1 files changed, 102 insertions, 59 deletions

diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index a96e65674ac3..9df4e635fb5f 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 */
@@ -366,13 +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, struct inet_peer_base *base)
+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(&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,
@@ -380,7 +369,6 @@ static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base)
          * We use refcnt=-1 to alert lockless readers this entry is deleted.
          */
         if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) {
-                struct inet_peer __rcu **stack[PEER_MAXDEPTH];
                 struct inet_peer __rcu ***stackptr, ***delp;
                 if (lookup(&p->daddr, stack, base) != p)
                         BUG();
@@ -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
@@ -435,7 +422,7 @@ static struct inet_peer_base *peer_to_base(struct inet_peer *p)
 }
 
 /* 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;
 
@@ -467,7 +454,7 @@ static int cleanup_once(unsigned long ttl)
                  * happen because of entry limits in route cache. */
                 return -1;
 
-        unlink_from_pool(p, peer_to_base(p));
+        unlink_from_pool(p, peer_to_base(p), stack);
         return 0;
 }
 
@@ -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);
 
 
@@ -519,11 +520,11 @@ 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. */
-                cleanup_once(0);
+                cleanup_once(0, stack);
 
         return p;
 }
@@ -539,6 +540,7 @@ static void peer_check_expire(unsigned long dummy)
 {
         unsigned long now = jiffies;
         int ttl, total;
+        struct inet_peer __rcu **stack[PEER_MAXDEPTH];
 
         total = compute_total();
         if (total >= inet_peer_threshold)
@@ -547,7 +549,7 @@ static void peer_check_expire(unsigned long dummy)
                 ttl = inet_peer_maxttl
                                 - (inet_peer_maxttl - inet_peer_minttl) / HZ *
                                         total / inet_peer_threshold * HZ;
-        while (!cleanup_once(ttl)) {
+        while (!cleanup_once(ttl, stack)) {
                 if (jiffies != now)
                         break;
         }
@@ -579,3 +581,44 @@ 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);