Add get_uid function for API resource

crates/rdsys-backend/Cargo.toml

@@ -10,6 +10,9 @@ serde_json = "1"
 futures-util = { version = "0.3"}
 serde = { version = "1", features = ["derive"]}
 bytes = "1"
+hex = "0.4.3"
+crc64 = "2.0.0"
+sha1 = "0.10.5"
 tokio = { version = "1", features = ["macros"]}
 reqwest = { version = "0.11", features = ["stream"]}
 tokio-stream = "0.1.12"

crates/rdsys-backend/src/main.rs

@@ -0,0 +1,22 @@
+use sha1::{Sha1, Digest};
+
+fn get_uid(fingerprint: String, pt_type: String) -> Result<u64, hex::FromHexError> {
+    let hex_fingerprint = match hex::decode(fingerprint) {
+        Ok(hex_fingerprint) => hex_fingerprint,
+        Err(e) => return Err(e),
+    };
+
+    let mut hasher = Sha1::new();
+    hasher.update(hex_fingerprint);
+    let result_fingerprint = hasher.finalize();
+    let uid_string = pt_type+&hex::encode_upper(result_fingerprint);
+    Ok(crc64::crc64(0, uid_string.as_bytes()))
+    }
+
+
+fn main() {
+let hex_stuff = get_uid("FD8DC7EF92F1F14D00CF9D6F6297A3468B59E707".to_string(), "obfs4".to_string());
+println!("The result is: {:?}", hex_stuff);
+let hex_stuff2 = get_uid("FD8DC7EF92F1F14D00CF9D6F6297A3468B59E707".to_string(), "scramblesuit".to_string());
+println!("The result is: {:?}", hex_stuff2);
+}

crates/rdsys-backend/src/proto.rs

@@ -1,6 +1,6 @@
-use std::collections::HashMap;
-
 use serde::{Deserialize, Serialize};
+use sha1::{Digest, Sha1};
+use std::collections::HashMap;
 
 /// The body of the request for resources made to the rdsys backend
 #[derive(Serialize)]
@@ -25,6 +25,30 @@ pub struct Resource {
     pub params: Option<HashMap<String, String>>,
 }
 
+impl Resource {
+    /// get_uid creates a unique identifier of the resource from a hash of the fingerprint
+    /// and bridge type. A similar process is used in rdsys
+    /// https://gitlab.torproject.org/tpo/anti-censorship/rdsys/-/blob/main/pkg/usecases/resources/bridges.go#L99
+    /// however, the golang and rust implementations of crc64 lead to different hash values.
+    /// The polynomial used for rust's crc64 package is: https://docs.rs/crc64/2.0.0/src/crc64/lib.rs.html#8
+    /// using "Jones" coefficients. Changing go's polynomial to match rust's still doesn't make the hashes the same.
+    /// We use the get_uid in this case for an identifier in the distributor so as long as it is unique, it doesn't
+    /// strictly need to match the value in rdsys' backend.
+    pub fn get_uid(self: &Self) -> Result<u64, hex::FromHexError> {
+        let hex_fingerprint = match hex::decode(self.fingerprint.clone()) {
+            Ok(hex_fingerprint) => hex_fingerprint,
+            Err(e) => return Err(e),
+        };
+
+        let mut hasher = Sha1::new();
+        hasher.update(hex_fingerprint);
+        let result_fingerprint = hasher.finalize();
+        let uid_string = self.r#type.clone() + &hex::encode_upper(result_fingerprint);
+
+        Ok(crc64::crc64(0, uid_string.as_bytes()))
+    }
+}
+
 /// A ResourceDiff holds information about new, changed, or pruned resources
 #[derive(Deserialize, PartialEq, Eq, Debug)]
 pub struct ResourceDiff {