From ed5941af3f67ba9062b98aba1a6ca398867dc0de Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 7 Nov 2019 10:09:05 -0800 Subject: bpf: Add cb access in kfree_skb test Access the skb->cb[] in the kfree_skb test. Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20191107180905.4097871-1-kafai@fb.com --- tools/testing/selftests/bpf/prog_tests/kfree_skb.c | 54 +++++++++++++++++----- tools/testing/selftests/bpf/progs/kfree_skb.c | 25 ++++++++-- 2 files changed, 63 insertions(+), 16 deletions(-) (limited to 'tools') diff --git a/tools/testing/selftests/bpf/prog_tests/kfree_skb.c b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c index 430b50de1583..55d36856e621 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfree_skb.c +++ b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c @@ -1,15 +1,38 @@ // SPDX-License-Identifier: GPL-2.0 #include +struct meta { + int ifindex; + __u32 cb32_0; + __u8 cb8_0; +}; + +static union { + __u32 cb32[5]; + __u8 cb8[20]; +} cb = { + .cb32[0] = 0x81828384, +}; + static void on_sample(void *ctx, int cpu, void *data, __u32 size) { - int ifindex = *(int *)data, duration = 0; - struct ipv6_packet *pkt_v6 = data + 4; + struct meta *meta = (struct meta *)data; + struct ipv6_packet *pkt_v6 = data + sizeof(*meta); + int duration = 0; - if (ifindex != 1) + if (CHECK(size != 72 + sizeof(*meta), "check_size", "size %u != %zu\n", + size, 72 + sizeof(*meta))) + return; + if (CHECK(meta->ifindex != 1, "check_meta_ifindex", + "meta->ifindex = %d\n", meta->ifindex)) /* spurious kfree_skb not on loopback device */ return; - if (CHECK(size != 76, "check_size", "size %u != 76\n", size)) + if (CHECK(meta->cb8_0 != cb.cb8[0], "check_cb8_0", "cb8_0 %x != %x\n", + meta->cb8_0, cb.cb8[0])) + return; + if (CHECK(meta->cb32_0 != cb.cb32[0], "check_cb32_0", + "cb32_0 %x != %x\n", + meta->cb32_0, cb.cb32[0])) return; if (CHECK(pkt_v6->eth.h_proto != 0xdd86, "check_eth", "h_proto %x\n", pkt_v6->eth.h_proto)) @@ -26,6 +49,13 @@ static void on_sample(void *ctx, int cpu, void *data, __u32 size) void test_kfree_skb(void) { + struct __sk_buff skb = {}; + struct bpf_prog_test_run_attr tattr = { + .data_in = &pkt_v6, + .data_size_in = sizeof(pkt_v6), + .ctx_in = &skb, + .ctx_size_in = sizeof(skb), + }; struct bpf_prog_load_attr attr = { .file = "./kfree_skb.o", }; @@ -36,11 +66,12 @@ void test_kfree_skb(void) struct bpf_link *link = NULL; struct bpf_map *perf_buf_map; struct bpf_program *prog; - __u32 duration, retval; - int err, pkt_fd, kfree_skb_fd; + int err, kfree_skb_fd; bool passed = false; + __u32 duration = 0; - err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_SCHED_CLS, &obj, &pkt_fd); + err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_SCHED_CLS, + &obj, &tattr.prog_fd); if (CHECK(err, "prog_load sched cls", "err %d errno %d\n", err, errno)) return; @@ -66,11 +97,12 @@ void test_kfree_skb(void) if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb))) goto close_prog; - err = bpf_prog_test_run(pkt_fd, 1, &pkt_v6, sizeof(pkt_v6), - NULL, NULL, &retval, &duration); - CHECK(err || retval, "ipv6", + memcpy(skb.cb, &cb, sizeof(cb)); + err = bpf_prog_test_run_xattr(&tattr); + duration = tattr.duration; + CHECK(err || tattr.retval, "ipv6", "err %d errno %d retval %d duration %d\n", - err, errno, retval, duration); + err, errno, tattr.retval, duration); /* read perf buffer */ err = perf_buffer__poll(pb, 100); diff --git a/tools/testing/selftests/bpf/progs/kfree_skb.c b/tools/testing/selftests/bpf/progs/kfree_skb.c index 489319ea1d6a..f769fdbf6725 100644 --- a/tools/testing/selftests/bpf/progs/kfree_skb.c +++ b/tools/testing/selftests/bpf/progs/kfree_skb.c @@ -43,6 +43,7 @@ struct sk_buff { refcount_t users; unsigned char *data; char __pkt_type_offset[0]; + char cb[48]; }; /* copy arguments from @@ -57,28 +58,41 @@ struct trace_kfree_skb { void *location; }; +struct meta { + int ifindex; + __u32 cb32_0; + __u8 cb8_0; +}; + SEC("tp_btf/kfree_skb") int trace_kfree_skb(struct trace_kfree_skb *ctx) { struct sk_buff *skb = ctx->skb; struct net_device *dev; - int ifindex; struct callback_head *ptr; void *func; int users; unsigned char *data; unsigned short pkt_data; + struct meta meta = {}; char pkt_type; + __u32 *cb32; + __u8 *cb8; __builtin_preserve_access_index(({ users = skb->users.refs.counter; data = skb->data; dev = skb->dev; - ifindex = dev->ifindex; ptr = dev->ifalias->rcuhead.next; func = ptr->func; + cb8 = (__u8 *)&skb->cb; + cb32 = (__u32 *)&skb->cb; })); + meta.ifindex = _(dev->ifindex); + meta.cb8_0 = cb8[8]; + meta.cb32_0 = cb32[2]; + bpf_probe_read_kernel(&pkt_type, sizeof(pkt_type), _(&skb->__pkt_type_offset)); pkt_type &= 7; @@ -90,14 +104,15 @@ int trace_kfree_skb(struct trace_kfree_skb *ctx) _(skb->len), users, pkt_type); bpf_printk("skb->queue_mapping %d\n", _(skb->queue_mapping)); bpf_printk("dev->ifindex %d data %llx pkt_data %x\n", - ifindex, data, pkt_data); + meta.ifindex, data, pkt_data); + bpf_printk("cb8_0:%x cb32_0:%x\n", meta.cb8_0, meta.cb32_0); - if (users != 1 || pkt_data != bpf_htons(0x86dd) || ifindex != 1) + if (users != 1 || pkt_data != bpf_htons(0x86dd) || meta.ifindex != 1) /* raw tp ignores return value */ return 0; /* send first 72 byte of the packet to user space */ bpf_skb_output(skb, &perf_buf_map, (72ull << 32) | BPF_F_CURRENT_CPU, - &ifindex, sizeof(ifindex)); + &meta, sizeof(meta)); return 0; } -- cgit v1.2.3-59-g8ed1b