Commit 7805fe84 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann

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: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Acked-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200121005348.2769920-4-ast@kernel.org
parent 2db6eab1
...@@ -26,7 +26,7 @@ static void test_fexit_bpf2bpf_common(const char *obj_file, ...@@ -26,7 +26,7 @@ static void test_fexit_bpf2bpf_common(const char *obj_file,
link = calloc(sizeof(struct bpf_link *), prog_cnt); link = calloc(sizeof(struct bpf_link *), prog_cnt);
prog = calloc(sizeof(struct bpf_program *), 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", if (CHECK(!link || !prog || !result, "alloc_memory",
"failed to alloc memory")) "failed to alloc memory"))
goto close_prog; goto close_prog;
...@@ -106,8 +106,26 @@ static void test_target_yes_callees(void) ...@@ -106,8 +106,26 @@ static void test_target_yes_callees(void)
prog_name); 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",
"freplace/get_skb_len",
"freplace/get_skb_ifindex",
"freplace/get_constant",
};
test_fexit_bpf2bpf_common("./fexit_bpf2bpf.o",
"./test_pkt_access.o",
ARRAY_SIZE(prog_name),
prog_name);
}
void test_fexit_bpf2bpf(void) void test_fexit_bpf2bpf(void)
{ {
test_target_no_callees(); test_target_no_callees();
test_target_yes_callees(); test_target_yes_callees();
test_func_replace();
} }
// SPDX-License-Identifier: GPL-2.0 // SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019 Facebook */ /* Copyright (c) 2019 Facebook */
#include <linux/stddef.h>
#include <linux/ipv6.h>
#include <linux/bpf.h> #include <linux/bpf.h>
#include <bpf/bpf_helpers.h> #include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
#include "bpf_trace_helpers.h" #include "bpf_trace_helpers.h"
struct sk_buff { struct sk_buff {
...@@ -94,4 +97,58 @@ int BPF_PROG(test_subprog3, int val, struct sk_buff *skb, int ret) ...@@ -94,4 +97,58 @@ int BPF_PROG(test_subprog3, int val, struct sk_buff *skb, int ret)
test_result_subprog3 = 1; test_result_subprog3 = 1;
return 0; return 0;
} }
__u64 test_get_skb_len = 0;
SEC("freplace/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("freplace/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("freplace/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"; char _license[] SEC("license") = "GPL";
...@@ -57,12 +57,18 @@ int get_skb_len(struct __sk_buff *skb) ...@@ -57,12 +57,18 @@ int get_skb_len(struct __sk_buff *skb)
return skb->len; return skb->len;
} }
__attribute__ ((noinline))
int get_constant(long val)
{
return val - 122;
}
int get_skb_ifindex(int, struct __sk_buff *skb, int); int get_skb_ifindex(int, struct __sk_buff *skb, int);
__attribute__ ((noinline)) __attribute__ ((noinline))
int test_pkt_access_subprog3(int val, struct __sk_buff *skb) 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)) __attribute__ ((noinline))
......
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