[PATCH v5 bpf-next 3/3] selftests/bpf: Add selftest for bpf_xdp_flow_lookup kfunc

Lorenzo Bianconi
2024-06-14T15:41:25Z

Introduce e2e selftest for bpf_xdp_flow_lookup kfunc through
xdp_flowtable utility.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
tools/testing/selftests/bpf/config | 13 ++
.../selftests/bpf/prog_tests/xdp_flowtable.c | 168 ++++++++++++++++++
.../selftests/bpf/progs/xdp_flowtable.c | 146 +++++++++++++++
3 files changed, 327 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_flowtable.c
create mode 100644 tools/testing/selftests/bpf/progs/xdp_flowtable.c

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 2fb16da78dce8..5291e97df7494 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -83,6 +83,19 @@ CONFIG_NF_CONNTRACK_MARK=y
CONFIG_NF_CONNTRACK_ZONES=y
CONFIG_NF_DEFRAG_IPV4=y
CONFIG_NF_DEFRAG_IPV6=y
+CONFIG_NF_TABLES=y
+CONFIG_NF_TABLES_INET=y
+CONFIG_NF_TABLES_NETDEV=y
+CONFIG_NF_TABLES_IPV4=y
+CONFIG_NF_TABLES_IPV6=y
+CONFIG_NETFILTER_INGRESS=y
+CONFIG_NF_FLOW_TABLE=y
+CONFIG_NF_FLOW_TABLE_INET=y
+CONFIG_NETFILTER_NETLINK=y
+CONFIG_NFT_FLOW_OFFLOAD=y
+CONFIG_IP_NF_IPTABLES=y
+CONFIG_IP6_NF_IPTABLES=y
+CONFIG_IP6_NF_FILTER=y
CONFIG_NF_NAT=y
CONFIG_RC_CORE=y
CONFIG_SECURITY=y
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_flowtable.c b/tools/testing/selftests/bpf/prog_tests/xdp_flowtable.c
new file mode 100644
index 0000000000000..e1bf141d34015
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_flowtable.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <network_helpers.h>
+#include <bpf/btf.h>
+#include <linux/if_link.h>
+#include <linux/udp.h>
+#include <net/if.h>
+#include <unistd.h>
+
+#include "xdp_flowtable.skel.h"
+
+#define TX_NETNS_NAME "ns0"
+#define RX_NETNS_NAME "ns1"
+
+#define TX_NAME "v0"
+#define FORWARD_NAME "v1"
+#define RX_NAME "d0"
+
+#define TX_MAC "00:00:00:00:00:01"
+#define FORWARD_MAC "00:00:00:00:00:02"
+#define RX_MAC "00:00:00:00:00:03"
+#define DST_MAC "00:00:00:00:00:04"
+
+#define TX_ADDR "10.0.0.1"
+#define FORWARD_ADDR "10.0.0.2"
+#define RX_ADDR "20.0.0.1"
+#define DST_ADDR "20.0.0.2"
+
+#define PREFIX_LEN "8"
+#define N_PACKETS 10
+#define UDP_PORT 12345
+#define UDP_PORT_STR "12345"
+
+static int send_udp_traffic(void)
+{
+ struct sockaddr_storage addr;
+ int i, sock;
+
+ if (make_sockaddr(AF_INET, DST_ADDR, UDP_PORT, &addr, NULL))
+ return -EINVAL;
+
+ sock = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sock < 0)
+ return sock;
+
+ for (i = 0; i < N_PACKETS; i++) {
+ unsigned char buf[] = { 0xaa, 0xbb, 0xcc };
+ int n;
+
+ n = sendto(sock, buf, sizeof(buf), MSG_NOSIGNAL | MSG_CONFIRM,
+ (struct sockaddr *)&addr, sizeof(addr));
+ if (n != sizeof(buf)) {
+ close(sock);
+ return -EINVAL;
+ }
+
+ usleep(50000); /* 50ms */
+ }
+ close(sock);
+
+ return 0;
+}
+
+void test_xdp_flowtable(void)
+{
+ struct xdp_flowtable *skel = NULL;
+ struct nstoken *tok = NULL;
+ int iifindex, stats_fd;
+ __u32 value, key = 0;
+ struct bpf_link *link;
+
+ if (SYS_NOFAIL("nft -v")) {
+ fprintf(stdout, "Missing required nft tool\n");
+ test__skip();
+ return;
+ }
+
+ SYS(out, "ip netns add " TX_NETNS_NAME);
+ SYS(out, "ip netns add " RX_NETNS_NAME);
+
+ tok = open_netns(RX_NETNS_NAME);
+ if (!ASSERT_OK_PTR(tok, "setns"))
+ goto out;
+
+ SYS(out, "sysctl -qw net.ipv4.conf.all.forwarding=1");
+
+ SYS(out, "ip link add " TX_NAME " type veth peer " FORWARD_NAME);
+ SYS(out, "ip link set " TX_NAME " netns " TX_NETNS_NAME);
+ SYS(out, "ip link set dev " FORWARD_NAME " address " FORWARD_MAC);
+ SYS(out,
+ "ip addr add " FORWARD_ADDR "/" PREFIX_LEN " dev " FORWARD_NAME);
+ SYS(out, "ip link set dev " FORWARD_NAME " up");
+
+ SYS(out, "ip link add " RX_NAME " type dummy");
+ SYS(out, "ip link set dev " RX_NAME " address " RX_MAC);
+ SYS(out, "ip addr add " RX_ADDR "/" PREFIX_LEN " dev " RX_NAME);
+ SYS(out, "ip link set dev " RX_NAME " up");
+
+ /* configure the flowtable */
+ SYS(out, "nft add table ip filter");
+ SYS(out,
+ "nft add flowtable ip filter f { hook ingress priority 0\\; "
+ "devices = { " FORWARD_NAME ", " RX_NAME " }\\; }");
+ SYS(out,
+ "nft add chain ip filter forward "
+ "{ type filter hook forward priority 0\\; }");
+ SYS(out,
+ "nft add rule ip filter forward ip protocol udp th dport "
+ UDP_PORT_STR " flow add @f");
+
+ /* Avoid ARP calls */
+ SYS(out,
+ "ip -4 neigh add " DST_ADDR " lladdr " DST_MAC " dev " RX_NAME);
+
+ close_netns(tok);
+ tok = open_netns(TX_NETNS_NAME);
+ if (!ASSERT_OK_PTR(tok, "setns"))
+ goto out;
+
+ SYS(out, "ip addr add " TX_ADDR "/" PREFIX_LEN " dev " TX_NAME);
+ SYS(out, "ip link set dev " TX_NAME " address " TX_MAC);
+ SYS(out, "ip link set dev " TX_NAME " up");
+ SYS(out, "ip route add default via " FORWARD_ADDR);
+
+ close_netns(tok);
+ tok = open_netns(RX_NETNS_NAME);
+ if (!ASSERT_OK_PTR(tok, "setns"))
+ goto out;
+
+ iifindex = if_nametoindex(FORWARD_NAME);
+ if (!ASSERT_NEQ(iifindex, 0, "iifindex"))
+ goto out;
+
+ skel = xdp_flowtable__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel"))
+ goto out;
+
+ link = bpf_program__attach_xdp(skel->progs.xdp_flowtable_do_lookup,
+ iifindex);
+ if (!ASSERT_OK_PTR(link, "prog_attach"))
+ goto out;
+
+ close_netns(tok);
+ tok = open_netns(TX_NETNS_NAME);
+ if (!ASSERT_OK_PTR(tok, "setns"))
+ goto out;
+
+ if (!ASSERT_OK(send_udp_traffic(), "send udp"))
+ goto out;
+
+ close_netns(tok);
+ tok = open_netns(RX_NETNS_NAME);
+ if (!ASSERT_OK_PTR(tok, "setns"))
+ goto out;
+
+ stats_fd = bpf_map__fd(skel->maps.stats);
+ if (!ASSERT_OK(bpf_map_lookup_elem(stats_fd, &key, &value),
+ "bpf_map_update_elem stats"))
+ goto out;
+
+ ASSERT_GE(value, N_PACKETS - 2, "bpf_xdp_flow_lookup failed");
+out:
+ xdp_flowtable__destroy(skel);
+ if (tok)
+ close_netns(tok);
+ SYS_NOFAIL("ip netns del " TX_NETNS_NAME);
+ SYS_NOFAIL("ip netns del " RX_NETNS_NAME);
+}
diff --git a/tools/testing/selftests/bpf/progs/xdp_flowtable.c b/tools/testing/selftests/bpf/progs/xdp_flowtable.c
new file mode 100644
index 0000000000000..8297b30b0764b
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/xdp_flowtable.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+#define BPF_NO_KFUNC_PROTOTYPES
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#define MAX_ERRNO 4095
+
+#define ETH_P_IP 0x0800
+#define ETH_P_IPV6 0x86dd
+#define IP_MF 0x2000 /* "More Fragments" */
+#define IP_OFFSET 0x1fff /* "Fragment Offset" */
+#define AF_INET 2
+#define AF_INET6 10
+
+struct bpf_flowtable_opts___local {
+ s32 error;
+};
+
+struct flow_offload_tuple_rhash *
+bpf_xdp_flow_lookup(struct xdp_md *, struct bpf_fib_lookup *,
+ struct bpf_flowtable_opts___local *, u32) __ksym;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __type(key, __u32);
+ __type(value, __u32);
+ __uint(max_entries, 1);
+} stats SEC(".maps");
+
+static bool xdp_flowtable_offload_check_iphdr(struct iphdr *iph)
+{
+ /* ip fragmented traffic */
+ if (iph->frag_off & bpf_htons(IP_MF | IP_OFFSET))
+ return false;
+
+ /* ip options */
+ if (iph->ihl * 4 != sizeof(*iph))
+ return false;
+
+ if (iph->ttl <= 1)
+ return false;
+
+ return true;
+}
+
+static bool xdp_flowtable_offload_check_tcp_state(void *ports, void *data_end,
+ u8 proto)
+{
+ if (proto == IPPROTO_TCP) {
+ struct tcphdr *tcph = ports;
+
+ if (tcph + 1 > data_end)
+ return false;
+
+ if (tcph->fin || tcph->rst)
+ return false;
+ }
+
+ return true;
+}
+
+SEC("xdp.frags")
+int xdp_flowtable_do_lookup(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ struct bpf_flowtable_opts___local opts = {};
+ struct flow_offload_tuple_rhash *tuplehash;
+ struct bpf_fib_lookup tuple = {
+ .ifindex = ctx->ingress_ifindex,
+ };
+ void *data = (void *)(long)ctx->data;
+ struct ethhdr *eth = data;
+ struct flow_ports *ports;
+ __u32 *val, key = 0;
+
+ if (eth + 1 > data_end)
+ return XDP_DROP;
+
+ switch (eth->h_proto) {
+ case bpf_htons(ETH_P_IP): {
+ struct iphdr *iph = data + sizeof(*eth);
+
+ ports = (struct flow_ports *)(iph + 1);
+ if (ports + 1 > data_end)
+ return XDP_PASS;
+
+ /* sanity check on ip header */
+ if (!xdp_flowtable_offload_check_iphdr(iph))
+ return XDP_PASS;
+
+ if (!xdp_flowtable_offload_check_tcp_state(ports, data_end,
+ iph->protocol))
+ return XDP_PASS;
+
+ tuple.family = AF_INET;
+ tuple.tos = iph->tos;
+ tuple.l4_protocol = iph->protocol;
+ tuple.tot_len = bpf_ntohs(iph->tot_len);
+ tuple.ipv4_src = iph->saddr;
+ tuple.ipv4_dst = iph->daddr;
+ tuple.sport = ports->source;
+ tuple.dport = ports->dest;
+ break;
+ }
+ case bpf_htons(ETH_P_IPV6): {
+ struct in6_addr *src = (struct in6_addr *)tuple.ipv6_src;
+ struct in6_addr *dst = (struct in6_addr *)tuple.ipv6_dst;
+ struct ipv6hdr *ip6h = data + sizeof(*eth);
+
+ ports = (struct flow_ports *)(ip6h + 1);
+ if (ports + 1 > data_end)
+ return XDP_PASS;
+
+ if (ip6h->hop_limit <= 1)
+ return XDP_PASS;
+
+ if (!xdp_flowtable_offload_check_tcp_state(ports, data_end,
+ ip6h->nexthdr))
+ return XDP_PASS;
+
+ tuple.family = AF_INET6;
+ tuple.l4_protocol = ip6h->nexthdr;
+ tuple.tot_len = bpf_ntohs(ip6h->payload_len);
+ *src = ip6h->saddr;
+ *dst = ip6h->daddr;
+ tuple.sport = ports->source;
+ tuple.dport = ports->dest;
+ break;
+ }
+ default:
+ return XDP_PASS;
+ }
+
+ tuplehash = bpf_xdp_flow_lookup(ctx, &tuple, &opts, sizeof(opts));
+ if (!tuplehash)
+ return XDP_PASS;
+
+ val = bpf_map_lookup_elem(&stats, &key);
+ if (val)
+ __sync_add_and_fetch(val, 1);
+
+ return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.45.1