从 Go 打开 pfring: pfring NewRing error: no such device

Question

I want to call pf_ring from Go code using the github.com/google/gopacket/pfring package and cannot get it working on a Debian 11 (my code is working on Debian 10).

This is my Go code:

package main

import (
    "github.com/google/gopacket/pfring"
    "log"
)

func main() {
    _, err := pfring.NewRing("eno1@0", 1574, pfring.FlagPromisc|pfring.Flag(1<<14))
    if err == nil {
        log.Printf("Success!")
        return
    }
    log.Fatalf("Failure: %s", err)
}

And when I run it:

# ./test-go 
2023/01/24 10:12:25 Failure: pfring NewRing error: no such device

Obviously the eno1 interface exists:

# pf_ringcfg --list-interfaces
Name: eno1                 Driver: i40e       RSS:     12   [Supported by ZC]
Name: enp3s0f1             Driver: i40e       RSS:     12   [Supported by ZC]
Name: enx0a229512eeb9      Driver: cdc_ether  RSS:     1    [Linux Driver] 

The odd thing is that the same code written in C works:

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <pfring.h>

int main() {
    pfring* ring = pfring_open("eno1@0", 1574, PF_RING_PROMISC | PF_RING_ZC_NOT_REPROGRAM_RSS);
    if (ring != NULL) {
        printf("Success!\n");
        exit(0);
    }
    int e = errno;
    char* msg = strerror(e);
    printf("Failure %d: %s\n", e, msg);
    exit(1);
}

# ./test-c 
Success!

Any idea?

Answer 1

It turns out this is a bug in gopacket/pfring, see issue #147 and the fix . The call to pfring_open made by this library reported no error, but the library misinterpreted the return code.