/*
* Test functionality of BPF filters for SO_REUSEPORT. The tests below will use
* a BPF program (both classic and extended) to read the first word from an
* incoming packet (expected to be in network byte-order), calculate a modulus
* of that number, and then dispatch the packet to the Nth socket using the
* result. These tests are run for each supported address family and protocol.
* Additionally, a few edge cases in the implementation are tested.
*/
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/unistd.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/resource.h>
#include <unistd.h>
#include "../kselftest.h"
struct test_params {
int recv_family;
int send_family;
int protocol;
size_t recv_socks;
uint16_t recv_port;
uint16_t send_port_min;
};
static size_t sockaddr_size(void)
{
return sizeof(struct sockaddr_storage);
}
static struct sockaddr *new_any_sockaddr(int family, uint16_t port)
{
struct sockaddr_storage *addr;
struct sockaddr_in *addr4;
struct sockaddr_in6 *addr6;
addr = malloc(sizeof(struct sockaddr_storage));
memset(addr, 0, sizeof(struct sockaddr_storage));
switch (family) {
case AF_INET:
addr4 = (struct sockaddr_in *)addr;
addr4->sin_family = AF_INET;
addr4->sin_addr.s_addr = htonl(INADDR_ANY);
addr4->sin_port = htons(port);
break;
case AF_INET6:
addr6 = (struct sockaddr_in6 *)addr;
addr6->sin6_family = AF_INET6;
addr6->sin6_addr = in6addr_any;
addr6->sin6_port = htons(port);
break;
default:
error(1, 0, "Unsupported family %d", family);
}
return (struct sockaddr *)addr;
}
static struct sockaddr *new_loopback_sockaddr(int family, uint16_t port)
{
struct sockaddr *addr = new_any_sockaddr(family, port);
struct sockaddr_in *addr4;
struct sockaddr_in6 *addr6;
switch (family) {
case AF_INET:
addr4 = (struct sockaddr_in *)addr;
addr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
break;
case AF_INET6:
addr6 = (struct sockaddr_in6 *)addr;
addr6->sin6_addr = in6addr_loopback;
break;
default:
error(1, 0, "Unsupported family %d", family);
}
return addr;
}
static void attach_ebpf(int fd, uint16_t mod)
{
static char bpf_log_buf[65536];
static const char bpf_license[] = "GPL";
int bpf_fd;
const struct bpf_insn prog[] = {
/* BPF_MOV64_REG(BPF_REG_6, BPF_REG_1) */
{ BPF_ALU64 | BPF_MOV | BPF_X, BPF_REG_6, BPF_REG_1, 0, 0 },
/* BPF_LD_ABS(BPF_W, 0) R0 = (uint32_t)skb[0] */
{ BPF_LD | BPF_ABS | BPF_W, 0, 0, 0, 0 },
/* BPF_ALU64_IMM(BPF_MOD, BPF_REG_0, mod) */
{ BPF_ALU64 | BPF_MOD | BPF_K, BPF_REG_0, 0, 0, mod },
/* BPF_EXIT_INSN() */
{ BPF_JMP | BPF_EXIT, 0, 0, 0, 0 }
};
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
attr.insn_cnt = ARRAY_SIZE(prog);
attr.insns = (unsigned long) &prog;
attr.license = (unsigned long) &bpf_license;
attr.log_buf = (unsigned long) &bpf_log_buf;
attr.log_size = sizeof(bpf_log_buf);
attr.log_level = 1;
attr.kern_version = 0;
bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
if (bpf_fd < 0)
error(1, errno, "ebpf error. log:\n%s\n", bpf_log_buf);
if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF, &bpf_fd,
sizeof(bpf_fd)))
error(1, errno, "failed to set SO_ATTACH_REUSEPORT_EBPF");
close(bpf_fd);
}
static void attach_cbpf(int fd, uint16_t mod)
{
struct sock_filter code[] = {
/* A = (uint32_t)skb[0] */
{ BPF_LD | BPF_W | BPF_ABS, 0, 0, 0 },
/* A = A % mod */
{ BPF_ALU | BPF_MOD, 0, 0, mod },
/* return A */
{ BPF_RET | BPF_A, 0, 0, 0 },
};
struct sock_fprog p = {
.len = ARRAY_SIZE(code),
.filter = code,
};
if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, &p, sizeof(p)))
error(1, errno, "failed to set SO_ATTACH_REUSEPORT_CBPF");
}
static void build_recv_group(const struct test_params p, int fd[], uint16_t mod,
void (*attach_bpf)(int, uint16_t))
{
struct sockaddr * const addr =
new_any_sockaddr(p.recv_family, p.recv_port);
int i, opt;
for (i = 0; i < p.recv_socks; ++i) {
fd[i] = socket(p.recv_family, p.protocol, 0);
if (fd[i] < 0)
error(1, errno, "failed to create recv %d", i);
opt = 1;
if (setsockopt(fd[i], SOL_SOCKET, SO_REUSEPORT, &opt,
sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT on %d", i);
if (i == 0)
attach_bpf(fd[i], mod);
if (bind(fd[i], addr, sockaddr_size()))
error(1, errno, "failed to bind recv socket %d", i);
if (p.protocol == SOCK_STREAM) {
opt = 4;
if (setsockopt(fd[i], SOL_TCP, TCP_FASTOPEN, &opt,
sizeof(opt)))
error(1, errno,
"failed to set TCP_FASTOPEN on %d", i);
if (listen(fd[i], p.recv_socks * 10))
error(1, errno, "failed to listen on socket");
}
}
free(addr);
}
static void send_from(struct test_params p, uint16_t sport, char *buf,
size_t len)
{
struct sockaddr * const saddr = new_any_sockaddr(p.send_family, sport);
struct sockaddr * const daddr =
new_loopback_sockaddr(p.send_family, p.recv_port);
const int fd = socket(p.send_family, p.protocol, 0), one = 1;
if (fd < 0)
error(1, errno, "failed to create send socket");
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
error(1, errno, "failed to set reuseaddr");
if (bind(fd, saddr, sockaddr_size()))
error(1, errno, "failed to bind send socket");
if (sendto(fd, buf, len, MSG_FASTOPEN, daddr, sockaddr_size()) < 0)
error(1, errno, "failed to send message");
close(fd);
free(saddr);
free(daddr);
}
static void test_recv_order(const struct test_params p, int fd[], int mod)
{
char recv_buf[8], send_buf[8];
struct msghdr msg;
struct iovec recv_io = { recv_buf, 8 };
struct epoll_event ev;
int epfd, conn, i, sport, expected;
uint32_t data, ndata;
epfd = epoll_create(1);
if (epfd < 0)
error(1, errno, "failed to create epoll");
for (i = 0; i < p.recv_socks; ++i) {
ev.events = EPOLLIN;
ev.data.fd = fd[i];
if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd[i], &ev))
error(1, errno, "failed to register sock %d epoll", i);
}
memset(&msg, 0, sizeof(msg));
msg.msg_iov = &recv_io;
msg.msg_iovlen = 1;
for (data = 0; data < p.recv_socks * 2; ++data) {
sport = p.send_port_min + data;
ndata = htonl(data);
memcpy(send_buf, &ndata, sizeof(ndata));
send_from(p, sport, send_buf, sizeof(ndata));
i = epoll_wait(epfd, &ev, 1, -1);
if (i < 0)
error(1, errno, "epoll wait failed");
if (p.protocol == SOCK_STREAM) {
conn = accept(ev.data.fd, NULL, NULL);
if (conn < 0)
error(1, errno, "error accepting");
i = recvmsg(conn, &msg, 0);
close(conn);
} else {
i = recvmsg(ev.data.fd, &msg, 0);
}
if (i < 0)
error(1, errno, "recvmsg error");
if (i != sizeof(ndata))
error(1, 0, "expected size %zd got %d",
sizeof(ndata), i);
for (i = 0; i < p.recv_socks; ++i)
if (ev.data.fd == fd[i])
break;
memcpy(&ndata, recv_buf, sizeof(ndata));
fprintf(stderr, "Socket %d: %d\n", i, ntohl(ndata));
expected = (sport % mod);
if (i != expected)
error(1, 0, "expected socket %d", expected);
}
}
static void test_reuseport_ebpf(struct test_params p)
{
int i, fd[p.recv_socks];
fprintf(stderr, "Testing EBPF mod %zd...\n", p.recv_socks);
build_recv_group(p, fd, p.recv_socks, attach_ebpf);
test_recv_order(p, fd, p.recv_socks);
p.send_port_min += p.recv_socks * 2;
fprintf(stderr, "Reprograming, testing mod %zd...\n", p.recv_socks / 2);
attach_ebpf(fd[0], p.recv_socks / 2);
test_recv_order(p, fd, p.recv_socks / 2);
for (i = 0; i < p.recv_socks; ++i)
close(fd[i]);
}
static void test_reuseport_cbpf(struct test_params p)
{
int i, fd[p.recv_socks];
fprintf(stderr, "Testing CBPF mod %zd...\n", p.recv_socks);
build_recv_group(p, fd, p.recv_socks, attach_cbpf);
test_recv_order(p, fd, p.recv_socks);
p.send_port_min += p.recv_socks * 2;
fprintf(stderr, "Reprograming, testing mod %zd...\n", p.recv_socks / 2);
attach_cbpf(fd[0], p.recv_socks / 2);
test_recv_order(p, fd, p.recv_socks / 2);
for (i = 0; i < p.recv_socks; ++i)
close(fd[i]);
}
static void test_extra_filter(const struct test_params p)
{
struct sockaddr * const addr =
new_any_sockaddr(p.recv_family, p.recv_port);
int fd1, fd2, opt;
fprintf(stderr, "Testing too many filters...\n");
fd1 = socket(p.recv_family, p.protocol, 0);
if (fd1 < 0)
error(1, errno, "failed to create socket 1");
fd2 = socket(p.recv_family, p.protocol, 0);
if (fd2 < 0)
error(1, errno, "failed to create socket 2");
opt = 1;
if (setsockopt(fd1, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT on socket 1");
if (setsockopt(fd2, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT on socket 2");
attach_ebpf(fd1, 10);
attach_ebpf(fd2, 10);
if (bind(fd1, addr, sockaddr_size()))
error(1, errno, "failed to bind recv socket 1");
if (!bind(fd2, addr, sockaddr_size()) || errno != EADDRINUSE)
error(1, errno, "bind socket 2 should fail with EADDRINUSE");
free(addr);
}
static void test_filter_no_reuseport(const struct test_params p)
{
struct sockaddr * const addr =
new_any_sockaddr(p.recv_family, p.recv_port);
const char bpf_license[] = "GPL";
struct bpf_insn ecode[] = {
{ BPF_ALU64 | BPF_MOV | BPF_K, BPF_REG_0, 0, 0, 10 },
{ BPF_JMP | BPF_EXIT, 0, 0, 0, 0 }
};
struct sock_filter ccode[] = {{ BPF_RET | BPF_A, 0, 0, 0 }};
union bpf_attr eprog;
struct sock_fprog cprog;
int fd, bpf_fd;
fprintf(stderr, "Testing filters on non-SO_REUSEPORT socket...\n");
memset(&eprog, 0, sizeof(eprog));
eprog.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
eprog.insn_cnt = ARRAY_SIZE(ecode);
eprog.insns = (unsigned long) &ecode;
eprog.license = (unsigned long) &bpf_license;
eprog.kern_version = 0;
memset(&cprog, 0, sizeof(cprog));
cprog.len = ARRAY_SIZE(ccode);
cprog.filter = ccode;
bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &eprog, sizeof(eprog));
if (bpf_fd < 0)
error(1, errno, "ebpf error");
fd = socket(p.recv_family, p.protocol, 0);
if (fd < 0)
error(1, errno, "failed to create socket 1");
if (bind(fd, addr, sockaddr_size()))
error(1, errno, "failed to bind recv socket 1");
errno = 0;
if (!setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF, &bpf_fd,
sizeof(bpf_fd)) || errno != EINVAL)
error(1, errno, "setsockopt should have returned EINVAL");
errno = 0;
if (!setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, &cprog,
sizeof(cprog)) || errno != EINVAL)
error(1, errno, "setsockopt should have returned EINVAL");
free(addr);
}
static void test_filter_without_bind(void)
{
int fd1, fd2, opt = 1;
fprintf(stderr, "Testing filter add without bind...\n");
fd1 = socket(AF_INET, SOCK_DGRAM, 0);
if (fd1 < 0)
error(1, errno, "failed to create socket 1");
fd2 = socket(AF_INET, SOCK_DGRAM, 0);
if (fd2 < 0)
error(1, errno, "failed to create socket 2");
if (setsockopt(fd1, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT on socket 1");
if (setsockopt(fd2, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT on socket 2");
attach_ebpf(fd1, 10);
attach_cbpf(fd2, 10);
close(fd1);
close(fd2);
}
void enable_fastopen(void)
{
int fd = open("/proc/sys/net/ipv4/tcp_fastopen", 0);
int rw_mask = 3; /* bit 1: client side; bit-2 server side */
int val, size;
char buf[16];
if (fd < 0)
error(1, errno, "Unable to open tcp_fastopen sysctl");
if (read(fd, buf, sizeof(buf)) <= 0)
error(1, errno, "Unable to read tcp_fastopen sysctl");
val = atoi(buf);
close(fd);
if ((val & rw_mask) != rw_mask) {
fd = open("/proc/sys/net/ipv4/tcp_fastopen", O_RDWR);
if (fd < 0)
error(1, errno,
"Unable to open tcp_fastopen sysctl for writing");
val |= rw_mask;
size = snprintf(buf, 16, "%d", val);
if (write(fd, buf, size) <= 0)
error(1, errno, "Unable to write tcp_fastopen sysctl");
close(fd);
}
}
static struct rlimit rlim_old;
static __attribute__((constructor)) void main_ctor(void)
{
getrlimit(RLIMIT_MEMLOCK, &rlim_old);
if (rlim_old.rlim_cur != RLIM_INFINITY) {
struct rlimit rlim_new;
rlim_new.rlim_cur = rlim_old.rlim_cur + (1UL << 20);
rlim_new.rlim_max = rlim_old.rlim_max + (1UL << 20);
setrlimit(RLIMIT_MEMLOCK, &rlim_new);
}
}
static __attribute__((destructor)) void main_dtor(void)
{
setrlimit(RLIMIT_MEMLOCK, &rlim_old);
}
int main(void)
{
fprintf(stderr, "---- IPv4 UDP ----\n");
/* NOTE: UDP socket lookups traverse a different code path when there
* are > 10 sockets in a group. Run the bpf test through both paths.
*/
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 10,
.recv_port = 8000,
.send_port_min = 9000});
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 20,
.recv_port = 8000,
.send_port_min = 9000});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 10,
.recv_port = 8001,
.send_port_min = 9020});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 20,
.recv_port = 8001,
.send_port_min = 9020});
test_extra_filter((struct test_params) {
.recv_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_port = 8002});
test_filter_no_reuseport((struct test_params) {
.recv_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_port = 8008});
fprintf(stderr, "---- IPv6 UDP ----\n");
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET6,
.protocol = SOCK_DGRAM,
.recv_socks = 10,
.recv_port = 8003,
.send_port_min = 9040});
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET6,
.protocol = SOCK_DGRAM,
.recv_socks = 20,
.recv_port = 8003,
.send_port_min = 9040});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET6,
.protocol = SOCK_DGRAM,
.recv_socks = 10,
.recv_port = 8004,
.send_port_min = 9060});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET6,
.protocol = SOCK_DGRAM,
.recv_socks = 20,
.recv_port = 8004,
.send_port_min = 9060});
test_extra_filter((struct test_params) {
.recv_family = AF_INET6,
.protocol = SOCK_DGRAM,
.recv_port = 8005});
test_filter_no_reuseport((struct test_params) {
.recv_family = AF_INET6,
.protocol = SOCK_DGRAM,
.recv_port = 8009});
fprintf(stderr, "---- IPv6 UDP w/ mapped IPv4 ----\n");
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 20,
.recv_port = 8006,
.send_port_min = 9080});
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 10,
.recv_port = 8006,
.send_port_min = 9080});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 10,
.recv_port = 8007,
.send_port_min = 9100});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET,
.protocol = SOCK_DGRAM,
.recv_socks = 20,
.recv_port = 8007,
.send_port_min = 9100});
/* TCP fastopen is required for the TCP tests */
enable_fastopen();
fprintf(stderr, "---- IPv4 TCP ----\n");
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET,
.send_family = AF_INET,
.protocol = SOCK_STREAM,
.recv_socks = 10,
.recv_port = 8008,
.send_port_min = 9120});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET,
.send_family = AF_INET,
.protocol = SOCK_STREAM,
.recv_socks = 10,
.recv_port = 8009,
.send_port_min = 9160});
test_extra_filter((struct test_params) {
.recv_family = AF_INET,
.protocol = SOCK_STREAM,
.recv_port = 8010});
test_filter_no_reuseport((struct test_params) {
.recv_family = AF_INET,
.protocol = SOCK_STREAM,
.recv_port = 8011});
fprintf(stderr, "---- IPv6 TCP ----\n");
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET6,
.protocol = SOCK_STREAM,
.recv_socks = 10,
.recv_port = 8012,
.send_port_min = 9200});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET6,
.protocol = SOCK_STREAM,
.recv_socks = 10,
.recv_port = 8013,
.send_port_min = 9240});
test_extra_filter((struct test_params) {
.recv_family = AF_INET6,
.protocol = SOCK_STREAM,
.recv_port = 8014});
test_filter_no_reuseport((struct test_params) {
.recv_family = AF_INET6,
.protocol = SOCK_STREAM,
.recv_port = 8015});
fprintf(stderr, "---- IPv6 TCP w/ mapped IPv4 ----\n");
test_reuseport_ebpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET,
.protocol = SOCK_STREAM,
.recv_socks = 10,
.recv_port = 8016,
.send_port_min = 9320});
test_reuseport_cbpf((struct test_params) {
.recv_family = AF_INET6,
.send_family = AF_INET,
.protocol = SOCK_STREAM,
.recv_socks = 10,
.recv_port = 8017,
.send_port_min = 9360});
test_filter_without_bind();
fprintf(stderr, "SUCCESS\n");
return 0;
}
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