stamparm/maltrail · error

src ipv4

Error message

src ipv4

What it means

Panic from `.expect("src ipv4")` when `crate::addr::addr_to_int(src)` cannot parse the source IPv4 address string passed to the packet builder `ipv4_opts`. Test helpers are strict: a malformed address means the test packet cannot be constructed.

Solutions

1. Validate the src string is a valid dotted-quad IPv4 before calling ipv4_opts
2. Use well-formed test literals like "10.0.0.1"
3. Match on addr_to_int to panic with the address value for easier diagnosis
4. Ensure no IPv6 addresses are passed to the IPv4 builder

Example fix

// before
ipv4_opts(proto, "10.0.0.300", dst, &[], payload) // invalid octet
// after
ipv4_opts(proto, "10.0.0.1", dst, &[], payload)

fn is_ipv4(s: &str) -> bool { s.parse::<std::net::Ipv4Addr>().is_ok() }
assert!(is_ipv4(src), "src must be valid IPv4: {src}");

fn is_ipv4(s: &str) -> bool { s.parse::<std::net::Ipv4Addr>().is_ok() }

let v = crate::addr::addr_to_int(src).unwrap_or_else(|e| panic!("src ipv4 '{src}': {e:?}"));

When it happens

Trigger: `ipv4_opts()` (and wrappers `ipv4`) called with a src string that is not a valid dotted-quad IPv4 address (empty string, hostname, octet >255, missing octets).

Common situations: Typo in a hardcoded test IP; substituting an IPv6 literal where an IPv4 is required; building addresses with format! that produce empty or malformed octets.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• dst ipv4
• src ipv6
• dst ipv6
• invalid USERS entry ' ' [?] (hint: add whitespace at start…
• invalid configuration

AI-assisted analysis of stamparm/maltrail@77cfb06d76 (2026-09-13). Data as JSON: /api/errors/a262388ba59cf7c7. Report an issue: GitHub.

Appendix: source

Thrown at sensor/src/testkit.rs:450

    out.extend_from_slice(payload);
    out
}

pub fn ipv4(proto: u8, src: &str, dst: &str, payload: &[u8]) -> Vec<u8> {
    ipv4_opts(proto, src, dst, payload, 5, 0)
}

pub fn ipv4_opts(proto: u8, src: &str, dst: &str, payload: &[u8], ihl: u8, frag: u16) -> Vec<u8> {
    let options = vec![0u8; ((ihl as usize).saturating_sub(5)) * 4];
    let total = (ihl as usize * 4 + payload.len()) as u16;
    let mut out = vec![0x40 | (ihl & 0x0f), 0];
    out.extend_from_slice(&total.to_be_bytes());
    out.extend_from_slice(&0x1234u16.to_be_bytes());
    out.extend_from_slice(&frag.to_be_bytes());
    out.push(64);
    out.push(proto);
    out.extend_from_slice(&[0, 0]);
    out.extend_from_slice(&crate::addr::addr_to_int(src).expect("src ipv4").to_be_bytes());
    out.extend_from_slice(&crate::addr::addr_to_int(dst).expect("dst ipv4").to_be_bytes());
    out.extend_from_slice(&options);
    out.extend_from_slice(payload);
    out
}

pub fn ipv6(proto: u8, src: &str, dst: &str, payload: &[u8]) -> Vec<u8> {
    let mut out = vec![0x60, 0, 0, 0];
    out.extend_from_slice(&(payload.len() as u16).to_be_bytes());
    out.push(proto);
    out.push(64);
    out.extend_from_slice(&crate::addr::parse_ipv6(src).expect("src ipv6").to_be_bytes());
    out.extend_from_slice(&crate::addr::parse_ipv6(dst).expect("dst ipv6").to_be_bytes());
    out.extend_from_slice(payload);
    out
}

/// IPv6 carrying a chain of extension headers before `proto`.

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