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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Check if we can fully utilize 4-tuples for connect().4 *5 * Rules to bind sockets to the same port when all ephemeral ports are6 * exhausted.7 *8 * 1. if there are TCP_LISTEN sockets on the port, fail to bind.9 * 2. if there are sockets without SO_REUSEADDR, fail to bind.10 * 3. if SO_REUSEADDR is disabled, fail to bind.11 * 4. if SO_REUSEADDR is enabled and SO_REUSEPORT is disabled,12 * succeed to bind.13 * 5. if SO_REUSEADDR and SO_REUSEPORT are enabled and14 * there is no socket having the both options and the same EUID,15 * succeed to bind.16 * 6. fail to bind.17 *18 * Author: Kuniyuki Iwashima <kuniyu@amazon.co.jp>19 */20#include <arpa/inet.h>21#include <netinet/in.h>22#include <sys/socket.h>23#include <sys/types.h>24#include <unistd.h>25#include "../kselftest_harness.h"26 27struct reuse_opts {28 int reuseaddr[2];29 int reuseport[2];30};31 32struct reuse_opts unreusable_opts[12] = {33 {{0, 0}, {0, 0}},34 {{0, 0}, {0, 1}},35 {{0, 0}, {1, 0}},36 {{0, 0}, {1, 1}},37 {{0, 1}, {0, 0}},38 {{0, 1}, {0, 1}},39 {{0, 1}, {1, 0}},40 {{0, 1}, {1, 1}},41 {{1, 0}, {0, 0}},42 {{1, 0}, {0, 1}},43 {{1, 0}, {1, 0}},44 {{1, 0}, {1, 1}},45};46 47struct reuse_opts reusable_opts[4] = {48 {{1, 1}, {0, 0}},49 {{1, 1}, {0, 1}},50 {{1, 1}, {1, 0}},51 {{1, 1}, {1, 1}},52};53 54int bind_port(struct __test_metadata *_metadata, int reuseaddr, int reuseport)55{56 struct sockaddr_in local_addr;57 int len = sizeof(local_addr);58 int fd, ret;59 60 fd = socket(AF_INET, SOCK_STREAM, 0);61 ASSERT_NE(-1, fd) TH_LOG("failed to open socket.");62 63 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(int));64 ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEADDR.");65 66 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &reuseport, sizeof(int));67 ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEPORT.");68 69 local_addr.sin_family = AF_INET;70 local_addr.sin_addr.s_addr = inet_addr("127.0.0.1");71 local_addr.sin_port = 0;72 73 if (bind(fd, (struct sockaddr *)&local_addr, len) == -1) {74 close(fd);75 return -1;76 }77 78 return fd;79}80 81TEST(reuseaddr_ports_exhausted_unreusable)82{83 struct reuse_opts *opts;84 int i, j, fd[2];85 86 for (i = 0; i < 12; i++) {87 opts = &unreusable_opts[i];88 89 for (j = 0; j < 2; j++)90 fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);91 92 ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");93 EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind.");94 95 for (j = 0; j < 2; j++)96 if (fd[j] != -1)97 close(fd[j]);98 }99}100 101TEST(reuseaddr_ports_exhausted_reusable_same_euid)102{103 struct reuse_opts *opts;104 int i, j, fd[2];105 106 for (i = 0; i < 4; i++) {107 opts = &reusable_opts[i];108 109 for (j = 0; j < 2; j++)110 fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);111 112 ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");113 114 if (opts->reuseport[0] && opts->reuseport[1]) {115 EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind because both sockets succeed to be listened.");116 } else {117 EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind to connect to different destinations.");118 }119 120 for (j = 0; j < 2; j++)121 if (fd[j] != -1)122 close(fd[j]);123 }124}125 126TEST(reuseaddr_ports_exhausted_reusable_different_euid)127{128 struct reuse_opts *opts;129 int i, j, ret, fd[2];130 uid_t euid[2] = {10, 20};131 132 for (i = 0; i < 4; i++) {133 opts = &reusable_opts[i];134 135 for (j = 0; j < 2; j++) {136 ret = seteuid(euid[j]);137 ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: %d.", euid[j]);138 139 fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]);140 141 ret = seteuid(0);142 ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: 0.");143 }144 145 ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind.");146 EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind because one socket can be bound in each euid.");147 148 if (fd[1] != -1) {149 ret = listen(fd[0], 5);150 ASSERT_EQ(0, ret) TH_LOG("failed to listen.");151 152 ret = listen(fd[1], 5);153 EXPECT_EQ(-1, ret) TH_LOG("should fail to listen because only one uid reserves the port in TCP_LISTEN.");154 }155 156 for (j = 0; j < 2; j++)157 if (fd[j] != -1)158 close(fd[j]);159 }160}161 162TEST_HARNESS_MAIN163