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-rw-r--r--net/ipv4/inetpeer.c148
1 files changed, 95 insertions, 53 deletions
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index a96e65674ac..dd1b20eca1a 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -81,19 +81,19 @@ static const struct inet_peer peer_fake_node = {
struct inet_peer_base {
struct inet_peer __rcu *root;
- spinlock_t lock;
+ seqlock_t lock;
int total;
};
static struct inet_peer_base v4_peers = {
.root = peer_avl_empty_rcu,
- .lock = __SPIN_LOCK_UNLOCKED(v4_peers.lock),
+ .lock = __SEQLOCK_UNLOCKED(v4_peers.lock),
.total = 0,
};
static struct inet_peer_base v6_peers = {
.root = peer_avl_empty_rcu,
- .lock = __SPIN_LOCK_UNLOCKED(v6_peers.lock),
+ .lock = __SEQLOCK_UNLOCKED(v6_peers.lock),
.total = 0,
};
@@ -167,9 +167,9 @@ static int addr_compare(const struct inetpeer_addr *a,
int i, n = (a->family == AF_INET ? 1 : 4);
for (i = 0; i < n; i++) {
- if (a->a6[i] == b->a6[i])
+ if (a->addr.a6[i] == b->addr.a6[i])
continue;
- if (a->a6[i] < b->a6[i])
+ if (a->addr.a6[i] < b->addr.a6[i])
return -1;
return 1;
}
@@ -177,6 +177,9 @@ static int addr_compare(const struct inetpeer_addr *a,
return 0;
}
+#define rcu_deref_locked(X, BASE) \
+ rcu_dereference_protected(X, lockdep_is_held(&(BASE)->lock.lock))
+
/*
* Called with local BH disabled and the pool lock held.
*/
@@ -187,8 +190,7 @@ static int addr_compare(const struct inetpeer_addr *a,
\
stackptr = _stack; \
*stackptr++ = &_base->root; \
- for (u = rcu_dereference_protected(_base->root, \
- lockdep_is_held(&_base->lock)); \
+ for (u = rcu_deref_locked(_base->root, _base); \
u != peer_avl_empty; ) { \
int cmp = addr_compare(_daddr, &u->daddr); \
if (cmp == 0) \
@@ -198,23 +200,22 @@ static int addr_compare(const struct inetpeer_addr *a,
else \
v = &u->avl_right; \
*stackptr++ = v; \
- u = rcu_dereference_protected(*v, \
- lockdep_is_held(&_base->lock)); \
+ u = rcu_deref_locked(*v, _base); \
} \
u; \
})
/*
- * Called with rcu_read_lock_bh()
+ * Called with rcu_read_lock()
* Because we hold no lock against a writer, its quite possible we fall
* in an endless loop.
* But every pointer we follow is guaranteed to be valid thanks to RCU.
* We exit from this function if number of links exceeds PEER_MAXDEPTH
*/
-static struct inet_peer *lookup_rcu_bh(const struct inetpeer_addr *daddr,
- struct inet_peer_base *base)
+static struct inet_peer *lookup_rcu(const struct inetpeer_addr *daddr,
+ struct inet_peer_base *base)
{
- struct inet_peer *u = rcu_dereference_bh(base->root);
+ struct inet_peer *u = rcu_dereference(base->root);
int count = 0;
while (u != peer_avl_empty) {
@@ -230,9 +231,9 @@ static struct inet_peer *lookup_rcu_bh(const struct inetpeer_addr *daddr,
return u;
}
if (cmp == -1)
- u = rcu_dereference_bh(u->avl_left);
+ u = rcu_dereference(u->avl_left);
else
- u = rcu_dereference_bh(u->avl_right);
+ u = rcu_dereference(u->avl_right);
if (unlikely(++count == PEER_MAXDEPTH))
break;
}
@@ -246,13 +247,11 @@ static struct inet_peer *lookup_rcu_bh(const struct inetpeer_addr *daddr,
struct inet_peer __rcu **v; \
*stackptr++ = &start->avl_left; \
v = &start->avl_left; \
- for (u = rcu_dereference_protected(*v, \
- lockdep_is_held(&base->lock)); \
+ for (u = rcu_deref_locked(*v, base); \
u->avl_right != peer_avl_empty_rcu; ) { \
v = &u->avl_right; \
*stackptr++ = v; \
- u = rcu_dereference_protected(*v, \
- lockdep_is_held(&base->lock)); \
+ u = rcu_deref_locked(*v, base); \
} \
u; \
})
@@ -271,21 +270,16 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
while (stackend > stack) {
nodep = *--stackend;
- node = rcu_dereference_protected(*nodep,
- lockdep_is_held(&base->lock));
- l = rcu_dereference_protected(node->avl_left,
- lockdep_is_held(&base->lock));
- r = rcu_dereference_protected(node->avl_right,
- lockdep_is_held(&base->lock));
+ node = rcu_deref_locked(*nodep, base);
+ l = rcu_deref_locked(node->avl_left, base);
+ r = rcu_deref_locked(node->avl_right, base);
lh = node_height(l);
rh = node_height(r);
if (lh > rh + 1) { /* l: RH+2 */
struct inet_peer *ll, *lr, *lrl, *lrr;
int lrh;
- ll = rcu_dereference_protected(l->avl_left,
- lockdep_is_held(&base->lock));
- lr = rcu_dereference_protected(l->avl_right,
- lockdep_is_held(&base->lock));
+ ll = rcu_deref_locked(l->avl_left, base);
+ lr = rcu_deref_locked(l->avl_right, base);
lrh = node_height(lr);
if (lrh <= node_height(ll)) { /* ll: RH+1 */
RCU_INIT_POINTER(node->avl_left, lr); /* lr: RH or RH+1 */
@@ -296,10 +290,8 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
l->avl_height = node->avl_height + 1;
RCU_INIT_POINTER(*nodep, l);
} else { /* ll: RH, lr: RH+1 */
- lrl = rcu_dereference_protected(lr->avl_left,
- lockdep_is_held(&base->lock)); /* lrl: RH or RH-1 */
- lrr = rcu_dereference_protected(lr->avl_right,
- lockdep_is_held(&base->lock)); /* lrr: RH or RH-1 */
+ lrl = rcu_deref_locked(lr->avl_left, base);/* lrl: RH or RH-1 */
+ lrr = rcu_deref_locked(lr->avl_right, base);/* lrr: RH or RH-1 */
RCU_INIT_POINTER(node->avl_left, lrr); /* lrr: RH or RH-1 */
RCU_INIT_POINTER(node->avl_right, r); /* r: RH */
node->avl_height = rh + 1; /* node: RH+1 */
@@ -314,10 +306,8 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
} else if (rh > lh + 1) { /* r: LH+2 */
struct inet_peer *rr, *rl, *rlr, *rll;
int rlh;
- rr = rcu_dereference_protected(r->avl_right,
- lockdep_is_held(&base->lock));
- rl = rcu_dereference_protected(r->avl_left,
- lockdep_is_held(&base->lock));
+ rr = rcu_deref_locked(r->avl_right, base);
+ rl = rcu_deref_locked(r->avl_left, base);
rlh = node_height(rl);
if (rlh <= node_height(rr)) { /* rr: LH+1 */
RCU_INIT_POINTER(node->avl_right, rl); /* rl: LH or LH+1 */
@@ -328,10 +318,8 @@ static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
r->avl_height = node->avl_height + 1;
RCU_INIT_POINTER(*nodep, r);
} else { /* rr: RH, rl: RH+1 */
- rlr = rcu_dereference_protected(rl->avl_right,
- lockdep_is_held(&base->lock)); /* rlr: LH or LH-1 */
- rll = rcu_dereference_protected(rl->avl_left,
- lockdep_is_held(&base->lock)); /* rll: LH or LH-1 */
+ rlr = rcu_deref_locked(rl->avl_right, base);/* rlr: LH or LH-1 */
+ rll = rcu_deref_locked(rl->avl_left, base);/* rll: LH or LH-1 */
RCU_INIT_POINTER(node->avl_right, rll); /* rll: LH or LH-1 */
RCU_INIT_POINTER(node->avl_left, l); /* l: LH */
node->avl_height = lh + 1; /* node: LH+1 */
@@ -372,7 +360,7 @@ static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base)
do_free = 0;
- spin_lock_bh(&base->lock);
+ write_seqlock_bh(&base->lock);
/* Check the reference counter. It was artificially incremented by 1
* in cleanup() function to prevent sudden disappearing. If we can
* atomically (because of lockless readers) take this last reference,
@@ -392,8 +380,7 @@ static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base)
/* look for a node to insert instead of p */
struct inet_peer *t;
t = lookup_rightempty(p, base);
- BUG_ON(rcu_dereference_protected(*stackptr[-1],
- lockdep_is_held(&base->lock)) != t);
+ BUG_ON(rcu_deref_locked(*stackptr[-1], base) != t);
**--stackptr = t->avl_left;
/* t is removed, t->daddr > x->daddr for any
* x in p->avl_left subtree.
@@ -409,10 +396,10 @@ static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base)
base->total--;
do_free = 1;
}
- spin_unlock_bh(&base->lock);
+ write_sequnlock_bh(&base->lock);
if (do_free)
- call_rcu_bh(&p->rcu, inetpeer_free_rcu);
+ call_rcu(&p->rcu, inetpeer_free_rcu);
else
/* The node is used again. Decrease the reference counter
* back. The loop "cleanup -> unlink_from_unused
@@ -477,13 +464,17 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr;
struct inet_peer_base *base = family_to_base(daddr->family);
struct inet_peer *p;
+ unsigned int sequence;
+ int invalidated;
/* Look up for the address quickly, lockless.
* Because of a concurrent writer, we might not find an existing entry.
*/
- rcu_read_lock_bh();
- p = lookup_rcu_bh(daddr, base);
- rcu_read_unlock_bh();
+ rcu_read_lock();
+ sequence = read_seqbegin(&base->lock);
+ p = lookup_rcu(daddr, base);
+ invalidated = read_seqretry(&base->lock, sequence);
+ rcu_read_unlock();
if (p) {
/* The existing node has been found.
@@ -493,14 +484,18 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
return p;
}
+ /* If no writer did a change during our lookup, we can return early. */
+ if (!create && !invalidated)
+ return NULL;
+
/* retry an exact lookup, taking the lock before.
* At least, nodes should be hot in our cache.
*/
- spin_lock_bh(&base->lock);
+ write_seqlock_bh(&base->lock);
p = lookup(daddr, stack, base);
if (p != peer_avl_empty) {
atomic_inc(&p->refcnt);
- spin_unlock_bh(&base->lock);
+ write_sequnlock_bh(&base->lock);
/* Remove the entry from unused list if it was there. */
unlink_from_unused(p);
return p;
@@ -510,8 +505,14 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
p->daddr = *daddr;
atomic_set(&p->refcnt, 1);
atomic_set(&p->rid, 0);
- atomic_set(&p->ip_id_count, secure_ip_id(daddr->a4));
+ atomic_set(&p->ip_id_count, secure_ip_id(daddr->addr.a4));
p->tcp_ts_stamp = 0;
+ p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
+ p->rate_tokens = 0;
+ p->rate_last = 0;
+ p->pmtu_expires = 0;
+ p->pmtu_orig = 0;
+ memset(&p->redirect_learned, 0, sizeof(p->redirect_learned));
INIT_LIST_HEAD(&p->unused);
@@ -519,7 +520,7 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
link_to_pool(p, base);
base->total++;
}
- spin_unlock_bh(&base->lock);
+ write_sequnlock_bh(&base->lock);
if (base->total >= inet_peer_threshold)
/* Remove one less-recently-used entry. */
@@ -579,3 +580,44 @@ void inet_putpeer(struct inet_peer *p)
local_bh_enable();
}
EXPORT_SYMBOL_GPL(inet_putpeer);
+
+/*
+ * Check transmit rate limitation for given message.
+ * The rate information is held in the inet_peer entries now.
+ * This function is generic and could be used for other purposes
+ * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
+ *
+ * Note that the same inet_peer fields are modified by functions in
+ * route.c too, but these work for packet destinations while xrlim_allow
+ * works for icmp destinations. This means the rate limiting information
+ * for one "ip object" is shared - and these ICMPs are twice limited:
+ * by source and by destination.
+ *
+ * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
+ * SHOULD allow setting of rate limits
+ *
+ * Shared between ICMPv4 and ICMPv6.
+ */
+#define XRLIM_BURST_FACTOR 6
+bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout)
+{
+ unsigned long now, token;
+ bool rc = false;
+
+ if (!peer)
+ return true;
+
+ token = peer->rate_tokens;
+ now = jiffies;
+ token += now - peer->rate_last;
+ peer->rate_last = now;
+ if (token > XRLIM_BURST_FACTOR * timeout)
+ token = XRLIM_BURST_FACTOR * timeout;
+ if (token >= timeout) {
+ token -= timeout;
+ rc = true;
+ }
+ peer->rate_tokens = token;
+ return rc;
+}
+EXPORT_SYMBOL(inet_peer_xrlim_allow);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-05 11:30:59 +0000