bird/proto/bfd/bfd.c
Ondrej Zajicek (work) 910adaa08b BFD: Dispatch sessions also by interface index
Direct BFD sessions needs to be dispatched not only by IP addresses, but
also by interfaces, in order to avoid collisions between neighbors with
the same IPv6 link-local addresses.

Extend BFD session hash_ip key by interface index to handle that. Use 0
for multihop sessions.

Thanks to Sebastian Hahn for the original patch.
2021-01-10 15:29:02 +01:00

1188 lines
30 KiB
C

/*
* BIRD -- Bidirectional Forwarding Detection (BFD)
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Bidirectional Forwarding Detection
*
* The BFD protocol is implemented in three files: |bfd.c| containing the
* protocol logic and the protocol glue with BIRD core, |packets.c| handling BFD
* packet processing, RX, TX and protocol sockets. |io.c| then contains generic
* code for the event loop, threads and event sources (sockets, microsecond
* timers). This generic code will be merged to the main BIRD I/O code in the
* future.
*
* The BFD implementation uses a separate thread with an internal event loop for
* handling the protocol logic, which requires high-res and low-latency timing,
* so it is not affected by the rest of BIRD, which has several low-granularity
* hooks in the main loop, uses second-based timers and cannot offer good
* latency. The core of BFD protocol (the code related to BFD sessions,
* interfaces and packets) runs in the BFD thread, while the rest (the code
* related to BFD requests, BFD neighbors and the protocol glue) runs in the
* main thread.
*
* BFD sessions are represented by structure &bfd_session that contains a state
* related to the session and two timers (TX timer for periodic packets and hold
* timer for session timeout). These sessions are allocated from @session_slab
* and are accessible by two hash tables, @session_hash_id (by session ID) and
* @session_hash_ip (by IP addresses of neighbors and associated interfaces).
* Slab and both hashes are in the main protocol structure &bfd_proto. The
* protocol logic related to BFD sessions is implemented in internal functions
* bfd_session_*(), which are expected to be called from the context of BFD
* thread, and external functions bfd_add_session(), bfd_remove_session() and
* bfd_reconfigure_session(), which form an interface to the BFD core for the
* rest and are expected to be called from the context of main thread.
*
* Each BFD session has an associated BFD interface, represented by structure
* &bfd_iface. A BFD interface contains a socket used for TX (the one for RX is
* shared in &bfd_proto), an interface configuration and reference counter.
* Compared to interface structures of other protocols, these structures are not
* created and removed based on interface notification events, but according to
* the needs of BFD sessions. When a new session is created, it requests a
* proper BFD interface by function bfd_get_iface(), which either finds an
* existing one in &iface_list (from &bfd_proto) or allocates a new one. When a
* session is removed, an associated iface is discharged by bfd_free_iface().
*
* BFD requests are the external API for the other protocols. When a protocol
* wants a BFD session, it calls bfd_request_session(), which creates a
* structure &bfd_request containing approprite information and an notify hook.
* This structure is a resource associated with the caller's resource pool. When
* a BFD protocol is available, a BFD request is submitted to the protocol, an
* appropriate BFD session is found or created and the request is attached to
* the session. When a session changes state, all attached requests (and related
* protocols) are notified. Note that BFD requests do not depend on BFD protocol
* running. When the BFD protocol is stopped or removed (or not available from
* beginning), related BFD requests are stored in @bfd_wait_list, where waits
* for a new protocol.
*
* BFD neighbors are just a way to statically configure BFD sessions without
* requests from other protocol. Structures &bfd_neighbor are part of BFD
* configuration (like static routes in the static protocol). BFD neighbors are
* handled by BFD protocol like it is a BFD client -- when a BFD neighbor is
* ready, the protocol just creates a BFD request like any other protocol.
*
* The protocol uses a new generic event loop (structure &birdloop) from |io.c|,
* which supports sockets, timers and events like the main loop. A birdloop is
* associated with a thread (field @thread) in which event hooks are executed.
* Most functions for setting event sources (like sk_start() or tm_start()) must
* be called from the context of that thread. Birdloop allows to temporarily
* acquire the context of that thread for the main thread by calling
* birdloop_enter() and then birdloop_leave(), which also ensures mutual
* exclusion with all event hooks. Note that resources associated with a
* birdloop (like timers) should be attached to the independent resource pool,
* detached from the main resource tree.
*
* There are two kinds of interaction between the BFD core (running in the BFD
* thread) and the rest of BFD (running in the main thread). The first kind are
* configuration calls from main thread to the BFD thread (like bfd_add_session()).
* These calls are synchronous and use birdloop_enter() mechanism for mutual
* exclusion. The second kind is a notification about session changes from the
* BFD thread to the main thread. This is done in an asynchronous way, sesions
* with pending notifications are linked (in the BFD thread) to @notify_list in
* &bfd_proto, and then bfd_notify_hook() in the main thread is activated using
* bfd_notify_kick() and a pipe. The hook then processes scheduled sessions and
* calls hooks from associated BFD requests. This @notify_list (and state fields
* in structure &bfd_session) is protected by a spinlock in &bfd_proto and
* functions bfd_lock_sessions() / bfd_unlock_sessions().
*
* There are few data races (accessing @p->p.debug from TRACE() from the BFD
* thread and accessing some some private fields of %bfd_session from
* bfd_show_sessions() from the main thread, but these are harmless (i hope).
*
* TODO: document functions and access restrictions for fields in BFD structures.
*
* Supported standards:
* - RFC 5880 - main BFD standard
* - RFC 5881 - BFD for IP links
* - RFC 5882 - generic application of BFD
* - RFC 5883 - BFD for multihop paths
*/
#include "bfd.h"
#define HASH_ID_KEY(n) n->loc_id
#define HASH_ID_NEXT(n) n->next_id
#define HASH_ID_EQ(a,b) a == b
#define HASH_ID_FN(k) k
#define HASH_IP_KEY(n) n->addr, n->ifindex
#define HASH_IP_NEXT(n) n->next_ip
#define HASH_IP_EQ(a1,n1,a2,n2) ipa_equal(a1, a2) && n1 == n2
#define HASH_IP_FN(a,n) ipa_hash(a) ^ u32_hash(n)
static list bfd_proto_list;
static list bfd_wait_list;
const char *bfd_state_names[] = { "AdminDown", "Down", "Init", "Up" };
static void bfd_session_set_min_tx(struct bfd_session *s, u32 val);
static struct bfd_iface *bfd_get_iface(struct bfd_proto *p, ip_addr local, struct iface *iface);
static void bfd_free_iface(struct bfd_iface *ifa);
static inline void bfd_notify_kick(struct bfd_proto *p);
/*
* BFD sessions
*/
static inline struct bfd_session_config
bfd_merge_options(const struct bfd_iface_config *cf, const struct bfd_options *opts)
{
return (struct bfd_session_config) {
.min_rx_int = opts->min_rx_int ?: cf->min_rx_int,
.min_tx_int = opts->min_tx_int ?: cf->min_tx_int,
.idle_tx_int = opts->idle_tx_int ?: cf->idle_tx_int,
.multiplier = opts->multiplier ?: cf->multiplier,
.passive = opts->passive_set ? opts->passive : cf->passive
};
}
static void
bfd_session_update_state(struct bfd_session *s, uint state, uint diag)
{
struct bfd_proto *p = s->ifa->bfd;
uint old_state = s->loc_state;
int notify;
if (state == old_state)
return;
TRACE(D_EVENTS, "Session to %I changed state from %s to %s",
s->addr, bfd_state_names[old_state], bfd_state_names[state]);
bfd_lock_sessions(p);
s->loc_state = state;
s->loc_diag = diag;
s->last_state_change = current_time();
notify = !NODE_VALID(&s->n);
if (notify)
add_tail(&p->notify_list, &s->n);
bfd_unlock_sessions(p);
if (state == BFD_STATE_UP)
bfd_session_set_min_tx(s, s->cf.min_tx_int);
if (old_state == BFD_STATE_UP)
bfd_session_set_min_tx(s, s->cf.idle_tx_int);
if (notify)
bfd_notify_kick(p);
}
static void
bfd_session_update_tx_interval(struct bfd_session *s)
{
u32 tx_int = MAX(s->des_min_tx_int, s->rem_min_rx_int);
u32 tx_int_l = tx_int - (tx_int / 4); // 75 %
u32 tx_int_h = tx_int - (tx_int / 10); // 90 %
s->tx_timer->recurrent = tx_int_l;
s->tx_timer->randomize = tx_int_h - tx_int_l;
/* Do not set timer if no previous event */
if (!s->last_tx)
return;
/* Set timer relative to last tx_timer event */
tm_set(s->tx_timer, s->last_tx + tx_int_l);
}
static void
bfd_session_update_detection_time(struct bfd_session *s, int kick)
{
btime timeout = (btime) MAX(s->req_min_rx_int, s->rem_min_tx_int) * s->rem_detect_mult;
if (kick)
s->last_rx = current_time();
if (!s->last_rx)
return;
tm_set(s->hold_timer, s->last_rx + timeout);
}
static void
bfd_session_control_tx_timer(struct bfd_session *s, int reset)
{
// if (!s->opened) goto stop;
if (s->passive && (s->rem_id == 0))
goto stop;
if (s->rem_demand_mode &&
!s->poll_active &&
(s->loc_state == BFD_STATE_UP) &&
(s->rem_state == BFD_STATE_UP))
goto stop;
if (s->rem_min_rx_int == 0)
goto stop;
/* So TX timer should run */
if (reset || !tm_active(s->tx_timer))
{
s->last_tx = 0;
tm_start(s->tx_timer, 0);
}
return;
stop:
tm_stop(s->tx_timer);
s->last_tx = 0;
}
static void
bfd_session_request_poll(struct bfd_session *s, u8 request)
{
/* Not sure about this, but doing poll in this case does not make sense */
if (s->rem_id == 0)
return;
s->poll_scheduled |= request;
if (s->poll_active)
return;
s->poll_active = s->poll_scheduled;
s->poll_scheduled = 0;
bfd_session_control_tx_timer(s, 1);
}
static void
bfd_session_terminate_poll(struct bfd_session *s)
{
u8 poll_done = s->poll_active & ~s->poll_scheduled;
if (poll_done & BFD_POLL_TX)
s->des_min_tx_int = s->des_min_tx_new;
if (poll_done & BFD_POLL_RX)
s->req_min_rx_int = s->req_min_rx_new;
s->poll_active = s->poll_scheduled;
s->poll_scheduled = 0;
/* Timers are updated by caller - bfd_session_process_ctl() */
}
void
bfd_session_process_ctl(struct bfd_session *s, u8 flags, u32 old_tx_int, u32 old_rx_int)
{
if (s->poll_active && (flags & BFD_FLAG_FINAL))
bfd_session_terminate_poll(s);
if ((s->des_min_tx_int != old_tx_int) || (s->rem_min_rx_int != old_rx_int))
bfd_session_update_tx_interval(s);
bfd_session_update_detection_time(s, 1);
/* Update session state */
int next_state = 0;
int diag = BFD_DIAG_NOTHING;
switch (s->loc_state)
{
case BFD_STATE_ADMIN_DOWN:
return;
case BFD_STATE_DOWN:
if (s->rem_state == BFD_STATE_DOWN) next_state = BFD_STATE_INIT;
else if (s->rem_state == BFD_STATE_INIT) next_state = BFD_STATE_UP;
break;
case BFD_STATE_INIT:
if (s->rem_state == BFD_STATE_ADMIN_DOWN) next_state = BFD_STATE_DOWN, diag = BFD_DIAG_NEIGHBOR_DOWN;
else if (s->rem_state >= BFD_STATE_INIT) next_state = BFD_STATE_UP;
break;
case BFD_STATE_UP:
if (s->rem_state <= BFD_STATE_DOWN) next_state = BFD_STATE_DOWN, diag = BFD_DIAG_NEIGHBOR_DOWN;
break;
}
if (next_state)
bfd_session_update_state(s, next_state, diag);
bfd_session_control_tx_timer(s, 0);
if (flags & BFD_FLAG_POLL)
bfd_send_ctl(s->ifa->bfd, s, 1);
}
static void
bfd_session_timeout(struct bfd_session *s)
{
struct bfd_proto *p = s->ifa->bfd;
TRACE(D_EVENTS, "Session to %I expired", s->addr);
s->rem_state = BFD_STATE_DOWN;
s->rem_id = 0;
s->rem_min_tx_int = 0;
s->rem_min_rx_int = 1;
s->rem_demand_mode = 0;
s->rem_detect_mult = 0;
s->rx_csn_known = 0;
s->poll_active = 0;
s->poll_scheduled = 0;
bfd_session_update_state(s, BFD_STATE_DOWN, BFD_DIAG_TIMEOUT);
bfd_session_control_tx_timer(s, 1);
}
static void
bfd_session_set_min_tx(struct bfd_session *s, u32 val)
{
/* Note that des_min_tx_int <= des_min_tx_new */
if (val == s->des_min_tx_new)
return;
s->des_min_tx_new = val;
/* Postpone timer update if des_min_tx_int increases and the session is up */
if ((s->loc_state != BFD_STATE_UP) || (val < s->des_min_tx_int))
{
s->des_min_tx_int = val;
bfd_session_update_tx_interval(s);
}
bfd_session_request_poll(s, BFD_POLL_TX);
}
static void
bfd_session_set_min_rx(struct bfd_session *s, u32 val)
{
/* Note that req_min_rx_int >= req_min_rx_new */
if (val == s->req_min_rx_new)
return;
s->req_min_rx_new = val;
/* Postpone timer update if req_min_rx_int decreases and the session is up */
if ((s->loc_state != BFD_STATE_UP) || (val > s->req_min_rx_int))
{
s->req_min_rx_int = val;
bfd_session_update_detection_time(s, 0);
}
bfd_session_request_poll(s, BFD_POLL_RX);
}
struct bfd_session *
bfd_find_session_by_id(struct bfd_proto *p, u32 id)
{
return HASH_FIND(p->session_hash_id, HASH_ID, id);
}
struct bfd_session *
bfd_find_session_by_addr(struct bfd_proto *p, ip_addr addr, uint ifindex)
{
return HASH_FIND(p->session_hash_ip, HASH_IP, addr, ifindex);
}
static void
bfd_tx_timer_hook(timer *t)
{
struct bfd_session *s = t->data;
s->last_tx = current_time();
bfd_send_ctl(s->ifa->bfd, s, 0);
}
static void
bfd_hold_timer_hook(timer *t)
{
bfd_session_timeout(t->data);
}
static u32
bfd_get_free_id(struct bfd_proto *p)
{
u32 id;
for (id = random_u32(); 1; id++)
if (id && !bfd_find_session_by_id(p, id))
break;
return id;
}
static struct bfd_session *
bfd_add_session(struct bfd_proto *p, ip_addr addr, ip_addr local, struct iface *iface, struct bfd_options *opts)
{
birdloop_enter(p->loop);
struct bfd_iface *ifa = bfd_get_iface(p, local, iface);
struct bfd_session *s = sl_allocz(p->session_slab);
s->addr = addr;
s->ifa = ifa;
s->ifindex = iface ? iface->index : 0;
s->loc_id = bfd_get_free_id(p);
HASH_INSERT(p->session_hash_id, HASH_ID, s);
HASH_INSERT(p->session_hash_ip, HASH_IP, s);
s->cf = bfd_merge_options(ifa->cf, opts);
/* Initialization of state variables - see RFC 5880 6.8.1 */
s->loc_state = BFD_STATE_DOWN;
s->rem_state = BFD_STATE_DOWN;
s->des_min_tx_int = s->des_min_tx_new = s->cf.idle_tx_int;
s->req_min_rx_int = s->req_min_rx_new = s->cf.min_rx_int;
s->rem_min_rx_int = 1;
s->detect_mult = s->cf.multiplier;
s->passive = s->cf.passive;
s->tx_csn = random_u32();
s->tx_timer = tm_new_init(p->tpool, bfd_tx_timer_hook, s, 0, 0);
s->hold_timer = tm_new_init(p->tpool, bfd_hold_timer_hook, s, 0, 0);
bfd_session_update_tx_interval(s);
bfd_session_control_tx_timer(s, 1);
init_list(&s->request_list);
s->last_state_change = current_time();
TRACE(D_EVENTS, "Session to %I added", s->addr);
birdloop_leave(p->loop);
return s;
}
/*
static void
bfd_open_session(struct bfd_proto *p, struct bfd_session *s, ip_addr local, struct iface *ifa)
{
birdloop_enter(p->loop);
s->opened = 1;
bfd_session_control_tx_timer(s);
birdloop_leave(p->loop);
}
static void
bfd_close_session(struct bfd_proto *p, struct bfd_session *s)
{
birdloop_enter(p->loop);
s->opened = 0;
bfd_session_update_state(s, BFD_STATE_DOWN, BFD_DIAG_PATH_DOWN);
bfd_session_control_tx_timer(s);
birdloop_leave(p->loop);
}
*/
static void
bfd_remove_session(struct bfd_proto *p, struct bfd_session *s)
{
ip_addr ip = s->addr;
/* Caller should ensure that request list is empty */
birdloop_enter(p->loop);
/* Remove session from notify list if scheduled for notification */
/* No need for bfd_lock_sessions(), we are already protected by birdloop_enter() */
if (NODE_VALID(&s->n))
rem_node(&s->n);
bfd_free_iface(s->ifa);
rfree(s->tx_timer);
rfree(s->hold_timer);
HASH_REMOVE(p->session_hash_id, HASH_ID, s);
HASH_REMOVE(p->session_hash_ip, HASH_IP, s);
sl_free(p->session_slab, s);
TRACE(D_EVENTS, "Session to %I removed", ip);
birdloop_leave(p->loop);
}
static void
bfd_reconfigure_session(struct bfd_proto *p, struct bfd_session *s)
{
if (EMPTY_LIST(s->request_list))
return;
birdloop_enter(p->loop);
struct bfd_request *req = SKIP_BACK(struct bfd_request, n, HEAD(s->request_list));
s->cf = bfd_merge_options(s->ifa->cf, &req->opts);
u32 tx = (s->loc_state == BFD_STATE_UP) ? s->cf.min_tx_int : s->cf.idle_tx_int;
bfd_session_set_min_tx(s, tx);
bfd_session_set_min_rx(s, s->cf.min_rx_int);
s->detect_mult = s->cf.multiplier;
s->passive = s->cf.passive;
bfd_session_control_tx_timer(s, 0);
birdloop_leave(p->loop);
TRACE(D_EVENTS, "Session to %I reconfigured", s->addr);
}
/*
* BFD interfaces
*/
static struct bfd_iface_config bfd_default_iface = {
.min_rx_int = BFD_DEFAULT_MIN_RX_INT,
.min_tx_int = BFD_DEFAULT_MIN_TX_INT,
.idle_tx_int = BFD_DEFAULT_IDLE_TX_INT,
.multiplier = BFD_DEFAULT_MULTIPLIER
};
static inline struct bfd_iface_config *
bfd_find_iface_config(struct bfd_config *cf, struct iface *iface)
{
struct bfd_iface_config *ic;
ic = iface ? (void *) iface_patt_find(&cf->patt_list, iface, NULL) : cf->multihop;
return ic ? ic : &bfd_default_iface;
}
static struct bfd_iface *
bfd_get_iface(struct bfd_proto *p, ip_addr local, struct iface *iface)
{
struct bfd_iface *ifa;
WALK_LIST(ifa, p->iface_list)
if (ipa_equal(ifa->local, local) && (ifa->iface == iface))
return ifa->uc++, ifa;
struct bfd_config *cf = (struct bfd_config *) (p->p.cf);
struct bfd_iface_config *ic = bfd_find_iface_config(cf, iface);
ifa = mb_allocz(p->tpool, sizeof(struct bfd_iface));
ifa->local = local;
ifa->iface = iface;
ifa->cf = ic;
ifa->bfd = p;
ifa->sk = bfd_open_tx_sk(p, local, iface);
ifa->uc = 1;
add_tail(&p->iface_list, &ifa->n);
return ifa;
}
static void
bfd_free_iface(struct bfd_iface *ifa)
{
if (!ifa || --ifa->uc)
return;
if (ifa->sk)
{
sk_stop(ifa->sk);
rfree(ifa->sk);
}
rem_node(&ifa->n);
mb_free(ifa);
}
static void
bfd_reconfigure_iface(struct bfd_proto *p, struct bfd_iface *ifa, struct bfd_config *nc)
{
struct bfd_iface_config *new = bfd_find_iface_config(nc, ifa->iface);
struct bfd_iface_config *old = ifa->cf;
/* Check options that are handled in bfd_reconfigure_session() */
ifa->changed =
(new->min_rx_int != old->min_rx_int) ||
(new->min_tx_int != old->min_tx_int) ||
(new->idle_tx_int != old->idle_tx_int) ||
(new->multiplier != old->multiplier) ||
(new->passive != old->passive);
/* This should be probably changed to not access ifa->cf from the BFD thread */
birdloop_enter(p->loop);
ifa->cf = new;
birdloop_leave(p->loop);
}
/*
* BFD requests
*/
static void
bfd_request_notify(struct bfd_request *req, u8 state, u8 diag)
{
u8 old_state = req->state;
if (state == old_state)
return;
req->state = state;
req->diag = diag;
req->old_state = old_state;
req->down = (old_state == BFD_STATE_UP) && (state == BFD_STATE_DOWN);
if (req->hook)
req->hook(req);
}
static int
bfd_add_request(struct bfd_proto *p, struct bfd_request *req)
{
struct bfd_config *cf = (struct bfd_config *) (p->p.cf);
if (p->p.vrf_set && (p->p.vrf != req->vrf))
return 0;
if (ipa_is_ip4(req->addr) ? !cf->accept_ipv4 : !cf->accept_ipv6)
return 0;
if (req->iface ? !cf->accept_direct : !cf->accept_multihop)
return 0;
uint ifindex = req->iface ? req->iface->index : 0;
struct bfd_session *s = bfd_find_session_by_addr(p, req->addr, ifindex);
u8 state, diag;
if (!s)
s = bfd_add_session(p, req->addr, req->local, req->iface, &req->opts);
rem_node(&req->n);
add_tail(&s->request_list, &req->n);
req->session = s;
bfd_lock_sessions(p);
state = s->loc_state;
diag = s->loc_diag;
bfd_unlock_sessions(p);
bfd_request_notify(req, state, diag);
return 1;
}
static void
bfd_submit_request(struct bfd_request *req)
{
node *n;
WALK_LIST(n, bfd_proto_list)
if (bfd_add_request(SKIP_BACK(struct bfd_proto, bfd_node, n), req))
return;
rem_node(&req->n);
add_tail(&bfd_wait_list, &req->n);
req->session = NULL;
bfd_request_notify(req, BFD_STATE_ADMIN_DOWN, 0);
}
static void
bfd_take_requests(struct bfd_proto *p)
{
node *n, *nn;
WALK_LIST_DELSAFE(n, nn, bfd_wait_list)
bfd_add_request(p, SKIP_BACK(struct bfd_request, n, n));
}
static void
bfd_drop_requests(struct bfd_proto *p)
{
node *n;
HASH_WALK(p->session_hash_id, next_id, s)
{
/* We assume that p is not in bfd_proto_list */
WALK_LIST_FIRST(n, s->request_list)
bfd_submit_request(SKIP_BACK(struct bfd_request, n, n));
}
HASH_WALK_END;
}
static struct resclass bfd_request_class;
struct bfd_request *
bfd_request_session(pool *p, ip_addr addr, ip_addr local,
struct iface *iface, struct iface *vrf,
void (*hook)(struct bfd_request *), void *data,
const struct bfd_options *opts)
{
struct bfd_request *req = ralloc(p, &bfd_request_class);
/* Hack: self-link req->n, we will call rem_node() on it */
req->n.prev = req->n.next = &req->n;
req->addr = addr;
req->local = local;
req->iface = iface;
req->vrf = vrf;
if (opts)
req->opts = *opts;
bfd_submit_request(req);
req->hook = hook;
req->data = data;
return req;
}
void
bfd_update_request(struct bfd_request *req, const struct bfd_options *opts)
{
struct bfd_session *s = req->session;
if (!memcmp(opts, &req->opts, sizeof(const struct bfd_options)))
return;
req->opts = *opts;
if (s)
bfd_reconfigure_session(s->ifa->bfd, s);
}
static void
bfd_request_free(resource *r)
{
struct bfd_request *req = (struct bfd_request *) r;
struct bfd_session *s = req->session;
rem_node(&req->n);
/* Remove the session if there is no request for it. Skip that if
inside notify hooks, will be handled by bfd_notify_hook() itself */
if (s && EMPTY_LIST(s->request_list) && !s->notify_running)
bfd_remove_session(s->ifa->bfd, s);
}
static void
bfd_request_dump(resource *r)
{
struct bfd_request *req = (struct bfd_request *) r;
debug("(code %p, data %p)\n", req->hook, req->data);
}
static struct resclass bfd_request_class = {
"BFD request",
sizeof(struct bfd_request),
bfd_request_free,
bfd_request_dump,
NULL,
NULL
};
/*
* BFD neighbors
*/
static void
bfd_neigh_notify(struct neighbor *nb)
{
struct bfd_proto *p = (struct bfd_proto *) nb->proto;
struct bfd_neighbor *n = nb->data;
if (!n)
return;
if ((nb->scope > 0) && !n->req)
{
ip_addr local = ipa_nonzero(n->local) ? n->local : nb->ifa->ip;
n->req = bfd_request_session(p->p.pool, n->addr, local, nb->iface, p->p.vrf, NULL, NULL, NULL);
}
if ((nb->scope <= 0) && n->req)
{
rfree(n->req);
n->req = NULL;
}
}
static void
bfd_start_neighbor(struct bfd_proto *p, struct bfd_neighbor *n)
{
n->active = 1;
if (n->multihop)
{
n->req = bfd_request_session(p->p.pool, n->addr, n->local, NULL, p->p.vrf, NULL, NULL, NULL);
return;
}
struct neighbor *nb = neigh_find(&p->p, n->addr, n->iface, NEF_STICKY);
if (!nb)
{
log(L_ERR "%s: Invalid remote address %I%J", p->p.name, n->addr, n->iface);
return;
}
if (nb->data)
{
log(L_ERR "%s: Duplicate neighbor %I", p->p.name, n->addr);
return;
}
n->neigh = nb;
nb->data = n;
if (nb->scope > 0)
bfd_neigh_notify(nb);
else
TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", n->addr, n->iface);
}
static void
bfd_stop_neighbor(struct bfd_proto *p UNUSED, struct bfd_neighbor *n)
{
if (n->neigh)
n->neigh->data = NULL;
n->neigh = NULL;
rfree(n->req);
n->req = NULL;
}
static inline int
bfd_same_neighbor(struct bfd_neighbor *x, struct bfd_neighbor *y)
{
return ipa_equal(x->addr, y->addr) && ipa_equal(x->local, y->local) &&
(x->iface == y->iface) && (x->multihop == y->multihop);
}
static void
bfd_reconfigure_neighbors(struct bfd_proto *p, struct bfd_config *new)
{
struct bfd_config *old = (struct bfd_config *) (p->p.cf);
struct bfd_neighbor *on, *nn;
WALK_LIST(on, old->neigh_list)
{
WALK_LIST(nn, new->neigh_list)
if (bfd_same_neighbor(nn, on))
{
nn->neigh = on->neigh;
if (nn->neigh)
nn->neigh->data = nn;
nn->req = on->req;
nn->active = 1;
goto next;
}
bfd_stop_neighbor(p, on);
next:;
}
WALK_LIST(nn, new->neigh_list)
if (!nn->active)
bfd_start_neighbor(p, nn);
}
/*
* BFD notify socket
*/
/* This core notify code should be replaced after main loop transition to birdloop */
int pipe(int pipefd[2]);
void pipe_drain(int fd);
void pipe_kick(int fd);
static int
bfd_notify_hook(sock *sk, uint len UNUSED)
{
struct bfd_proto *p = sk->data;
struct bfd_session *s;
list tmp_list;
u8 state, diag;
node *n, *nn;
pipe_drain(sk->fd);
bfd_lock_sessions(p);
init_list(&tmp_list);
add_tail_list(&tmp_list, &p->notify_list);
init_list(&p->notify_list);
bfd_unlock_sessions(p);
WALK_LIST_FIRST(s, tmp_list)
{
bfd_lock_sessions(p);
rem_node(&s->n);
state = s->loc_state;
diag = s->loc_diag;
bfd_unlock_sessions(p);
s->notify_running = 1;
WALK_LIST_DELSAFE(n, nn, s->request_list)
bfd_request_notify(SKIP_BACK(struct bfd_request, n, n), state, diag);
s->notify_running = 0;
/* Remove the session if all requests were removed in notify hooks */
if (EMPTY_LIST(s->request_list))
bfd_remove_session(p, s);
}
return 0;
}
static inline void
bfd_notify_kick(struct bfd_proto *p)
{
pipe_kick(p->notify_ws->fd);
}
static void
bfd_noterr_hook(sock *sk, int err)
{
struct bfd_proto *p = sk->data;
log(L_ERR "%s: Notify socket error: %m", p->p.name, err);
}
static void
bfd_notify_init(struct bfd_proto *p)
{
int pfds[2];
sock *sk;
int rv = pipe(pfds);
if (rv < 0)
die("pipe: %m");
sk = sk_new(p->p.pool);
sk->type = SK_MAGIC;
sk->rx_hook = bfd_notify_hook;
sk->err_hook = bfd_noterr_hook;
sk->fd = pfds[0];
sk->data = p;
if (sk_open(sk) < 0)
die("bfd: sk_open failed");
p->notify_rs = sk;
/* The write sock is not added to any event loop */
sk = sk_new(p->p.pool);
sk->type = SK_MAGIC;
sk->fd = pfds[1];
sk->data = p;
sk->flags = SKF_THREAD;
if (sk_open(sk) < 0)
die("bfd: sk_open failed");
p->notify_ws = sk;
}
/*
* BFD protocol glue
*/
void
bfd_init_all(void)
{
init_list(&bfd_proto_list);
init_list(&bfd_wait_list);
}
static struct proto *
bfd_init(struct proto_config *c)
{
struct proto *p = proto_new(c);
p->neigh_notify = bfd_neigh_notify;
return p;
}
static int
bfd_start(struct proto *P)
{
struct bfd_proto *p = (struct bfd_proto *) P;
struct bfd_config *cf = (struct bfd_config *) (P->cf);
p->loop = birdloop_new();
p->tpool = rp_new(NULL, "BFD thread root");
pthread_spin_init(&p->lock, PTHREAD_PROCESS_PRIVATE);
p->session_slab = sl_new(P->pool, sizeof(struct bfd_session));
HASH_INIT(p->session_hash_id, P->pool, 8);
HASH_INIT(p->session_hash_ip, P->pool, 8);
init_list(&p->iface_list);
init_list(&p->notify_list);
bfd_notify_init(p);
add_tail(&bfd_proto_list, &p->bfd_node);
birdloop_enter(p->loop);
if (cf->accept_ipv4 && cf->accept_direct)
p->rx4_1 = bfd_open_rx_sk(p, 0, SK_IPV4);
if (cf->accept_ipv4 && cf->accept_multihop)
p->rx4_m = bfd_open_rx_sk(p, 1, SK_IPV4);
if (cf->accept_ipv6 && cf->accept_direct)
p->rx6_1 = bfd_open_rx_sk(p, 0, SK_IPV6);
if (cf->accept_ipv6 && cf->accept_multihop)
p->rx6_m = bfd_open_rx_sk(p, 1, SK_IPV6);
birdloop_leave(p->loop);
bfd_take_requests(p);
struct bfd_neighbor *n;
WALK_LIST(n, cf->neigh_list)
bfd_start_neighbor(p, n);
birdloop_start(p->loop);
return PS_UP;
}
static int
bfd_shutdown(struct proto *P)
{
struct bfd_proto *p = (struct bfd_proto *) P;
struct bfd_config *cf = (struct bfd_config *) (P->cf);
rem_node(&p->bfd_node);
birdloop_stop(p->loop);
struct bfd_neighbor *n;
WALK_LIST(n, cf->neigh_list)
bfd_stop_neighbor(p, n);
bfd_drop_requests(p);
/* FIXME: This is hack */
birdloop_enter(p->loop);
rfree(p->tpool);
birdloop_leave(p->loop);
birdloop_free(p->loop);
return PS_DOWN;
}
static int
bfd_reconfigure(struct proto *P, struct proto_config *c)
{
struct bfd_proto *p = (struct bfd_proto *) P;
struct bfd_config *old = (struct bfd_config *) (P->cf);
struct bfd_config *new = (struct bfd_config *) c;
struct bfd_iface *ifa;
/* TODO: Improve accept reconfiguration */
if ((new->accept_ipv4 != old->accept_ipv4) ||
(new->accept_ipv6 != old->accept_ipv6) ||
(new->accept_direct != old->accept_direct) ||
(new->accept_multihop != old->accept_multihop))
return 0;
birdloop_mask_wakeups(p->loop);
WALK_LIST(ifa, p->iface_list)
bfd_reconfigure_iface(p, ifa, new);
HASH_WALK(p->session_hash_id, next_id, s)
{
if (s->ifa->changed)
bfd_reconfigure_session(p, s);
}
HASH_WALK_END;
bfd_reconfigure_neighbors(p, new);
birdloop_unmask_wakeups(p->loop);
return 1;
}
static void
bfd_copy_config(struct proto_config *dest, struct proto_config *src UNUSED)
{
struct bfd_config *d = (struct bfd_config *) dest;
// struct bfd_config *s = (struct bfd_config *) src;
/* We clean up patt_list and neigh_list, neighbors and ifaces are non-sharable */
init_list(&d->patt_list);
init_list(&d->neigh_list);
}
void
bfd_show_sessions(struct proto *P)
{
byte tbuf[TM_DATETIME_BUFFER_SIZE];
struct bfd_proto *p = (struct bfd_proto *) P;
uint state, diag UNUSED;
btime tx_int, timeout;
const char *ifname;
if (p->p.proto_state != PS_UP)
{
cli_msg(-1020, "%s: is not up", p->p.name);
return;
}
cli_msg(-1020, "%s:", p->p.name);
cli_msg(-1020, "%-25s %-10s %-10s %-12s %8s %8s",
"IP address", "Interface", "State", "Since", "Interval", "Timeout");
HASH_WALK(p->session_hash_id, next_id, s)
{
/* FIXME: this is thread-unsafe, but perhaps harmless */
state = s->loc_state;
diag = s->loc_diag;
ifname = (s->ifa && s->ifa->iface) ? s->ifa->iface->name : "---";
tx_int = s->last_tx ? MAX(s->des_min_tx_int, s->rem_min_rx_int) : 0;
timeout = (btime) MAX(s->req_min_rx_int, s->rem_min_tx_int) * s->rem_detect_mult;
state = (state < 4) ? state : 0;
tm_format_time(tbuf, &config->tf_proto, s->last_state_change);
cli_msg(-1020, "%-25I %-10s %-10s %-12s %7t %7t",
s->addr, ifname, bfd_state_names[state], tbuf, tx_int, timeout);
}
HASH_WALK_END;
}
struct protocol proto_bfd = {
.name = "BFD",
.template = "bfd%d",
.class = PROTOCOL_BFD,
.proto_size = sizeof(struct bfd_proto),
.config_size = sizeof(struct bfd_config),
.init = bfd_init,
.start = bfd_start,
.shutdown = bfd_shutdown,
.reconfigure = bfd_reconfigure,
.copy_config = bfd_copy_config,
};