cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

reuseport_bpf_cpu.c (6714B)


      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
     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
    150static
    151void 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}