// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Test suite of lwt_xmit BPF programs that redirect packets
* The file tests focus not only if these programs work as expected normally,
* but also if they can handle abnormal situations gracefully.
*
* WARNING
* -------
* This test suite may crash the kernel, thus should be run in a VM.
*
* Setup:
* ---------
* All tests are performed in a single netns. Two lwt encap routes are setup for
* each subtest:
*
* ip route add 10.0.0.0/24 encap bpf xmit <obj> sec "<ingress_sec>" dev link_err
* ip route add 20.0.0.0/24 encap bpf xmit <obj> sec "<egress_sec>" dev link_err
*
* Here <obj> is statically defined to test_lwt_redirect.bpf.o, and each section
* of this object holds a program entry to test. The BPF object is built from
* progs/test_lwt_redirect.c. We didn't use generated BPF skeleton since the
* attachment for lwt programs are not supported by libbpf yet.
*
* For testing, ping commands are run in the test netns:
*
* ping 10.0.0.<ifindex> -c 1 -w 1 -s 100
* ping 20.0.0.<ifindex> -c 1 -w 1 -s 100
*
* Scenarios:
* --------------------------------
* 1. Redirect to a running tap/tun device
* 2. Redirect to a down tap/tun device
* 3. Redirect to a vlan device with lower layer down
*
* Case 1, ping packets should be received by packet socket on target device
* when redirected to ingress, and by tun/tap fd when redirected to egress.
*
* Case 2,3 are considered successful as long as they do not crash the kernel
* as a regression.
*
* Case 1,2 use tap device to test redirect to device that requires MAC
* header, and tun device to test the case with no MAC header added.
*/
#include <sys/socket.h>
#include <net/if.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/if_tun.h>
#include <linux/icmp.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#define NETNS "ns_lwt_redirect"
#include "lwt_helpers.h"
#include "test_progs.h"
#include "network_helpers.h"
#define BPF_OBJECT "test_lwt_redirect.bpf.o"
#define INGRESS_SEC(need_mac) ((need_mac) ? "redir_ingress" : "redir_ingress_nomac")
#define EGRESS_SEC(need_mac) ((need_mac) ? "redir_egress" : "redir_egress_nomac")
#define LOCAL_SRC "10.0.0.1"
#define CIDR_TO_INGRESS "10.0.0.0/24"
#define CIDR_TO_EGRESS "20.0.0.0/24"
/* ping to redirect toward given dev, with last byte of dest IP being the target
* device index.
*
* Note: ping command inside BPF-CI is busybox version, so it does not have certain
* function, such like -m option to set packet mark.
*/
static void ping_dev(const char *dev, bool is_ingress)
{
int link_index = if_nametoindex(dev);
char ip[256];
if (!ASSERT_GE(link_index, 0, "if_nametoindex"))
return;
if (is_ingress)
snprintf(ip, sizeof(ip), "10.0.0.%d", link_index);
else
snprintf(ip, sizeof(ip), "20.0.0.%d", link_index);
/* We won't get a reply. Don't fail here */
SYS_NOFAIL("ping %s -c1 -W1 -s %d",
ip, ICMP_PAYLOAD_SIZE);
}
static int new_packet_sock(const char *ifname)
{
int err = 0;
int ignore_outgoing = 1;
int ifindex = -1;
int s = -1;
s = socket(AF_PACKET, SOCK_RAW, 0);
if (!ASSERT_GE(s, 0, "socket(AF_PACKET)"))
return -1;
ifindex = if_nametoindex(ifname);
if (!ASSERT_GE(ifindex, 0, "if_nametoindex")) {
close(s);
return -1;
}
struct sockaddr_ll addr = {
.sll_family = AF_PACKET,
.sll_protocol = htons(ETH_P_IP),
.sll_ifindex = ifindex,
};
err = bind(s, (struct sockaddr *)&addr, sizeof(addr));
if (!ASSERT_OK(err, "bind(AF_PACKET)")) {
close(s);
return -1;
}
/* Use packet socket to capture only the ingress, so we can distinguish
* the case where a regression that actually redirects the packet to
* the egress.
*/
err = setsockopt(s, SOL_PACKET, PACKET_IGNORE_OUTGOING,
&ignore_outgoing, sizeof(ignore_outgoing));
if (!ASSERT_OK(err, "setsockopt(PACKET_IGNORE_OUTGOING)")) {
close(s);
return -1;
}
err = fcntl(s, F_SETFL, O_NONBLOCK);
if (!ASSERT_OK(err, "fcntl(O_NONBLOCK)")) {
close(s);
return -1;
}
return s;
}
static int expect_icmp(char *buf, ssize_t len)
{
struct ethhdr *eth = (struct ethhdr *)buf;
if (len < (ssize_t)sizeof(*eth))
return -1;
if (eth->h_proto == htons(ETH_P_IP))
return __expect_icmp_ipv4((char *)(eth + 1), len - sizeof(*eth));
return -1;
}
static int expect_icmp_nomac(char *buf, ssize_t len)
{
return __expect_icmp_ipv4(buf, len);
}
static void send_and_capture_test_packets(const char *test_name, int tap_fd,
const char *target_dev, bool need_mac)
{
int psock = -1;
struct timeval timeo = {
.tv_sec = 0,
.tv_usec = 250000,
};
int ret = -1;
filter_t filter = need_mac ? expect_icmp : expect_icmp_nomac;
ping_dev(target_dev, false);
ret = wait_for_packet(tap_fd, filter, &timeo);
if (!ASSERT_EQ(ret, 1, "wait_for_epacket")) {
log_err("%s egress test fails", test_name);
goto out;
}
psock = new_packet_sock(target_dev);
ping_dev(target_dev, true);
ret = wait_for_packet(psock, filter, &timeo);
if (!ASSERT_EQ(ret, 1, "wait_for_ipacket")) {
log_err("%s ingress test fails", test_name);
goto out;
}
out:
if (psock >= 0)
close(psock);
}
static int setup_redirect_target(const char *target_dev, bool need_mac)
{
int target_index = -1;
int tap_fd = -1;
tap_fd = open_tuntap(target_dev, need_mac);
if (!ASSERT_GE(tap_fd, 0, "open_tuntap"))
goto fail;
target_index = if_nametoindex(target_dev);
if (!ASSERT_GE(target_index, 0, "if_nametoindex"))
goto fail;
SYS(fail, "sysctl -w net.ipv6.conf.all.disable_ipv6=1");
SYS(fail, "ip link add link_err type dummy");
SYS(fail, "ip link set lo up");
SYS(fail, "ip addr add dev lo " LOCAL_SRC "/32");
SYS(fail, "ip link set link_err up");
SYS(fail, "ip link set %s up", target_dev);
SYS(fail, "ip route add %s dev link_err encap bpf xmit obj %s sec %s",
CIDR_TO_INGRESS, BPF_OBJECT, INGRESS_SEC(need_mac));
SYS(fail, "ip route add %s dev link_err encap bpf xmit obj %s sec %s",
CIDR_TO_EGRESS, BPF_OBJECT, EGRESS_SEC(need_mac));
return tap_fd;
fail:
if (tap_fd >= 0)
close(tap_fd);
return -1;
}
static void test_lwt_redirect_normal(void)
{
const char *target_dev = "tap0";
int tap_fd = -1;
bool need_mac = true;
tap_fd = setup_redirect_target(target_dev, need_mac);
if (!ASSERT_GE(tap_fd, 0, "setup_redirect_target"))
return;
send_and_capture_test_packets(__func__, tap_fd, target_dev, need_mac);
close(tap_fd);
}
static void test_lwt_redirect_normal_nomac(void)
{
const char *target_dev = "tun0";
int tap_fd = -1;
bool need_mac = false;
tap_fd = setup_redirect_target(target_dev, need_mac);
if (!ASSERT_GE(tap_fd, 0, "setup_redirect_target"))
return;
send_and_capture_test_packets(__func__, tap_fd, target_dev, need_mac);
close(tap_fd);
}
/* This test aims to prevent regression of future. As long as the kernel does
* not panic, it is considered as success.
*/
static void __test_lwt_redirect_dev_down(bool need_mac)
{
const char *target_dev = "tap0";
int tap_fd = -1;
tap_fd = setup_redirect_target(target_dev, need_mac);
if (!ASSERT_GE(tap_fd, 0, "setup_redirect_target"))
return;
SYS(out, "ip link set %s down", target_dev);
ping_dev(target_dev, true);
ping_dev(target_dev, false);
out:
close(tap_fd);
}
static void test_lwt_redirect_dev_down(void)
{
__test_lwt_redirect_dev_down(true);
}
static void test_lwt_redirect_dev_down_nomac(void)
{
__test_lwt_redirect_dev_down(false);
}
/* This test aims to prevent regression of future. As long as the kernel does
* not panic, it is considered as success.
*/
static void test_lwt_redirect_dev_carrier_down(void)
{
const char *lower_dev = "tap0";
const char *vlan_dev = "vlan100";
int tap_fd = -1;
tap_fd = setup_redirect_target(lower_dev, true);
if (!ASSERT_GE(tap_fd, 0, "setup_redirect_target"))
return;
SYS(out, "ip link add vlan100 link %s type vlan id 100", lower_dev);
SYS(out, "ip link set %s up", vlan_dev);
SYS(out, "ip link set %s down", lower_dev);
ping_dev(vlan_dev, true);
ping_dev(vlan_dev, false);
out:
close(tap_fd);
}
static void *test_lwt_redirect_run(void *arg)
{
netns_delete();
RUN_TEST(lwt_redirect_normal);
RUN_TEST(lwt_redirect_normal_nomac);
RUN_TEST(lwt_redirect_dev_down);
RUN_TEST(lwt_redirect_dev_down_nomac);
RUN_TEST(lwt_redirect_dev_carrier_down);
return NULL;
}
void test_lwt_redirect(void)
{
pthread_t test_thread;
int err;
/* Run the tests in their own thread to isolate the namespace changes
* so they do not affect the environment of other tests.
* (specifically needed because of unshare(CLONE_NEWNS) in open_netns())
*/
err = pthread_create(&test_thread, NULL, &test_lwt_redirect_run, NULL);
if (ASSERT_OK(err, "pthread_create"))
ASSERT_OK(pthread_join(test_thread, NULL), "pthread_join");
}
Codebase Browser
linux