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// 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
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