From: John Fastabend <john.fastabend@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>, davem@davemloft.net
Cc: daniel@iogearbox.net, netdev@vger.kernel.org,
bpf@vger.kernel.org, kernel-team@fb.com
Subject: RE: [PATCH v2 bpf-next 2/3] selftests/bpf: Add skb_pkt_end test
Date: Thu, 12 Nov 2020 11:19:54 -0800 [thread overview]
Message-ID: <5fad8adaa7c5d_2a6120828@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20201111031213.25109-3-alexei.starovoitov@gmail.com>
Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@kernel.org>
>
> Add a test that currently makes LLVM generate assembly code:
>
> $ llvm-objdump -S skb_pkt_end.o
> 0000000000000000 <main_prog>:
> ; 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 <LBB0_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 <LBB0_2>:
> 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 <LBB0_6>
> ; 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 <LBB0_6>
> ; 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 <LBB0_6>
> ; return tcp->urg_ptr;
> 14: 69 10 26 00 00 00 00 00 r0 = *(u16 *)(r1 + 38)
> 0000000000000078 <LBB0_6>:
> ; }
> 15: 95 00 00 00 00 00 00 00 exit
>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> ---
Acked-by: John Fastabend <john.fastabend@gmail.com>
next prev parent reply other threads:[~2020-11-12 19:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 3:12 [PATCH v2 bpf-next 0/3] bpf: Pointers beyond packet end Alexei Starovoitov
2020-11-11 3:12 ` [PATCH v2 bpf-next 1/3] bpf: Support for pointers beyond pkt_end Alexei Starovoitov
2020-11-12 19:16 ` John Fastabend
2020-11-12 23:56 ` Daniel Borkmann
2020-11-13 0:09 ` Alexei Starovoitov
2020-11-13 0:50 ` Daniel Borkmann
2020-11-12 23:59 ` Alexei Starovoitov
2020-11-13 0:35 ` John Fastabend
2020-11-11 3:12 ` [PATCH v2 bpf-next 2/3] selftests/bpf: Add skb_pkt_end test Alexei Starovoitov
2020-11-12 19:19 ` John Fastabend [this message]
2020-11-11 3:12 ` [PATCH v2 bpf-next 3/3] selftests/bpf: Add asm tests for pkt vs pkt_end comparison Alexei Starovoitov
2020-11-12 19:24 ` John Fastabend
2021-01-20 20:51 ` Jiri Olsa
2020-11-13 0:50 ` [PATCH v2 bpf-next 0/3] bpf: Pointers beyond packet end patchwork-bot+netdevbpf
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