2022-11-08 16:18:03

by Yonghong Song

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Subject: Re: [PATCH bpf] selftests/bpf: Fix xdp_synproxy compilation failure in 32-bit arch



On 11/8/22 5:12 AM, Yang Jihong wrote:
> xdp_synproxy fails to be compiled in the 32-bit arch, log is as follows:
>
> xdp_synproxy.c: In function 'parse_options':
> xdp_synproxy.c:175:36: error: left shift count >= width of type [-Werror=shift-count-overflow]
> 175 | *tcpipopts = (mss6 << 32) | (ttl << 24) | (wscale << 16) | mss4;
> | ^~
> xdp_synproxy.c: In function 'syncookie_open_bpf_maps':
> xdp_synproxy.c:289:28: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
> 289 | .map_ids = (__u64)map_ids,
> | ^
>
> Fix it.
>
> Fixes: fb5cd0ce70d4 ("selftests/bpf: Add selftests for raw syncookie helpers")
> Signed-off-by: Yang Jihong <[email protected]>
> ---
> tools/testing/selftests/bpf/xdp_synproxy.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/xdp_synproxy.c b/tools/testing/selftests/bpf/xdp_synproxy.c
> index ff35320d2be9..45fef01a87a8 100644
> --- a/tools/testing/selftests/bpf/xdp_synproxy.c
> +++ b/tools/testing/selftests/bpf/xdp_synproxy.c
> @@ -172,7 +172,7 @@ static void parse_options(int argc, char *argv[], unsigned int *ifindex, __u32 *
> if (tcpipopts_mask == 0xf) {
> if (mss4 == 0 || mss6 == 0 || wscale == 0 || ttl == 0)
> usage(argv[0]);
> - *tcpipopts = (mss6 << 32) | (ttl << 24) | (wscale << 16) | mss4;
> + *tcpipopts = ((unsigned long long)mss6 << 32) | (ttl << 24) | (wscale << 16) | mss4;

This looks weird. Maybe we should define mss6 as unsigned long long to
avoid this casting at all?

> } else if (tcpipopts_mask != 0) {
> usage(argv[0]);
> }
> @@ -286,7 +286,7 @@ static int syncookie_open_bpf_maps(__u32 prog_id, int *values_map_fd, int *ports
>
> prog_info = (struct bpf_prog_info) {
> .nr_map_ids = 8,
> - .map_ids = (__u64)map_ids,
> + .map_ids = (__u64)(unsigned long)map_ids,
> };
> info_len = sizeof(prog_info);
>