fn parse_and_save_conntrack_line()

in nfm-controller/src/kubernetes/remote_nat_resolver.rs [131:176]

• 43 lines of code
• 5 McCabe index (conditional complexity)

    fn parse_and_save_conntrack_line(&mut self, line: &str) -> Option<()> {
        let parts: Vec<&str> = line.split_whitespace().collect();
        if parts.len() < 14 {
            // safety check
            return Some(());
        }
        if parts[2] != "tcp" {
            return Some(());
        };
        if parts[10].starts_with('[') {
            // ipv4 2 tcp 6 118 SYN_SENT src=172.19.107.118 dst=2.2.2.2 sport=33424 dport=80 [UNREPLIED] src=2.2.2.2 dst=172.19.107.118 sport=80 dport=33424 mark=0 use=1
            return Some(()); // means this isnt an established connection no need to track
        }

        let ip_version = parts[0].to_string();
        let local_ip_that_sends_the_packet = parts[6].split('=').nth(1)?.to_string();
        let local_port_that_sends_the_packet = parts[8].split('=').nth(1)?.parse().ok()?;
        let remote_ip_we_think_we_send_to = parts[7].split('=').nth(1)?.to_string();
        let remote_ip_that_hits_the_wire = parts[10].split('=').nth(1)?.to_string();
        let remote_port_that_hits_the_wire = parts[12].split('=').nth(1)?.parse().ok()?;
        if remote_ip_we_think_we_send_to != remote_ip_that_hits_the_wire {
            let (local_ip, remote_ip) = match ip_version.as_str() {
                "ipv4" => (
                    Self::string_to_ipv4(&local_ip_that_sends_the_packet).unwrap(),
                    Self::string_to_ipv4(&remote_ip_that_hits_the_wire).unwrap(),
                ),
                "ipv6" => (
                    Self::string_to_ipv6(&local_ip_that_sends_the_packet).unwrap(),
                    Self::string_to_ipv6(&remote_ip_that_hits_the_wire).unwrap(),
                ),
                _ => return None,
            };
            self.insert(
                RemoteNatLookupEntry {
                    local_ip,
                    local_port: local_port_that_sends_the_packet,
                },
                RemoteNatEntry {
                    remote_ip_actual: remote_ip,
                    remote_port_actual: remote_port_that_hits_the_wire,
                },
            );
            self.remote_nat_entries_detected += 1;
        }
        Some(())
    }