[PATCH bpf-next 2/8] tcp, ulp: remove ulp bits from sockmap

[Daniel Borkmann <daniel@iogearbox.net>]

In order to prepare sockmap logic to be used in combination with kTLS
we need to detangle it from ULP, and further split it in later commits
into a generic API.

Joint work with John.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
 include/net/tcp.h    |  1 -
 kernel/bpf/sockmap.c | 39 ++++++++---------------------
 net/ipv4/tcp_ulp.c   | 71 ++++++++++------------------------------------------
 3 files changed, 23 insertions(+), 88 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 0d29292..8f5cef6 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2057,7 +2057,6 @@ struct tcp_ulp_ops {
 int tcp_register_ulp(struct tcp_ulp_ops *type);
 void tcp_unregister_ulp(struct tcp_ulp_ops *type);
 int tcp_set_ulp(struct sock *sk, const char *name);
-int tcp_set_ulp_id(struct sock *sk, const int ulp);
 void tcp_get_available_ulp(char *buf, size_t len);
 void tcp_cleanup_ulp(struct sock *sk);
 
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 5d0677d..de6f7a6 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -182,6 +182,7 @@ enum {
 static struct proto *saved_tcpv6_prot __read_mostly;
 static DEFINE_SPINLOCK(tcpv6_prot_lock);
 static struct proto bpf_tcp_prots[SOCKMAP_NUM_PROTS][SOCKMAP_NUM_CONFIGS];
+
 static void build_protos(struct proto prot[SOCKMAP_NUM_CONFIGS],
 			 struct proto *base)
 {
@@ -239,6 +240,13 @@ static int bpf_tcp_init(struct sock *sk)
 	return 0;
 }
 
+static int __init bpf_sock_init(void)
+{
+	build_protos(bpf_tcp_prots[SOCKMAP_IPV4], &tcp_prot);
+	return 0;
+}
+core_initcall(bpf_sock_init);
+
 static void smap_release_sock(struct smap_psock *psock, struct sock *sock);
 static int free_start_sg(struct sock *sk, struct sk_msg_buff *md, bool charge);
 
@@ -413,15 +421,6 @@ enum __sk_action {
 	__SK_NONE,
 };
 
-static struct tcp_ulp_ops bpf_tcp_ulp_ops __read_mostly = {
-	.name		= "bpf_tcp",
-	.uid		= TCP_ULP_BPF,
-	.user_visible	= false,
-	.owner		= NULL,
-	.init		= bpf_tcp_init,
-	.release	= bpf_tcp_release,
-};
-
 static int memcopy_from_iter(struct sock *sk,
 			     struct sk_msg_buff *md,
 			     struct iov_iter *from, int bytes)
@@ -1236,16 +1235,6 @@ static void bpf_tcp_msg_add(struct smap_psock *psock,
 		bpf_prog_put(orig_tx_msg);
 }
 
-static int bpf_tcp_ulp_register(void)
-{
-	build_protos(bpf_tcp_prots[SOCKMAP_IPV4], &tcp_prot);
-	/* Once BPF TX ULP is registered it is never unregistered. It
-	 * will be in the ULP list for the lifetime of the system. Doing
-	 * duplicate registers is not a problem.
-	 */
-	return tcp_register_ulp(&bpf_tcp_ulp_ops);
-}
-
 static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb)
 {
 	struct bpf_prog *prog = READ_ONCE(psock->bpf_verdict);
@@ -1491,7 +1480,7 @@ static void smap_release_sock(struct smap_psock *psock, struct sock *sock)
 {
 	if (refcount_dec_and_test(&psock->refcnt)) {
 		if (psock_is_smap_sk(sock))
-			tcp_cleanup_ulp(sock);
+			bpf_tcp_release(sock);
 		write_lock_bh(&sock->sk_callback_lock);
 		smap_stop_sock(psock, sock);
 		write_unlock_bh(&sock->sk_callback_lock);
@@ -1666,10 +1655,6 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
 	    attr->value_size != 4 || attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
 		return ERR_PTR(-EINVAL);
 
-	err = bpf_tcp_ulp_register();
-	if (err && err != -EEXIST)
-		return ERR_PTR(err);
-
 	stab = kzalloc(sizeof(*stab), GFP_USER);
 	if (!stab)
 		return ERR_PTR(-ENOMEM);
@@ -1951,7 +1936,7 @@ static int __sock_map_ctx_update_elem(struct bpf_map *map,
 	if (tx_msg)
 		bpf_tcp_msg_add(psock, sock, tx_msg);
 	if (new) {
-		err = tcp_set_ulp_id(sock, TCP_ULP_BPF);
+		err = bpf_tcp_init(sock);
 		if (err)
 			goto out_free;
 	}
@@ -2187,10 +2172,6 @@ static struct bpf_map *sock_hash_alloc(union bpf_attr *attr)
 		 */
 		return ERR_PTR(-E2BIG);
 
-	err = bpf_tcp_ulp_register();
-	if (err && err != -EEXIST)
-		return ERR_PTR(err);
-
 	htab = kzalloc(sizeof(*htab), GFP_USER);
 	if (!htab)
 		return ERR_PTR(-ENOMEM);
diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 34e9635..a9162aa 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -6,7 +6,7 @@
  *
  */
 
-#include<linux/module.h>
+#include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/types.h>
 #include <linux/list.h>
@@ -29,18 +29,6 @@ static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
 	return NULL;
 }
 
-static struct tcp_ulp_ops *tcp_ulp_find_id(const int ulp)
-{
-	struct tcp_ulp_ops *e;
-
-	list_for_each_entry_rcu(e, &tcp_ulp_list, list) {
-		if (e->uid == ulp)
-			return e;
-	}
-
-	return NULL;
-}
-
 static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
 {
 	const struct tcp_ulp_ops *ulp = NULL;
@@ -63,18 +51,6 @@ static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
 	return ulp;
 }
 
-static const struct tcp_ulp_ops *__tcp_ulp_lookup(const int uid)
-{
-	const struct tcp_ulp_ops *ulp;
-
-	rcu_read_lock();
-	ulp = tcp_ulp_find_id(uid);
-	if (!ulp || !try_module_get(ulp->owner))
-		ulp = NULL;
-	rcu_read_unlock();
-	return ulp;
-}
-
 /* Attach new upper layer protocol to the list
  * of available protocols.
  */
@@ -135,56 +111,35 @@ void tcp_cleanup_ulp(struct sock *sk)
 	icsk->icsk_ulp_ops = NULL;
 }
 
-/* Change upper layer protocol for socket */
-int tcp_set_ulp(struct sock *sk, const char *name)
+static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
-	const struct tcp_ulp_ops *ulp_ops;
-	int err = 0;
+	int err;
 
-	sock_owned_by_me(sk);
+	err = -EEXIST;
 	if (icsk->icsk_ulp_ops)
-		return -EEXIST;
-
-	ulp_ops = __tcp_ulp_find_autoload(name);
-	if (!ulp_ops)
-		return -ENOENT;
-
-	if (!ulp_ops->user_visible) {
-		module_put(ulp_ops->owner);
-		return -ENOENT;
-	}
+		goto out_err;
 
 	err = ulp_ops->init(sk);
-	if (err) {
-		module_put(ulp_ops->owner);
-		return err;
-	}
+	if (err)
+		goto out_err;
 
 	icsk->icsk_ulp_ops = ulp_ops;
 	return 0;
+out_err:
+	module_put(ulp_ops->owner);
+	return err;
 }
 
-int tcp_set_ulp_id(struct sock *sk, int ulp)
+int tcp_set_ulp(struct sock *sk, const char *name)
 {
-	struct inet_connection_sock *icsk = inet_csk(sk);
 	const struct tcp_ulp_ops *ulp_ops;
-	int err;
 
 	sock_owned_by_me(sk);
-	if (icsk->icsk_ulp_ops)
-		return -EEXIST;
 
-	ulp_ops = __tcp_ulp_lookup(ulp);
+	ulp_ops = __tcp_ulp_find_autoload(name);
 	if (!ulp_ops)
 		return -ENOENT;
 
-	err = ulp_ops->init(sk);
-	if (err) {
-		module_put(ulp_ops->owner);
-		return err;
-	}
-
-	icsk->icsk_ulp_ops = ulp_ops;
-	return 0;
+	return __tcp_set_ulp(sk, ulp_ops);
 }
-- 
2.9.5