update README and output

Signed-off-by: Sanskar Jaiswal <[email protected]>

Author: aryan9600

README.md

@@ -1,44 +1,67 @@
 # dns-resolver
 
 dns-resolver is a toy DNS resolver. It can handle A, NS, CNAME and TXT records.
+Its a recursive resolver that can be used as DNS client or server. The server supports
+caching via a fixed size LRU cache.
+
 It's mainly written by understanding the contents of https://implement-dns.wizardzines.com/book/intro.html
 and https://datatracker.ietf.org/doc/html/rfc1035. The primary goal of this project
 is to understand how DNS works from the ground up and brush up on my Rust skills.
 
 ## Usage
 
+### Client
+
+Fetch the A records for google.com:
+
 ```bash
-❯ cargo run --bin client google.com TXT
+❯ cargo run --bin client google.com A
 
-Querying 198.41.0.4 for google.com about TXT type
-Querying 192.12.94.30 for google.com about TXT type
-Querying 216.239.34.10 for google.com about TXT type
-answer(s): ["atlassian-domain-verification=5YjTmWmjI92ewqkx2oXmBaD60Td9zWon9r6eakvHX6B77zzkFQto8PQ9QsKnbf4I", "facebook-domain-verification=22rm551cu4k0ab0bxsw536tlds4h95", "globalsign-smime-dv=CDYX+XFHUw2wml6/Gb8+59BsH31KzUr6c1l2BPvqKX8=", "MS=E4A68B9AB2BB9670BCE15412F62916164C0B20BB", "v=spf1 include:_spf.google.com ~all", "google-site-verification=TV9-DBe4R80X4v0M4U_bd_J9cpOJM0nikft0jAgjmsQ"]
+Querying 198.41.0.4 for google.com about record type A
+Querying 192.12.94.30 for google.com about record type A
+Querying 216.239.34.10 for google.com about record type A
+answer(s): ["142.250.76.174"]
 ```
 
+Fetch the CNAME records for www.github.com:
+
 ```bash
-❯ cargo run --bin client google.com NS
+❯ cargo run --bin client www.github.com CNAME
 
-Querying 198.41.0.4 for google.com about NS type
-Querying 192.12.94.30 for google.com about NS type
-Querying 216.239.34.10 for google.com about NS type
-answer(s): ["ns1.google.com", "ns3.google.com", "ns4.google.com", "ns2.google.com"]
+Querying 198.41.0.4 for www.github.com about record type CNAME
+Querying 192.12.94.30 for www.github.com about record type CNAME
+Querying 205.251.193.165 for www.github.com about record type CNAME
+answer(s): ["github.com"]
 ```
 
-```bash
-❯ cargo run --bin client google.com A
+### Server
 
-Querying 198.41.0.4 for google.com about A type
-Querying 192.12.94.30 for google.com about A type
-Querying 216.239.34.10 for google.com about A type
-answer(s): ["74.125.24.101", "74.125.24.139", "74.125.24.138", "74.125.24.113", "74.125.24.102", "74.125.24.100"]
+Run the server:
+
+```bash
+❯ cargo run --bin server
 ```
 
+Open another terminal window and use `dig` to access the server:
+
 ```bash
-❯ cargo run --bin client www.github.com CNAME
+❯ dig @127.0.0.1 -p 3500 google.com A
 
-Querying 198.41.0.4 for www.github.com about CNAME type
-Querying 192.12.94.30 for www.github.com about CNAME type
-Querying 205.251.193.165 for www.github.com about CNAME type
-answer(s): ["github.com"]
+; <<>> DiG 9.10.6 <<>> @127.0.0.1 -p 3500 google.com A
+; (1 server found)
+;; global options: +cmd
+;; Got answer:
+;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34233
+;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
+
+;; QUESTION SECTION:
+;google.com.                    IN      A
+
+;; ANSWER SECTION:
+google.com.             300     IN      A       142.250.67.206
+
+;; Query time: 305 msec
+;; SERVER: 127.0.0.1#3500(127.0.0.1)
+;; WHEN: Mon Jan 08 01:37:32 IST 2024
+;; MSG SIZE  rcvd: 44
 ```

src/resolver.rs

@@ -41,7 +41,7 @@ impl Resolver {
 
         loop {
             println!(
-                "Querying {} for {} about {:?} type",
+                "Querying {} for {} about record type {:?}",
                 nameserver, domain, record_type
             );
             let response = self
@@ -72,7 +72,7 @@ impl Resolver {
 
         loop {
             println!(
-                "Querying {} for {} about {:?} type",
+                "Querying {} for {} about record type {:?}",
                 nameserver, domain, record_type
             );
             let response = self
@@ -102,7 +102,7 @@ impl Resolver {
 
         loop {
             println!(
-                "Querying {} for {} about {:?} type",
+                "Querying {} for {} about record type {:?}",
                 nameserver, domain, record_type
             );
             let response = self
@@ -133,7 +133,7 @@ impl Resolver {
 
             loop {
                 println!(
-                    "Querying {} for {} about {:?} type",
+                    "Querying {} for {} about record type {:?}",
                     nameserver, domain, record_type
                 );
                 let response = self