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Message-ID: <20200118000657.2135859-4-ast@kernel.org>
Date: Fri, 17 Jan 2020 16:06:57 -0800
From: Alexei Starovoitov <ast@...nel.org>
To: <davem@...emloft.net>
CC: <daniel@...earbox.net>, <netdev@...r.kernel.org>,
<bpf@...r.kernel.org>, <kernel-team@...com>
Subject: [PATCH bpf-next 3/3] selftests/bpf: Add tests for program extensions
Add program extension tests that build on top of fexit_bpf2bpf tests.
Replace three global functions in previously loaded test_pkt_access.c program
with three new implementations:
int get_skb_len(struct __sk_buff *skb);
int get_constant(long val);
int get_skb_ifindex(int val, struct __sk_buff *skb, int var);
New function return the same results as original only if arguments match.
new_get_skb_ifindex() demonstrates that 'skb' argument doesn't have to be first
and only argument of BPF program. All normal skb based accesses are available.
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
---
.../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 20 ++++++-
.../selftests/bpf/progs/fexit_bpf2bpf.c | 57 +++++++++++++++++++
.../selftests/bpf/progs/test_pkt_access.c | 8 ++-
3 files changed, 83 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
index 7d3740d38965..53d21d40cbe9 100644
--- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
@@ -26,7 +26,7 @@ static void test_fexit_bpf2bpf_common(const char *obj_file,
link = calloc(sizeof(struct bpf_link *), prog_cnt);
prog = calloc(sizeof(struct bpf_program *), prog_cnt);
- result = malloc(prog_cnt * sizeof(u64));
+ result = malloc((prog_cnt + 32 /* spare */) * sizeof(u64));
if (CHECK(!link || !prog || !result, "alloc_memory",
"failed to alloc memory"))
goto close_prog;
@@ -106,8 +106,26 @@ static void test_target_yes_callees(void)
prog_name);
}
+static void test_func_replace(void)
+{
+ const char *prog_name[] = {
+ "fexit/test_pkt_access",
+ "fexit/test_pkt_access_subprog1",
+ "fexit/test_pkt_access_subprog2",
+ "fexit/test_pkt_access_subprog3",
+ "replace/get_skb_len",
+ "replace/get_skb_ifindex",
+ "replace/get_constant",
+ };
+ test_fexit_bpf2bpf_common("./fexit_bpf2bpf.o",
+ "./test_pkt_access.o",
+ ARRAY_SIZE(prog_name),
+ prog_name);
+}
+
void test_fexit_bpf2bpf(void)
{
test_target_no_callees();
test_target_yes_callees();
+ test_func_replace();
}
diff --git a/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c
index 7c17ee159378..8662f1998571 100644
--- a/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c
@@ -1,8 +1,11 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019 Facebook */
+#include <linux/stddef.h>
+#include <linux/ipv6.h>
#include <linux/bpf.h>
#include "bpf_helpers.h"
#include "bpf_trace_helpers.h"
+#include "bpf_endian.h"
struct sk_buff {
unsigned int len;
@@ -94,4 +97,58 @@ int BPF_PROG(test_subprog3, int val, struct sk_buff *skb, int ret)
test_result_subprog3 = 1;
return 0;
}
+
+__u64 test_get_skb_len = 0;
+SEC("replace/get_skb_len")
+int new_get_skb_len(struct __sk_buff *skb)
+{
+ int len = skb->len;
+
+ if (len != 74)
+ return 0;
+ test_get_skb_len = 1;
+ return 74; /* original get_skb_len() returns skb->len */
+}
+
+__u64 test_get_skb_ifindex = 0;
+SEC("replace/get_skb_ifindex")
+int new_get_skb_ifindex(int val, struct __sk_buff *skb, int var)
+{
+ void *data_end = (void *)(long)skb->data_end;
+ void *data = (void *)(long)skb->data;
+ struct ipv6hdr ip6, *ip6p;
+ int ifindex = skb->ifindex;
+ __u32 eth_proto;
+ __u32 nh_off;
+
+ /* check that BPF extension can read packet via direct packet access */
+ if (data + 14 + sizeof(ip6) > data_end)
+ return 0;
+ ip6p = data + 14;
+
+ if (ip6p->nexthdr != 6 || ip6p->payload_len != __bpf_constant_htons(123))
+ return 0;
+
+ /* check that legacy packet access helper works too */
+ if (bpf_skb_load_bytes(skb, 14, &ip6, sizeof(ip6)) < 0)
+ return 0;
+ ip6p = &ip6;
+ if (ip6p->nexthdr != 6 || ip6p->payload_len != __bpf_constant_htons(123))
+ return 0;
+
+ if (ifindex != 1 || val != 3 || var != 1)
+ return 0;
+ test_get_skb_ifindex = 1;
+ return 3; /* original get_skb_ifindex() returns val * ifindex * var */
+}
+
+volatile __u64 test_get_constant = 0;
+SEC("replace/get_constant")
+int new_get_constant(long val)
+{
+ if (val != 123)
+ return 0;
+ test_get_constant = 1;
+ return test_get_constant; /* original get_constant() returns val - 122 */
+}
char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/test_pkt_access.c b/tools/testing/selftests/bpf/progs/test_pkt_access.c
index b77cebf71e66..3c7b326c4bff 100644
--- a/tools/testing/selftests/bpf/progs/test_pkt_access.c
+++ b/tools/testing/selftests/bpf/progs/test_pkt_access.c
@@ -57,12 +57,18 @@ int get_skb_len(struct __sk_buff *skb)
return skb->len;
}
+__attribute__ ((noinline))
+int get_constant(long val)
+{
+ return val - 122;
+}
+
int get_skb_ifindex(int, struct __sk_buff *skb, int);
__attribute__ ((noinline))
int test_pkt_access_subprog3(int val, struct __sk_buff *skb)
{
- return get_skb_len(skb) * get_skb_ifindex(val, skb, 1);
+ return get_skb_len(skb) * get_skb_ifindex(val, skb, get_constant(123));
}
__attribute__ ((noinline))
--
2.23.0
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