bpf, selftests: Add redirect_neigh selftest

Add a small test that exercises the new redirect_neigh() helper for the
IPv4 and IPv6 case.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/0fc7d9c5f9a6cc1c65b0d3be83b44b1ec9889f43.1601477936.git.daniel@iogearbox.net
This commit is contained in:
Daniel Borkmann 2020-09-30 17:18:20 +02:00 committed by Alexei Starovoitov
parent faef26fa44
commit eef4a011f3
2 changed files with 312 additions and 0 deletions

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// SPDX-License-Identifier: GPL-2.0
#include <stdint.h>
#include <stdbool.h>
#include <linux/bpf.h>
#include <linux/stddef.h>
#include <linux/pkt_cls.h>
#include <linux/if_ether.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
#ifndef barrier_data
# define barrier_data(ptr) asm volatile("": :"r"(ptr) :"memory")
#endif
#ifndef ctx_ptr
# define ctx_ptr(field) (void *)(long)(field)
#endif
#define dst_to_src_tmp 0xeeddddeeU
#define src_to_dst_tmp 0xeeffffeeU
#define ip4_src 0xac100164 /* 172.16.1.100 */
#define ip4_dst 0xac100264 /* 172.16.2.100 */
#define ip6_src { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
0x00, 0x01, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe }
#define ip6_dst { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
0x00, 0x02, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe }
#ifndef v6_equal
# define v6_equal(a, b) (a.s6_addr32[0] == b.s6_addr32[0] && \
a.s6_addr32[1] == b.s6_addr32[1] && \
a.s6_addr32[2] == b.s6_addr32[2] && \
a.s6_addr32[3] == b.s6_addr32[3])
#endif
static __always_inline bool is_remote_ep_v4(struct __sk_buff *skb,
__be32 addr)
{
void *data_end = ctx_ptr(skb->data_end);
void *data = ctx_ptr(skb->data);
struct iphdr *ip4h;
if (data + sizeof(struct ethhdr) > data_end)
return false;
ip4h = (struct iphdr *)(data + sizeof(struct ethhdr));
if ((void *)(ip4h + 1) > data_end)
return false;
return ip4h->daddr == addr;
}
static __always_inline bool is_remote_ep_v6(struct __sk_buff *skb,
struct in6_addr addr)
{
void *data_end = ctx_ptr(skb->data_end);
void *data = ctx_ptr(skb->data);
struct ipv6hdr *ip6h;
if (data + sizeof(struct ethhdr) > data_end)
return false;
ip6h = (struct ipv6hdr *)(data + sizeof(struct ethhdr));
if ((void *)(ip6h + 1) > data_end)
return false;
return v6_equal(ip6h->daddr, addr);
}
SEC("chk_neigh") int tc_chk(struct __sk_buff *skb)
{
void *data_end = ctx_ptr(skb->data_end);
void *data = ctx_ptr(skb->data);
__u32 *raw = data;
if (data + sizeof(struct ethhdr) > data_end)
return TC_ACT_SHOT;
return !raw[0] && !raw[1] && !raw[2] ? TC_ACT_SHOT : TC_ACT_OK;
}
SEC("dst_ingress") int tc_dst(struct __sk_buff *skb)
{
int idx = dst_to_src_tmp;
__u8 zero[ETH_ALEN * 2];
bool redirect = false;
switch (skb->protocol) {
case __bpf_constant_htons(ETH_P_IP):
redirect = is_remote_ep_v4(skb, __bpf_constant_htonl(ip4_src));
break;
case __bpf_constant_htons(ETH_P_IPV6):
redirect = is_remote_ep_v6(skb, (struct in6_addr)ip6_src);
break;
}
if (!redirect)
return TC_ACT_OK;
barrier_data(&idx);
idx = bpf_ntohl(idx);
__builtin_memset(&zero, 0, sizeof(zero));
if (bpf_skb_store_bytes(skb, 0, &zero, sizeof(zero), 0) < 0)
return TC_ACT_SHOT;
return bpf_redirect_neigh(idx, 0);
}
SEC("src_ingress") int tc_src(struct __sk_buff *skb)
{
int idx = src_to_dst_tmp;
__u8 zero[ETH_ALEN * 2];
bool redirect = false;
switch (skb->protocol) {
case __bpf_constant_htons(ETH_P_IP):
redirect = is_remote_ep_v4(skb, __bpf_constant_htonl(ip4_dst));
break;
case __bpf_constant_htons(ETH_P_IPV6):
redirect = is_remote_ep_v6(skb, (struct in6_addr)ip6_dst);
break;
}
if (!redirect)
return TC_ACT_OK;
barrier_data(&idx);
idx = bpf_ntohl(idx);
__builtin_memset(&zero, 0, sizeof(zero));
if (bpf_skb_store_bytes(skb, 0, &zero, sizeof(zero), 0) < 0)
return TC_ACT_SHOT;
return bpf_redirect_neigh(idx, 0);
}
char __license[] SEC("license") = "GPL";

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#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
#
# This test sets up 3 netns (src <-> fwd <-> dst). There is no direct veth link
# between src and dst. The netns fwd has veth links to each src and dst. The
# client is in src and server in dst. The test installs a TC BPF program to each
# host facing veth in fwd which calls into bpf_redirect_peer() to perform the
# neigh addr population and redirect; it also installs a dropper prog on the
# egress side to drop skbs if neigh addrs were not populated.
if [[ $EUID -ne 0 ]]; then
echo "This script must be run as root"
echo "FAIL"
exit 1
fi
# check that nc, dd, ping, ping6 and timeout are present
command -v nc >/dev/null 2>&1 || \
{ echo >&2 "nc is not available"; exit 1; }
command -v dd >/dev/null 2>&1 || \
{ echo >&2 "dd is not available"; exit 1; }
command -v timeout >/dev/null 2>&1 || \
{ echo >&2 "timeout is not available"; exit 1; }
command -v ping >/dev/null 2>&1 || \
{ echo >&2 "ping is not available"; exit 1; }
command -v ping6 >/dev/null 2>&1 || \
{ echo >&2 "ping6 is not available"; exit 1; }
readonly GREEN='\033[0;92m'
readonly RED='\033[0;31m'
readonly NC='\033[0m' # No Color
readonly PING_ARG="-c 3 -w 10 -q"
readonly TIMEOUT=10
readonly NS_SRC="ns-src-$(mktemp -u XXXXXX)"
readonly NS_FWD="ns-fwd-$(mktemp -u XXXXXX)"
readonly NS_DST="ns-dst-$(mktemp -u XXXXXX)"
readonly IP4_SRC="172.16.1.100"
readonly IP4_DST="172.16.2.100"
readonly IP6_SRC="::1:dead:beef:cafe"
readonly IP6_DST="::2:dead:beef:cafe"
readonly IP4_SLL="169.254.0.1"
readonly IP4_DLL="169.254.0.2"
readonly IP4_NET="169.254.0.0"
cleanup()
{
ip netns del ${NS_SRC}
ip netns del ${NS_FWD}
ip netns del ${NS_DST}
}
trap cleanup EXIT
set -e
ip netns add "${NS_SRC}"
ip netns add "${NS_FWD}"
ip netns add "${NS_DST}"
ip link add veth_src type veth peer name veth_src_fwd
ip link add veth_dst type veth peer name veth_dst_fwd
ip link set veth_src netns ${NS_SRC}
ip link set veth_src_fwd netns ${NS_FWD}
ip link set veth_dst netns ${NS_DST}
ip link set veth_dst_fwd netns ${NS_FWD}
ip -netns ${NS_SRC} addr add ${IP4_SRC}/32 dev veth_src
ip -netns ${NS_DST} addr add ${IP4_DST}/32 dev veth_dst
# The fwd netns automatically get a v6 LL address / routes, but also needs v4
# one in order to start ARP probing. IP4_NET route is added to the endpoints
# so that the ARP processing will reply.
ip -netns ${NS_FWD} addr add ${IP4_SLL}/32 dev veth_src_fwd
ip -netns ${NS_FWD} addr add ${IP4_DLL}/32 dev veth_dst_fwd
ip -netns ${NS_SRC} addr add ${IP6_SRC}/128 dev veth_src nodad
ip -netns ${NS_DST} addr add ${IP6_DST}/128 dev veth_dst nodad
ip -netns ${NS_SRC} link set dev veth_src up
ip -netns ${NS_FWD} link set dev veth_src_fwd up
ip -netns ${NS_DST} link set dev veth_dst up
ip -netns ${NS_FWD} link set dev veth_dst_fwd up
ip -netns ${NS_SRC} route add ${IP4_DST}/32 dev veth_src scope global
ip -netns ${NS_SRC} route add ${IP4_NET}/16 dev veth_src scope global
ip -netns ${NS_FWD} route add ${IP4_SRC}/32 dev veth_src_fwd scope global
ip -netns ${NS_SRC} route add ${IP6_DST}/128 dev veth_src scope global
ip -netns ${NS_FWD} route add ${IP6_SRC}/128 dev veth_src_fwd scope global
ip -netns ${NS_DST} route add ${IP4_SRC}/32 dev veth_dst scope global
ip -netns ${NS_DST} route add ${IP4_NET}/16 dev veth_dst scope global
ip -netns ${NS_FWD} route add ${IP4_DST}/32 dev veth_dst_fwd scope global
ip -netns ${NS_DST} route add ${IP6_SRC}/128 dev veth_dst scope global
ip -netns ${NS_FWD} route add ${IP6_DST}/128 dev veth_dst_fwd scope global
fmac_src=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_src_fwd/address)
fmac_dst=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_dst_fwd/address)
ip -netns ${NS_SRC} neigh add ${IP4_DST} dev veth_src lladdr $fmac_src
ip -netns ${NS_DST} neigh add ${IP4_SRC} dev veth_dst lladdr $fmac_dst
ip -netns ${NS_SRC} neigh add ${IP6_DST} dev veth_src lladdr $fmac_src
ip -netns ${NS_DST} neigh add ${IP6_SRC} dev veth_dst lladdr $fmac_dst
veth_dst=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_dst_fwd/ifindex | awk '{printf "%08x\n", $1}')
veth_src=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_src_fwd/ifindex | awk '{printf "%08x\n", $1}')
xxd -p < test_tc_neigh.o | sed "s/eeddddee/$veth_src/g" | xxd -r -p > test_tc_neigh.x.o
xxd -p < test_tc_neigh.x.o | sed "s/eeffffee/$veth_dst/g" | xxd -r -p > test_tc_neigh.y.o
ip netns exec ${NS_FWD} tc qdisc add dev veth_src_fwd clsact
ip netns exec ${NS_FWD} tc filter add dev veth_src_fwd ingress bpf da obj test_tc_neigh.y.o sec src_ingress
ip netns exec ${NS_FWD} tc filter add dev veth_src_fwd egress bpf da obj test_tc_neigh.y.o sec chk_neigh
ip netns exec ${NS_FWD} tc qdisc add dev veth_dst_fwd clsact
ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd ingress bpf da obj test_tc_neigh.y.o sec dst_ingress
ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd egress bpf da obj test_tc_neigh.y.o sec chk_neigh
rm -f test_tc_neigh.x.o test_tc_neigh.y.o
ip netns exec ${NS_DST} bash -c "nc -4 -l -p 9004 &"
ip netns exec ${NS_DST} bash -c "nc -6 -l -p 9006 &"
set +e
TEST="TCPv4 connectivity test"
ip netns exec ${NS_SRC} bash -c "timeout ${TIMEOUT} dd if=/dev/zero bs=1000 count=100 > /dev/tcp/${IP4_DST}/9004"
if [ $? -ne 0 ]; then
echo -e "${TEST}: ${RED}FAIL${NC}"
exit 1
fi
echo -e "${TEST}: ${GREEN}PASS${NC}"
TEST="TCPv6 connectivity test"
ip netns exec ${NS_SRC} bash -c "timeout ${TIMEOUT} dd if=/dev/zero bs=1000 count=100 > /dev/tcp/${IP6_DST}/9006"
if [ $? -ne 0 ]; then
echo -e "${TEST}: ${RED}FAIL${NC}"
exit 1
fi
echo -e "${TEST}: ${GREEN}PASS${NC}"
TEST="ICMPv4 connectivity test"
ip netns exec ${NS_SRC} ping $PING_ARG ${IP4_DST}
if [ $? -ne 0 ]; then
echo -e "${TEST}: ${RED}FAIL${NC}"
exit 1
fi
echo -e "${TEST}: ${GREEN}PASS${NC}"
TEST="ICMPv6 connectivity test"
ip netns exec ${NS_SRC} ping6 $PING_ARG ${IP6_DST}
if [ $? -ne 0 ]; then
echo -e "${TEST}: ${RED}FAIL${NC}"
exit 1
fi
echo -e "${TEST}: ${GREEN}PASS${NC}"