From 9cc873e85800ccde80aa2e4b2bae9f1b5fa4c478 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 10 Nov 2020 19:12:12 -0800 Subject: [PATCH] selftests/bpf: Add skb_pkt_end test Add a test that currently makes LLVM generate assembly code: $ llvm-objdump -S skb_pkt_end.o 0000000000000000 : ; if (skb_shorter(skb, ETH_IPV4_TCP_SIZE)) 0: 61 12 50 00 00 00 00 00 r2 = *(u32 *)(r1 + 80) 1: 61 14 4c 00 00 00 00 00 r4 = *(u32 *)(r1 + 76) 2: bf 43 00 00 00 00 00 00 r3 = r4 3: 07 03 00 00 36 00 00 00 r3 += 54 4: b7 01 00 00 00 00 00 00 r1 = 0 5: 2d 23 02 00 00 00 00 00 if r3 > r2 goto +2 6: 07 04 00 00 0e 00 00 00 r4 += 14 ; if (skb_shorter(skb, ETH_IPV4_TCP_SIZE)) 7: bf 41 00 00 00 00 00 00 r1 = r4 0000000000000040 : 8: b4 00 00 00 ff ff ff ff w0 = -1 ; if (!(ip = get_iphdr(skb))) 9: 2d 23 05 00 00 00 00 00 if r3 > r2 goto +5 ; proto = ip->protocol; 10: 71 12 09 00 00 00 00 00 r2 = *(u8 *)(r1 + 9) ; if (proto != IPPROTO_TCP) 11: 56 02 03 00 06 00 00 00 if w2 != 6 goto +3 ; if (tcp->dest != 0) 12: 69 12 16 00 00 00 00 00 r2 = *(u16 *)(r1 + 22) 13: 56 02 01 00 00 00 00 00 if w2 != 0 goto +1 ; return tcp->urg_ptr; 14: 69 10 26 00 00 00 00 00 r0 = *(u16 *)(r1 + 38) 0000000000000078 : ; } 15: 95 00 00 00 00 00 00 00 exit Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20201111031213.25109-3-alexei.starovoitov@gmail.com --- .../bpf/prog_tests/test_skb_pkt_end.c | 41 ++++++++++++++ .../testing/selftests/bpf/progs/skb_pkt_end.c | 54 +++++++++++++++++++ 2 files changed, 95 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c create mode 100644 tools/testing/selftests/bpf/progs/skb_pkt_end.c diff --git a/tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c b/tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c new file mode 100644 index 000000000000..cf1215531920 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ +#include +#include +#include "skb_pkt_end.skel.h" + +static int sanity_run(struct bpf_program *prog) +{ + __u32 duration, retval; + int err, prog_fd; + + prog_fd = bpf_program__fd(prog); + err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4), + NULL, NULL, &retval, &duration); + if (CHECK(err || retval != 123, "test_run", + "err %d errno %d retval %d duration %d\n", + err, errno, retval, duration)) + return -1; + return 0; +} + +void test_test_skb_pkt_end(void) +{ + struct skb_pkt_end *skb_pkt_end_skel = NULL; + __u32 duration = 0; + int err; + + skb_pkt_end_skel = skb_pkt_end__open_and_load(); + if (CHECK(!skb_pkt_end_skel, "skb_pkt_end_skel_load", "skb_pkt_end skeleton failed\n")) + goto cleanup; + + err = skb_pkt_end__attach(skb_pkt_end_skel); + if (CHECK(err, "skb_pkt_end_attach", "skb_pkt_end attach failed: %d\n", err)) + goto cleanup; + + if (sanity_run(skb_pkt_end_skel->progs.main_prog)) + goto cleanup; + +cleanup: + skb_pkt_end__destroy(skb_pkt_end_skel); +} diff --git a/tools/testing/selftests/bpf/progs/skb_pkt_end.c b/tools/testing/selftests/bpf/progs/skb_pkt_end.c new file mode 100644 index 000000000000..cf6823f42e80 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/skb_pkt_end.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +#define BPF_NO_PRESERVE_ACCESS_INDEX +#include +#include +#include + +#define NULL 0 +#define INLINE __always_inline + +#define skb_shorter(skb, len) ((void *)(long)(skb)->data + (len) > (void *)(long)skb->data_end) + +#define ETH_IPV4_TCP_SIZE (14 + sizeof(struct iphdr) + sizeof(struct tcphdr)) + +static INLINE struct iphdr *get_iphdr(struct __sk_buff *skb) +{ + struct iphdr *ip = NULL; + struct ethhdr *eth; + + if (skb_shorter(skb, ETH_IPV4_TCP_SIZE)) + goto out; + + eth = (void *)(long)skb->data; + ip = (void *)(eth + 1); + +out: + return ip; +} + +SEC("classifier/cls") +int main_prog(struct __sk_buff *skb) +{ + struct iphdr *ip = NULL; + struct tcphdr *tcp; + __u8 proto = 0; + + if (!(ip = get_iphdr(skb))) + goto out; + + proto = ip->protocol; + + if (proto != IPPROTO_TCP) + goto out; + + tcp = (void*)(ip + 1); + if (tcp->dest != 0) + goto out; + if (!tcp) + goto out; + + return tcp->urg_ptr; +out: + return -1; +} +char _license[] SEC("license") = "GPL";