selftests: add selftest for tcp SO_PEEK_OFF support

[Jon Maloy <jmaloy@redhat.com>]

We add a selftest to check that the SO_PEEK_OFF feature
recently added to tcp works correctly.

Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/net/Makefile          |   1 +
 tools/testing/selftests/net/tcp_so_peek_off.c | 161 ++++++++++++++++++
 3 files changed, 163 insertions(+)
 create mode 100644 tools/testing/selftests/net/tcp_so_peek_off.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index a5f1c0c27dff..70537151b59d 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -69,6 +69,7 @@ TARGETS += net/openvswitch
 TARGETS += net/tcp_ao
 TARGETS += net/netfilter
 TARGETS += net/rds
+TARGETS += net/tcp_so_peek_off
 TARGETS += nsfs
 TARGETS += perf_events
 TARGETS += pidfd
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 8eaffd7a641c..5dfe912e3fbb 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -63,6 +63,7 @@ TEST_GEN_FILES += tcp_mmap tcp_inq psock_snd txring_overwrite
 TEST_GEN_FILES += udpgso udpgso_bench_tx udpgso_bench_rx ip_defrag
 TEST_GEN_FILES += so_txtime ipv6_flowlabel ipv6_flowlabel_mgr so_netns_cookie
 TEST_GEN_FILES += tcp_fastopen_backup_key
+TEST_GEN_FILES += tcp_so_peek_off
 TEST_GEN_FILES += fin_ack_lat
 TEST_GEN_FILES += reuseaddr_ports_exhausted
 TEST_GEN_FILES += hwtstamp_config rxtimestamp timestamping txtimestamp
diff --git a/tools/testing/selftests/net/tcp_so_peek_off.c b/tools/testing/selftests/net/tcp_so_peek_off.c
new file mode 100644
index 000000000000..b4fd8a940795
--- /dev/null
+++ b/tools/testing/selftests/net/tcp_so_peek_off.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+int tcp_peek_offset_probe(sa_family_t af)
+{
+	int optv = 0;
+	int ret = 0;
+	int s;
+
+	s = socket(af, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+	if (s < 0) {
+		perror("Temporary TCP socket creation failed");
+	} else {
+		if (!setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &optv, sizeof(int)))
+			ret = 1;
+		close(s);
+	}
+	return ret;
+}
+
+
+static void tcp_peek_offset_set(int s, int offset)
+{
+	if (setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &offset, sizeof(offset)))
+		perror("Failed to set SO_PEEK_OFF value\n");
+}
+
+static int tcp_peek_offset_get(int s)
+{
+	int offset;
+	socklen_t len = sizeof(offset);
+
+	if (getsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &offset, &len))
+		perror("Failed to get SO_PEEK_OFF value\n");
+	return offset;
+}
+
+static int tcp_peek_offset_test(void)
+{
+	struct sockaddr a = { AF_INET, {0, }};
+	int err = EXIT_FAILURE;
+	int s[2] = {0, 0};
+	int recv_sock = 0;
+	int offset = 0;
+	ssize_t len;
+	char buf;
+
+	s[0] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	s[1] = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
+
+	if (s[0] < 0 || s[1] < 0) {
+		perror("Temporary probe socket creation failed\n");
+		goto out;
+	}
+	if (0 > bind(s[0], &a, sizeof(a))) {
+		perror("Temporary probe socket bind() failed\n");
+		goto out;
+	}
+	if (0 > getsockname(s[0], &a, &((socklen_t) { sizeof(a) }))) {
+		perror("Temporary probe socket getsockname() failed\n");
+		goto out;
+	}
+	if (0 > listen(s[0], 0)) {
+		perror("Temporary probe socket listen() failed\n");
+		goto out;
+	}
+	if (0 <= connect(s[1], &a, sizeof(a)) || errno != EINPROGRESS) {
+		perror("Temporary probe socket connect() failed\n");
+		goto out;
+	}
+	recv_sock = accept(s[0], NULL, NULL);
+	if (recv_sock <= 0) {
+		perror("Temporary probe socket accept() failed\n");
+		goto out;
+	}
+
+	/* Some basic tests of getting/setting offset */
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != -1) {
+		perror("Initial value of socket offset not -1\n");
+		goto out;
+	}
+	tcp_peek_offset_set(recv_sock, 0);
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 0) {
+		perror("Failed to set socket offset to 0\n");
+		goto out;
+	}
+
+	/* Transfer a message */
+	if (0 >= send(s[1], (char *)("ab"), 2, 0) || errno != EINPROGRESS) {
+		perror("Temporary probe socket send() failed\n");
+		goto out;
+	}
+	/* Read first byte */
+	len = recv(recv_sock, &buf, 1, MSG_PEEK);
+	if (len != 1 || buf != 'a') {
+		perror("Failed to read first byte of message\n");
+		goto out;
+	}
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 1) {
+		perror("Offset not forwarded correctly at first byte\n");
+		goto out;
+	}
+	/* Try to read beyond last byte */
+	len = recv(recv_sock, &buf, 2, MSG_PEEK);
+	if (len != 1 || buf != 'b') {
+		perror("Failed to read last byte of message\n");
+		goto out;
+	}
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 2) {
+		perror("Offset not forwarded correctly at last byte\n");
+		goto out;
+	}
+	/* Flush message */
+	len = recv(recv_sock, NULL, 2, MSG_TRUNC);
+	if (len != 2) {
+		perror("Failed to flush message\n");
+		goto out;
+	}
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 0) {
+		perror("Offset not reverted correctly after flush\n");
+		goto out;
+	}
+
+	printf("TCP with MSG_PEEK_OFF works correctly\n");
+	err = EXIT_SUCCESS;
+out:
+	close(recv_sock);
+	close(s[1]);
+	close(s[0]);
+	return err;
+}
+
+int main(int argc, char *argv[])
+{
+	int cap4 = 0, cap6 = 0;
+
+	cap4 = tcp_peek_offset_probe(AF_INET);
+	if (!cap4)
+		printf("SO_PEEK_OFF not supported for TCP/IPv4\n");
+	cap6 = tcp_peek_offset_probe(AF_INET6);
+	if (!cap6)
+		printf("SO_PEEK_OFF not supported for TCP/IPv6\n");
+	if (!cap4 || !cap6)
+		exit(EXIT_SUCCESS);
+
+	exit(tcp_peek_offset_test());
+}
+
-- 
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+int tcp_peek_offset_probe(sa_family_t af)
+{
+	int optv = 0;
+	int ret = 0;
+	int s;
+
+	s = socket(af, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+	if (s < 0) {
+		perror("Temporary TCP socket creation failed");
+	} else {
+		if (!setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &optv, sizeof(int)))
+			ret = 1;
+		close(s);
+	}
+	return ret;
+}
+
+
+static void tcp_peek_offset_set(int s, int offset)
+{
+	if (setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &offset, sizeof(offset)))
+		perror("Failed to set SO_PEEK_OFF value\n");
+}
+
+static int tcp_peek_offset_get(int s)
+{
+	int offset;
+	socklen_t len = sizeof(offset);
+
+	if (getsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &offset, &len))
+		perror("Failed to get SO_PEEK_OFF value\n");
+	return offset;
+}
+
+static int tcp_peek_offset_test(void)
+{
+	struct sockaddr a = { AF_INET, {0, }};
+	int err = EXIT_FAILURE;
+	int s[2] = {0, 0};
+	int recv_sock = 0;
+	int offset = 0;
+	ssize_t len;
+	char buf;
+
+	s[0] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	s[1] = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
+
+	if (s[0] < 0 || s[1] < 0) {
+		perror("Temporary probe socket creation failed\n");
+		goto out;
+	}
+	if (0 > bind(s[0], &a, sizeof(a))) {
+		perror("Temporary probe socket bind() failed\n");
+		goto out;
+	}
+	if (0 > getsockname(s[0], &a, &((socklen_t) { sizeof(a) }))) {
+		perror("Temporary probe socket getsockname() failed\n");
+		goto out;
+	}
+	if (0 > listen(s[0], 0)) {
+		perror("Temporary probe socket listen() failed\n");
+		goto out;
+	}
+	if (0 <= connect(s[1], &a, sizeof(a)) || errno != EINPROGRESS) {
+		perror("Temporary probe socket connect() failed\n");
+		goto out;
+	}
+	recv_sock = accept(s[0], NULL, NULL);
+	if (recv_sock <= 0) {
+		perror("Temporary probe socket accept() failed\n");
+		goto out;
+	}
+
+	/* Some basic tests of getting/setting offset */
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != -1) {
+		perror("Initial value of socket offset not -1\n");
+		goto out;
+	}
+	tcp_peek_offset_set(recv_sock, 0);
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 0) {
+		perror("Failed to set socket offset to 0\n");
+		goto out;
+	}
+
+	/* Transfer a message */
+	if (0 >= send(s[1], (char *)("ab"), 2, 0) || errno != EINPROGRESS) {
+		perror("Temporary probe socket send() failed\n");
+		goto out;
+	}
+	/* Read first byte */
+	len = recv(recv_sock, &buf, 1, MSG_PEEK);
+	if (len != 1 || buf != 'a') {
+		perror("Failed to read first byte of message\n");
+		goto out;
+	}
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 1) {
+		perror("Offset not forwarded correctly at first byte\n");
+		goto out;
+	}
+	/* Try to read beyond last byte */
+	len = recv(recv_sock, &buf, 2, MSG_PEEK);
+	if (len != 1 || buf != 'b') {
+		perror("Failed to read last byte of message\n");
+		goto out;
+	}
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 2) {
+		perror("Offset not forwarded correctly at last byte\n");
+		goto out;
+	}
+	/* Flush message */
+	len = recv(recv_sock, NULL, 2, MSG_TRUNC);
+	if (len != 2) {
+		perror("Failed to flush message\n");
+		goto out;
+	}
+	offset = tcp_peek_offset_get(recv_sock);
+	if (offset != 0) {
+		perror("Offset not reverted correctly after flush\n");
+		goto out;
+	}
+
+	printf("TCP with MSG_PEEK_OFF works correctly\n");
+	err = EXIT_SUCCESS;
+out:
+	close(recv_sock);
+	close(s[1]);
+	close(s[0]);
+	return err;
+}
+
+int main(int argc, char *argv[])
+{
+	int cap4 = 0, cap6 = 0;
+
+	cap4 = tcp_peek_offset_probe(AF_INET);
+	if (!cap4)
+		printf("SO_PEEK_OFF not supported for TCP/IPv4\n");
+	cap6 = tcp_peek_offset_probe(AF_INET6);
+	if (!cap6)
+		printf("SO_PEEK_OFF not supported for TCP/IPv6\n");
+	if (!cap4 || !cap6)
+		exit(EXIT_SUCCESS);
+
+	exit(tcp_peek_offset_test());
+}
+
-- 
2.45.2