* MA name string format. */
ma_p[1] = ma_len; /* MA name size. */
memcpy(&ma_p[2], ovs_ma_name, ma_len); /* MA name. */
}
static int
ccm_interval_to_ms(uint8_t interval)
{
switch (interval) {
case 0: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
case 1: return 3; /* Not recommended due to timer resolution. */
case 2: return 10; /* Not recommended due to timer resolution. */
case 3: return 100;
case 4: return 1000;
case 5: return 10000;
case 6: return 60000;
case 7: return 600000;
default: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
}
NOT_REACHED();
}
static long long int
cfm_fault_interval(struct cfm *cfm)
{
/* According to the 802.1ag specification we should assume every other MP
* with the same MAID has the same transmission interval that we have. If
* an MP has a different interval, cfm_process_heartbeat will register it
* as a fault (likely due to a configuration error). Thus we can check all
* MPs at once making this quite a bit simpler.
*
* According to the specification we should check when (ccm_interval_ms *
* 3.5)ms have passed. */
return (cfm->ccm_interval_ms * 7) / 2;
}
static uint8_t
ms_to_ccm_interval(int interval_ms)
{
uint8_t i;
for (i = 7; i > 0; i--) {
if (ccm_interval_to_ms(i) <= interval_ms) {
return i;
}
}
return 1;
}
static uint32_t
hash_mpid(uint64_t mpid)
{
return hash_bytes(&mpid, sizeof mpid, 0);
}
static bool
cfm_is_valid_mpid(bool extended, uint64_t mpid)
{
/* 802.1ag specification requires MPIDs to be within the range [1, 8191].
* In extended mode we relax this requirement. */
return mpid >= 1 && (extended || mpid <= 8191);
}
static struct remote_mp *
lookup_remote_mp(const struct cfm *cfm, uint64_t mpid)
{
struct remote_mp *rmp;
HMAP_FOR_EACH_IN_BUCKET (rmp, node, hash_mpid(mpid), &cfm->remote_mps) {
if (rmp->mpid == mpid) {
return rmp;
}
}
return NULL;
}
void
cfm_init(void)
{
unixctl_command_register("cfm/show", "[interface]", cfm_unixctl_show,
NULL);
}
/* Allocates a 'cfm' object called 'name'. 'cfm' should be initialized by
* cfm_configure() before use. */
struct cfm *
cfm_create(const char *name)
{
struct cfm *cfm;
cfm = xzalloc(sizeof *cfm);
cfm->name = xstrdup(name);
hmap_init(&cfm->remote_mps);
cfm_generate_maid(cfm);
hmap_insert(&all_cfms, &cfm->hmap_node, hash_string(cfm->name, 0));
cfm->remote_opup = true;
return cfm;
}
void
cfm_destroy(struct cfm *cfm)
{
struct remote_mp *rmp, *rmp_next;
if (!cfm) {
return;
}
HMAP_FOR_EACH_SAFE (rmp, rmp_next, node, &cfm->remote_mps) {
hmap_remove(&cfm->remote_mps, &rmp->node);
free(rmp);
}
hmap_destroy(&cfm->remote_mps);
hmap_remove(&all_cfms, &cfm->hmap_node);
free(cfm->rmps_array);
free(cfm->name);
free(cfm);
}
/* Should be run periodically to update fault statistics messages. */
void
cfm_run(struct cfm *cfm)
{
if (timer_expired(&cfm->fault_timer)) {
long long int interval = cfm_fault_interval(cfm);
struct remote_mp *rmp, *rmp_next;
cfm->fault = cfm->unexpected_recv;
cfm->unexpected_recv = false;
cfm->rmps_array_len = 0;
free(cfm->rmps_array);
cfm->rmps_array = xmalloc(hmap_count(&cfm->remote_mps) *
sizeof *cfm->rmps_array);
cfm->remote_opup = true;
HMAP_FOR_EACH_SAFE (rmp, rmp_next, node, &cfm->remote_mps) {
if (!rmp->recv) {
VLOG_DBG("%s: no CCM from RMP %"PRIu64" in the last %lldms",
cfm->name, rmp->mpid, interval);
hmap_remove(&cfm->remote_mps, &rmp->node);
free(rmp);
} else {
rmp->recv = false;
if (rmp->mpid == cfm->mpid) {
VLOG_WARN_RL(&rl,"%s: received CCM with local MPID"
" %"PRIu64, cfm->name, rmp->mpid);
cfm->fault = true;
}
if (rmp->rdi) {
VLOG_DBG("%s: RDI bit flagged from RMP %"PRIu64, cfm->name,
rmp->mpid);
cfm->fault = true;
}
if (!rmp->opup) {
cfm->remote_opup = rmp->opup;
}
cfm->rmps_array[cfm->rmps_array_len++] = rmp->mpid;
}
}
if (hmap_is_empty(&cfm->remote_mps)) {
cfm->fault = true;
}
timer_set_duration(&cfm->fault_timer, interval);
}
}
/* Should be run periodically to check if the CFM module has a CCM message it
* wishes to send. */
bool
cfm_should_send_ccm(struct cfm *cfm)
{
return timer_expired(&cfm->tx_timer);
}
/* Composes a CCM message into 'packet'. Messages generated with this function
* should be sent whenever cfm_should_send_ccm() indicates. */
void
cfm_compose_ccm(struct cfm *cfm, struct ofpbuf *packet,
uint8_t eth_src[ETH_ADDR_LEN])
{
struct ccm *ccm;
timer_set_duration(&cfm->tx_timer, cfm->ccm_interval_ms);
eth_compose(packet, cfm_ccm_addr(cfm), eth_src, ETH_TYPE_CFM, sizeof *ccm);
if (cfm->ccm_vlan) {
eth_push_vlan(packet, htons(cfm->ccm_vlan));
}
ccm = packet->l3;
ccm->mdlevel_version = 0;
ccm->opcode = CCM_OPCODE;
ccm->tlv_offset = 70;
ccm->seq = htonl(++cfm->seq);
ccm->flags = cfm->ccm_interval;
memcpy(ccm->maid, cfm->maid, sizeof ccm->maid);
memset(ccm->zero, 0, sizeof ccm->zero);
ccm->end_tlv = 0;
if (cfm->extended) {
ccm->mpid = htons(hash_mpid(cfm->mpid));
ccm->mpid64 = htonll(cfm->mpid);
ccm->opdown = !cfm->opup;
} else {
ccm->mpid = htons(cfm->mpid);
ccm->mpid64 = htonll(0);
ccm->opdown = 0;
}
if (cfm->ccm_interval == 0) {
assert(cfm->extended);
ccm->interval_ms_x = htons(cfm->ccm_interval_ms);
}
if (hmap_is_empty(&cfm->remote_mps)) {
ccm->flags |= CCM_RDI_MASK;
}
}
void
cfm_wait(struct cfm *cfm)
{
timer_wait(&cfm->tx_timer);
timer_wait(&cfm->fault_timer);
}
/* Configures 'cfm' with settings from 's'. */
bool
cfm_configure(struct cfm *cfm, const struct cfm_settings *s)
{
uint8_t interval;
int interval_ms;
if (!cfm_is_valid_mpid(s->extended, s->mpid) || s->interval <= 0) {
return false;
}
cfm->mpid = s->mpid;
cfm->extended = s->extended;
cfm->opup = s->opup;
interval = ms_to_ccm_interval(s->interval);
interval_ms = ccm_interval_to_ms(interval);
cfm->ccm_vlan = s->ccm_vlan & VLAN_VID_MASK;
if (cfm->extended && interval_ms != s->interval) {
interval = 0;
interval_ms = MIN(s->interval, UINT16_MAX);
}
if (interval != cfm->ccm_interval || interval_ms != cfm->ccm_interval_ms) {
cfm->ccm_interval = interval;
cfm->ccm_interval_ms = interval_ms;
timer_set_expired(&cfm->tx_timer);
timer_set_duration(&cfm->fault_timer, cfm_fault_interval(cfm));
}
return true;
}
/* Returns true if 'cfm' should process packets from 'flow'. */
bool
cfm_should_process_flow(const struct cfm *cfm, const struct flow *flow)
{
return (ntohs(flow->dl_type) == ETH_TYPE_CFM
&& eth_addr_equals(flow->dl_dst, cfm_ccm_addr(cfm)));
}
/* Updates internal statistics relevant to packet 'p'. Should be called on
* every packet whose flow returned true when passed to
* cfm_should_process_flow. */
void
cfm_process_heartbeat(struct cfm *cfm, const struct ofpbuf *p)
{
struct ccm *ccm;
struct eth_header *eth;
eth = p->l2;
ccm = ofpbuf_at(p, (uint8_t *)p->l3 - (uint8_t *)p->data, CCM_ACCEPT_LEN);
if (!ccm) {
VLOG_INFO_RL(&rl, "%s: Received an unparseable 802.1ag CCM heartbeat.",
cfm->name);
return;
}
if (ccm->opcode != CCM_OPCODE) {
VLOG_INFO_RL(&rl, "%s: Received an unsupported 802.1ag message. "
"(opcode %u)", cfm->name, ccm->opcode);
return;
}
/* According to the 802.1ag specification, reception of a CCM with an
* incorrect ccm_interval, unexpected MAID, or unexpected MPID should
* trigger a fault. We ignore this requirement for several reasons.
*
* Faults can cause a controller or Open vSwitch to make potentially
* expensive changes to the network topology. It seems prudent to trigger
* them judiciously, especially when CFM is used to check slave status of
* bonds. Furthermore, faults can be maliciously triggered by crafting
* invalid CCMs. */
if (memcmp(ccm->maid, cfm->maid, sizeof ccm->maid)) {
cfm->unexpected_recv = true;
VLOG_WARN_RL(&rl, "%s: Received unexpected remote MAID from MAC "
ETH_ADDR_FMT, cfm->name, ETH_ADDR_ARGS(eth->eth_src));
} else {
uint8_t ccm_interval = ccm->flags & 0x7;
bool ccm_rdi = ccm->flags & CCM_RDI_MASK;
uint16_t ccm_interval_ms_x = ntohs(ccm->interval_ms_x);
struct remote_mp *rmp;
uint64_t ccm_mpid;
bool ccm_opdown;
if (cfm->extended) {
ccm_mpid = ntohll(ccm->mpid64);
ccm_opdown = ccm->opdown;
} else {
ccm_mpid = ntohs(ccm->mpid);
ccm_opdown = false;
}
if (ccm_interval != cfm->ccm_interval) {
VLOG_WARN_RL(&rl, "%s: received a CCM with an invalid interval"
" (%"PRIu8") from RMP %"PRIu64, cfm->name,
ccm_interval, ccm_mpid);
}
if (cfm->extended && ccm_interval == 0
&& ccm_interval_ms_x != cfm->ccm_interval_ms) {
VLOG_WARN_RL(&rl, "%s: received a CCM with an invalid extended"
" interval (%"PRIu16"ms) from RMP %"PRIu64, cfm->name,
ccm_interval_ms_x, ccm_mpid);
}
rmp = lookup_remote_mp(cfm, ccm_mpid);
if (!rmp) {
if (hmap_count(&cfm->remote_mps) < CFM_MAX_RMPS) {
rmp = xmalloc(sizeof *rmp);
hmap_insert(&cfm->remote_mps, &rmp->node, hash_mpid(ccm_mpid));
} else {
cfm->unexpected_recv = true;
VLOG_WARN_RL(&rl,
"%s: dropped CCM with MPID %"PRIu64" from MAC "
ETH_ADDR_FMT, cfm->name, ccm_mpid,
ETH_ADDR_ARGS(eth->eth_src));
}
}
if (rmp) {
rmp->mpid = ccm_mpid;
rmp->recv = true;
rmp->rdi = ccm_rdi;
rmp->opup = !ccm_opdown;
}
VLOG_DBG("%s: received CCM (seq %"PRIu32") (mpid %"PRIu64")"
" (interval %"PRIu8") (RDI %s)", cfm->name, ntohl(ccm->seq),
ccm_mpid, ccm_interval, ccm_rdi ? "true" : "false");
}
}
/* Gets the fault status of 'cfm'. Returns true when 'cfm' has detected
* connectivity problems, false otherwise. */
bool
cfm_get_fault(const struct cfm *cfm)
{
return cfm->fault;
}
/* Gets the operational state of 'cfm'. 'cfm' is considered operationally down
* if it has received a CCM with the operationally down bit set from any of its
* remote maintenance points. Returns true if 'cfm' is operationally up. False
* otherwise. */
bool
cfm_get_opup(const struct cfm *cfm)
{
return cfm->remote_opup;
}
/* Populates 'rmps' with an array of remote maintenance points reachable by
* 'cfm'. The number of remote maintenance points is written to 'n_rmps'.
* 'cfm' retains ownership of the array written to 'rmps' */
void
cfm_get_remote_mpids(const struct cfm *cfm, const uint64_t **rmps,
size_t *n_rmps)
{
*rmps = cfm->rmps_array;
*n_rmps = cfm->rmps_array_len;
}
static struct cfm *
cfm_find(const char *name)
{
struct cfm *cfm;
HMAP_FOR_EACH_WITH_HASH (cfm, hmap_node, hash_string(name, 0), &all_cfms) {
if (!strcmp(cfm->name, name)) {
return cfm;
}
}
return NULL;
}
static void
cfm_print_details(struct ds *ds, const struct cfm *cfm)
{
struct remote_mp *rmp;
ds_put_format(ds, "---- %s ----\n", cfm->name);
ds_put_format(ds, "MPID %"PRIu64":%s%s%s\n", cfm->mpid,
cfm->extended ? " extended" : "",
cfm->fault ? " fault" : "",
cfm->unexpected_recv ? " unexpected_recv" : "");
ds_put_format(ds, "\topstate: %s\n", cfm->opup ? "up" : "down");
ds_put_format(ds, "\tremote_opstate: %s\n",
cfm->remote_opup ? "up" : "down");
ds_put_format(ds, "\tinterval: %dms\n", cfm->ccm_interval_ms);
ds_put_format(ds, "\tnext CCM tx: %lldms\n",
timer_msecs_until_expired(&cfm->tx_timer));
ds_put_format(ds, "\tnext fault check: %lldms\n",
timer_msecs_until_expired(&cfm->fault_timer));
HMAP_FOR_EACH (rmp, node, &cfm->remote_mps) {
ds_put_format(ds, "Remote MPID %"PRIu64":%s\n",
rmp->mpid,
rmp->rdi ? " rdi" : "");
ds_put_format(ds, "\trecv since check: %s\n",
rmp->recv ? "true" : "false");
ds_put_format(ds, "\topstate: %s\n", rmp->opup? "up" : "down");
}
}
static void
cfm_unixctl_show(struct unixctl_conn *conn,
const char *args, void *aux OVS_UNUSED)
{
struct ds ds = DS_EMPTY_INITIALIZER;
const struct cfm *cfm;
if (strlen(args)) {
cfm = cfm_find(args);
if (!cfm) {
unixctl_command_reply(conn, 501, "no such CFM object");
return;
}
cfm_print_details(&ds, cfm);
} else {
HMAP_FOR_EACH (cfm, hmap_node, &all_cfms) {
cfm_print_details(&ds, cfm);
}
}
unixctl_command_reply(conn, 200, ds_cstr(&ds));
ds_destroy(&ds);
}
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