From 7805fe843964f81f98592bf580b9cd736ac4ad4c Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 20 Jan 2020 16:53:48 -0800 Subject: selftests/bpf: Add tests for program extensions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Andrii Nakryiko Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20200121005348.2769920-4-ast@kernel.org --- .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 20 +++++++- tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c | 57 ++++++++++++++++++++++ .../testing/selftests/bpf/progs/test_pkt_access.c | 8 ++- 3 files changed, 83 insertions(+), 2 deletions(-) (limited to 'tools/testing/selftests/bpf') diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c index 7d3740d38965..db5c74d2ce6d 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", + "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) { 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 ec5710767d13..c329fccf9842 100644 --- a/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c +++ b/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c @@ -1,7 +1,10 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2019 Facebook */ +#include +#include #include #include +#include #include "bpf_trace_helpers.h" struct sk_buff { @@ -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("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"; diff --git a/tools/testing/selftests/bpf/progs/test_pkt_access.c b/tools/testing/selftests/bpf/progs/test_pkt_access.c index 7c9fcfd2b463..e72eba4a93d2 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)) -- cgit v1.2.3-59-g8ed1b