Implemented DNS on blockchain. Beautified a lot of code, fixed some things.

src/blockchain/filter.rs

@@ -0,0 +1,54 @@
+use crate::Context;
+use std::sync::{Mutex, Arc};
+use crate::dns::filter::DnsFilter;
+use crate::dns::protocol::{DnsPacket, QueryType, DnsRecord, DnsQuestion};
+
+pub struct BlockchainFilter {
+    context: Arc<Mutex<Context>>
+}
+
+impl BlockchainFilter {
+    pub fn new(context: Arc<Mutex<Context>>) -> Self {
+        BlockchainFilter { context }
+    }
+}
+
+impl DnsFilter for BlockchainFilter {
+    fn lookup(&self, qname: &str, qtype: QueryType) -> Option<DnsPacket> {
+        let data = self.context.lock().unwrap().blockchain.get_domain_info(qname);
+        match data {
+            None => { println!("Not found info for domain {}", &qname); }
+            Some(data) => {
+                let records: Vec<DnsRecord> = match serde_json::from_str(&data) {
+                    Err(_) => { return None; }
+                    Ok(records) => { records }
+                };
+                let mut answers: Vec<DnsRecord> = Vec::new();
+                for mut record in records {
+                    if record.get_querytype() == qtype {
+                        match &mut record {
+                            // TODO make it for all types of records
+                            DnsRecord::A { domain, .. } | DnsRecord::AAAA { domain, .. } if domain == "@" => {
+                                *domain = String::from(qname);
+                            }
+                            _ => ()
+                        }
+
+                        answers.push(record);
+                    }
+                }
+                if !answers.is_empty() {
+                    // Create DnsPacket
+                    let mut packet = DnsPacket::new();
+                    packet.questions.push(DnsQuestion::new(String::from(qname), qtype));
+                    for answer in answers {
+                        packet.answers.push(answer);
+                    }
+                    return Some(packet);
+                }
+            }
+        }
+
+        None
+    }
+}