1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Test functionality of BPF filters with SO_REUSEPORT. This program creates 4 * an SO_REUSEPORT receiver group containing one socket per CPU core. It then 5 * creates a BPF program that will select a socket from this group based 6 * on the core id that receives the packet. The sending code artificially 7 * moves itself to run on different core ids and sends one message from 8 * each core. Since these packets are delivered over loopback, they should 9 * arrive on the same core that sent them. The receiving code then ensures 10 * that the packet was received on the socket for the corresponding core id. 11 * This entire process is done for several different core id permutations 12 * and for each IPv4/IPv6 and TCP/UDP combination. 13 */ 14 15 #define _GNU_SOURCE 16 17 #include <arpa/inet.h> 18 #include <errno.h> 19 #include <error.h> 20 #include <linux/filter.h> 21 #include <linux/in.h> 22 #include <linux/unistd.h> 23 #include <sched.h> 24 #include <stdio.h> 25 #include <stdlib.h> 26 #include <string.h> 27 #include <sys/epoll.h> 28 #include <sys/types.h> 29 #include <sys/socket.h> 30 #include <unistd.h> 31 32 static const int PORT = 8888; 33 34 static void build_rcv_group(int *rcv_fd, size_t len, int family, int proto) 35 { 36 struct sockaddr_storage addr; 37 struct sockaddr_in *addr4; 38 struct sockaddr_in6 *addr6; 39 size_t i; 40 int opt; 41 42 switch (family) { 43 case AF_INET: 44 addr4 = (struct sockaddr_in *)&addr; 45 addr4->sin_family = AF_INET; 46 addr4->sin_addr.s_addr = htonl(INADDR_ANY); 47 addr4->sin_port = htons(PORT); 48 break; 49 case AF_INET6: 50 addr6 = (struct sockaddr_in6 *)&addr; 51 addr6->sin6_family = AF_INET6; 52 addr6->sin6_addr = in6addr_any; 53 addr6->sin6_port = htons(PORT); 54 break; 55 default: 56 error(1, 0, "Unsupported family %d", family); 57 } 58 59 for (i = 0; i < len; ++i) { 60 rcv_fd[i] = socket(family, proto, 0); 61 if (rcv_fd[i] < 0) 62 error(1, errno, "failed to create receive socket"); 63 64 opt = 1; 65 if (setsockopt(rcv_fd[i], SOL_SOCKET, SO_REUSEPORT, &opt, 66 sizeof(opt))) 67 error(1, errno, "failed to set SO_REUSEPORT"); 68 69 if (bind(rcv_fd[i], (struct sockaddr *)&addr, sizeof(addr))) 70 error(1, errno, "failed to bind receive socket"); 71 72 if (proto == SOCK_STREAM && listen(rcv_fd[i], len * 10)) 73 error(1, errno, "failed to listen on receive port"); 74 } 75 } 76 77 static void attach_bpf(int fd) 78 { 79 struct sock_filter code[] = { 80 /* A = raw_smp_processor_id() */ 81 { BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_CPU }, 82 /* return A */ 83 { BPF_RET | BPF_A, 0, 0, 0 }, 84 }; 85 struct sock_fprog p = { 86 .len = 2, 87 .filter = code, 88 }; 89 90 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, &p, sizeof(p))) 91 error(1, errno, "failed to set SO_ATTACH_REUSEPORT_CBPF"); 92 } 93 94 static void send_from_cpu(int cpu_id, int family, int proto) 95 { 96 struct sockaddr_storage saddr, daddr; 97 struct sockaddr_in *saddr4, *daddr4; 98 struct sockaddr_in6 *saddr6, *daddr6; 99 cpu_set_t cpu_set; 100 int fd; 101 102 switch (family) { 103 case AF_INET: 104 saddr4 = (struct sockaddr_in *)&saddr; 105 saddr4->sin_family = AF_INET; 106 saddr4->sin_addr.s_addr = htonl(INADDR_ANY); 107 saddr4->sin_port = 0; 108 109 daddr4 = (struct sockaddr_in *)&daddr; 110 daddr4->sin_family = AF_INET; 111 daddr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK); 112 daddr4->sin_port = htons(PORT); 113 break; 114 case AF_INET6: 115 saddr6 = (struct sockaddr_in6 *)&saddr; 116 saddr6->sin6_family = AF_INET6; 117 saddr6->sin6_addr = in6addr_any; 118 saddr6->sin6_port = 0; 119 120 daddr6 = (struct sockaddr_in6 *)&daddr; 121 daddr6->sin6_family = AF_INET6; 122 daddr6->sin6_addr = in6addr_loopback; 123 daddr6->sin6_port = htons(PORT); 124 break; 125 default: 126 error(1, 0, "Unsupported family %d", family); 127 } 128 129 memset(&cpu_set, 0, sizeof(cpu_set)); 130 CPU_SET(cpu_id, &cpu_set); 131 if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) 132 error(1, errno, "failed to pin to cpu"); 133 134 fd = socket(family, proto, 0); 135 if (fd < 0) 136 error(1, errno, "failed to create send socket"); 137 138 if (bind(fd, (struct sockaddr *)&saddr, sizeof(saddr))) 139 error(1, errno, "failed to bind send socket"); 140 141 if (connect(fd, (struct sockaddr *)&daddr, sizeof(daddr))) 142 error(1, errno, "failed to connect send socket"); 143 144 if (send(fd, "a", 1, 0) < 0) 145 error(1, errno, "failed to send message"); 146 147 close(fd); 148 } 149 150 static 151 void receive_on_cpu(int *rcv_fd, int len, int epfd, int cpu_id, int proto) 152 { 153 struct epoll_event ev; 154 int i, fd; 155 char buf[8]; 156 157 i = epoll_wait(epfd, &ev, 1, -1); 158 if (i < 0) 159 error(1, errno, "epoll_wait failed"); 160 161 if (proto == SOCK_STREAM) { 162 fd = accept(ev.data.fd, NULL, NULL); 163 if (fd < 0) 164 error(1, errno, "failed to accept"); 165 i = recv(fd, buf, sizeof(buf), 0); 166 close(fd); 167 } else { 168 i = recv(ev.data.fd, buf, sizeof(buf), 0); 169 } 170 171 if (i < 0) 172 error(1, errno, "failed to recv"); 173 174 for (i = 0; i < len; ++i) 175 if (ev.data.fd == rcv_fd[i]) 176 break; 177 if (i == len) 178 error(1, 0, "failed to find socket"); 179 fprintf(stderr, "send cpu %d, receive socket %d\n", cpu_id, i); 180 if (cpu_id != i) 181 error(1, 0, "cpu id/receive socket mismatch"); 182 } 183 184 static void test(int *rcv_fd, int len, int family, int proto) 185 { 186 struct epoll_event ev; 187 int epfd, cpu; 188 189 build_rcv_group(rcv_fd, len, family, proto); 190 attach_bpf(rcv_fd[0]); 191 192 epfd = epoll_create(1); 193 if (epfd < 0) 194 error(1, errno, "failed to create epoll"); 195 for (cpu = 0; cpu < len; ++cpu) { 196 ev.events = EPOLLIN; 197 ev.data.fd = rcv_fd[cpu]; 198 if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fd[cpu], &ev)) 199 error(1, errno, "failed to register sock epoll"); 200 } 201 202 /* Forward iterate */ 203 for (cpu = 0; cpu < len; ++cpu) { 204 send_from_cpu(cpu, family, proto); 205 receive_on_cpu(rcv_fd, len, epfd, cpu, proto); 206 } 207 208 /* Reverse iterate */ 209 for (cpu = len - 1; cpu >= 0; --cpu) { 210 send_from_cpu(cpu, family, proto); 211 receive_on_cpu(rcv_fd, len, epfd, cpu, proto); 212 } 213 214 /* Even cores */ 215 for (cpu = 0; cpu < len; cpu += 2) { 216 send_from_cpu(cpu, family, proto); 217 receive_on_cpu(rcv_fd, len, epfd, cpu, proto); 218 } 219 220 /* Odd cores */ 221 for (cpu = 1; cpu < len; cpu += 2) { 222 send_from_cpu(cpu, family, proto); 223 receive_on_cpu(rcv_fd, len, epfd, cpu, proto); 224 } 225 226 close(epfd); 227 for (cpu = 0; cpu < len; ++cpu) 228 close(rcv_fd[cpu]); 229 } 230 231 int main(void) 232 { 233 int *rcv_fd, cpus; 234 235 cpus = sysconf(_SC_NPROCESSORS_ONLN); 236 if (cpus <= 0) 237 error(1, errno, "failed counting cpus"); 238 239 rcv_fd = calloc(cpus, sizeof(int)); 240 if (!rcv_fd) 241 error(1, 0, "failed to allocate array"); 242 243 fprintf(stderr, "---- IPv4 UDP ----\n"); 244 test(rcv_fd, cpus, AF_INET, SOCK_DGRAM); 245 246 fprintf(stderr, "---- IPv6 UDP ----\n"); 247 test(rcv_fd, cpus, AF_INET6, SOCK_DGRAM); 248 249 fprintf(stderr, "---- IPv4 TCP ----\n"); 250 test(rcv_fd, cpus, AF_INET, SOCK_STREAM); 251 252 fprintf(stderr, "---- IPv6 TCP ----\n"); 253 test(rcv_fd, cpus, AF_INET6, SOCK_STREAM); 254 255 free(rcv_fd); 256 257 fprintf(stderr, "SUCCESS\n"); 258 return 0; 259 } 260