Commit e2d2b3ef by Michal Vaner Committed by Ondřej Zajíček

RAdv: Buffer prefixes awhile after they disappear

Keep a cache of all the relevant prefixes we send out. When a prefix
appears, insert it into the cache. If it dies, keep it there for a
while, marked as dead.

Send out the dead prefixes with zero lifetime.
parent 3ac5d1ce
......@@ -70,36 +70,6 @@ struct radv_opt_dnssl
char domain[];
};
static struct radv_prefix_config default_prefix = {
.onlink = 1,
.autonomous = 1,
.valid_lifetime = DEFAULT_VALID_LIFETIME,
.preferred_lifetime = DEFAULT_PREFERRED_LIFETIME
};
static struct radv_prefix_config *
radv_prefix_match(struct radv_iface *ifa, struct ifa *a)
{
struct radv_proto *p = ifa->ra;
struct radv_config *cf = (struct radv_config *) (p->p.cf);
struct radv_prefix_config *pc;
if (a->scope <= SCOPE_LINK)
return NULL;
WALK_LIST(pc, ifa->cf->pref_list)
if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
return pc;
WALK_LIST(pc, cf->pref_list)
if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
return pc;
return &default_prefix;
}
static int
radv_prepare_rdnss(struct radv_iface *ifa, list *rdnss_list, char **buf, char *bufend)
{
......@@ -236,9 +206,10 @@ radv_prepare_dnssl(struct radv_iface *ifa, list *dnssl_list, char **buf, char *b
}
static int
radv_prepare_prefix(struct radv_iface *ifa, struct radv_prefix_config *pc,
struct ifa *addr, char **buf, char *bufend)
radv_prepare_prefix(struct radv_iface *ifa, struct radv_prefix *prefix,
char **buf, char *bufend)
{
struct radv_prefix_config *pc = prefix->config;
struct radv_opt_prefix *op = (void *) *buf;
if (*buf + sizeof(*op) > bufend)
......@@ -250,7 +221,7 @@ radv_prepare_prefix(struct radv_iface *ifa, struct radv_prefix_config *pc,
op->type = OPT_PREFIX;
op->length = 4;
op->pxlen = addr->pxlen;
op->pxlen = prefix->len;
op->flags = (pc->onlink ? OPT_PX_ONLINK : 0) |
(pc->autonomous ? OPT_PX_AUTONOMOUS : 0);
op->valid_lifetime = (ifa->ra->active || !pc->valid_lifetime_sensitive) ?
......@@ -258,7 +229,7 @@ radv_prepare_prefix(struct radv_iface *ifa, struct radv_prefix_config *pc,
op->preferred_lifetime = (ifa->ra->active || !pc->preferred_lifetime_sensitive) ?
htonl(pc->preferred_lifetime) : 0;
op->reserved = 0;
op->prefix = addr->prefix;
op->prefix = prefix->prefix;
ipa_hton(op->prefix);
*buf += sizeof(*op);
......@@ -300,16 +271,10 @@ radv_prepare_ra(struct radv_iface *ifa)
buf += sizeof (*om);
}
struct ifa *addr;
WALK_LIST(addr, ifa->iface->addrs)
struct radv_prefix *prefix;
WALK_LIST(prefix, ifa->prefixes)
{
struct radv_prefix_config *pc;
pc = radv_prefix_match(ifa, addr);
if (!pc || pc->skip)
continue;
if (radv_prepare_prefix(ifa, pc, addr, &buf, bufend) < 0)
if (radv_prepare_prefix(ifa, prefix, &buf, bufend) < 0)
goto done;
}
......@@ -419,7 +384,7 @@ radv_err_hook(sock *sk, int err)
int
radv_sk_open(struct radv_iface *ifa)
{
sock *sk = sk_new(ifa->ra->p.pool);
sock *sk = sk_new(ifa->pool);
sk->type = SK_IP;
sk->dport = ICMPV6_PROTO;
sk->saddr = ifa->addr->ip;
......
......@@ -51,6 +51,15 @@ radv_timer(timer *tm)
RADV_TRACE(D_EVENTS, "Timer fired on %s", ifa->iface->name);
/* If some dead prefixes expired, regenerate the prefix list and the packet.
* We do so by pretending there was a change on the interface.
*
* This sets the timer, but we replace it just at the end of this function
* (replacing a timer is fine).
*/
if (ifa->prefix_expires != 0 && ifa->prefix_expires <= now)
radv_iface_notify(ifa, RA_EV_GC);
radv_send_ra(ifa, 0);
/* Update timer */
......@@ -67,7 +76,129 @@ radv_timer(timer *tm)
tm_start(ifa->timer, after);
}
static char* ev_name[] = { NULL, "Init", "Change", "RS" };
static struct radv_prefix_config default_prefix = {
.onlink = 1,
.autonomous = 1,
.valid_lifetime = DEFAULT_VALID_LIFETIME,
.preferred_lifetime = DEFAULT_PREFERRED_LIFETIME
};
static struct radv_prefix_config dead_prefix = {
};
/* Find a corresponding config for the given prefix */
static struct radv_prefix_config *
radv_prefix_match(struct radv_iface *ifa, struct ifa *a)
{
struct radv_proto *p = ifa->ra;
struct radv_config *cf = (struct radv_config *) (p->p.cf);
struct radv_prefix_config *pc;
if (a->scope <= SCOPE_LINK)
return NULL;
WALK_LIST(pc, ifa->cf->pref_list)
if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
return pc;
WALK_LIST(pc, cf->pref_list)
if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
return pc;
return &default_prefix;
}
/*
* Go through the list of prefixes, compare them with configs and decide if we
* want them or not. */
static void
prefixes_prepare(struct radv_iface *ifa)
{
struct radv_proto *p = ifa->ra;
/* First mark all the prefixes as unused */
struct radv_prefix *pfx;
WALK_LIST(pfx, ifa->prefixes)
pfx->mark = 0;
/* Now find all the prefixes we want to use and make sure they are in the
* list. */
struct ifa *addr;
WALK_LIST(addr, ifa->iface->addrs)
{
struct radv_prefix_config *pc = radv_prefix_match(ifa, addr);
if (!pc || pc->skip)
continue;
/* Do we have it already? */
struct radv_prefix *existing = NULL;
WALK_LIST(pfx, ifa->prefixes)
if (pfx->len == addr->pxlen &&
memcmp(&pfx->prefix, &addr->prefix, sizeof pfx->prefix) == 0)
{
existing = pfx;
break;
}
if (!existing)
{
RADV_TRACE(D_EVENTS, "Allocating new prefix %I on %s", addr->prefix,
ifa->iface->name);
existing = mb_allocz(ifa->pool, sizeof *existing);
existing->prefix = addr->prefix;
existing->len = addr->pxlen;
add_tail(&ifa->prefixes, NODE existing);
}
/*
* Update the information (it may have changed, or even bring a prefix back
* to life).
*/
existing->alive = 1;
existing->mark = 1;
existing->config = pc;
}
/*
* Garbage-collect the prefixes. If something isn't used, it dies (but isn't
* dropped just yet). If something is dead and rots there for long enough,
* clean it up.
*/
// XXX: Make these 5 minutes it configurable
bird_clock_t rotten = now + 300;
struct radv_prefix *next;
bird_clock_t expires_soonest = 0;
WALK_LIST_DELSAFE(pfx, next, ifa->prefixes) {
if (pfx->alive && !pfx->mark)
{
RADV_TRACE(D_EVENTS, "Marking prefix %I on %s as dead", pfx->prefix,
ifa->iface->name);
// It just died
pfx->alive = 0;
pfx->expires = rotten;
pfx->config = &dead_prefix;
}
if (!pfx->alive)
if (pfx->expires <= now)
{
RADV_TRACE(D_EVENTS, "Dropping long dead prefix %I on %s", pfx->prefix,
ifa->iface->name);
// It's dead and rotten, clean it up
rem_node(NODE pfx);
mb_free(pfx);
}
else
{
ASSERT(pfx->expires != 0);
// Let it rot for a while more, but look when it's ripe.
if (expires_soonest == 0 || pfx->expires < expires_soonest)
expires_soonest = pfx->expires;
}
}
ifa->prefix_expires = expires_soonest;
}
static char* ev_name[] = { NULL, "Init", "Change", "RS", "Garbage collect" };
void
radv_iface_notify(struct radv_iface *ifa, int event)
......@@ -82,6 +213,7 @@ radv_iface_notify(struct radv_iface *ifa, int event)
switch (event)
{
case RA_EV_CHANGE:
case RA_EV_GC:
ifa->plen = 0;
case RA_EV_INIT:
ifa->initial = MAX_INITIAL_RTR_ADVERTISEMENTS;
......@@ -91,6 +223,8 @@ radv_iface_notify(struct radv_iface *ifa, int event)
break;
}
prefixes_prepare(ifa);
/* Update timer */
unsigned delta = now - ifa->last;
unsigned after = 0;
......@@ -152,15 +286,17 @@ find_lladdr(struct iface *iface)
static void
radv_iface_new(struct radv_proto *p, struct iface *iface, struct radv_iface_config *cf)
{
pool *pool = p->p.pool;
struct radv_iface *ifa;
RADV_TRACE(D_EVENTS, "Adding interface %s", iface->name);
pool *pool = rp_new(p->p.pool, iface->name);
ifa = mb_allocz(pool, sizeof(struct radv_iface));
ifa->pool = pool;
ifa->ra = p;
ifa->cf = cf;
ifa->iface = iface;
init_list(&ifa->prefixes);
add_tail(&p->iface_list, NODE ifa);
......@@ -198,11 +334,7 @@ radv_iface_remove(struct radv_iface *ifa)
rem_node(NODE ifa);
rfree(ifa->sk);
rfree(ifa->timer);
rfree(ifa->lock);
mb_free(ifa);
rfree(ifa->pool);
}
static void
......
......@@ -121,6 +121,23 @@ struct radv_proto
u8 active; /* Whether radv is active w.r.t. triggers */
};
struct radv_prefix /* One prefix we advertise */
{
node n;
ip_addr prefix;
u8 len;
/* Is the prefix alive? If not, we advertise it with 0 lifetime, so clients
* stop using it. */
u8 alive;
u8 mark; /* A temporary mark for processing */
/* The (absolute) time when we drop this prefix from advertising. It is valid
* only if !alive. */
bird_clock_t expires;
/* The config tied to this prefix. Always valid (we place a dummy config here
* when !alive). */
struct radv_prefix_config *config;
};
struct radv_iface
{
node n;
......@@ -128,6 +145,9 @@ struct radv_iface
struct radv_iface_config *cf; /* Related config, must be updated in reconfigure */
struct iface *iface;
struct ifa *addr; /* Link-local address of iface */
struct pool *pool; /* A pool for interface-specific things */
list prefixes; /* The prefixes we advertise */
bird_clock_t prefix_expires; /* When the soonest prefix expires (0 = none dead) */
timer *timer;
struct object_lock *lock;
......@@ -135,12 +155,13 @@ struct radv_iface
bird_clock_t last; /* Time of last sending of RA */
u16 plen; /* Length of prepared RA in tbuf, or 0 if not valid */
byte initial; /* List of active ifaces */
byte initial; /* How many RAs are still to be sent as initial */
};
#define RA_EV_INIT 1 /* Switch to initial mode */
#define RA_EV_CHANGE 2 /* Change of options or prefixes */
#define RA_EV_RS 3 /* Received RS */
#define RA_EV_GC 4 /* Internal garbage collection of prefixes */
/* Default Router Preferences (RFC 4191) */
#define RA_PREF_LOW 0x18
......
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