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Questions - xdp-bpf

Unable to fetch data using bpf_map_lookup_elem()

I am trying to write a code for XDP where a user space program will populate a bpf map and then later the Kernel will look into the map. For creating the map I have added a SEC(".maps") in t...
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Rishab

ebpf

bpf

xdp-bpf

xdp-ebpf

libbpf

Votes: 0

Answers: 1

Latest Answer

Actually, I found the issue. I had to change my key definition from: struct Key { uint32_t srcIP; uint16_t srcPort; }; to: struct Key { uint32_t IP; uint32_t port; }; This has someth...
test-img

Rishab

BPF / XDP: 'bpftool batch file' returns 'Error: reading batch file failed: Operation not permitted'

I have a docker container with an XDP program loaded on it. I also have a batch file for the bpftool to run. When I run bpftool batch file tmp_bpftool.txt, I get Error: reading batch file failed: Oper...
test-img

Ferrar

ebpf

bpf

xdp-bpf

Votes: 0

Answers: 1

Latest Answer

TL;DR: Your map update works fine. The message is a bug in bpftool. Bpftool updates the maps just as you would expect; and then, after processing all the batch file, it checks errno. If errno is 0, it...
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Qeole

eBPF: 'bpf_map_update()' returns the 'invalid indirect read from stack' error

I have an eBPF program with the following map definitions: struct bpf_map_def SEC("maps") servers = { .type = BPF_MAP_TYPE_HASH, .key_size = sizeof(struct ip_key), .value_size = ...
test-img

Ferrar

ebpf

bpf

xdp-bpf

Votes: 0

Answers: 1

Latest Answer

The verifier complains because your code is trying to read uninitialised data from the stack, in particular in your variable val. If we look at your code: struct client_port_addr { __u32 client_ip...
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Qeole

eBPF / XDP map not getting created

I have an implementation in BPF for XDP, wherein I specify five maps to be created as follows: struct bpf_map_def SEC("maps") servers = { .type = BPF_MAP_TYPE_HASH, .key_...
test-img

Ferrar

ebpf

bpf

xdp-bpf

Votes: 0

Answers: 1

Latest Answer

As per the discussion in the comments, the map is not created because it is not actually used in your eBPF code (not provided in the question). As you realised yourself, the branch in your code that w...
test-img

Qeole

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