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|
// SPDX-License-Identifier: GPL-2.0-or-later
/**
* bfd.c: BFD handling routines
*
* @copyright Copyright (C) 2015 Cumulus Networks, Inc.
*/
#include <zebra.h>
#include "command.h"
#include "memory.h"
#include "prefix.h"
#include "frrevent.h"
#include "stream.h"
#include "vrf.h"
#include "zclient.h"
#include "libfrr.h"
#include "table.h"
#include "vty.h"
#include "bfd.h"
DEFINE_MTYPE_STATIC(LIB, BFD_INFO, "BFD info");
DEFINE_MTYPE_STATIC(LIB, BFD_SOURCE, "BFD source cache");
/**
* BFD protocol integration configuration.
*/
/** Events definitions. */
enum bfd_session_event {
/** Remove the BFD session configuration. */
BSE_UNINSTALL,
/** Install the BFD session configuration. */
BSE_INSTALL,
};
/**
* BFD source selection result cache.
*
* This structure will keep track of the result based on the destination
* prefix. When the result changes all related BFD sessions with automatic
* source will be updated.
*/
struct bfd_source_cache {
/** Address VRF belongs. */
vrf_id_t vrf_id;
/** Destination network address. */
struct prefix address;
/** Source selected. */
struct prefix source;
/** Is the source address valid? */
bool valid;
/** BFD sessions using this. */
size_t refcount;
SLIST_ENTRY(bfd_source_cache) entry;
};
SLIST_HEAD(bfd_source_list, bfd_source_cache);
/**
* Data structure to do the necessary tricks to hide the BFD protocol
* integration internals.
*/
struct bfd_session_params {
/** Contains the session parameters and more. */
struct bfd_session_arg args;
/** Contains the session state. */
struct bfd_session_status bss;
/** Protocol implementation status update callback. */
bsp_status_update updatecb;
/** Protocol implementation custom data pointer. */
void *arg;
/**
* Next event.
*
* This variable controls what action to execute when the command batch
* finishes. Normally we'd use `event_add_event` value, however since
* that function is going to be called multiple times and the value
* might be different we'll use this variable to keep track of it.
*/
enum bfd_session_event lastev;
/**
* BFD session configuration event.
*
* Multiple actions might be asked during a command batch (either via
* configuration load or northbound batch), so we'll use this to
* install/uninstall the BFD session parameters only once.
*/
struct event *installev;
/** BFD session installation state. */
bool installed;
/** Automatic source selection. */
bool auto_source;
/** Currently selected source. */
struct bfd_source_cache *source_cache;
/** Global BFD paramaters list. */
TAILQ_ENTRY(bfd_session_params) entry;
};
struct bfd_sessions_global {
/**
* Global BFD session parameters list for (re)installation and update
* without code duplication among daemons.
*/
TAILQ_HEAD(bsplist, bfd_session_params) bsplist;
/** BFD automatic source selection cache. */
struct bfd_source_list source_list;
/** Pointer to FRR's event manager. */
struct event_loop *tm;
/** Pointer to zebra client data structure. */
struct zclient *zc;
/** Debugging state. */
bool debugging;
/** Is shutting down? */
bool shutting_down;
};
/** Global configuration variable. */
static struct bfd_sessions_global bsglobal;
/** Global empty address for IPv4/IPv6. */
static const struct in6_addr i6a_zero;
/*
* Prototypes
*/
static void bfd_source_cache_get(struct bfd_session_params *session);
static void bfd_source_cache_put(struct bfd_session_params *session);
/*
* bfd_get_peer_info - Extract the Peer information for which the BFD session
* went down from the message sent from Zebra to clients.
*/
static struct interface *bfd_get_peer_info(struct stream *s, struct prefix *dp,
struct prefix *sp, int *status,
int *remote_cbit, vrf_id_t vrf_id)
{
unsigned int ifindex;
struct interface *ifp = NULL;
int plen;
int local_remote_cbit;
/*
* If the ifindex lookup fails the
* rest of the data in the stream is
* not read. All examples of this function
* call immediately use the dp->family which
* is not good. Ensure we are not using
* random data
*/
memset(dp, 0, sizeof(*dp));
memset(sp, 0, sizeof(*sp));
/* Get interface index. */
STREAM_GETL(s, ifindex);
/* Lookup index. */
if (ifindex != 0) {
ifp = if_lookup_by_index(ifindex, vrf_id);
if (ifp == NULL) {
if (bsglobal.debugging)
zlog_debug(
"%s: Can't find interface by ifindex: %d ",
__func__, ifindex);
return NULL;
}
}
/* Fetch destination address. */
STREAM_GETC(s, dp->family);
plen = prefix_blen(dp);
STREAM_GET(&dp->u.prefix, s, plen);
STREAM_GETC(s, dp->prefixlen);
/* Get BFD status. */
STREAM_GETL(s, (*status));
STREAM_GETC(s, sp->family);
plen = prefix_blen(sp);
STREAM_GET(&sp->u.prefix, s, plen);
STREAM_GETC(s, sp->prefixlen);
STREAM_GETC(s, local_remote_cbit);
if (remote_cbit)
*remote_cbit = local_remote_cbit;
return ifp;
stream_failure:
/*
* Clean dp and sp because caller
* will immediately check them valid or not
*/
memset(dp, 0, sizeof(*dp));
memset(sp, 0, sizeof(*sp));
return NULL;
}
/*
* bfd_get_status_str - Convert BFD status to a display string.
*/
const char *bfd_get_status_str(int status)
{
switch (status) {
case BFD_STATUS_DOWN:
return "Down";
case BFD_STATUS_UP:
return "Up";
case BFD_STATUS_ADMIN_DOWN:
return "Admin Down";
case BFD_STATUS_UNKNOWN:
default:
return "Unknown";
}
}
/*
* bfd_last_update - Calculate the last BFD update time and convert it
* into a dd:hh:mm:ss display format.
*/
static void bfd_last_update(time_t last_update, char *buf, size_t len)
{
time_t curr;
time_t diff;
struct tm tm;
struct timeval tv;
/* If no BFD status update has ever been received, print `never'. */
if (last_update == 0) {
snprintf(buf, len, "never");
return;
}
/* Get current time. */
monotime(&tv);
curr = tv.tv_sec;
diff = curr - last_update;
gmtime_r(&diff, &tm);
snprintf(buf, len, "%d:%02d:%02d:%02d", tm.tm_yday, tm.tm_hour,
tm.tm_min, tm.tm_sec);
}
/*
* bfd_client_sendmsg - Format and send a client register
* command to Zebra to be forwarded to BFD
*/
void bfd_client_sendmsg(struct zclient *zclient, int command,
vrf_id_t vrf_id)
{
struct stream *s;
enum zclient_send_status ret;
/* Check socket. */
if (!zclient || zclient->sock < 0) {
if (bsglobal.debugging)
zlog_debug(
"%s: Can't send BFD client register, Zebra client not established",
__func__);
return;
}
s = zclient->obuf;
stream_reset(s);
zclient_create_header(s, command, vrf_id);
stream_putl(s, getpid());
stream_putw_at(s, 0, stream_get_endp(s));
ret = zclient_send_message(zclient);
if (ret == ZCLIENT_SEND_FAILURE) {
if (bsglobal.debugging)
zlog_debug(
"%s: %ld: zclient_send_message() failed",
__func__, (long)getpid());
return;
}
return;
}
int zclient_bfd_command(struct zclient *zc, struct bfd_session_arg *args)
{
struct stream *s;
size_t addrlen;
/* Individual reg/dereg messages are suppressed during shutdown. */
if (bsglobal.shutting_down) {
if (bsglobal.debugging)
zlog_debug(
"%s: Suppressing BFD peer reg/dereg messages",
__func__);
return -1;
}
/* Check socket. */
if (!zc || zc->sock < 0) {
if (bsglobal.debugging)
zlog_debug("%s: zclient unavailable", __func__);
return -1;
}
s = zc->obuf;
stream_reset(s);
/* Create new message. */
zclient_create_header(s, args->command, args->vrf_id);
stream_putl(s, getpid());
/* Encode destination address. */
stream_putw(s, args->family);
addrlen = (args->family == AF_INET) ? sizeof(struct in_addr)
: sizeof(struct in6_addr);
stream_put(s, &args->dst, addrlen);
/*
* For more BFD integration protocol details, see function
* `_ptm_msg_read` in `bfdd/ptm_adapter.c`.
*/
#if HAVE_BFDD > 0
/* Session timers. */
stream_putl(s, args->min_rx);
stream_putl(s, args->min_tx);
stream_putc(s, args->detection_multiplier);
/* Is multi hop? */
stream_putc(s, args->mhop != 0);
/* Source address. */
stream_putw(s, args->family);
stream_put(s, &args->src, addrlen);
/* Send the expected hops. */
stream_putc(s, args->hops);
/* Send interface name if any. */
if (args->mhop) {
/* Don't send interface. */
stream_putc(s, 0);
if (bsglobal.debugging && args->ifnamelen)
zlog_debug("%s: multi hop is configured, not sending interface",
__func__);
} else {
stream_putc(s, args->ifnamelen);
if (args->ifnamelen)
stream_put(s, args->ifname, args->ifnamelen);
}
/* Send the C bit indicator. */
stream_putc(s, args->cbit);
/* Send profile name if any. */
stream_putc(s, args->profilelen);
if (args->profilelen)
stream_put(s, args->profile, args->profilelen);
#else /* PTM BFD */
/* Encode timers if this is a registration message. */
if (args->command != ZEBRA_BFD_DEST_DEREGISTER) {
stream_putl(s, args->min_rx);
stream_putl(s, args->min_tx);
stream_putc(s, args->detection_multiplier);
}
if (args->mhop) {
/* Multi hop indicator. */
stream_putc(s, 1);
/* Multi hop always sends the source address. */
stream_putw(s, args->family);
stream_put(s, &args->src, addrlen);
/* Send the expected hops. */
stream_putc(s, args->hops);
} else {
/* Multi hop indicator. */
stream_putc(s, 0);
/* Single hop only sends the source address when IPv6. */
if (args->family == AF_INET6) {
stream_putw(s, args->family);
stream_put(s, &args->src, addrlen);
}
/* Send interface name if any. */
stream_putc(s, args->ifnamelen);
if (args->ifnamelen)
stream_put(s, args->ifname, args->ifnamelen);
}
/* Send the C bit indicator. */
stream_putc(s, args->cbit);
#endif /* HAVE_BFDD */
/* Finish the message by writing the size. */
stream_putw_at(s, 0, stream_get_endp(s));
/* Send message to zebra. */
if (zclient_send_message(zc) == ZCLIENT_SEND_FAILURE) {
if (bsglobal.debugging)
zlog_debug("%s: zclient_send_message failed", __func__);
return -1;
}
return 0;
}
struct bfd_session_params *bfd_sess_new(bsp_status_update updatecb, void *arg)
{
struct bfd_session_params *bsp;
bsp = XCALLOC(MTYPE_BFD_INFO, sizeof(*bsp));
/* Save application data. */
bsp->updatecb = updatecb;
bsp->arg = arg;
/* Set defaults. */
bsp->args.detection_multiplier = BFD_DEF_DETECT_MULT;
bsp->args.hops = 1;
bsp->args.min_rx = BFD_DEF_MIN_RX;
bsp->args.min_tx = BFD_DEF_MIN_TX;
bsp->args.vrf_id = VRF_DEFAULT;
/* Register in global list. */
TAILQ_INSERT_TAIL(&bsglobal.bsplist, bsp, entry);
return bsp;
}
static bool _bfd_sess_valid(const struct bfd_session_params *bsp)
{
/* Peer/local address not configured. */
if (bsp->args.family == 0)
return false;
/* Address configured but invalid. */
if (bsp->args.family != AF_INET && bsp->args.family != AF_INET6) {
if (bsglobal.debugging)
zlog_debug("%s: invalid session family: %d", __func__,
bsp->args.family);
return false;
}
/* Invalid address. */
if (memcmp(&bsp->args.dst, &i6a_zero, sizeof(i6a_zero)) == 0) {
if (bsglobal.debugging) {
if (bsp->args.family == AF_INET)
zlog_debug("%s: invalid address: %pI4",
__func__,
(struct in_addr *)&bsp->args.dst);
else
zlog_debug("%s: invalid address: %pI6",
__func__, &bsp->args.dst);
}
return false;
}
/* Multi hop requires local address. */
if (bsp->args.mhop
&& memcmp(&i6a_zero, &bsp->args.src, sizeof(i6a_zero)) == 0) {
if (bsglobal.debugging)
zlog_debug(
"%s: multi hop but no local address provided",
__func__);
return false;
}
/* Check VRF ID. */
if (bsp->args.vrf_id == VRF_UNKNOWN) {
if (bsglobal.debugging)
zlog_debug("%s: asked for unknown VRF", __func__);
return false;
}
return true;
}
static void _bfd_sess_send(struct event *t)
{
struct bfd_session_params *bsp = EVENT_ARG(t);
int rv;
/* Validate configuration before trying to send bogus data. */
if (!_bfd_sess_valid(bsp))
return;
if (bsp->lastev == BSE_INSTALL) {
bsp->args.command = bsp->installed ? ZEBRA_BFD_DEST_UPDATE
: ZEBRA_BFD_DEST_REGISTER;
} else
bsp->args.command = ZEBRA_BFD_DEST_DEREGISTER;
/* If not installed and asked for uninstall, do nothing. */
if (!bsp->installed && bsp->args.command == ZEBRA_BFD_DEST_DEREGISTER)
return;
rv = zclient_bfd_command(bsglobal.zc, &bsp->args);
/* Command was sent successfully. */
if (rv == 0) {
/* Update installation status. */
if (bsp->args.command == ZEBRA_BFD_DEST_DEREGISTER)
bsp->installed = false;
else if (bsp->args.command == ZEBRA_BFD_DEST_REGISTER)
bsp->installed = true;
} else {
struct ipaddr src, dst;
src.ipa_type = bsp->args.family;
src.ipaddr_v6 = bsp->args.src;
dst.ipa_type = bsp->args.family;
dst.ipaddr_v6 = bsp->args.dst;
zlog_err(
"%s: BFD session %pIA -> %pIA interface %s VRF %s(%u) was not %s",
__func__, &src, &dst,
bsp->args.ifnamelen ? bsp->args.ifname : "*",
vrf_id_to_name(bsp->args.vrf_id), bsp->args.vrf_id,
bsp->lastev == BSE_INSTALL ? "installed"
: "uninstalled");
}
}
static void _bfd_sess_remove(struct bfd_session_params *bsp)
{
/* Cancel any pending installation request. */
EVENT_OFF(bsp->installev);
/* Not installed, nothing to do. */
if (!bsp->installed)
return;
/* Send request to remove any session. */
bsp->lastev = BSE_UNINSTALL;
event_execute(bsglobal.tm, _bfd_sess_send, bsp, 0);
}
void bfd_sess_free(struct bfd_session_params **bsp)
{
if (*bsp == NULL)
return;
/* Remove any installed session. */
_bfd_sess_remove(*bsp);
/* Remove from global list. */
TAILQ_REMOVE(&bsglobal.bsplist, (*bsp), entry);
bfd_source_cache_put(*bsp);
/* Free the memory and point to NULL. */
XFREE(MTYPE_BFD_INFO, (*bsp));
}
static bool bfd_sess_address_changed(const struct bfd_session_params *bsp,
uint32_t family,
const struct in6_addr *src,
const struct in6_addr *dst)
{
size_t addrlen;
if (bsp->args.family != family)
return true;
addrlen = (family == AF_INET) ? sizeof(struct in_addr)
: sizeof(struct in6_addr);
if ((src == NULL && memcmp(&bsp->args.src, &i6a_zero, addrlen))
|| (src && memcmp(src, &bsp->args.src, addrlen))
|| memcmp(dst, &bsp->args.dst, addrlen))
return true;
return false;
}
void bfd_sess_set_ipv4_addrs(struct bfd_session_params *bsp,
const struct in_addr *src,
const struct in_addr *dst)
{
if (!bfd_sess_address_changed(bsp, AF_INET, (struct in6_addr *)src,
(struct in6_addr *)dst))
return;
/* If already installed, remove the old setting. */
_bfd_sess_remove(bsp);
/* Address changed so we must reapply auto source. */
bfd_source_cache_put(bsp);
bsp->args.family = AF_INET;
/* Clean memory, set zero value and avoid static analyser warnings. */
memset(&bsp->args.src, 0, sizeof(bsp->args.src));
memset(&bsp->args.dst, 0, sizeof(bsp->args.dst));
/* Copy the equivalent of IPv4 to arguments structure. */
if (src)
memcpy(&bsp->args.src, src, sizeof(struct in_addr));
assert(dst);
memcpy(&bsp->args.dst, dst, sizeof(struct in_addr));
if (bsp->auto_source)
bfd_source_cache_get(bsp);
}
void bfd_sess_set_ipv6_addrs(struct bfd_session_params *bsp,
const struct in6_addr *src,
const struct in6_addr *dst)
{
if (!bfd_sess_address_changed(bsp, AF_INET6, src, dst))
return;
/* If already installed, remove the old setting. */
_bfd_sess_remove(bsp);
/* Address changed so we must reapply auto source. */
bfd_source_cache_put(bsp);
bsp->args.family = AF_INET6;
/* Clean memory, set zero value and avoid static analyser warnings. */
memset(&bsp->args.src, 0, sizeof(bsp->args.src));
if (src)
bsp->args.src = *src;
assert(dst);
bsp->args.dst = *dst;
if (bsp->auto_source)
bfd_source_cache_get(bsp);
}
void bfd_sess_set_interface(struct bfd_session_params *bsp, const char *ifname)
{
if ((ifname == NULL && bsp->args.ifnamelen == 0)
|| (ifname && strcmp(bsp->args.ifname, ifname) == 0))
return;
/* If already installed, remove the old setting. */
_bfd_sess_remove(bsp);
if (ifname == NULL) {
bsp->args.ifname[0] = 0;
bsp->args.ifnamelen = 0;
return;
}
if (strlcpy(bsp->args.ifname, ifname, sizeof(bsp->args.ifname))
> sizeof(bsp->args.ifname))
zlog_warn("%s: interface name truncated: %s", __func__, ifname);
bsp->args.ifnamelen = strlen(bsp->args.ifname);
}
void bfd_sess_set_profile(struct bfd_session_params *bsp, const char *profile)
{
if (profile == NULL) {
bsp->args.profile[0] = 0;
bsp->args.profilelen = 0;
return;
}
if (strlcpy(bsp->args.profile, profile, sizeof(bsp->args.profile))
> sizeof(bsp->args.profile))
zlog_warn("%s: profile name truncated: %s", __func__, profile);
bsp->args.profilelen = strlen(bsp->args.profile);
}
void bfd_sess_set_vrf(struct bfd_session_params *bsp, vrf_id_t vrf_id)
{
if (bsp->args.vrf_id == vrf_id)
return;
/* If already installed, remove the old setting. */
_bfd_sess_remove(bsp);
/* Address changed so we must reapply auto source. */
bfd_source_cache_put(bsp);
bsp->args.vrf_id = vrf_id;
if (bsp->auto_source)
bfd_source_cache_get(bsp);
}
void bfd_sess_set_hop_count(struct bfd_session_params *bsp, uint8_t hops)
{
if (bsp->args.hops == hops)
return;
/* If already installed, remove the old setting. */
_bfd_sess_remove(bsp);
bsp->args.hops = hops;
bsp->args.mhop = (hops > 1);
}
void bfd_sess_set_cbit(struct bfd_session_params *bsp, bool enable)
{
bsp->args.cbit = enable;
}
void bfd_sess_set_timers(struct bfd_session_params *bsp,
uint8_t detection_multiplier, uint32_t min_rx,
uint32_t min_tx)
{
bsp->args.detection_multiplier = detection_multiplier;
bsp->args.min_rx = min_rx;
bsp->args.min_tx = min_tx;
}
void bfd_sess_set_auto_source(struct bfd_session_params *bsp, bool enable)
{
if (bsp->auto_source == enable)
return;
bsp->auto_source = enable;
if (enable)
bfd_source_cache_get(bsp);
else
bfd_source_cache_put(bsp);
}
void bfd_sess_install(struct bfd_session_params *bsp)
{
bsp->lastev = BSE_INSTALL;
event_add_event(bsglobal.tm, _bfd_sess_send, bsp, 0, &bsp->installev);
}
void bfd_sess_uninstall(struct bfd_session_params *bsp)
{
bsp->lastev = BSE_UNINSTALL;
event_add_event(bsglobal.tm, _bfd_sess_send, bsp, 0, &bsp->installev);
}
enum bfd_session_state bfd_sess_status(const struct bfd_session_params *bsp)
{
return bsp->bss.state;
}
uint8_t bfd_sess_hop_count(const struct bfd_session_params *bsp)
{
return bsp->args.hops;
}
const char *bfd_sess_profile(const struct bfd_session_params *bsp)
{
return bsp->args.profilelen ? bsp->args.profile : NULL;
}
void bfd_sess_addresses(const struct bfd_session_params *bsp, int *family,
struct in6_addr *src, struct in6_addr *dst)
{
*family = bsp->args.family;
if (src)
*src = bsp->args.src;
if (dst)
*dst = bsp->args.dst;
}
const char *bfd_sess_interface(const struct bfd_session_params *bsp)
{
if (bsp->args.ifnamelen)
return bsp->args.ifname;
return NULL;
}
const char *bfd_sess_vrf(const struct bfd_session_params *bsp)
{
return vrf_id_to_name(bsp->args.vrf_id);
}
vrf_id_t bfd_sess_vrf_id(const struct bfd_session_params *bsp)
{
return bsp->args.vrf_id;
}
bool bfd_sess_cbit(const struct bfd_session_params *bsp)
{
return bsp->args.cbit;
}
void bfd_sess_timers(const struct bfd_session_params *bsp,
uint8_t *detection_multiplier, uint32_t *min_rx,
uint32_t *min_tx)
{
*detection_multiplier = bsp->args.detection_multiplier;
*min_rx = bsp->args.min_rx;
*min_tx = bsp->args.min_tx;
}
bool bfd_sess_auto_source(const struct bfd_session_params *bsp)
{
return bsp->auto_source;
}
void bfd_sess_show(struct vty *vty, struct json_object *json,
struct bfd_session_params *bsp)
{
json_object *json_bfd = NULL;
char time_buf[64];
if (!bsp)
return;
/* Show type. */
if (json) {
json_bfd = json_object_new_object();
if (bsp->args.mhop)
json_object_string_add(json_bfd, "type", "multi hop");
else
json_object_string_add(json_bfd, "type", "single hop");
} else
vty_out(vty, " BFD: Type: %s\n",
bsp->args.mhop ? "multi hop" : "single hop");
/* Show configuration. */
if (json) {
json_object_int_add(json_bfd, "detectMultiplier",
bsp->args.detection_multiplier);
json_object_int_add(json_bfd, "rxMinInterval",
bsp->args.min_rx);
json_object_int_add(json_bfd, "txMinInterval",
bsp->args.min_tx);
} else {
vty_out(vty,
" Detect Multiplier: %d, Min Rx interval: %d, Min Tx interval: %d\n",
bsp->args.detection_multiplier, bsp->args.min_rx,
bsp->args.min_tx);
}
bfd_last_update(bsp->bss.last_event, time_buf, sizeof(time_buf));
if (json) {
json_object_string_add(json_bfd, "status",
bfd_get_status_str(bsp->bss.state));
json_object_string_add(json_bfd, "lastUpdate", time_buf);
} else
vty_out(vty, " Status: %s, Last update: %s\n",
bfd_get_status_str(bsp->bss.state), time_buf);
if (json)
json_object_object_add(json, "peerBfdInfo", json_bfd);
else
vty_out(vty, "\n");
}
/*
* Zebra communication related.
*/
/**
* Callback for reinstallation of all registered BFD sessions.
*
* Use this as `zclient` `bfd_dest_replay` callback.
*/
int zclient_bfd_session_replay(ZAPI_CALLBACK_ARGS)
{
struct bfd_session_params *bsp;
if (!zclient->bfd_integration)
return 0;
/* Do nothing when shutting down. */
if (bsglobal.shutting_down)
return 0;
if (bsglobal.debugging)
zlog_debug("%s: sending all sessions registered", __func__);
/* Send the client registration */
bfd_client_sendmsg(zclient, ZEBRA_BFD_CLIENT_REGISTER, vrf_id);
/* Replay all activated peers. */
TAILQ_FOREACH (bsp, &bsglobal.bsplist, entry) {
/* Skip not installed sessions. */
if (!bsp->installed)
continue;
/* We are reconnecting, so we must send installation. */
bsp->installed = false;
/* Cancel any pending installation request. */
EVENT_OFF(bsp->installev);
/* Ask for installation. */
bsp->lastev = BSE_INSTALL;
event_execute(bsglobal.tm, _bfd_sess_send, bsp, 0);
}
return 0;
}
int zclient_bfd_session_update(ZAPI_CALLBACK_ARGS)
{
struct bfd_session_params *bsp, *bspn;
size_t sessions_updated = 0;
struct interface *ifp;
int remote_cbit = false;
int state = BFD_STATUS_UNKNOWN;
time_t now;
size_t addrlen;
struct prefix dp;
struct prefix sp;
char ifstr[128], cbitstr[32];
if (!zclient->bfd_integration)
return 0;
/* Do nothing when shutting down. */
if (bsglobal.shutting_down)
return 0;
ifp = bfd_get_peer_info(zclient->ibuf, &dp, &sp, &state, &remote_cbit,
vrf_id);
/*
* When interface lookup fails or an invalid stream is read, we must
* not proceed otherwise it will trigger an assertion while checking
* family type below.
*/
if (dp.family == 0 || sp.family == 0)
return 0;
if (bsglobal.debugging) {
ifstr[0] = 0;
if (ifp)
snprintf(ifstr, sizeof(ifstr), " (interface %s)",
ifp->name);
snprintf(cbitstr, sizeof(cbitstr), " (CPI bit %s)",
remote_cbit ? "yes" : "no");
zlog_debug("%s: %pFX -> %pFX%s VRF %s(%u)%s: %s", __func__, &sp,
&dp, ifstr, vrf_id_to_name(vrf_id), vrf_id, cbitstr,
bfd_get_status_str(state));
}
switch (dp.family) {
case AF_INET:
addrlen = sizeof(struct in_addr);
break;
case AF_INET6:
addrlen = sizeof(struct in6_addr);
break;
default:
/* Unexpected value. */
assert(0);
break;
}
/* Cache current time to avoid multiple monotime clock calls. */
now = monotime(NULL);
/* Notify all matching sessions about update. */
TAILQ_FOREACH_SAFE (bsp, &bsglobal.bsplist, entry, bspn) {
/* Skip not installed entries. */
if (!bsp->installed)
continue;
/* Skip different VRFs. */
if (bsp->args.vrf_id != vrf_id)
continue;
/* Skip different families. */
if (bsp->args.family != dp.family)
continue;
/* Skip different interface. */
if (bsp->args.ifnamelen && ifp
&& strcmp(bsp->args.ifname, ifp->name) != 0)
continue;
/* Skip non matching destination addresses. */
if (memcmp(&bsp->args.dst, &dp.u, addrlen) != 0)
continue;
/*
* Source comparison test:
* We will only compare source if BFD daemon provided the
* source address and the protocol set a source address in
* the configuration otherwise we'll just skip it.
*/
if (sp.family && memcmp(&bsp->args.src, &i6a_zero, addrlen) != 0
&& memcmp(&sp.u, &i6a_zero, addrlen) != 0
&& memcmp(&bsp->args.src, &sp.u, addrlen) != 0)
continue;
/* No session state change. */
if ((int)bsp->bss.state == state)
continue;
bsp->bss.last_event = now;
bsp->bss.previous_state = bsp->bss.state;
bsp->bss.state = state;
bsp->bss.remote_cbit = remote_cbit;
bsp->updatecb(bsp, &bsp->bss, bsp->arg);
sessions_updated++;
}
if (bsglobal.debugging)
zlog_debug("%s: sessions updated: %zu", __func__,
sessions_updated);
return 0;
}
/**
* Frees all allocated resources and stops any activity.
*
* Must be called after every BFD session has been successfully
* unconfigured otherwise this function will `free()` any available
* session causing existing pointers to dangle.
*
* This is just a comment, in practice it will be called by the FRR
* library late finish hook. \see `bfd_protocol_integration_init`.
*/
static int bfd_protocol_integration_finish(void)
{
if (bsglobal.zc == NULL)
return 0;
while (!TAILQ_EMPTY(&bsglobal.bsplist)) {
struct bfd_session_params *session =
TAILQ_FIRST(&bsglobal.bsplist);
bfd_sess_free(&session);
}
/*
* BFD source cache is linked to sessions, if all sessions are gone
* then the source cache must be empty.
*/
if (!SLIST_EMPTY(&bsglobal.source_list))
zlog_warn("BFD integration source cache not empty");
return 0;
}
void bfd_protocol_integration_init(struct zclient *zc, struct event_loop *tm)
{
/* Initialize data structure. */
TAILQ_INIT(&bsglobal.bsplist);
SLIST_INIT(&bsglobal.source_list);
/* Copy pointers. */
bsglobal.zc = zc;
bsglobal.tm = tm;
/* Enable BFD callbacks. */
zc->bfd_integration = true;
/* Send the client registration */
bfd_client_sendmsg(zc, ZEBRA_BFD_CLIENT_REGISTER, VRF_DEFAULT);
hook_register(frr_fini, bfd_protocol_integration_finish);
}
void bfd_protocol_integration_set_debug(bool enable)
{
bsglobal.debugging = enable;
}
void bfd_protocol_integration_set_shutdown(bool enable)
{
bsglobal.shutting_down = enable;
}
bool bfd_protocol_integration_debug(void)
{
return bsglobal.debugging;
}
bool bfd_protocol_integration_shutting_down(void)
{
return bsglobal.shutting_down;
}
/*
* BFD automatic source selection
*
* This feature will use the next hop tracking (NHT) provided by zebra
* to find out the source address by looking at the output interface.
*
* When the interface address / routing table change we'll be notified
* and be able to update the source address accordingly.
*
* <daemon> zebra
* |
* +-----------------+
* | BFD session set |
* | to auto source |
* +-----------------+
* |
* \ +-----------------+
* --------------> | Resolves |
* | destination |
* | address |
* +-----------------+
* |
* +-----------------+ /
* | Sets resolved | <----------
* | source address |
* +-----------------+
*/
static bool
bfd_source_cache_session_match(const struct bfd_source_cache *source,
const struct bfd_session_params *session)
{
const struct in_addr *address;
const struct in6_addr *address_v6;
if (session->args.vrf_id != source->vrf_id)
return false;
if (session->args.family != source->address.family)
return false;
switch (session->args.family) {
case AF_INET:
address = (const struct in_addr *)&session->args.dst;
if (address->s_addr != source->address.u.prefix4.s_addr)
return false;
break;
case AF_INET6:
address_v6 = &session->args.dst;
if (memcmp(address_v6, &source->address.u.prefix6,
sizeof(struct in6_addr)))
return false;
break;
default:
return false;
}
return true;
}
static struct bfd_source_cache *
bfd_source_cache_find(vrf_id_t vrf_id, const struct prefix *prefix)
{
struct bfd_source_cache *source;
SLIST_FOREACH (source, &bsglobal.source_list, entry) {
if (source->vrf_id != vrf_id)
continue;
if (!prefix_same(&source->address, prefix))
continue;
return source;
}
return NULL;
}
static void bfd_source_cache_get(struct bfd_session_params *session)
{
struct bfd_source_cache *source;
struct prefix target = {};
switch (session->args.family) {
case AF_INET:
target.family = AF_INET;
target.prefixlen = IPV4_MAX_BITLEN;
memcpy(&target.u.prefix4, &session->args.dst,
sizeof(struct in_addr));
break;
case AF_INET6:
target.family = AF_INET6;
target.prefixlen = IPV6_MAX_BITLEN;
memcpy(&target.u.prefix6, &session->args.dst,
sizeof(struct in6_addr));
break;
default:
return;
}
source = bfd_source_cache_find(session->args.vrf_id, &target);
if (source) {
if (session->source_cache == source)
return;
bfd_source_cache_put(session);
session->source_cache = source;
source->refcount++;
return;
}
source = XCALLOC(MTYPE_BFD_SOURCE, sizeof(*source));
prefix_copy(&source->address, &target);
source->vrf_id = session->args.vrf_id;
SLIST_INSERT_HEAD(&bsglobal.source_list, source, entry);
bfd_source_cache_put(session);
session->source_cache = source;
source->refcount = 1;
return;
}
static void bfd_source_cache_put(struct bfd_session_params *session)
{
if (session->source_cache == NULL)
return;
session->source_cache->refcount--;
if (session->source_cache->refcount > 0) {
session->source_cache = NULL;
return;
}
SLIST_REMOVE(&bsglobal.source_list, session->source_cache,
bfd_source_cache, entry);
XFREE(MTYPE_BFD_SOURCE, session->source_cache);
}
/** Updates BFD running session if source address has changed. */
static void
bfd_source_cache_update_session(const struct bfd_source_cache *source,
struct bfd_session_params *session)
{
const struct in_addr *address;
const struct in6_addr *address_v6;
switch (session->args.family) {
case AF_INET:
address = (const struct in_addr *)&session->args.src;
if (memcmp(address, &source->source.u.prefix4,
sizeof(struct in_addr)) == 0)
return;
_bfd_sess_remove(session);
memcpy(&session->args.src, &source->source.u.prefix4,
sizeof(struct in_addr));
break;
case AF_INET6:
address_v6 = &session->args.src;
if (memcmp(address_v6, &source->source.u.prefix6,
sizeof(struct in6_addr)) == 0)
return;
_bfd_sess_remove(session);
memcpy(&session->args.src, &source->source.u.prefix6,
sizeof(struct in6_addr));
break;
default:
return;
}
bfd_sess_install(session);
}
static void
bfd_source_cache_update_sessions(const struct bfd_source_cache *source)
{
struct bfd_session_params *session;
if (!source->valid)
return;
TAILQ_FOREACH (session, &bsglobal.bsplist, entry) {
if (!session->auto_source)
continue;
if (!bfd_source_cache_session_match(source, session))
continue;
bfd_source_cache_update_session(source, session);
}
}
/**
* Try to translate next hop information into source address.
*
* \returns `true` if source changed otherwise `false`.
*/
static bool bfd_source_cache_update(struct bfd_source_cache *source,
const struct zapi_route *route)
{
size_t nh_index;
for (nh_index = 0; nh_index < route->nexthop_num; nh_index++) {
const struct zapi_nexthop *nh = &route->nexthops[nh_index];
const struct interface *interface;
const struct connected *connected;
const struct listnode *node;
interface = if_lookup_by_index(nh->ifindex, nh->vrf_id);
if (interface == NULL) {
zlog_err("next hop interface not found (index %d)",
nh->ifindex);
continue;
}
for (ALL_LIST_ELEMENTS_RO(interface->connected, node,
connected)) {
if (source->address.family !=
connected->address->family)
continue;
if (prefix_same(connected->address, &source->source))
return false;
/*
* Skip link-local as it is only useful for single hop
* and in that case no source is specified usually.
*/
if (source->address.family == AF_INET6 &&
IN6_IS_ADDR_LINKLOCAL(
&connected->address->u.prefix6))
continue;
prefix_copy(&source->source, connected->address);
source->valid = true;
return true;
}
}
memset(&source->source, 0, sizeof(source->source));
source->valid = false;
return false;
}
int bfd_nht_update(const struct prefix *match, const struct zapi_route *route)
{
struct bfd_source_cache *source;
if (bsglobal.debugging)
zlog_debug("BFD NHT update for %pFX", &route->prefix);
SLIST_FOREACH (source, &bsglobal.source_list, entry) {
if (source->vrf_id != route->vrf_id)
continue;
if (!prefix_same(match, &source->address))
continue;
if (bfd_source_cache_update(source, route))
bfd_source_cache_update_sessions(source);
}
return 0;
}
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