Why i can't capture any packets? about xdpcap

[marshalWS]

what's mean with Note: 8 bytes struct bpf_elf_map fixup performed due to size mismatch!？

root@xxx:/home/tttt/bin# ip link set dev ens3 xdp obj xdp-pass-ebpf.o
Note: 8 bytes struct bpf_elf_map fixup performed due to size mismatch!
root@xxx:/home/tttt/bin#

[arthurfabre]

Thanks for the example, I didn't realize that maps could be pinned with ip link set xdp.

The only problem I can spot is that your program doesn't tail_call into the map. Instead of:

    return XDP_PASS;

You need to:

#include "hook.h"

...

    return xdpcap_exit(ctx, &bpf_elf_map, XDP_PASS);

You also don't need max_elem to be 100, there are only 5 possible actions (but it should work with 100 too).

[marshalWS]

Thanks for the example, I didn't realize that maps could be pinned with ip link set xdp.

The only problem I can spot is that your program doesn't tail_call into the map. Instead of:

    return XDP_PASS;

You need to:

#include "hook.h"

...

    return xdpcap_exit(ctx, &bpf_elf_map, XDP_PASS);

You also don't need max_elem to be 100, there are only 5 possible actions (but it should work with 100 too).

thanks very much ! I get it. xdpcap run successfully
Best wishes ~~.
root@xxx:/home/tttt/bin# ./xdpcap /sys/fs/bpf/xdp/globals/action_map dump-new.pcap
ws----- os.Args[0]= ./xdpcap [1:]= [/sys/fs/bpf/xdp/globals/action_map dump-new.pcap]
************ write packet pkt.data
aborted: 0/0 drop: 0/0 pass: 1/1 tx: 0/0 redirect: 0/0 (received/matched packets)
************ write packet pkt.data
aborted: 0/0 drop: 0/0 pass: 2/2 tx: 0/0 redirect: 0/0 (received/matched packets)
************ write packet pkt.data
aborted: 0/0 drop: 0/0 pass: 3/3 tx: 0/0 redirect: 0/0 (received/matched packets)
************ write packet pkt.data
aborted: 0/0 drop: 0/0 pass: 4/4 tx: 0/0 redirect: 0/0 (received/matched packets)
************ write packet pkt.data

[marshalWS]

This problem has been solved perfectly!