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-rw-r--r--net/ipv4/inetpeer.c330
1 files changed, 222 insertions, 108 deletions
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 9ffa24b9a804..9df4e635fb5f 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -63,7 +63,7 @@
* refcnt: atomically against modifications on other CPU;
* usually under some other lock to prevent node disappearing
* dtime: unused node list lock
- * v4daddr: unchangeable
+ * daddr: unchangeable
* ip_id_count: atomic value (no lock needed)
*/
@@ -72,21 +72,31 @@ static struct kmem_cache *peer_cachep __read_mostly;
#define node_height(x) x->avl_height
#define peer_avl_empty ((struct inet_peer *)&peer_fake_node)
+#define peer_avl_empty_rcu ((struct inet_peer __rcu __force *)&peer_fake_node)
static const struct inet_peer peer_fake_node = {
- .avl_left = peer_avl_empty,
- .avl_right = peer_avl_empty,
+ .avl_left = peer_avl_empty_rcu,
+ .avl_right = peer_avl_empty_rcu,
.avl_height = 0
};
-static struct {
- struct inet_peer *root;
- spinlock_t lock;
+struct inet_peer_base {
+ struct inet_peer __rcu *root;
+ seqlock_t lock;
int total;
-} peers = {
- .root = peer_avl_empty,
- .lock = __SPIN_LOCK_UNLOCKED(peers.lock),
+};
+
+static struct inet_peer_base v4_peers = {
+ .root = peer_avl_empty_rcu,
+ .lock = __SEQLOCK_UNLOCKED(v4_peers.lock),
.total = 0,
};
+
+static struct inet_peer_base v6_peers = {
+ .root = peer_avl_empty_rcu,
+ .lock = __SEQLOCK_UNLOCKED(v6_peers.lock),
+ .total = 0,
+};
+
#define PEER_MAXDEPTH 40 /* sufficient for about 2^27 nodes */
/* Exported for sysctl_net_ipv4. */
@@ -151,42 +161,66 @@ static void unlink_from_unused(struct inet_peer *p)
}
}
+static int addr_compare(const struct inetpeer_addr *a,
+ const struct inetpeer_addr *b)
+{
+ int i, n = (a->family == AF_INET ? 1 : 4);
+
+ for (i = 0; i < n; i++) {
+ if (a->addr.a6[i] == b->addr.a6[i])
+ continue;
+ if (a->addr.a6[i] < b->addr.a6[i])
+ return -1;
+ return 1;
+ }
+
+ 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.
*/
-#define lookup(_daddr, _stack) \
+#define lookup(_daddr, _stack, _base) \
({ \
- struct inet_peer *u, **v; \
+ struct inet_peer *u; \
+ struct inet_peer __rcu **v; \
\
stackptr = _stack; \
- *stackptr++ = &peers.root; \
- for (u = peers.root; u != peer_avl_empty; ) { \
- if (_daddr == u->v4daddr) \
+ *stackptr++ = &_base->root; \
+ for (u = rcu_deref_locked(_base->root, _base); \
+ u != peer_avl_empty; ) { \
+ int cmp = addr_compare(_daddr, &u->daddr); \
+ if (cmp == 0) \
break; \
- if ((__force __u32)_daddr < (__force __u32)u->v4daddr) \
+ if (cmp == -1) \
v = &u->avl_left; \
else \
v = &u->avl_right; \
*stackptr++ = v; \
- u = *v; \
+ 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(__be32 daddr)
+static struct inet_peer *lookup_rcu(const struct inetpeer_addr *daddr,
+ struct inet_peer_base *base)
{
- struct inet_peer *u = rcu_dereference_bh(peers.root);
+ struct inet_peer *u = rcu_dereference(base->root);
int count = 0;
while (u != peer_avl_empty) {
- if (daddr == u->v4daddr) {
+ int cmp = addr_compare(daddr, &u->daddr);
+ if (cmp == 0) {
/* Before taking a reference, check if this entry was
* deleted, unlink_from_pool() sets refcnt=-1 to make
* distinction between an unused entry (refcnt=0) and
@@ -196,10 +230,10 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr)
u = NULL;
return u;
}
- if ((__force __u32)daddr < (__force __u32)u->v4daddr)
- u = rcu_dereference_bh(u->avl_left);
+ if (cmp == -1)
+ 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;
}
@@ -207,15 +241,17 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr)
}
/* Called with local BH disabled and the pool lock held. */
-#define lookup_rightempty(start) \
+#define lookup_rightempty(start, base) \
({ \
- struct inet_peer *u, **v; \
+ struct inet_peer *u; \
+ struct inet_peer __rcu **v; \
*stackptr++ = &start->avl_left; \
v = &start->avl_left; \
- for (u = *v; u->avl_right != peer_avl_empty; ) { \
+ for (u = rcu_deref_locked(*v, base); \
+ u->avl_right != peer_avl_empty_rcu; ) { \
v = &u->avl_right; \
*stackptr++ = v; \
- u = *v; \
+ u = rcu_deref_locked(*v, base); \
} \
u; \
})
@@ -224,74 +260,76 @@ static struct inet_peer *lookup_rcu_bh(__be32 daddr)
* Variable names are the proof of operation correctness.
* Look into mm/map_avl.c for more detail description of the ideas.
*/
-static void peer_avl_rebalance(struct inet_peer **stack[],
- struct inet_peer ***stackend)
+static void peer_avl_rebalance(struct inet_peer __rcu **stack[],
+ struct inet_peer __rcu ***stackend,
+ struct inet_peer_base *base)
{
- struct inet_peer **nodep, *node, *l, *r;
+ struct inet_peer __rcu **nodep;
+ struct inet_peer *node, *l, *r;
int lh, rh;
while (stackend > stack) {
nodep = *--stackend;
- node = *nodep;
- l = node->avl_left;
- r = node->avl_right;
+ 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 = l->avl_left;
- lr = l->avl_right;
+ 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 */
- node->avl_left = lr; /* lr: RH or RH+1 */
- node->avl_right = r; /* r: RH */
+ RCU_INIT_POINTER(node->avl_left, lr); /* lr: RH or RH+1 */
+ RCU_INIT_POINTER(node->avl_right, r); /* r: RH */
node->avl_height = lrh + 1; /* RH+1 or RH+2 */
- l->avl_left = ll; /* ll: RH+1 */
- l->avl_right = node; /* node: RH+1 or RH+2 */
+ RCU_INIT_POINTER(l->avl_left, ll); /* ll: RH+1 */
+ RCU_INIT_POINTER(l->avl_right, node); /* node: RH+1 or RH+2 */
l->avl_height = node->avl_height + 1;
- *nodep = l;
+ RCU_INIT_POINTER(*nodep, l);
} else { /* ll: RH, lr: RH+1 */
- lrl = lr->avl_left; /* lrl: RH or RH-1 */
- lrr = lr->avl_right; /* lrr: RH or RH-1 */
- node->avl_left = lrr; /* lrr: RH or RH-1 */
- node->avl_right = r; /* r: RH */
+ 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 */
- l->avl_left = ll; /* ll: RH */
- l->avl_right = lrl; /* lrl: RH or RH-1 */
+ RCU_INIT_POINTER(l->avl_left, ll); /* ll: RH */
+ RCU_INIT_POINTER(l->avl_right, lrl); /* lrl: RH or RH-1 */
l->avl_height = rh + 1; /* l: RH+1 */
- lr->avl_left = l; /* l: RH+1 */
- lr->avl_right = node; /* node: RH+1 */
+ RCU_INIT_POINTER(lr->avl_left, l); /* l: RH+1 */
+ RCU_INIT_POINTER(lr->avl_right, node); /* node: RH+1 */
lr->avl_height = rh + 2;
- *nodep = lr;
+ RCU_INIT_POINTER(*nodep, lr);
}
} else if (rh > lh + 1) { /* r: LH+2 */
struct inet_peer *rr, *rl, *rlr, *rll;
int rlh;
- rr = r->avl_right;
- rl = r->avl_left;
+ 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 */
- node->avl_right = rl; /* rl: LH or LH+1 */
- node->avl_left = l; /* l: LH */
+ RCU_INIT_POINTER(node->avl_right, rl); /* rl: LH or LH+1 */
+ RCU_INIT_POINTER(node->avl_left, l); /* l: LH */
node->avl_height = rlh + 1; /* LH+1 or LH+2 */
- r->avl_right = rr; /* rr: LH+1 */
- r->avl_left = node; /* node: LH+1 or LH+2 */
+ RCU_INIT_POINTER(r->avl_right, rr); /* rr: LH+1 */
+ RCU_INIT_POINTER(r->avl_left, node); /* node: LH+1 or LH+2 */
r->avl_height = node->avl_height + 1;
- *nodep = r;
+ RCU_INIT_POINTER(*nodep, r);
} else { /* rr: RH, rl: RH+1 */
- rlr = rl->avl_right; /* rlr: LH or LH-1 */
- rll = rl->avl_left; /* rll: LH or LH-1 */
- node->avl_right = rll; /* rll: LH or LH-1 */
- node->avl_left = l; /* l: LH */
+ 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 */
- r->avl_right = rr; /* rr: LH */
- r->avl_left = rlr; /* rlr: LH or LH-1 */
+ RCU_INIT_POINTER(r->avl_right, rr); /* rr: LH */
+ RCU_INIT_POINTER(r->avl_left, rlr); /* rlr: LH or LH-1 */
r->avl_height = lh + 1; /* r: LH+1 */
- rl->avl_right = r; /* r: LH+1 */
- rl->avl_left = node; /* node: LH+1 */
+ RCU_INIT_POINTER(rl->avl_right, r); /* r: LH+1 */
+ RCU_INIT_POINTER(rl->avl_left, node); /* node: LH+1 */
rl->avl_height = lh + 2;
- *nodep = rl;
+ RCU_INIT_POINTER(*nodep, rl);
}
} else {
node->avl_height = (lh > rh ? lh : rh) + 1;
@@ -300,14 +338,14 @@ static void peer_avl_rebalance(struct inet_peer **stack[],
}
/* Called with local BH disabled and the pool lock held. */
-#define link_to_pool(n) \
+#define link_to_pool(n, base) \
do { \
n->avl_height = 1; \
- n->avl_left = peer_avl_empty; \
- n->avl_right = peer_avl_empty; \
- smp_wmb(); /* lockless readers can catch us now */ \
- **--stackptr = n; \
- peer_avl_rebalance(stack, stackptr); \
+ n->avl_left = peer_avl_empty_rcu; \
+ n->avl_right = peer_avl_empty_rcu; \
+ /* lockless readers can catch us now */ \
+ rcu_assign_pointer(**--stackptr, n); \
+ peer_avl_rebalance(stack, stackptr, base); \
} while (0)
static void inetpeer_free_rcu(struct rcu_head *head)
@@ -316,13 +354,14 @@ static void inetpeer_free_rcu(struct rcu_head *head)
}
/* May be called with local BH enabled. */
-static void unlink_from_pool(struct inet_peer *p)
+static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base,
+ struct inet_peer __rcu **stack[PEER_MAXDEPTH])
{
int do_free;
do_free = 0;
- spin_lock_bh(&peers.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,
@@ -330,38 +369,37 @@ static void unlink_from_pool(struct inet_peer *p)
* We use refcnt=-1 to alert lockless readers this entry is deleted.
*/
if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) {
- struct inet_peer **stack[PEER_MAXDEPTH];
- struct inet_peer ***stackptr, ***delp;
- if (lookup(p->v4daddr, stack) != p)
+ struct inet_peer __rcu ***stackptr, ***delp;
+ if (lookup(&p->daddr, stack, base) != p)
BUG();
delp = stackptr - 1; /* *delp[0] == p */
- if (p->avl_left == peer_avl_empty) {
+ if (p->avl_left == peer_avl_empty_rcu) {
*delp[0] = p->avl_right;
--stackptr;
} else {
/* look for a node to insert instead of p */
struct inet_peer *t;
- t = lookup_rightempty(p);
- BUG_ON(*stackptr[-1] != t);
+ t = lookup_rightempty(p, base);
+ BUG_ON(rcu_deref_locked(*stackptr[-1], base) != t);
**--stackptr = t->avl_left;
- /* t is removed, t->v4daddr > x->v4daddr for any
+ /* t is removed, t->daddr > x->daddr for any
* x in p->avl_left subtree.
* Put t in the old place of p. */
- *delp[0] = t;
+ RCU_INIT_POINTER(*delp[0], t);
t->avl_left = p->avl_left;
t->avl_right = p->avl_right;
t->avl_height = p->avl_height;
BUG_ON(delp[1] != &p->avl_left);
delp[1] = &t->avl_left; /* was &p->avl_left */
}
- peer_avl_rebalance(stack, stackptr);
- peers.total--;
+ peer_avl_rebalance(stack, stackptr, base);
+ base->total--;
do_free = 1;
}
- spin_unlock_bh(&peers.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
@@ -373,8 +411,18 @@ static void unlink_from_pool(struct inet_peer *p)
inet_putpeer(p);
}
+static struct inet_peer_base *family_to_base(int family)
+{
+ return (family == AF_INET ? &v4_peers : &v6_peers);
+}
+
+static struct inet_peer_base *peer_to_base(struct inet_peer *p)
+{
+ return family_to_base(p->daddr.family);
+}
+
/* May be called with local BH enabled. */
-static int cleanup_once(unsigned long ttl)
+static int cleanup_once(unsigned long ttl, struct inet_peer __rcu **stack[PEER_MAXDEPTH])
{
struct inet_peer *p = NULL;
@@ -406,22 +454,27 @@ static int cleanup_once(unsigned long ttl)
* happen because of entry limits in route cache. */
return -1;
- unlink_from_pool(p);
+ unlink_from_pool(p, peer_to_base(p), stack);
return 0;
}
/* Called with or without local BH being disabled. */
-struct inet_peer *inet_getpeer(__be32 daddr, int create)
+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;
- struct inet_peer **stack[PEER_MAXDEPTH], ***stackptr;
+ 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);
- 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.
@@ -431,54 +484,72 @@ struct inet_peer *inet_getpeer(__be32 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(&peers.lock);
- p = lookup(daddr, stack);
+ write_seqlock_bh(&base->lock);
+ p = lookup(daddr, stack, base);
if (p != peer_avl_empty) {
atomic_inc(&p->refcnt);
- spin_unlock_bh(&peers.lock);
+ write_sequnlock_bh(&base->lock);
/* Remove the entry from unused list if it was there. */
unlink_from_unused(p);
return p;
}
p = create ? kmem_cache_alloc(peer_cachep, GFP_ATOMIC) : NULL;
if (p) {
- p->v4daddr = daddr;
+ p->daddr = *daddr;
atomic_set(&p->refcnt, 1);
atomic_set(&p->rid, 0);
- atomic_set(&p->ip_id_count, secure_ip_id(daddr));
+ 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);
/* Link the node. */
- link_to_pool(p);
- peers.total++;
+ link_to_pool(p, base);
+ base->total++;
}
- spin_unlock_bh(&peers.lock);
+ write_sequnlock_bh(&base->lock);
- if (peers.total >= inet_peer_threshold)
+ if (base->total >= inet_peer_threshold)
/* Remove one less-recently-used entry. */
- cleanup_once(0);
+ cleanup_once(0, stack);
return p;
}
+static int compute_total(void)
+{
+ return v4_peers.total + v6_peers.total;
+}
+EXPORT_SYMBOL_GPL(inet_getpeer);
+
/* Called with local BH disabled. */
static void peer_check_expire(unsigned long dummy)
{
unsigned long now = jiffies;
- int ttl;
+ int ttl, total;
+ struct inet_peer __rcu **stack[PEER_MAXDEPTH];
- if (peers.total >= inet_peer_threshold)
+ total = compute_total();
+ if (total >= inet_peer_threshold)
ttl = inet_peer_minttl;
else
ttl = inet_peer_maxttl
- (inet_peer_maxttl - inet_peer_minttl) / HZ *
- peers.total / inet_peer_threshold * HZ;
- while (!cleanup_once(ttl)) {
+ total / inet_peer_threshold * HZ;
+ while (!cleanup_once(ttl, stack)) {
if (jiffies != now)
break;
}
@@ -486,13 +557,14 @@ static void peer_check_expire(unsigned long dummy)
/* Trigger the timer after inet_peer_gc_mintime .. inet_peer_gc_maxtime
* interval depending on the total number of entries (more entries,
* less interval). */
- if (peers.total >= inet_peer_threshold)
+ total = compute_total();
+ if (total >= inet_peer_threshold)
peer_periodic_timer.expires = jiffies + inet_peer_gc_mintime;
else
peer_periodic_timer.expires = jiffies
+ inet_peer_gc_maxtime
- (inet_peer_gc_maxtime - inet_peer_gc_mintime) / HZ *
- peers.total / inet_peer_threshold * HZ;
+ total / inet_peer_threshold * HZ;
add_timer(&peer_periodic_timer);
}
@@ -508,3 +580,45 @@ 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 (git 2.46.0) at 2025-09-01 07:51:30 +0000