163 lines
3.9 KiB
C
163 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Check if we can fully utilize 4-tuples for connect().
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*
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* Rules to bind sockets to the same port when all ephemeral ports are
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* exhausted.
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*
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* 1. if there are TCP_LISTEN sockets on the port, fail to bind.
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* 2. if there are sockets without SO_REUSEADDR, fail to bind.
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* 3. if SO_REUSEADDR is disabled, fail to bind.
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* 4. if SO_REUSEADDR is enabled and SO_REUSEPORT is disabled,
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* succeed to bind.
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* 5. if SO_REUSEADDR and SO_REUSEPORT are enabled and
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* there is no socket having the both options and the same EUID,
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* succeed to bind.
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* 6. fail to bind.
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*
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* Author: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
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*/
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "../kselftest_harness.h"
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struct reuse_opts {
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int reuseaddr[2];
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int reuseport[2];
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};
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struct reuse_opts unreusable_opts[12] = {
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{0, 0, 0, 0},
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{0, 0, 0, 1},
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{0, 0, 1, 0},
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{0, 0, 1, 1},
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{0, 1, 0, 0},
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{0, 1, 0, 1},
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{0, 1, 1, 0},
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{0, 1, 1, 1},
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{1, 0, 0, 0},
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{1, 0, 0, 1},
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{1, 0, 1, 0},
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{1, 0, 1, 1},
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};
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struct reuse_opts reusable_opts[4] = {
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{1, 1, 0, 0},
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{1, 1, 0, 1},
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{1, 1, 1, 0},
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{1, 1, 1, 1},
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};
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int bind_port(struct __test_metadata *_metadata, int reuseaddr, int reuseport)
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{
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struct sockaddr_in local_addr;
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int len = sizeof(local_addr);
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int fd, ret;
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fd = socket(AF_INET, SOCK_STREAM, 0);
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ASSERT_NE(-1, fd) TH_LOG("failed to open socket.");
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ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(int));
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ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEADDR.");
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ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &reuseport, sizeof(int));
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ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEPORT.");
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local_addr.sin_family = AF_INET;
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local_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
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local_addr.sin_port = 0;
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if (bind(fd, (struct sockaddr *)&local_addr, len) == -1) {
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close(fd);
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return -1;
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}
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return fd;
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}
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TEST(reuseaddr_ports_exhausted_unreusable)
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{
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struct reuse_opts *opts;
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int i, j, fd[2];
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for (i = 0; i < 12; i++) {
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opts = &unreusable_opts[i];
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for (j = 0; j < 2; j++)
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fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);
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ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");
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EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind.");
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for (j = 0; j < 2; j++)
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if (fd[j] != -1)
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close(fd[j]);
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}
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}
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TEST(reuseaddr_ports_exhausted_reusable_same_euid)
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{
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struct reuse_opts *opts;
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int i, j, fd[2];
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for (i = 0; i < 4; i++) {
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opts = &reusable_opts[i];
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for (j = 0; j < 2; j++)
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fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);
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ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");
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if (opts->reuseport[0] && opts->reuseport[1]) {
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EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind because both sockets succeed to be listened.");
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} else {
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EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind to connect to different destinations.");
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}
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for (j = 0; j < 2; j++)
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if (fd[j] != -1)
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close(fd[j]);
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}
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}
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TEST(reuseaddr_ports_exhausted_reusable_different_euid)
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{
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struct reuse_opts *opts;
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int i, j, ret, fd[2];
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uid_t euid[2] = {10, 20};
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for (i = 0; i < 4; i++) {
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opts = &reusable_opts[i];
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for (j = 0; j < 2; j++) {
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ret = seteuid(euid[j]);
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ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: %d.", euid[j]);
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fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);
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ret = seteuid(0);
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ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: 0.");
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}
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ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");
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EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind because one socket can be bound in each euid.");
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if (fd[1] != -1) {
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ret = listen(fd[0], 5);
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ASSERT_EQ(0, ret) TH_LOG("failed to listen.");
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ret = listen(fd[1], 5);
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EXPECT_EQ(-1, ret) TH_LOG("should fail to listen because only one uid reserves the port in TCP_LISTEN.");
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}
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for (j = 0; j < 2; j++)
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if (fd[j] != -1)
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close(fd[j]);
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}
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}
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TEST_HARNESS_MAIN
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