summaryrefslogtreecommitdiffstats
path: root/tools/testing/selftests/net/reuseaddr_ports_exhausted.c
blob: 066efd30e29460f81956ad9023f21200221e86cb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Check if we can fully utilize 4-tuples for connect().
 *
 * Rules to bind sockets to the same port when all ephemeral ports are
 * exhausted.
 *
 *   1. if there are TCP_LISTEN sockets on the port, fail to bind.
 *   2. if there are sockets without SO_REUSEADDR, fail to bind.
 *   3. if SO_REUSEADDR is disabled, fail to bind.
 *   4. if SO_REUSEADDR is enabled and SO_REUSEPORT is disabled,
 *        succeed to bind.
 *   5. if SO_REUSEADDR and SO_REUSEPORT are enabled and
 *        there is no socket having the both options and the same EUID,
 *        succeed to bind.
 *   6. fail to bind.
 *
 * Author: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
 */
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include "../kselftest_harness.h"

struct reuse_opts {
	int reuseaddr[2];
	int reuseport[2];
};

struct reuse_opts unreusable_opts[12] = {
	{{0, 0}, {0, 0}},
	{{0, 0}, {0, 1}},
	{{0, 0}, {1, 0}},
	{{0, 0}, {1, 1}},
	{{0, 1}, {0, 0}},
	{{0, 1}, {0, 1}},
	{{0, 1}, {1, 0}},
	{{0, 1}, {1, 1}},
	{{1, 0}, {0, 0}},
	{{1, 0}, {0, 1}},
	{{1, 0}, {1, 0}},
	{{1, 0}, {1, 1}},
};

struct reuse_opts reusable_opts[4] = {
	{{1, 1}, {0, 0}},
	{{1, 1}, {0, 1}},
	{{1, 1}, {1, 0}},
	{{1, 1}, {1, 1}},
};

int bind_port(struct __test_metadata *_metadata, int reuseaddr, int reuseport)
{
	struct sockaddr_in local_addr;
	int len = sizeof(local_addr);
	int fd, ret;

	fd = socket(AF_INET, SOCK_STREAM, 0);
	ASSERT_NE(-1, fd) TH_LOG("failed to open socket.");

	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(int));
	ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEADDR.");

	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &reuseport, sizeof(int));
	ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEPORT.");

	local_addr.sin_family = AF_INET;
	local_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
	local_addr.sin_port = 0;

	if (bind(fd, (struct sockaddr *)&local_addr, len) == -1) {
		close(fd);
		return -1;
	}

	return fd;
}

TEST(reuseaddr_ports_exhausted_unreusable)
{
	struct reuse_opts *opts;
	int i, j, fd[2];

	for (i = 0; i < 12; i++) {
		opts = &unreusable_opts[i];

		for (j = 0; j < 2; j++)
			fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);

		ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");
		EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind.");

		for (j = 0; j < 2; j++)
			if (fd[j] != -1)
				close(fd[j]);
	}
}

TEST(reuseaddr_ports_exhausted_reusable_same_euid)
{
	struct reuse_opts *opts;
	int i, j, fd[2];

	for (i = 0; i < 4; i++) {
		opts = &reusable_opts[i];

		for (j = 0; j < 2; j++)
			fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);

		ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");

		if (opts->reuseport[0] && opts->reuseport[1]) {
			EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind because both sockets succeed to be listened.");
		} else {
			EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind to connect to different destinations.");
		}

		for (j = 0; j < 2; j++)
			if (fd[j] != -1)
				close(fd[j]);
	}
}

TEST(reuseaddr_ports_exhausted_reusable_different_euid)
{
	struct reuse_opts *opts;
	int i, j, ret, fd[2];
	uid_t euid[2] = {10, 20};

	for (i = 0; i < 4; i++) {
		opts = &reusable_opts[i];

		for (j = 0; j < 2; j++) {
			ret = seteuid(euid[j]);
			ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: %d.", euid[j]);

			fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);

			ret = seteuid(0);
			ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: 0.");
		}

		ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");
		EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind because one socket can be bound in each euid.");

		if (fd[1] != -1) {
			ret = listen(fd[0], 5);
			ASSERT_EQ(0, ret) TH_LOG("failed to listen.");

			ret = listen(fd[1], 5);
			EXPECT_EQ(-1, ret) TH_LOG("should fail to listen because only one uid reserves the port in TCP_LISTEN.");
		}

		for (j = 0; j < 2; j++)
			if (fd[j] != -1)
				close(fd[j]);
	}
}

TEST_HARNESS_MAIN