Date:   Wed, 6 Oct 2021 16:05:43 -0700
From:   Joanne Koong <joannekoong@...com>
To:     <bpf@...r.kernel.org>
CC:     <kafai@...com>, <netdev@...r.kernel.org>, <Kernel-team@...com>,
        Joanne Koong <joannekoong@...com>
Subject: [PATCH bpf-next v2 3/3] bpf/selftests: Add xdp bpf_load_tcp_hdr_options tests

This patch adds tests for bpf_load_tcp_hdr_options used by xdp
programs.

test_xdp_tcp_hdr_options.c:
- Tests ipv4 and ipv6 packets with TCPOPT_EXP and non-TCPOPT_EXP
tcp options set. Verify that options can be parsed and loaded
successfully.
- Tests error paths: TCPOPT_EXP with invalid magic, option with
invalid kind_len, non-existent option, invalid flags, option size
smaller than kind_len, invalid packet

Signed-off-by: Joanne Koong <joannekoong@...com>
---
 .../bpf/prog_tests/xdp_tcp_hdr_options.c      | 144 +++++++++++++
 .../bpf/progs/test_xdp_tcp_hdr_options.c      | 198 ++++++++++++++++++
 2 files changed, 342 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_tcp_hdr_options.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_tcp_hdr_options.c

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_tcp_hdr_options.c b/tools/testing/selftests/bpf/prog_tests/xdp_tcp_hdr_options.c
new file mode 100644
index 000000000000..2148199f2fcc
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_tcp_hdr_options.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include "test_progs.h"
+#include "network_helpers.h"
+#include "test_tcp_hdr_options.h"
+#include "test_xdp_tcp_hdr_options.skel.h"
+
+struct xdp_exprm_opt {
+	__u8 kind;
+	__u8 len;
+	__u16 magic;
+	struct bpf_test_option data;
+} __packed;
+
+struct xdp_regular_opt {
+	__u8 kind;
+	__u8 len;
+	struct bpf_test_option data;
+} __packed;
+
+struct xdp_test_opt {
+	struct xdp_exprm_opt exprm_opt;
+	struct xdp_regular_opt regular_opt;
+} __packed;
+
+struct xdp_ipv4_packet {
+	struct ipv4_packet pkt_v4;
+	struct xdp_test_opt test_opt;
+} __packed;
+
+struct xdp_ipv6_packet {
+	struct ipv6_packet pkt_v6;
+	struct xdp_test_opt test_opt;
+} __packed;
+
+static __u8 opt_flags = OPTION_MAX_DELACK_MS | OPTION_RAND;
+static __u8 exprm_max_delack_ms = 12;
+static __u8 regular_max_delack_ms = 21;
+static __u8 exprm_rand = 0xfa;
+static __u8 regular_rand = 0xce;
+
+static void init_test_opt(struct xdp_test_opt *test_opt,
+			  struct test_xdp_tcp_hdr_options *skel)
+{
+	test_opt->exprm_opt.kind = TCPOPT_EXP;
+	/* +1 for kind, +1 for kind-len, +2 for magic, +1 for flags, +1 for
+	 * OPTION_MAX_DELACK_MAX, +1 FOR OPTION_RAND
+	 */
+	test_opt->exprm_opt.len = 3 + TCP_BPF_EXPOPT_BASE_LEN;
+	test_opt->exprm_opt.magic = __bpf_htons(skel->rodata->test_magic);
+	test_opt->exprm_opt.data.flags = opt_flags;
+	test_opt->exprm_opt.data.max_delack_ms = exprm_max_delack_ms;
+	test_opt->exprm_opt.data.rand = exprm_rand;
+
+	test_opt->regular_opt.kind = skel->rodata->test_kind;
+	/* +1 for kind, +1 for kind-len, +1 for flags, +1 FOR
+	 * OPTION_MAX_DELACK_MS, +1 FOR OPTION_RAND
+	 */
+	test_opt->regular_opt.len = 5;
+	test_opt->regular_opt.data.flags = opt_flags;
+	test_opt->regular_opt.data.max_delack_ms = regular_max_delack_ms;
+	test_opt->regular_opt.data.rand = regular_rand;
+}
+
+static void check_opt_out(struct test_xdp_tcp_hdr_options *skel)
+{
+	struct bpf_test_option *opt_out;
+
+	opt_out = &skel->bss->exprm_opt_out;
+	ASSERT_EQ(opt_out->flags, opt_flags, "check exprm flags");
+	ASSERT_EQ(opt_out->max_delack_ms, exprm_max_delack_ms,
+		  "check exprm max_delack_ms");
+	ASSERT_EQ(opt_out->rand, exprm_rand, "check exprm rand");
+
+	opt_out = &skel->bss->regular_opt_out;
+	ASSERT_EQ(opt_out->flags, opt_flags, "check regular flags");
+	ASSERT_EQ(opt_out->max_delack_ms, regular_max_delack_ms,
+		  "check regular max_delack_ms");
+	ASSERT_EQ(opt_out->rand, regular_rand, "check regular rand");
+}
+
+void test_xdp_tcp_hdr_options(void)
+{
+	int err, prog_fd, prog_err_path_fd, prog_invalid_pkt_fd;
+	struct xdp_ipv6_packet ipv6_pkt, invalid_pkt;
+	struct test_xdp_tcp_hdr_options *skel;
+	struct xdp_ipv4_packet ipv4_pkt;
+	struct xdp_test_opt test_opt;
+	__u32 duration, retval, size;
+	char buf[128];
+
+	/* Load XDP program to introspect */
+	skel = test_xdp_tcp_hdr_options__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel open and load"))
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs._xdp_load_hdr_opt);
+
+	init_test_opt(&test_opt, skel);
+
+	/* Init the packets */
+	ipv4_pkt.pkt_v4 = pkt_v4;
+	ipv4_pkt.pkt_v4.tcp.doff += 3;
+	ipv4_pkt.test_opt = test_opt;
+
+	ipv6_pkt.pkt_v6 = pkt_v6;
+	ipv6_pkt.pkt_v6.tcp.doff += 3;
+	ipv6_pkt.test_opt = test_opt;
+
+	invalid_pkt.pkt_v6 = pkt_v6;
+	/* Set to an offset that will exceed the xdp data_end */
+	invalid_pkt.pkt_v6.tcp.doff += 4;
+	invalid_pkt.test_opt = test_opt;
+
+	/* Test on ipv4 packet */
+	err = bpf_prog_test_run(prog_fd, 1, &ipv4_pkt, sizeof(ipv4_pkt),
+				buf, &size, &retval, &duration);
+	if (ASSERT_TRUE(!err && retval == XDP_PASS, "xdp_tcp_hdr_options ipv4"))
+		check_opt_out(skel);
+
+	/* Test on ipv6 packet */
+	err = bpf_prog_test_run(prog_fd, 1, &ipv6_pkt, sizeof(ipv6_pkt),
+				buf, &size, &retval, &duration);
+	if (ASSERT_TRUE(!err && retval == XDP_PASS, "xdp_tcp_hdr_options ipv6"))
+		check_opt_out(skel);
+
+	/* Test error paths */
+	prog_err_path_fd =
+		bpf_program__fd(skel->progs._xdp_load_hdr_opt_err_paths);
+	err = bpf_prog_test_run(prog_err_path_fd, 1, &ipv6_pkt, sizeof(ipv6_pkt),
+				buf, &size, &retval, &duration);
+	ASSERT_TRUE(!err && retval == XDP_PASS, "xdp_tcp_hdr_options err_path");
+
+	/* Test invalid packet */
+	prog_invalid_pkt_fd =
+		bpf_program__fd(skel->progs._xdp_load_hdr_opt_invalid_pkt);
+	err = bpf_prog_test_run(prog_invalid_pkt_fd, 1, &invalid_pkt,
+				sizeof(invalid_pkt), buf, &size, &retval,
+				&duration);
+	ASSERT_TRUE(!err && retval == XDP_PASS, "xdp_tcp_hdr_options invalid_pkt");
+
+	test_xdp_tcp_hdr_options__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_tcp_hdr_options.c b/tools/testing/selftests/bpf/progs/test_xdp_tcp_hdr_options.c
new file mode 100644
index 000000000000..3fe6e1ebd78a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_tcp_hdr_options.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <string.h>
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/tcp.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#define BPF_PROG_TEST_TCP_HDR_OPTIONS
+#include "test_tcp_hdr_options.h"
+
+struct bpf_test_option regular_opt_out;
+struct bpf_test_option exprm_opt_out;
+
+const __u16 test_magic = 0xeB9F;
+const __u8 test_kind = 0xB9;
+
+int err_val = 0;
+
+static void copy_opt_to_out(struct bpf_test_option *test_option, __u8 *data)
+{
+	test_option->flags = data[0];
+	test_option->max_delack_ms = data[1];
+	test_option->rand = data[2];
+}
+
+static int parse_xdp(struct xdp_md *xdp, __u64 *out_flags)
+{
+	void *data_end = (void *)(long)xdp->data_end;
+	__u64 tcphdr_offset = 0, nh_off;
+	void *data = (void *)(long)xdp->data;
+	struct ethhdr *eth = data;
+	int ret;
+
+	nh_off = sizeof(*eth);
+	if (data + nh_off > data_end) {
+		err_val = 1;
+		return XDP_DROP;
+	}
+
+	/* Calculate the offset to the tcp hdr */
+	if (eth->h_proto == __bpf_constant_htons(ETH_P_IPV6)) {
+		tcphdr_offset = sizeof(struct ethhdr) +
+			sizeof(struct ipv6hdr);
+	} else if (eth->h_proto == bpf_htons(ETH_P_IP)) {
+		tcphdr_offset = sizeof(struct ethhdr) +
+			sizeof(struct iphdr);
+	} else {
+		err_val = 2;
+		return XDP_DROP;
+	}
+
+	*out_flags = tcphdr_offset << BPF_LOAD_HDR_OPT_TCP_OFFSET_SHIFT;
+
+	return XDP_PASS;
+}
+
+SEC("xdp")
+int _xdp_load_hdr_opt(struct xdp_md *xdp)
+{
+	struct tcp_exprm_opt exprm_opt = { 0 };
+	struct tcp_opt regular_opt = { 0 };
+	__u64 flags = 0;
+	int ret;
+
+	ret = parse_xdp(xdp, &flags);
+	if (ret != XDP_PASS)
+		return ret;
+
+	/* Test TCPOPT_EXP */
+	exprm_opt.kind = TCPOPT_EXP;
+	exprm_opt.len = 4;
+	exprm_opt.magic = __bpf_htons(test_magic);
+	ret = bpf_load_hdr_opt(xdp, &exprm_opt,
+			       sizeof(exprm_opt), flags);
+	if (ret < 0) {
+		err_val = 3;
+		return XDP_DROP;
+	}
+
+	copy_opt_to_out(&exprm_opt_out, exprm_opt.data);
+
+	/* Test non-TCP_OPT_EXP */
+	regular_opt.kind = test_kind;
+	ret = bpf_load_hdr_opt(xdp, &regular_opt,
+			       sizeof(regular_opt), flags);
+	if (ret < 0) {
+		err_val = 4;
+		return XDP_DROP;
+	}
+
+	copy_opt_to_out(&regular_opt_out, regular_opt.data);
+
+	return XDP_PASS;
+}
+
+SEC("xdp")
+int _xdp_load_hdr_opt_err_paths(struct xdp_md *xdp)
+{
+	struct tcp_exprm_opt exprm_opt = { 0 };
+	struct tcp_opt regular_opt = { 0 };
+	__u64 flags = 0;
+	int ret;
+
+	ret = parse_xdp(xdp, &flags);
+	if (ret != XDP_PASS)
+		return ret;
+
+	/* Test TCPOPT_EXP with invalid magic */
+	exprm_opt.kind = TCPOPT_EXP;
+	exprm_opt.len = 4;
+	exprm_opt.magic = __bpf_htons(test_magic + 1);
+	ret = bpf_load_hdr_opt(xdp, &exprm_opt,
+			       sizeof(exprm_opt), flags);
+	if (ret != -ENOMSG) {
+		err_val = 3;
+		return XDP_DROP;
+	}
+
+	/* Test TCPOPT_EXP with 0 magic */
+	exprm_opt.magic = 0;
+	ret = bpf_load_hdr_opt(xdp, &exprm_opt,
+			       sizeof(exprm_opt), flags);
+	if (ret != -ENOMSG) {
+		err_val = 4;
+		return XDP_DROP;
+	}
+
+	exprm_opt.magic = __bpf_htons(test_magic);
+
+	/* Test TCPOPT_EXP with invalid kind length */
+	exprm_opt.len = 5;
+	ret = bpf_load_hdr_opt(xdp, &exprm_opt,
+			       sizeof(exprm_opt), flags);
+	if (ret != -EINVAL) {
+		err_val = 5;
+		return XDP_DROP;
+	}
+
+	/* Test that non-existent option is not found */
+	regular_opt.kind = test_kind + 1;
+	ret = bpf_load_hdr_opt(xdp, &regular_opt,
+			       sizeof(regular_opt), flags);
+	if (ret != -ENOMSG) {
+		err_val = 6;
+		return XDP_DROP;
+	}
+
+	/* Test invalid flags */
+	regular_opt.kind = test_kind;
+	ret = bpf_load_hdr_opt(xdp, &regular_opt, sizeof(regular_opt),
+			       flags | BPF_LOAD_HDR_OPT_TCP_SYN);
+	if (ret != -EINVAL) {
+		err_val = 7;
+		return XDP_DROP;
+	}
+
+	/* Test non-TCP_OPT_EXP with option size smaller than kind len */
+	ret = bpf_load_hdr_opt(xdp, &regular_opt,
+			       sizeof(regular_opt) - 2, flags);
+	if (ret != -ENOSPC) {
+		err_val = 8;
+		return XDP_DROP;
+	}
+
+	return XDP_PASS;
+}
+
+SEC("xdp")
+int _xdp_load_hdr_opt_invalid_pkt(struct xdp_md *xdp)
+{
+	struct tcp_exprm_opt exprm_opt = { 0 };
+	__u64 flags = 0;
+	int ret;
+
+	ret = parse_xdp(xdp, &flags);
+	if (ret != XDP_PASS)
+		return ret;
+
+	exprm_opt.kind = TCPOPT_EXP;
+	exprm_opt.len = 4;
+	exprm_opt.magic = __bpf_htons(test_magic);
+	ret = bpf_load_hdr_opt(xdp, &exprm_opt,
+			       sizeof(exprm_opt), flags);
+	if (ret != -EINVAL) {
+		err_val = 3;
+		return XDP_DROP;
+	}
+
+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.30.2

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