Merge branch 'bpf-skmsg-simplify-restore'

Jakub Sitnicki says:

====================
This series has been split out from "Extend SOCKMAP to store listening
sockets" [0]. I think it stands on its own, and makes the latter series
smaller, which will make the review easier, hopefully.

The essence is that we don't need to do a complicated dance in
sk_psock_restore_proto, if we agree that the contract with tcp_update_ulp
is to restore callbacks even when the socket doesn't use ULP. This is what
tcp_update_ulp currently does, and we just make use of it.

Series is accompanied by a test for a particularly tricky case of restoring
callbacks when we have both sockmap and tls callbacks configured in
sk->sk_prot.

[0] https://lore.kernel.org/bpf/20200127131057.150941-1-jakub@cloudflare.com/
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

2 files changed, 124 insertions, 16 deletions

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14d61bba0b79..d90ef61712a1 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -359,22 +359,7 @@ static inline void sk_psock_restore_proto(struct sock *sk,
 					  struct sk_psock *psock)
 {
 	sk->sk_prot->unhash = psock->saved_unhash;
-
-	if (psock->sk_proto) {
-		struct inet_connection_sock *icsk = inet_csk(sk);
-		bool has_ulp = !!icsk->icsk_ulp_data;
-
-		if (has_ulp) {
-			tcp_update_ulp(sk, psock->sk_proto,
-				       psock->saved_write_space);
-		} else {
-			sk->sk_prot = psock->sk_proto;
-			sk->sk_write_space = psock->saved_write_space;
-		}
-		psock->sk_proto = NULL;
-	} else {
-		sk->sk_write_space = psock->saved_write_space;
-	}
+	tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
 }
 
 static inline void sk_psock_set_state(struct sk_psock *psock,
diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c
new file mode 100644
index 000000000000..589b50c91b96
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Cloudflare
+/*
+ * Tests for sockmap/sockhash holding kTLS sockets.
+ */
+
+#include "test_progs.h"
+
+#define MAX_TEST_NAME 80
+
+static int tcp_server(int family)
+{
+	int err, s;
+
+	s = socket(family, SOCK_STREAM, 0);
+	if (CHECK_FAIL(s == -1)) {
+		perror("socket");
+		return -1;
+	}
+
+	err = listen(s, SOMAXCONN);
+	if (CHECK_FAIL(err)) {
+		perror("listen");
+		return -1;
+	}
+
+	return s;
+}
+
+static int disconnect(int fd)
+{
+	struct sockaddr unspec = { AF_UNSPEC };
+
+	return connect(fd, &unspec, sizeof(unspec));
+}
+
+/* Disconnect (unhash) a kTLS socket after removing it from sockmap. */
+static void test_sockmap_ktls_disconnect_after_delete(int family, int map)
+{
+	struct sockaddr_storage addr = {0};
+	socklen_t len = sizeof(addr);
+	int err, cli, srv, zero = 0;
+
+	srv = tcp_server(family);
+	if (srv == -1)
+		return;
+
+	err = getsockname(srv, (struct sockaddr *)&addr, &len);
+	if (CHECK_FAIL(err)) {
+		perror("getsockopt");
+		goto close_srv;
+	}
+
+	cli = socket(family, SOCK_STREAM, 0);
+	if (CHECK_FAIL(cli == -1)) {
+		perror("socket");
+		goto close_srv;
+	}
+
+	err = connect(cli, (struct sockaddr *)&addr, len);
+	if (CHECK_FAIL(err)) {
+		perror("connect");
+		goto close_cli;
+	}
+
+	err = bpf_map_update_elem(map, &zero, &cli, 0);
+	if (CHECK_FAIL(err)) {
+		perror("bpf_map_update_elem");
+		goto close_cli;
+	}
+
+	err = setsockopt(cli, IPPROTO_TCP, TCP_ULP, "tls", strlen("tls"));
+	if (CHECK_FAIL(err)) {
+		perror("setsockopt(TCP_ULP)");
+		goto close_cli;
+	}
+
+	err = bpf_map_delete_elem(map, &zero);
+	if (CHECK_FAIL(err)) {
+		perror("bpf_map_delete_elem");
+		goto close_cli;
+	}
+
+	err = disconnect(cli);
+	if (CHECK_FAIL(err))
+		perror("disconnect");
+
+close_cli:
+	close(cli);
+close_srv:
+	close(srv);
+}
+
+static void run_tests(int family, enum bpf_map_type map_type)
+{
+	char test_name[MAX_TEST_NAME];
+	int map;
+
+	map = bpf_create_map(map_type, sizeof(int), sizeof(int), 1, 0);
+	if (CHECK_FAIL(map == -1)) {
+		perror("bpf_map_create");
+		return;
+	}
+
+	snprintf(test_name, MAX_TEST_NAME,
+		 "sockmap_ktls disconnect_after_delete %s %s",
+		 family == AF_INET ? "IPv4" : "IPv6",
+		 map_type == BPF_MAP_TYPE_SOCKMAP ? "SOCKMAP" : "SOCKHASH");
+	if (!test__start_subtest(test_name))
+		return;
+
+	test_sockmap_ktls_disconnect_after_delete(family, map);
+
+	close(map);
+}
+
+void test_sockmap_ktls(void)
+{
+	run_tests(AF_INET, BPF_MAP_TYPE_SOCKMAP);
+	run_tests(AF_INET, BPF_MAP_TYPE_SOCKHASH);
+	run_tests(AF_INET6, BPF_MAP_TYPE_SOCKMAP);
+	run_tests(AF_INET6, BPF_MAP_TYPE_SOCKHASH);
+}