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-rw-r--r--include/net/sock.h37
-rw-r--r--net/core/sock.c3
-rw-r--r--net/ipv4/udp.c35
-rw-r--r--net/ipv4/udplite.c1
-rw-r--r--net/ipv6/udp.c31
-rw-r--r--net/ipv6/udplite.c1
6 files changed, 90 insertions, 18 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index d200dfbe1ef6..0bea25db5471 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -363,6 +363,27 @@ static __inline__ int sk_del_node_init(struct sock *sk)
return rc;
}
+static __inline__ int __sk_del_node_init_rcu(struct sock *sk)
+{
+ if (sk_hashed(sk)) {
+ hlist_del_init_rcu(&sk->sk_node);
+ return 1;
+ }
+ return 0;
+}
+
+static __inline__ int sk_del_node_init_rcu(struct sock *sk)
+{
+ int rc = __sk_del_node_init_rcu(sk);
+
+ if (rc) {
+ /* paranoid for a while -acme */
+ WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
+ __sock_put(sk);
+ }
+ return rc;
+}
+
static __inline__ void __sk_add_node(struct sock *sk, struct hlist_head *list)
{
hlist_add_head(&sk->sk_node, list);
@@ -374,6 +395,17 @@ static __inline__ void sk_add_node(struct sock *sk, struct hlist_head *list)
__sk_add_node(sk, list);
}
+static __inline__ void __sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
+{
+ hlist_add_head_rcu(&sk->sk_node, list);
+}
+
+static __inline__ void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
+{
+ sock_hold(sk);
+ __sk_add_node_rcu(sk, list);
+}
+
static __inline__ void __sk_del_bind_node(struct sock *sk)
{
__hlist_del(&sk->sk_bind_node);
@@ -387,6 +419,8 @@ static __inline__ void sk_add_bind_node(struct sock *sk,
#define sk_for_each(__sk, node, list) \
hlist_for_each_entry(__sk, node, list, sk_node)
+#define sk_for_each_rcu(__sk, node, list) \
+ hlist_for_each_entry_rcu(__sk, node, list, sk_node)
#define sk_for_each_from(__sk, node) \
if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
hlist_for_each_entry_from(__sk, node, sk_node)
@@ -589,8 +623,9 @@ struct proto {
int *sysctl_rmem;
int max_header;
- struct kmem_cache *slab;
+ struct kmem_cache *slab;
unsigned int obj_size;
+ int slab_flags;
atomic_t *orphan_count;
diff --git a/net/core/sock.c b/net/core/sock.c
index 5e2a3132a8c9..ded1eb5d2fd4 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2042,7 +2042,8 @@ int proto_register(struct proto *prot, int alloc_slab)
if (alloc_slab) {
prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0,
- SLAB_HWCACHE_ALIGN, NULL);
+ SLAB_HWCACHE_ALIGN | prot->slab_flags,
+ NULL);
if (prot->slab == NULL) {
printk(KERN_CRIT "%s: Can't create sock SLAB cache!\n",
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 2a6c491f97d7..0ea974bf7962 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -187,7 +187,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
inet_sk(sk)->num = snum;
sk->sk_hash = snum;
if (sk_unhashed(sk)) {
- sk_add_node(sk, &hslot->head);
+ sk_add_node_rcu(sk, &hslot->head);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
}
error = 0;
@@ -253,15 +253,24 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
__be16 sport, __be32 daddr, __be16 dport,
int dif, struct udp_table *udptable)
{
- struct sock *sk, *result = NULL;
+ struct sock *sk, *result;
struct hlist_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
- int score, badness = -1;
+ int score, badness;
- spin_lock(&hslot->lock);
- sk_for_each(sk, node, &hslot->head) {
+ rcu_read_lock();
+begin:
+ result = NULL;
+ badness = -1;
+ sk_for_each_rcu(sk, node, &hslot->head) {
+ /*
+ * lockless reader, and SLAB_DESTROY_BY_RCU items:
+ * We must check this item was not moved to another chain
+ */
+ if (udp_hashfn(net, sk->sk_hash) != hash)
+ goto begin;
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
@@ -269,9 +278,16 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
badness = score;
}
}
- if (result)
- sock_hold(result);
- spin_unlock(&hslot->lock);
+ if (result) {
+ if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+ result = NULL;
+ else if (unlikely(compute_score(result, net, saddr, hnum, sport,
+ daddr, dport, dif) < badness)) {
+ sock_put(result);
+ goto begin;
+ }
+ }
+ rcu_read_unlock();
return result;
}
@@ -953,7 +969,7 @@ void udp_lib_unhash(struct sock *sk)
struct udp_hslot *hslot = &udptable->hash[hash];
spin_lock(&hslot->lock);
- if (sk_del_node_init(sk)) {
+ if (sk_del_node_init_rcu(sk)) {
inet_sk(sk)->num = 0;
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
}
@@ -1517,6 +1533,7 @@ struct proto udp_prot = {
.sysctl_wmem = &sysctl_udp_wmem_min,
.sysctl_rmem = &sysctl_udp_rmem_min,
.obj_size = sizeof(struct udp_sock),
+ .slab_flags = SLAB_DESTROY_BY_RCU,
.h.udp_table = &udp_table,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udp_setsockopt,
diff --git a/net/ipv4/udplite.c b/net/ipv4/udplite.c
index d8ea8e5f5ea3..c784891cb7e5 100644
--- a/net/ipv4/udplite.c
+++ b/net/ipv4/udplite.c
@@ -51,6 +51,7 @@ struct proto udplite_prot = {
.unhash = udp_lib_unhash,
.get_port = udp_v4_get_port,
.obj_size = sizeof(struct udp_sock),
+ .slab_flags = SLAB_DESTROY_BY_RCU,
.h.udp_table = &udplite_table,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udp_setsockopt,
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index ccee7244ca0f..1d9790e43dfc 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -97,24 +97,40 @@ static struct sock *__udp6_lib_lookup(struct net *net,
struct in6_addr *daddr, __be16 dport,
int dif, struct udp_table *udptable)
{
- struct sock *sk, *result = NULL;
+ struct sock *sk, *result;
struct hlist_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
- int score, badness = -1;
+ int score, badness;
- spin_lock(&hslot->lock);
- sk_for_each(sk, node, &hslot->head) {
+ rcu_read_lock();
+begin:
+ result = NULL;
+ badness = -1;
+ sk_for_each_rcu(sk, node, &hslot->head) {
+ /*
+ * lockless reader, and SLAB_DESTROY_BY_RCU items:
+ * We must check this item was not moved to another chain
+ */
+ if (udp_hashfn(net, sk->sk_hash) != hash)
+ goto begin;
score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
- if (result)
- sock_hold(result);
- spin_unlock(&hslot->lock);
+ if (result) {
+ if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+ result = NULL;
+ else if (unlikely(compute_score(result, net, hnum, saddr, sport,
+ daddr, dport, dif) < badness)) {
+ sock_put(result);
+ goto begin;
+ }
+ }
+ rcu_read_unlock();
return result;
}
@@ -1062,6 +1078,7 @@ struct proto udpv6_prot = {
.sysctl_wmem = &sysctl_udp_wmem_min,
.sysctl_rmem = &sysctl_udp_rmem_min,
.obj_size = sizeof(struct udp6_sock),
+ .slab_flags = SLAB_DESTROY_BY_RCU,
.h.udp_table = &udp_table,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udpv6_setsockopt,
diff --git a/net/ipv6/udplite.c b/net/ipv6/udplite.c
index f1e892a99e05..ba162a824585 100644
--- a/net/ipv6/udplite.c
+++ b/net/ipv6/udplite.c
@@ -49,6 +49,7 @@ struct proto udplitev6_prot = {
.unhash = udp_lib_unhash,
.get_port = udp_v6_get_port,
.obj_size = sizeof(struct udp6_sock),
+ .slab_flags = SLAB_DESTROY_BY_RCU,
.h.udp_table = &udplite_table,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udpv6_setsockopt,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.