Refactor capabilities requester

- Implement a correct check for cap. response flags
- Create type aliases to clarify GET_CAPABILITIES and CAPABILITIES
- Fix CAPABILITIES response handler

Author: embediver

src/commands/capabilities/mod.rs

@@ -8,10 +8,7 @@ pub(crate) use response::*;
 
 use zerocopy::{FromBytes, Immutable, IntoBytes};
 
-use crate::{
-    codec::CommonCodec,
-    protocol::{CapabilityFlags, EpInfoCapability, PskCapability, SpdmVersion},
-};
+use crate::{codec::CommonCodec, protocol::CapabilityFlags};
 
 use crate::protocol::capabilities::DeviceCapabilities;
 
@@ -21,6 +18,10 @@ pub struct GetCapabilitiesBase {
     param1: u8,
     param2: u8,
 }
+/// CAPABILITIES response base
+///
+/// v1.0 CAPABILITIES response is constructed by `CapabilitiesBase`+`Capabilities`.
+pub type CapabilitiesBase = GetCapabilitiesBase;
 
 impl CommonCodec for GetCapabilitiesBase {}
 
@@ -50,6 +51,8 @@ pub struct GetCapabilitiesV11 {
     /// Capability flags.
     flags: CapabilityFlags,
 }
+/// CAPABILITIES response
+pub type Capabilities = GetCapabilitiesV11;
 
 impl GetCapabilitiesV11 {
     pub fn new(ct_exponent: u8, flags: CapabilityFlags) -> Self {
@@ -82,6 +85,8 @@ pub struct GetCapabilitiesV12 {
     /// Large SPDM message.
     max_spdm_msg_size: u32,
 }
+/// CAPABILITIES response v1.2 additions
+pub type CapabilitiesV12 = GetCapabilitiesV12;
 
 impl CommonCodec for GetCapabilitiesV12 {}
 
@@ -111,107 +116,3 @@ impl Default for GetCapabilitiesV12 {
         }
     }
 }
-
-/// Checks if the request capability flags are compatible with the SPDM version
-///# Arguments
-/// - `version`: SPDM version
-/// - `flags`: Capability flags from the request
-///
-/// # Returns
-/// - true if compatible
-/// - false if incompatible
-pub(crate) fn req_flag_compatible(version: SpdmVersion, flags: &CapabilityFlags) -> bool {
-    // Checks specific to 1.1
-    if version == SpdmVersion::V11 && flags.mut_auth_cap() == 1 && flags.encap_cap() == 0 {
-        return false;
-    }
-
-    // Check if MEAS_CAP is valid
-    // 0b11 is reserved
-    if flags.meas_cap() == 0b11 {
-        return false;
-    }
-
-    // Checks common to 1.1 and higher
-    if version >= SpdmVersion::V11 {
-        // Illegal to return reserved values (2 and 3)
-        if flags.psk_cap() >= PskCapability::PskWithContext as u8 {
-            return false;
-        }
-
-        // Checks that originate from key exchange capabilities
-        if flags.key_ex_cap() == 1 || flags.psk_cap() != PskCapability::NoPsk as u8 {
-            if flags.mac_cap() == 0 && flags.encrypt_cap() == 0 {
-                return false;
-            }
-        } else {
-            if flags.mac_cap() == 1
-                || flags.encrypt_cap() == 1
-                || flags.handshake_in_the_clear_cap() == 1
-                || flags.hbeat_cap() == 1
-                || flags.key_upd_cap() == 1
-            {
-                return false;
-            }
-
-            if version >= SpdmVersion::V13 && flags.event_cap() == 1 {
-                return false;
-            }
-        }
-
-        if flags.key_ex_cap() == 0
-            && flags.psk_cap() == PskCapability::PskWithNoContext as u8
-            && flags.handshake_in_the_clear_cap() == 1
-        {
-            return false;
-        }
-
-        // Checks that originate from certificate or public key capabilities
-        if flags.cert_cap() == 1 || flags.pub_key_id_cap() == 1 {
-            // Certificate capabilities and public key capabilities can not both be set
-            if flags.cert_cap() == 1 && flags.pub_key_id_cap() == 1 {
-                return false;
-            }
-
-            if flags.chal_cap() == 0 && flags.pub_key_id_cap() == 1 {
-                return false;
-            }
-        } else {
-            // If certificates or public keys are not enabled then these capabilities are not allowed
-            if flags.chal_cap() == 1 || flags.mut_auth_cap() == 1 {
-                return false;
-            }
-
-            if version >= SpdmVersion::V13
-                && flags.ep_info_cap() == EpInfoCapability::EpInfoWithSignature as u8
-            {
-                return false;
-            }
-        }
-
-        // Checks that originate from mutual authentication capabilities
-        if flags.mut_auth_cap() == 1 {
-            // Mutual authentication with asymmetric keys can only occur through the basic mutual
-            // authentication flow (CHAL_CAP == 1) or the session-based mutual authentication flow
-            // (KEY_EX_CAP == 1)
-            if flags.cert_cap() == 0 && flags.pub_key_id_cap() == 0 {
-                return false;
-            }
-        }
-    }
-
-    // Checks specific to 1.3 and higher
-    if version >= SpdmVersion::V13 {
-        // Illegal to return reserved values
-        if flags.ep_info_cap() == EpInfoCapability::Reserved as u8 || flags.multi_key_cap() == 3 {
-            return false;
-        }
-
-        // Check multi_key_cap and pub_key_id_cap
-        if flags.multi_key_cap() != 0 && flags.pub_key_id_cap() == 1 {
-            return false;
-        }
-    }
-
-    true
-}