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