bird/proto/bfd/bfd.c

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/*
* BIRD -- Bidirectional Forwarding Detection (BFD)
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
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/**
* 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). 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
*/
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#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
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#define HASH_IP_KEY(n) n->addr
#define HASH_IP_NEXT(n) n->next_ip
#define HASH_IP_EQ(a,b) ipa_equal(a,b)
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#define HASH_IP_FN(k) ipa_hash(k)
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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);
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/*
* 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)
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{
struct bfd_proto *p = s->ifa->bfd;
uint old_state = s->loc_state;
int notify;
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if (state == old_state)
return;
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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();
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notify = !NODE_VALID(&s->n);
if (notify)
add_tail(&p->notify_list, &s->n);
bfd_unlock_sessions(p);
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if (state == BFD_STATE_UP)
bfd_session_set_min_tx(s, s->cf.min_tx_int);
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if (old_state == BFD_STATE_UP)
bfd_session_set_min_tx(s, s->cf.idle_tx_int);
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if (notify)
bfd_notify_kick(p);
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}
static void
bfd_session_update_tx_interval(struct bfd_session *s)
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{
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 %
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s->tx_timer->recurrent = tx_int_l;
s->tx_timer->randomize = tx_int_h - tx_int_l;
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/* Do not set timer if no previous event */
if (!s->last_tx)
return;
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/* Set timer relative to last tx_timer event */
tm_set(s->tx_timer, s->last_tx + tx_int_l);
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}
static void
bfd_session_update_detection_time(struct bfd_session *s, int kick)
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{
btime timeout = (btime) MAX(s->req_min_rx_int, s->rem_min_tx_int) * s->rem_detect_mult;
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if (kick)
s->last_rx = current_time();
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if (!s->last_rx)
return;
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tm_set(s->hold_timer, s->last_rx + timeout);
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}
static void
bfd_session_control_tx_timer(struct bfd_session *s, int reset)
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{
// if (!s->opened) goto stop;
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if (s->passive && (s->rem_id == 0))
goto stop;
if (s->rem_demand_mode &&
!s->poll_active &&
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(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);
}
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return;
stop:
tm_stop(s->tx_timer);
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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;
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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);
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}
static void
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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;
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/* 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)
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{
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))
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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);
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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);
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}
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;
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/* 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)
{
return HASH_FIND(p->session_hash_ip, HASH_IP, addr);
}
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_alloc(p->session_slab);
bzero(s, sizeof(struct bfd_session));
s->addr = addr;
s->ifa = ifa;
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 *nic = bfd_find_iface_config(nc, ifa->iface);
ifa->changed = !!memcmp(nic, ifa->cf, sizeof(struct bfd_iface_config));
/* This should be probably changed to not access ifa->cf from the BFD thread */
birdloop_enter(p->loop);
ifa->cf = nic;
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;
struct bfd_session *s = bfd_find_session_by_addr(p, req->addr);
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;
}
}
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static void
bfd_start_neighbor(struct bfd_proto *p, struct bfd_neighbor *n)
{
n->active = 1;
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if (n->multihop)
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{
n->req = bfd_request_session(p->p.pool, n->addr, n->local, NULL, p->p.vrf, NULL, NULL, NULL);
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return;
}
struct neighbor *nb = neigh_find(&p->p, n->addr, n->iface, NEF_STICKY);
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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);
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return;
}
n->neigh = nb;
nb->data = n;
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if (nb->scope > 0)
bfd_neigh_notify(nb);
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else
TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", n->addr, n->iface);
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}
static void
bfd_stop_neighbor(struct bfd_proto *p UNUSED, struct bfd_neighbor *n)
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{
if (n->neigh)
n->neigh->data = NULL;
n->neigh = NULL;
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rfree(n->req);
n->req = NULL;
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}
static inline int
bfd_same_neighbor(struct bfd_neighbor *x, struct bfd_neighbor *y)
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{
return ipa_equal(x->addr, y->addr) && ipa_equal(x->local, y->local) &&
(x->iface == y->iface) && (x->multihop == y->multihop);
}
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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;
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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:;
}
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WALK_LIST(nn, new->neigh_list)
if (!nn->active)
bfd_start_neighbor(p, nn);
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}
/*
* 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;
}
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/*
* BFD protocol glue
*/
void
bfd_init_all(void)
{
init_list(&bfd_proto_list);
init_list(&bfd_wait_list);
}
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static struct proto *
bfd_init(struct proto_config *c)
{
struct proto *p = proto_new(c);
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p->neigh_notify = bfd_neigh_notify;
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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);
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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);
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bfd_take_requests(p);
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struct bfd_neighbor *n;
WALK_LIST(n, cf->neigh_list)
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bfd_start_neighbor(p, n);
birdloop_start(p->loop);
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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);
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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);
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return PS_DOWN;
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}
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);
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struct bfd_config *new = (struct bfd_config *) c;
struct bfd_iface *ifa;
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/* 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;
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bfd_reconfigure_neighbors(p, new);
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birdloop_unmask_wakeups(p->loop);
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return 1;
}
static void
bfd_copy_config(struct proto_config *dest, struct proto_config *src UNUSED)
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{
struct bfd_config *d = (struct bfd_config *) dest;
// struct bfd_config *s = (struct bfd_config *) src;
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/* We clean up patt_list and neigh_list, neighbors and ifaces are non-sharable */
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init_list(&d->patt_list);
init_list(&d->neigh_list);
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}
void
bfd_show_sessions(struct proto *P)
{
byte tbuf[TM_DATETIME_BUFFER_SIZE];
struct bfd_proto *p = (struct bfd_proto *) P;
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uint state, diag UNUSED;
btime tx_int, timeout;
const char *ifname;
if (p->p.proto_state != PS_UP)
{
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cli_msg(-1020, "%s: is not up", p->p.name);
return;
}
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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;
}
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struct protocol proto_bfd = {
.name = "BFD",
.template = "bfd%d",
.class = PROTOCOL_BFD,
.proto_size = sizeof(struct bfd_proto),
.config_size = sizeof(struct bfd_config),
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.init = bfd_init,
.start = bfd_start,
.shutdown = bfd_shutdown,
.reconfigure = bfd_reconfigure,
.copy_config = bfd_copy_config,
};