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Interface updates are asynchronous

Browse Source 
Instead of propagating interface updates as they are loaded from kernel,
they are enqueued and all the notifications are called from a
protocol-specific event. This change allows to break the locking loop
between protocols and interfaces.

Anyway, this change is based on v2 branch to keep the changes between v2
and v3 smaller.
This commit is contained in:
Maria Matejka 2023-01-31 13:07:46 +01:00
parent 64e0877525
commit c354e8f4c1
15 changed files with 315 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

203
nest/iface.c
View File

@ -34,6 +34,9 @@
#include "conf/conf.h"
#include "sysdep/unix/krt.h"
static TLIST_LIST(ifsub) iface_sub_list;
static slab *iface_sub_slab;
static pool *if_pool;
list iface_list;
@ -140,13 +143,51 @@ if_copy(struct iface *to, struct iface *from)
to->flags = from->flags | (to->flags & IF_TMP_DOWN);
to->mtu = from->mtu;
to->master_index = from->master_index;
to->master = from->master;
if_unlink(to->master);
if_link(to->master = from->master);
}
void
if_enqueue_notify_to(struct iface_notification x, struct iface_subscription *s)
{
switch (x.type) {
case IFNOT_ADDRESS:
if (!s->ifa_notify) return;
ifa_link(x.a);
break;
case IFNOT_INTERFACE:
if (!s->if_notify) return;
if_link(x.i);
break;
case IFNOT_NEIGHBOR:
if (!s->neigh_notify) return;
neigh_link(x.n);
break;
default:
bug("Unknown interface notification type: %d", x.type);
}
struct iface_notification *in = sl_alloc(iface_sub_slab);
*in = x;
ifnot_add_tail(&s->queue, in);
ev_schedule(&s->event);
}
void
if_enqueue_notify(struct iface_notification x)
{
WALK_TLIST(ifsub, s, &iface_sub_list)
if_enqueue_notify_to(x, s);
}
static inline void
ifa_send_notify(struct proto *p, unsigned c, struct ifa *a)
ifa_send_notify(struct iface_subscription *s, unsigned c, struct ifa *a)
{
if (p->ifa_notify &&
struct proto *p = SKIP_BACK(struct proto, iface_sub, s);
if (s->ifa_notify &&
(p->proto_state != PS_DOWN) &&
(!p->vrf || p->vrf == a->iface->master))
{
@ -154,19 +195,21 @@ ifa_send_notify(struct proto *p, unsigned c, struct ifa *a)
log(L_TRACE "%s < address %N on interface %s %s",
p->name, &a->prefix, a->iface->name,
(c & IF_CHANGE_UP) ? "added" : "removed");
p->ifa_notify(p, c, a);
s->ifa_notify(p, c, a);
}
}
static void
ifa_notify_change_(unsigned c, struct ifa *a)
{
struct proto *p;
DBG("IFA change notification (%x) for %s:%I\n", c, a->iface->name, a->ip);
WALK_LIST(p, proto_list)
ifa_send_notify(p, c, a);
if_enqueue_notify((struct iface_notification) {
.type = IFNOT_ADDRESS,
.a = a,
.flags = c,
});
}
static inline void
@ -182,9 +225,11 @@ ifa_notify_change(unsigned c, struct ifa *a)
}
static inline void
if_send_notify(struct proto *p, unsigned c, struct iface *i)
if_send_notify(struct iface_subscription *s, unsigned c, struct iface *i)
{
if (p->if_notify &&
struct proto *p = SKIP_BACK(struct proto, iface_sub, s);
if (s->if_notify &&
(p->proto_state != PS_DOWN) &&
(!p->vrf || p->vrf == i->master))
{
@ -197,14 +242,13 @@ if_send_notify(struct proto *p, unsigned c, struct iface *i)
(c & IF_CHANGE_PREFERRED) ? "changes preferred address" :
(c & IF_CHANGE_CREATE) ? "created" :
"sends unknown event");
p->if_notify(p, c, i);
s->if_notify(p, c, i);
}
}
static void
if_notify_change(unsigned c, struct iface *i)
{
struct proto *p;
struct ifa *a;
if (i->flags & IF_JUST_CREATED)
@ -225,8 +269,11 @@ if_notify_change(unsigned c, struct iface *i)
WALK_LIST(a, i->addrs)
ifa_notify_change_(IF_CHANGE_DOWN, a);
WALK_LIST(p, proto_list)
if_send_notify(p, c, i);
if_enqueue_notify((struct iface_notification) {
.type = IFNOT_INTERFACE,
.i = i,
.flags = c,
});
if (c & IF_CHANGE_UP)
WALK_LIST(a, i->addrs)
@ -320,6 +367,7 @@ if_update(struct iface *new)
new->llv6 = i->llv6;
new->sysdep = i->sysdep;
memcpy(&new->addrs, &i->addrs, sizeof(i->addrs));
memcpy(&new->neighbors, &i->neighbors, sizeof(i->neighbors));
memcpy(i, new, sizeof(*i));
i->flags &= ~IF_UP; /* IF_TMP_DOWN will be added later */
goto newif;
@ -334,9 +382,10 @@ if_update(struct iface *new)
}
i = mb_alloc(if_pool, sizeof(struct iface));
memcpy(i, new, sizeof(*i));
if_link(i->master);
init_list(&i->addrs);
newif:
init_list(&i->neighbors);
newif:
i->flags |= IF_UPDATED | IF_TMP_DOWN; /* Tmp down as we don't have addresses yet */
add_tail(&iface_list, &i->n);
return i;
@ -386,31 +435,116 @@ if_end_update(void)
}
}
void
if_link(struct iface *i)
{
if (i)
i->uc++;
}
void
if_unlink(struct iface *i)
{
if (i)
i->uc--;
/* TODO: Do some interface object cleanup */
}
static void
iface_notify_hook(void *_s)
{
struct iface_subscription *s = _s;
while (!EMPTY_TLIST(ifnot, &s->queue))
{
struct iface_notification *n = THEAD(ifnot, &s->queue);
switch (n->type) {
case IFNOT_ADDRESS:
ifa_send_notify(s, n->flags, n->a);
ifa_unlink(n->a);
break;
case IFNOT_INTERFACE:
if_send_notify(s, n->flags, n->i);
if_unlink(n->i);
break;
case IFNOT_NEIGHBOR:
s->neigh_notify(n->n);
neigh_unlink(n->n);
break;
default:
bug("Bad interface notification type: %d", n->type);
}
ifnot_rem_node(&s->queue, n);
sl_free(n);
}
}
/**
* if_feed_baby - advertise interfaces to a new protocol
* @p: protocol to feed
* iface_subscribe - request interface updates
* @s: subscription structure
*
* When a new protocol starts, this function sends it a series
* of notifications about all existing interfaces.
*/
void
if_feed_baby(struct proto *p)
iface_subscribe(struct iface_subscription *s)
{
struct iface *i;
struct ifa *a;
ifsub_add_tail(&iface_sub_list, s);
s->event = (event) {
.hook = iface_notify_hook,
.data = s,
};
if (!p->if_notify && !p->ifa_notify) /* shortcut */
if (!s->if_notify && !s->ifa_notify) /* shortcut */
return;
struct iface *i;
DBG("Announcing interfaces to new protocol %s\n", p->name);
WALK_LIST(i, iface_list)
{
if_send_notify(p, IF_CHANGE_CREATE | ((i->flags & IF_UP) ? IF_CHANGE_UP : 0), i);
if_send_notify(s, IF_CHANGE_CREATE | ((i->flags & IF_UP) ? IF_CHANGE_UP : 0), i);
struct ifa *a;
if (i->flags & IF_UP)
WALK_LIST(a, i->addrs)
ifa_send_notify(p, IF_CHANGE_CREATE | IF_CHANGE_UP, a);
ifa_send_notify(s, IF_CHANGE_CREATE | IF_CHANGE_UP, a);
}
}
/**
* iface_unsubscribe - unsubscribe from interface updates
* @s: subscription structure
*/
void
iface_unsubscribe(struct iface_subscription *s)
{
ifsub_rem_node(&iface_sub_list, s);
ev_postpone(&s->event);
WALK_TLIST_DELSAFE(ifnot, n, &s->queue)
{
switch (n->type)
{
case IFNOT_ADDRESS:
ifa_unlink(n->a);
break;
case IFNOT_INTERFACE:
if_unlink(n->i);
break;
case IFNOT_NEIGHBOR:
neigh_unlink(n->n);
break;
default:
bug("Bad interface notification type: %d", n->type);
}
ifnot_rem_node(&s->queue, n);
sl_free(n);
}
}
/**
* if_find_by_index - find interface by ifindex
* @idx: ifindex
@ -600,6 +734,8 @@ ifa_update(struct ifa *a)
b = mb_alloc(if_pool, sizeof(struct ifa));
memcpy(b, a, sizeof(struct ifa));
ifa_link(b);
if_link(i);
add_tail(&i->addrs, &b->n);
b->flags |= IA_UPDATED;
@ -646,11 +782,29 @@ ifa_delete(struct ifa *a)
if (i->flags & IF_UP)
ifa_notify_change(IF_CHANGE_DOWN, b);
mb_free(b);
ifa_unlink(b);
return;
}
}
void ifa_link(struct ifa *a)
{
if (a)
a->uc++;
}
void ifa_unlink(struct ifa *a)
{
if (!a)
return;
if (--a->uc)
return;
if_unlink(a->iface);
mb_free(a);
}
u32
if_choose_router_id(struct iface_patt *mask, u32 old_id)
{
@ -706,6 +860,7 @@ if_init(void)
{
if_pool = rp_new(&root_pool, "Interfaces");
init_list(&iface_list);
iface_sub_slab = sl_new(if_pool, sizeof(struct iface_notification));
strcpy(default_vrf.name, "default");
neigh_init(if_pool);
}

66
nest/iface.h
View File

@ -9,6 +9,7 @@
#ifndef _BIRD_IFACE_H_
#define _BIRD_IFACE_H_
#include "lib/event.h"
#include "lib/lists.h"
#include "lib/tlists.h"
#include "lib/ip.h"
@ -27,6 +28,7 @@ struct ifa { /* Interface address */
ip_addr opposite; /* Opposite end of a point-to-point link */
unsigned scope; /* Interface address scope */
unsigned flags; /* Analogous to iface->flags */
unsigned uc; /* Use (link) count */
};
extern struct iface default_vrf;
@ -45,6 +47,7 @@ struct iface {
struct ifa *llv6; /* Primary link-local address for IPv6 */
ip4_addr sysdep; /* Arbitrary IPv4 address for internal sysdep use */
list neighbors; /* All neighbors on this interface */
unsigned uc; /* Use (link) count */
};
#define IF_UP 1 /* Currently just IF_ADMIN_UP */
@ -115,12 +118,15 @@ void ifa_delete(struct ifa *);
void if_start_update(void);
void if_end_partial_update(struct iface *);
void if_end_update(void);
void if_feed_baby(struct proto *);
struct iface *if_find_by_index(unsigned);
struct iface *if_find_by_name(const char *);
struct iface *if_get_by_name(const char *);
void if_recalc_all_preferred_addresses(void);
void if_link(struct iface *);
void if_unlink(struct iface *);
void ifa_link(struct ifa *);
void ifa_unlink(struct ifa *);
/* The Neighbor Cache */
@ -138,6 +144,7 @@ typedef struct neighbor {
u16 flags; /* NEF_* flags */
s16 scope; /* Address scope, -1 for unreachable neighbors,
SCOPE_HOST when it's our own address */
uint uc; /* Use (link) count */
} neighbor;
#define TLIST_PREFIX proto_neigh
@ -164,6 +171,63 @@ void neigh_ifa_up(struct ifa *a);
void neigh_ifa_down(struct ifa *a);
void neigh_init(struct pool *);
void neigh_link(neighbor *);
void neigh_unlink(neighbor *);
/*
* Notification mechanism
*/
#define TLIST_PREFIX ifnot
#define TLIST_TYPE struct iface_notification
#define TLIST_ITEM nn
#define TLIST_WANT_WALK
#define TLIST_WANT_ADD_TAIL
struct iface_notification {
TLIST_DEFAULT_NODE;
enum {
IFNOT_INVALID,
IFNOT_ADDRESS,
IFNOT_INTERFACE,
IFNOT_NEIGHBOR,
} type;
unsigned flags;
union {
struct ifa *a;
struct iface *i;
neighbor *n;
};
};
#include "lib/tlists.h"
#define TLIST_PREFIX ifsub
#define TLIST_TYPE struct iface_subscription
#define TLIST_ITEM n
#define TLIST_WANT_WALK
#define TLIST_WANT_ADD_TAIL
struct iface_subscription {
TLIST_DEFAULT_NODE;
event event;
TLIST_LIST(ifnot) queue;
void (*if_notify)(struct proto *, unsigned flags, struct iface *i);
void (*ifa_notify)(struct proto *, unsigned flags, struct ifa *a);
void (*neigh_notify)(struct neighbor *neigh);
};
#include "lib/tlists.h"
void if_enqueue_notify(struct iface_notification);
void if_enqueue_notify_to(struct iface_notification x, struct iface_subscription *s);
void iface_flush_notifications(struct iface_subscription *);
void iface_subscribe(struct iface_subscription *);
void iface_unsubscribe(struct iface_subscription *);
/*
* Interface Pattern Lists
*/

63
nest/neighbor.c
View File

@ -258,13 +258,15 @@ neigh_find(struct proto *p, ip_addr a, struct iface *iface, uint flags)
add_tail((scope >= 0) ? &iface->neighbors : &sticky_neigh_list, &n->if_n);
proto_neigh_add_tail(&p->neighbors, n);
n->addr = a;
n->ifa = addr;
n->iface = iface;
n->ifreq = ifreq;
ifa_link(n->ifa = addr);
if_link(n->iface = iface);
if_link(n->ifreq = ifreq);
n->proto = p;
n->flags = flags;
n->scope = scope;
neigh_link(n);
return n;
}
@ -309,19 +311,20 @@ neigh_dump_all(void)
static inline void
neigh_notify(neighbor *n)
{
if (n->proto && n->proto->neigh_notify && (n->proto->proto_state != PS_STOP))
n->proto->neigh_notify(n);
if_enqueue_notify_to((struct iface_notification) { .type = IFNOT_NEIGHBOR, .n = n, }, &n->proto->iface_sub);
}
static void
neigh_up(neighbor *n, struct iface *i, struct ifa *a, int scope)
{
DBG("Waking up sticky neighbor %I\n", n->addr);
n->iface = i;
n->ifa = a;
if_link(n->iface = i);
ifa_link(n->ifa = a);
n->scope = scope;
rem_node(&n->if_n);
rem_node(&n->if_n); /* HACK: Here the neighbor is always in the sticky list,
regardless whether it is sticky or not */
add_tail(&i->neighbors, &n->if_n);
neigh_notify(n);
@ -331,25 +334,48 @@ static void
neigh_down(neighbor *n)
{
DBG("Flushing neighbor %I on %s\n", n->addr, n->iface->name);
n->iface = NULL;
n->ifa = NULL;
n->scope = -1;
rem_node(&n->if_n);
add_tail(&sticky_neigh_list, &n->if_n);
ifa_unlink(n->ifa);
n->ifa = NULL;
if_unlink(n->iface);
n->iface = NULL;
neigh_notify(n);
}
static inline void
neigh_free(neighbor *n)
void
neigh_link(neighbor *n)
{
proto_neigh_rem_node(&n->proto->neighbors, n);
n->uc++;
}
void
neigh_unlink(neighbor *n)
{
if (--n->uc)
return;
struct proto *p = n->proto;
proto_neigh_rem_node(&p->neighbors, n);
if ((p->proto_state == PS_DOWN) && EMPTY_TLIST(proto_neigh, &p->neighbors))
ev_schedule(p->event);
n->proto = NULL;
rem_node(&n->n);
rem_node(&n->if_n);
ifa_unlink(n->ifa);
if_unlink(n->iface);
if_unlink(n->ifreq);
sl_free(n);
}
@ -399,7 +425,8 @@ neigh_update(neighbor *n, struct iface *iface)
{
if (ifa != n->ifa)
{
n->ifa = ifa;
ifa_unlink(n->ifa);
ifa_link(n->ifa = ifa);
neigh_notify(n);
}
@ -413,7 +440,7 @@ neigh_update(neighbor *n, struct iface *iface)
if ((n->scope < 0) && !(n->flags & NEF_STICKY))
{
neigh_free(n);
neigh_unlink(n);
return;
}
@ -534,8 +561,10 @@ neigh_ifa_down(struct ifa *a)
void
neigh_prune(struct proto *p)
{
while (!EMPTY_TLIST(proto_neigh, &p->neighbors))
neigh_free(THEAD(proto_neigh, &p->neighbors));
WALK_TLIST_DELSAFE(proto_neigh, n, &p->neighbors)
neigh_unlink(n);
ASSERT_DIE(EMPTY_TLIST(proto_neigh, &p->neighbors));
}
/**

14
nest/proto.c
View File

@ -57,7 +57,11 @@ static inline void channel_reset_limit(struct channel_limit *l);
static inline int proto_is_done(struct proto *p)
{ return (p->proto_state == PS_DOWN) && (p->active_channels == 0); }
{
return (p->proto_state == PS_DOWN)
&& (p->active_channels == 0)
&& EMPTY_TLIST(proto_neigh, &p->neighbors);
}
static inline int channel_is_active(struct channel *c)
{ return (c->channel_state == CS_START) || (c->channel_state == CS_UP); }
@ -962,14 +966,18 @@ proto_event(void *ptr)
if (p->do_start)
{
if_feed_baby(p);
iface_subscribe(&p->iface_sub);
p->do_start = 0;
}
if (p->do_stop)
{
iface_unsubscribe(&p->iface_sub);
neigh_prune(p);
p->do_stop = 0;
}
if (proto_is_done(p))
{
if (p->proto->cleanup)
@ -1860,7 +1868,6 @@ proto_do_stop(struct proto *p)
p->down_sched = 0;
p->gr_recovery = 0;
if (p->main_source)
{
rt_unlock_source(p->main_source);
@ -1877,7 +1884,6 @@ static void
proto_do_down(struct proto *p)
{
p->down_code = 0;
neigh_prune(p);
rfree(p->pool);
p->pool = NULL;

4
nest/protocol.h
View File

@ -171,6 +171,7 @@ struct proto {
struct rte_src *main_source; /* Primary route source */
struct iface *vrf; /* Related VRF instance, NULL if global */
TLIST_LIST(proto_neigh) neighbors; /* List of neighbor structures */
struct iface_subscription iface_sub; /* Interface notification subscription */
const char *name; /* Name of this instance (== cf->name) */
u32 debug; /* Debugging flags */
@ -210,10 +211,7 @@ struct proto {
* feed_end Notify channel about finish of route feeding.
*/
void (*if_notify)(struct proto *, unsigned flags, struct iface *i);
void (*ifa_notify)(struct proto *, unsigned flags, struct ifa *a);
void (*rt_notify)(struct proto *, struct channel *, struct network *net, struct rte *new, struct rte *old);
void (*neigh_notify)(struct neighbor *neigh);
int (*preexport)(struct channel *, struct rte *rt);
void (*reload_routes)(struct channel *);
void (*feed_begin)(struct channel *, int initial);

4
nest/rt-dev.c
View File

@ -141,8 +141,8 @@ dev_init(struct proto_config *CF)
proto_configure_channel(P, &p->ip4_channel, cf->ip4_channel);
proto_configure_channel(P, &p->ip6_channel, cf->ip6_channel);
P->if_notify = dev_if_notify;
P->ifa_notify = dev_ifa_notify;
P->iface_sub.if_notify = dev_if_notify;
P->iface_sub.ifa_notify = dev_ifa_notify;
return P;
}

2
proto/babel/babel.c
View File

@ -2424,7 +2424,7 @@ babel_init(struct proto_config *CF)
proto_configure_channel(P, &p->ip4_channel, cf->ip4_channel);
proto_configure_channel(P, &p->ip6_channel, cf->ip6_channel);
P->if_notify = babel_if_notify;
P->iface_sub.if_notify = babel_if_notify;
P->rt_notify = babel_rt_notify;
P->preexport = babel_preexport;
P->rte_better = babel_rte_better;

2
proto/bfd/bfd.c
View File

@ -1012,7 +1012,7 @@ bfd_init(struct proto_config *c)
{
struct proto *p = proto_new(c);
p->neigh_notify = bfd_neigh_notify;
p->iface_sub.neigh_notify = bfd_neigh_notify;
return p;
}

2
proto/bgp/bgp.c
View File

@ -1686,7 +1686,7 @@ bgp_init(struct proto_config *CF)
P->rt_notify = bgp_rt_notify;
P->preexport = bgp_preexport;
P->neigh_notify = bgp_neigh_notify;
P->iface_sub.neigh_notify = bgp_neigh_notify;
P->reload_routes = bgp_reload_routes;
P->feed_begin = bgp_feed_begin;
P->feed_end = bgp_feed_end;

4
proto/ospf/ospf.c
View File

@ -370,8 +370,8 @@ ospf_init(struct proto_config *CF)
P->main_channel = proto_add_channel(P, proto_cf_main_channel(CF));
P->rt_notify = ospf_rt_notify;
P->if_notify = ospf_if_notify;
P->ifa_notify = cf->ospf2 ? ospf_ifa_notify2 : ospf_ifa_notify3;
P->iface_sub.if_notify = ospf_if_notify;
P->iface_sub.ifa_notify = cf->ospf2 ? ospf_ifa_notify2 : ospf_ifa_notify3;
P->preexport = ospf_preexport;
P->reload_routes = ospf_reload_routes;
P->feed_begin = ospf_feed_begin;

2
proto/perf/perf.c
View File

@ -266,7 +266,7 @@ perf_init(struct proto_config *CF)
switch (p->mode) {
case PERF_MODE_IMPORT:
P->ifa_notify = perf_ifa_notify;
P->iface_sub.ifa_notify = perf_ifa_notify;
break;
case PERF_MODE_EXPORT:
P->rt_notify = perf_rt_notify;

4
proto/radv/radv.c
View File

@ -579,8 +579,8 @@ radv_init(struct proto_config *CF)
P->preexport = radv_preexport;
P->rt_notify = radv_rt_notify;
P->if_notify = radv_if_notify;
P->ifa_notify = radv_ifa_notify;
P->iface_sub.if_notify = radv_if_notify;
P->iface_sub.ifa_notify = radv_ifa_notify;
return P;
}

4
proto/rip/rip.c
View File

@ -1135,9 +1135,9 @@ rip_init(struct proto_config *CF)
P->main_channel = proto_add_channel(P, proto_cf_main_channel(CF));
P->if_notify = rip_if_notify;
P->iface_sub.if_notify = rip_if_notify;
P->rt_notify = rip_rt_notify;
P->neigh_notify = rip_neigh_notify;
P->iface_sub.neigh_notify = rip_neigh_notify;
P->reload_routes = rip_reload_routes;
P->rte_better = rip_rte_better;
P->rte_igp_metric = rip_rte_igp_metric;

2
proto/static/static.c
View File

@ -463,7 +463,7 @@ static_init(struct proto_config *CF)
P->main_channel = proto_add_channel(P, proto_cf_main_channel(CF));
P->neigh_notify = static_neigh_notify;
P->iface_sub.neigh_notify = static_neigh_notify;
P->reload_routes = static_reload_routes;
P->rte_better = static_rte_better;
P->rte_mergable = static_rte_mergable;

2
sysdep/unix/krt.c
View File

@ -1046,7 +1046,7 @@ krt_init(struct proto_config *CF)
p->p.preexport = krt_preexport;
p->p.rt_notify = krt_rt_notify;
p->p.if_notify = krt_if_notify;
p->p.iface_sub.if_notify = krt_if_notify;
p->p.reload_routes = krt_reload_routes;
p->p.feed_end = krt_feed_end;