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BFD: Fix session reconfiguration locking order

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The sessions have to be updated asynchronously to avoid
cross-locking between protocols.

Testsuite: cf-ibgp-bfd-switch, cf-ibgp-multi-bfd-auth
Fixes: #139

Thanks to Daniel Suchy <danny@danysek.cz> for reporting:
https://trubka.network.cz/pipermail/bird-users/2024-December/017984.html
This commit is contained in:
Maria Matejka 2024-12-21 19:02:22 +01:00
parent 6779e5da69
commit 8349536278
5 changed files with 98 additions and 120 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
nest/bfd.h
View File

@ -18,8 +18,11 @@ struct bfd_options {
u32 min_tx_int; u32 min_tx_int;
u32 idle_tx_int; u32 idle_tx_int;
u8 multiplier; u8 multiplier;
u8 passive; PACKED enum bfd_opt_passive {
u8 passive_set; BFD_OPT_PASSIVE_UNKNOWN = 0,
BFD_OPT_PASSIVE,
BFD_OPT_NOT_PASSIVE,
} passive;
u8 mode; u8 mode;
u8 auth_type; /* Authentication type (BFD_AUTH_*) */ u8 auth_type; /* Authentication type (BFD_AUTH_*) */
list *passwords; /* Passwords for authentication */ list *passwords; /* Passwords for authentication */

144
proto/bfd/bfd.c
View File

@ -172,17 +172,17 @@ static void bfd_free_iface(struct bfd_iface *ifa);
* BFD sessions * BFD sessions
*/ */
static inline struct bfd_session_config static inline struct bfd_options
bfd_merge_options(const struct bfd_iface_config *cf, const struct bfd_options *opts) bfd_merge_options(const struct bfd_options *bottom, const struct bfd_options *top)
{ {
return (struct bfd_session_config) { return (struct bfd_options) {
.min_rx_int = opts->min_rx_int ?: cf->min_rx_int, .min_rx_int = top->min_rx_int ?: bottom->min_rx_int,
.min_tx_int = opts->min_tx_int ?: cf->min_tx_int, .min_tx_int = top->min_tx_int ?: bottom->min_tx_int,
.idle_tx_int = opts->idle_tx_int ?: cf->idle_tx_int, .idle_tx_int = top->idle_tx_int ?: bottom->idle_tx_int,
.multiplier = opts->multiplier ?: cf->multiplier, .multiplier = top->multiplier ?: bottom->multiplier,
.passive = opts->passive_set ? opts->passive : cf->passive, .passive = top->passive ?: bottom->passive,
.auth_type = opts->auth_type ?: cf->auth_type, .auth_type = top->auth_type ?: bottom->auth_type,
.passwords = opts->passwords ?: cf->passwords, .passwords = top->passwords ?: bottom->passwords,
}; };
} }
@ -478,7 +478,7 @@ bfd_add_session(struct bfd_proto *p, ip_addr addr, ip_addr local, struct iface *
HASH_INSERT(p->session_hash_id, HASH_ID, s); HASH_INSERT(p->session_hash_id, HASH_ID, s);
HASH_INSERT(p->session_hash_ip, HASH_IP, s); HASH_INSERT(p->session_hash_ip, HASH_IP, s);
s->cf = bfd_merge_options(ifa->cf, opts); s->cf = bfd_merge_options(&ifa->cf->opts, opts);
/* Initialization of state variables - see RFC 5880 6.8.1 */ /* Initialization of state variables - see RFC 5880 6.8.1 */
s->loc_state = BFD_STATE_DOWN; s->loc_state = BFD_STATE_DOWN;
@ -561,26 +561,58 @@ bfd_remove_session(struct bfd_proto *p, struct bfd_session *s)
birdloop_leave(p->p.loop); birdloop_leave(p->p.loop);
} }
struct bfd_reconfigure_sessions_deferred_call {
struct deferred_call dc;
struct bfd_proto *p;
config_ref old_config;
};
static void static void
bfd_reconfigure_session(struct bfd_proto *p, struct bfd_session *s) bfd_reconfigure_sessions(struct deferred_call *dc)
{ {
if (EMPTY_LIST(s->request_list)) SKIP_BACK_DECLARE(struct bfd_reconfigure_sessions_deferred_call,
return; brsdc, dc, dc);
ASSERT_DIE(birdloop_inside(p->p.loop)); struct bfd_proto *p = brsdc->p;
birdloop_enter(p->p.loop);
SKIP_BACK_DECLARE(struct bfd_request, req, n, HEAD(s->request_list)); HASH_WALK(p->session_hash_id, next_id, s)
s->cf = bfd_merge_options(s->ifa->cf, &req->opts); {
if (!EMPTY_LIST(s->request_list))
{
SKIP_BACK_DECLARE(struct bfd_request, req, n, HEAD(s->request_list));
struct bfd_options opts = bfd_merge_options(&s->ifa->cf->opts, &req->opts);
u32 tx = (s->loc_state == BFD_STATE_UP) ? s->cf.min_tx_int : s->cf.idle_tx_int; #define CHK(x) (opts.x != s->cf.x) ||
bfd_session_set_min_tx(s, tx); bool reload = MACRO_FOREACH(CHK,
bfd_session_set_min_rx(s, s->cf.min_rx_int); min_rx_int,
s->detect_mult = s->cf.multiplier; min_tx_int,
s->passive = s->cf.passive; idle_tx_int,
multiplier,
passive) false; /* terminating the || chain */
#undef CHK
bfd_session_control_tx_timer(s, 0); s->cf = opts;
TRACE(D_EVENTS, "Session to %I reconfigured", s->addr); if (reload)
{
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);
TRACE(D_EVENTS, "Session to %I reconfigured", s->addr);
}
}
}
HASH_WALK_END;
birdloop_leave(p->p.loop);
/* Now the config is clean */
OBSREF_CLEAR(brsdc->old_config);
} }
@ -589,10 +621,12 @@ bfd_reconfigure_session(struct bfd_proto *p, struct bfd_session *s)
*/ */
static struct bfd_iface_config bfd_default_iface = { static struct bfd_iface_config bfd_default_iface = {
.min_rx_int = BFD_DEFAULT_MIN_RX_INT, .opts = {
.min_tx_int = BFD_DEFAULT_MIN_TX_INT, .min_rx_int = BFD_DEFAULT_MIN_RX_INT,
.idle_tx_int = BFD_DEFAULT_IDLE_TX_INT, .min_tx_int = BFD_DEFAULT_MIN_TX_INT,
.multiplier = BFD_DEFAULT_MULTIPLIER, .idle_tx_int = BFD_DEFAULT_IDLE_TX_INT,
.multiplier = BFD_DEFAULT_MULTIPLIER,
},
}; };
static inline struct bfd_iface_config * static inline struct bfd_iface_config *
@ -650,24 +684,6 @@ bfd_free_iface(struct bfd_iface *ifa)
mb_free(ifa); mb_free(ifa);
} }
static void
bfd_reconfigure_iface(struct bfd_proto *p UNUSED, 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 */
ifa->cf = new;
}
/* /*
* BFD requests * BFD requests
@ -900,20 +916,7 @@ bfd_request_session(pool *p, ip_addr addr, ip_addr local,
void void
bfd_update_request(struct bfd_request *req, const struct bfd_options *opts) 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; req->opts = *opts;
if (s)
{
struct bfd_proto *p = s->ifa->bfd;
birdloop_enter(p->p.loop);
bfd_reconfigure_session(p, s);
birdloop_leave(p->p.loop);
}
} }
static void static void
@ -1193,21 +1196,22 @@ bfd_reconfigure(struct proto *P, struct proto_config *c)
(new->zero_udp6_checksum_rx != old->zero_udp6_checksum_rx)) (new->zero_udp6_checksum_rx != old->zero_udp6_checksum_rx))
return 0; return 0;
birdloop_mask_wakeups(p->p.loop);
WALK_LIST(ifa, p->iface_list) WALK_LIST(ifa, p->iface_list)
bfd_reconfigure_iface(p, ifa, new); ifa->cf = bfd_find_iface_config(new, ifa->iface);
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); bfd_reconfigure_neighbors(p, new);
birdloop_unmask_wakeups(p->p.loop); /* Sessions get reconfigured after all the config is applied */
struct bfd_reconfigure_sessions_deferred_call brsdc = {
.dc.hook = bfd_reconfigure_sessions,
.p = p,
};
SKIP_BACK_DECLARE(struct bfd_reconfigure_sessions_deferred_call,
brsdcp, dc, defer_call(&brsdc.dc, sizeof brsdc));
/* We need to keep the old config alive until all the sessions get
* reconfigured */
OBSREF_SET(brsdcp->old_config, P->cf->global);
return 1; return 1;
} }

21
proto/bfd/bfd.h
View File

@ -54,24 +54,7 @@ struct bfd_config
struct bfd_iface_config struct bfd_iface_config
{ {
struct iface_patt i; struct iface_patt i;
u32 min_rx_int; struct bfd_options opts;
u32 min_tx_int;
u32 idle_tx_int;
u8 multiplier;
u8 passive;
u8 auth_type; /* Authentication type (BFD_AUTH_*) */
list *passwords; /* Passwords for authentication */
};
struct bfd_session_config
{
u32 min_rx_int;
u32 min_tx_int;
u32 idle_tx_int;
u8 multiplier;
u8 passive;
u8 auth_type; /* Authentication type (BFD_AUTH_*) */
list *passwords; /* Passwords for authentication */
}; };
struct bfd_neighbor struct bfd_neighbor
@ -146,7 +129,7 @@ struct bfd_session
u32 loc_id; /* Local session ID (local discriminator) */ u32 loc_id; /* Local session ID (local discriminator) */
u32 rem_id; /* Remote session ID (remote discriminator) */ u32 rem_id; /* Remote session ID (remote discriminator) */
struct bfd_session_config cf; /* Static configuration parameters */ struct bfd_options cf; /* Static configuration parameters */
u32 des_min_tx_int; /* Desired min rx interval, local option */ u32 des_min_tx_int; /* Desired min rx interval, local option */
u32 des_min_tx_new; /* Used for des_min_tx_int change */ u32 des_min_tx_new; /* Used for des_min_tx_int change */

42
proto/bfd/config.Y
View File

@ -86,44 +86,37 @@ bfd_iface_start:
add_tail(&BFD_CFG->patt_list, NODE this_ipatt); add_tail(&BFD_CFG->patt_list, NODE this_ipatt);
init_list(&this_ipatt->ipn_list); init_list(&this_ipatt->ipn_list);
BFD_IFACE->min_rx_int = BFD_DEFAULT_MIN_RX_INT; this_bfd_opts = &BFD_IFACE->opts;
BFD_IFACE->min_tx_int = BFD_DEFAULT_MIN_TX_INT;
BFD_IFACE->idle_tx_int = BFD_DEFAULT_IDLE_TX_INT; this_bfd_opts->min_rx_int = BFD_DEFAULT_MIN_RX_INT;
BFD_IFACE->multiplier = BFD_DEFAULT_MULTIPLIER; this_bfd_opts->min_tx_int = BFD_DEFAULT_MIN_TX_INT;
this_bfd_opts->idle_tx_int = BFD_DEFAULT_IDLE_TX_INT;
this_bfd_opts->multiplier = BFD_DEFAULT_MULTIPLIER;
reset_passwords(); reset_passwords();
}; };
bfd_iface_finish: bfd_iface_finish:
{ {
BFD_IFACE->passwords = get_passwords(); this_bfd_opts->passwords = get_passwords();
if (!BFD_IFACE->auth_type != !BFD_IFACE->passwords) if (!this_bfd_opts->auth_type != !this_bfd_opts->passwords)
cf_warn("Authentication and password options should be used together"); cf_warn("Authentication and password options should be used together");
if (BFD_IFACE->passwords) if (this_bfd_opts->passwords)
{ {
struct password_item *pass; struct password_item *pass;
WALK_LIST(pass, *BFD_IFACE->passwords) WALK_LIST(pass, *this_bfd_opts->passwords)
{ {
if (pass->alg) if (pass->alg)
cf_error("Password algorithm option not available in BFD protocol"); cf_error("Password algorithm option not available in BFD protocol");
pass->alg = bfd_auth_type_to_hash_alg[BFD_IFACE->auth_type]; pass->alg = bfd_auth_type_to_hash_alg[this_bfd_opts->auth_type];
} }
} }
};
bfd_iface_item: this_bfd_opts = NULL;
INTERVAL expr_us { BFD_IFACE->min_rx_int = BFD_IFACE->min_tx_int = $2; } };
| MIN RX INTERVAL expr_us { BFD_IFACE->min_rx_int = $4; }
| MIN TX INTERVAL expr_us { BFD_IFACE->min_tx_int = $4; }
| IDLE TX INTERVAL expr_us { BFD_IFACE->idle_tx_int = $4; }
| MULTIPLIER expr { BFD_IFACE->multiplier = $2; }
| PASSIVE bool { BFD_IFACE->passive = $2; }
| AUTHENTICATION bfd_auth_type { BFD_IFACE->auth_type = $2; }
| password_list {}
;
bfd_auth_type: bfd_auth_type:
NONE { $$ = BFD_AUTH_NONE; } NONE { $$ = BFD_AUTH_NONE; }
@ -134,14 +127,9 @@ bfd_auth_type:
| METICULOUS KEYED SHA1 { $$ = BFD_AUTH_METICULOUS_KEYED_SHA1; } | METICULOUS KEYED SHA1 { $$ = BFD_AUTH_METICULOUS_KEYED_SHA1; }
; ;
bfd_iface_opts:
/* empty */
| bfd_iface_opts bfd_iface_item ';'
;
bfd_iface_opt_list: bfd_iface_opt_list:
/* empty */ /* empty */
| '{' bfd_iface_opts '}' | '{' bfd_items '}'
; ;
bfd_iface: bfd_iface:
@ -194,7 +182,7 @@ bfd_item:
| MIN TX INTERVAL expr_us { this_bfd_opts->min_tx_int = $4; } | MIN TX INTERVAL expr_us { this_bfd_opts->min_tx_int = $4; }
| IDLE TX INTERVAL expr_us { this_bfd_opts->idle_tx_int = $4; } | IDLE TX INTERVAL expr_us { this_bfd_opts->idle_tx_int = $4; }
| MULTIPLIER expr { this_bfd_opts->multiplier = $2; } | MULTIPLIER expr { this_bfd_opts->multiplier = $2; }
| PASSIVE bool { this_bfd_opts->passive = $2; this_bfd_opts->passive_set = 1; } | PASSIVE bool { this_bfd_opts->passive = $2 ? BFD_OPT_PASSIVE : BFD_OPT_NOT_PASSIVE; }
| GRACEFUL { this_bfd_opts->mode = BGP_BFD_GRACEFUL; } | GRACEFUL { this_bfd_opts->mode = BGP_BFD_GRACEFUL; }
| AUTHENTICATION bfd_auth_type { this_bfd_opts->auth_type = $2; } | AUTHENTICATION bfd_auth_type { this_bfd_opts->auth_type = $2; }
| password_list {} | password_list {}

4
proto/bfd/packets.c
View File

@ -109,7 +109,7 @@ const u8 bfd_auth_type_to_hash_alg[] = {
static void static void
bfd_fill_authentication(struct bfd_proto *p, struct bfd_session *s, struct bfd_ctl_packet *pkt) bfd_fill_authentication(struct bfd_proto *p, struct bfd_session *s, struct bfd_ctl_packet *pkt)
{ {
struct bfd_session_config *cf = &s->cf; struct bfd_options *cf = &s->cf;
struct password_item *pass = password_find(cf->passwords, 0); struct password_item *pass = password_find(cf->passwords, 0);
uint meticulous = 0; uint meticulous = 0;
@ -179,7 +179,7 @@ bfd_fill_authentication(struct bfd_proto *p, struct bfd_session *s, struct bfd_c
static int static int
bfd_check_authentication(struct bfd_proto *p, struct bfd_session *s, struct bfd_ctl_packet *pkt) bfd_check_authentication(struct bfd_proto *p, struct bfd_session *s, struct bfd_ctl_packet *pkt)
{ {
struct bfd_session_config *cf = &s->cf; struct bfd_options *cf = &s->cf;
const char *err_dsc = NULL; const char *err_dsc = NULL;
uint err_val = 0; uint err_val = 0;
uint auth_type = 0; uint auth_type = 0;