DEFINE_SPINLOCK(reuseport_lock);
static DEFINE_IDA(reuseport_ida);
+static int reuseport_resurrect(struct sock *sk, struct sock_reuseport *old_reuse,
+ struct sock_reuseport *reuse, bool bind_inany);
static int reuseport_sock_index(struct sock *sk,
const struct sock_reuseport *reuse,
return true;
}
+static void __reuseport_add_closed_sock(struct sock *sk,
+ struct sock_reuseport *reuse)
+{
+ reuse->socks[reuse->max_socks - reuse->num_closed_socks - 1] = sk;
+ /* paired with READ_ONCE() in inet_csk_bind_conflict() */
+ WRITE_ONCE(reuse->num_closed_socks, reuse->num_closed_socks + 1);
+}
+
+static bool __reuseport_detach_closed_sock(struct sock *sk,
+ struct sock_reuseport *reuse)
+{
+ int i = reuseport_sock_index(sk, reuse, true);
+
+ if (i == -1)
+ return false;
+
+ reuse->socks[i] = reuse->socks[reuse->max_socks - reuse->num_closed_socks];
+ /* paired with READ_ONCE() in inet_csk_bind_conflict() */
+ WRITE_ONCE(reuse->num_closed_socks, reuse->num_closed_socks - 1);
+
+ return true;
+}
+
static struct sock_reuseport *__reuseport_alloc(unsigned int max_socks)
{
unsigned int size = sizeof(struct sock_reuseport) +
reuse = rcu_dereference_protected(sk->sk_reuseport_cb,
lockdep_is_held(&reuseport_lock));
if (reuse) {
+ if (reuse->num_closed_socks) {
+ /* sk was shutdown()ed before */
+ ret = reuseport_resurrect(sk, reuse, NULL, bind_inany);
+ goto out;
+ }
+
/* Only set reuse->bind_inany if the bind_inany is true.
* Otherwise, it will overwrite the reuse->bind_inany
* which was set by the bind/hash path.
u32 more_socks_size, i;
more_socks_size = reuse->max_socks * 2U;
- if (more_socks_size > U16_MAX)
+ if (more_socks_size > U16_MAX) {
+ if (reuse->num_closed_socks) {
+ /* Make room by removing a closed sk.
+ * The child has already been migrated.
+ * Only reqsk left at this point.
+ */
+ struct sock *sk;
+
+ sk = reuse->socks[reuse->max_socks - reuse->num_closed_socks];
+ RCU_INIT_POINTER(sk->sk_reuseport_cb, NULL);
+ __reuseport_detach_closed_sock(sk, reuse);
+
+ return reuse;
+ }
+
return NULL;
+ }
more_reuse = __reuseport_alloc(more_socks_size);
if (!more_reuse)
reuse = rcu_dereference_protected(sk2->sk_reuseport_cb,
lockdep_is_held(&reuseport_lock));
old_reuse = rcu_dereference_protected(sk->sk_reuseport_cb,
- lockdep_is_held(&reuseport_lock));
+ lockdep_is_held(&reuseport_lock));
+ if (old_reuse && old_reuse->num_closed_socks) {
+ /* sk was shutdown()ed before */
+ int err = reuseport_resurrect(sk, old_reuse, reuse, reuse->bind_inany);
+
+ spin_unlock_bh(&reuseport_lock);
+ return err;
+ }
+
if (old_reuse && old_reuse->num_socks != 1) {
spin_unlock_bh(&reuseport_lock);
return -EBUSY;
}
EXPORT_SYMBOL(reuseport_add_sock);
+static int reuseport_resurrect(struct sock *sk, struct sock_reuseport *old_reuse,
+ struct sock_reuseport *reuse, bool bind_inany)
+{
+ if (old_reuse == reuse) {
+ /* If sk was in the same reuseport group, just pop sk out of
+ * the closed section and push sk into the listening section.
+ */
+ __reuseport_detach_closed_sock(sk, old_reuse);
+ __reuseport_add_sock(sk, old_reuse);
+ return 0;
+ }
+
+ if (!reuse) {
+ /* In bind()/listen() path, we cannot carry over the eBPF prog
+ * for the shutdown()ed socket. In setsockopt() path, we should
+ * not change the eBPF prog of listening sockets by attaching a
+ * prog to the shutdown()ed socket. Thus, we will allocate a new
+ * reuseport group and detach sk from the old group.
+ */
+ int id;
+
+ reuse = __reuseport_alloc(INIT_SOCKS);
+ if (!reuse)
+ return -ENOMEM;
+
+ id = ida_alloc(&reuseport_ida, GFP_ATOMIC);
+ if (id < 0) {
+ kfree(reuse);
+ return id;
+ }
+
+ reuse->reuseport_id = id;
+ reuse->bind_inany = bind_inany;
+ } else {
+ /* Move sk from the old group to the new one if
+ * - all the other listeners in the old group were close()d or
+ * shutdown()ed, and then sk2 has listen()ed on the same port
+ * OR
+ * - sk listen()ed without bind() (or with autobind), was
+ * shutdown()ed, and then listen()s on another port which
+ * sk2 listen()s on.
+ */
+ if (reuse->num_socks + reuse->num_closed_socks == reuse->max_socks) {
+ reuse = reuseport_grow(reuse);
+ if (!reuse)
+ return -ENOMEM;
+ }
+ }
+
+ __reuseport_detach_closed_sock(sk, old_reuse);
+ __reuseport_add_sock(sk, reuse);
+ rcu_assign_pointer(sk->sk_reuseport_cb, reuse);
+
+ if (old_reuse->num_socks + old_reuse->num_closed_socks == 0)
+ call_rcu(&old_reuse->rcu, reuseport_free_rcu);
+
+ return 0;
+}
+
void reuseport_detach_sock(struct sock *sk)
{
struct sock_reuseport *reuse;
reuse = rcu_dereference_protected(sk->sk_reuseport_cb,
lockdep_is_held(&reuseport_lock));
+ /* reuseport_grow() has detached a closed sk */
+ if (!reuse)
+ goto out;
+
/* Notify the bpf side. The sk may be added to a sockarray
* map. If so, sockarray logic will remove it from the map.
*
bpf_sk_reuseport_detach(sk);
rcu_assign_pointer(sk->sk_reuseport_cb, NULL);
- __reuseport_detach_sock(sk, reuse);
+
+ if (!__reuseport_detach_closed_sock(sk, reuse))
+ __reuseport_detach_sock(sk, reuse);
if (reuse->num_socks + reuse->num_closed_socks == 0)
call_rcu(&reuse->rcu, reuseport_free_rcu);
+out:
spin_unlock_bh(&reuseport_lock);
}
EXPORT_SYMBOL(reuseport_detach_sock);
+void reuseport_stop_listen_sock(struct sock *sk)
+{
+ if (sk->sk_protocol == IPPROTO_TCP) {
+ struct sock_reuseport *reuse;
+
+ spin_lock_bh(&reuseport_lock);
+
+ reuse = rcu_dereference_protected(sk->sk_reuseport_cb,
+ lockdep_is_held(&reuseport_lock));
+
+ if (sock_net(sk)->ipv4.sysctl_tcp_migrate_req) {
+ /* Migration capable, move sk from the listening section
+ * to the closed section.
+ */
+ bpf_sk_reuseport_detach(sk);
+
+ __reuseport_detach_sock(sk, reuse);
+ __reuseport_add_closed_sock(sk, reuse);
+
+ spin_unlock_bh(&reuseport_lock);
+ return;
+ }
+
+ spin_unlock_bh(&reuseport_lock);
+ }
+
+ /* Not capable to do migration, detach immediately */
+ reuseport_detach_sock(sk);
+}
+EXPORT_SYMBOL(reuseport_stop_listen_sock);
+
static struct sock *run_bpf_filter(struct sock_reuseport *reuse, u16 socks,
struct bpf_prog *prog, struct sk_buff *skb,
int hdr_len)
struct sock_reuseport *reuse;
struct bpf_prog *old_prog;
- if (sk_unhashed(sk) && sk->sk_reuseport) {
- int err = reuseport_alloc(sk, false);
+ if (sk_unhashed(sk)) {
+ int err;
+ if (!sk->sk_reuseport)
+ return -EINVAL;
+
+ err = reuseport_alloc(sk, false);
if (err)
return err;
} else if (!rcu_access_pointer(sk->sk_reuseport_cb)) {
struct sock_reuseport *reuse;
struct bpf_prog *old_prog;
- if (!rcu_access_pointer(sk->sk_reuseport_cb))
- return sk->sk_reuseport ? -ENOENT : -EINVAL;
-
old_prog = NULL;
spin_lock_bh(&reuseport_lock);
reuse = rcu_dereference_protected(sk->sk_reuseport_cb,
lockdep_is_held(&reuseport_lock));
+
+ /* reuse must be checked after acquiring the reuseport_lock
+ * because reuseport_grow() can detach a closed sk.
+ */
+ if (!reuse) {
+ spin_unlock_bh(&reuseport_lock);
+ return sk->sk_reuseport ? -ENOENT : -EINVAL;
+ }
+
+ if (sk_unhashed(sk) && reuse->num_closed_socks) {
+ spin_unlock_bh(&reuseport_lock);
+ return -ENOENT;
+ }
+
old_prog = rcu_replace_pointer(reuse->prog, old_prog,
lockdep_is_held(&reuseport_lock));
spin_unlock_bh(&reuseport_lock);