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1// SPDX-License-Identifier: GPL-2.02/*3 * Test functionality of BPF filters with SO_REUSEPORT. This program creates4 * an SO_REUSEPORT receiver group containing one socket per CPU core. It then5 * creates a BPF program that will select a socket from this group based6 * on the core id that receives the packet. The sending code artificially7 * moves itself to run on different core ids and sends one message from8 * each core. Since these packets are delivered over loopback, they should9 * arrive on the same core that sent them. The receiving code then ensures10 * that the packet was received on the socket for the corresponding core id.11 * This entire process is done for several different core id permutations12 * and for each IPv4/IPv6 and TCP/UDP combination.13 */14 15#define _GNU_SOURCE16 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 32static const int PORT = 8888;33 34static 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 77static 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 94static 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 150static151void 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 184static 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 231int 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