unknown func bpf_get_current_pid_tgid - but it actually exists about aya

[alessandrod]

This is a bug in TcContext, it should return the skb.pid and not use the helper. Want to try to make a patch? 😊

[emanuele-em]

@alessandrod sure! You can assign the issue if you want

[alessandrod]

As per discord conversation, I was wrong, there's no way to directly get the pid from an egress tc program. The only way is to correlate local_port with a pid manually.

[gotoolkits]

use aya_bpf::helpers::bpf_get_current_pid_tgid
...
let pid = bpf_get_current_pid_tgid() as u32;

The same error has occurred. May I ask what the reason is?

15: (15) if r1 == 0x7 goto pc-8
R0_w=inv0 R1_w=inv(id=0) R2_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff)) R6_w=ctx(id=0,off=0,imm=0) R7_w=inv2 R10=fp0 fp-16=??mmmmmm fp-24=mmmmmmmm
16: (55) if r1 != 0x8 goto pc+62
R0=inv0 R1=inv8 R2=inv(id=0,umax_value=255,var_off=(0x0; 0xff)) R6=ctx(id=0,off=0,imm=0) R7=inv2 R10=fp0 fp-16=??mmmmmm fp-24=mmmmmmmm
17: (85) call bpf_get_current_pid_tgid#14
unknown func bpf_get_current_pid_tgid#14
verification time 48 usec
stack depth 24
processed 18 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1

[gotoolkits]

Oh, I misunderstood. You can use TracepointContext to correct it.

#[tracepoint]
pub fn tracepoint_demo(ctx: TracePointContext) -> u32 {
match try_tracepoint_demo(ctx) {
Ok(ret) => ret,
Err(ret) => ret,
}
}

fn try_tracepoint_demo(ctx: TracePointContext) -> Result<u32, u32> {
let pid = ctx.pid();
info!(&ctx, "tracepoint inet_sock_set_state called, pid: {}",pid);
Ok(0)
}