1 files changed, 294 insertions, 0 deletions
diff --git a/src/vhost_user/dummy_slave.rs b/src/vhost_user/dummy_slave.rs
new file mode 100644
index 0000000..ae728a0
--- /dev/null
+++ b/src/vhost_user/dummy_slave.rs
@@ -0,0 +1,294 @@
+// Copyright (C) 2019 Alibaba Cloud Computing. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+use std::fs::File;
+
+use super::message::*;
+use super::*;
+
+pub const MAX_QUEUE_NUM: usize = 2;
+pub const MAX_VRING_NUM: usize = 256;
+pub const MAX_MEM_SLOTS: usize = 32;
+pub const VIRTIO_FEATURES: u64 = 0x40000003;
+
+#[derive(Default)]
+pub struct DummySlaveReqHandler {
+    pub owned: bool,
+    pub features_acked: bool,
+    pub acked_features: u64,
+    pub acked_protocol_features: u64,
+    pub queue_num: usize,
+    pub vring_num: [u32; MAX_QUEUE_NUM],
+    pub vring_base: [u32; MAX_QUEUE_NUM],
+    pub call_fd: [Option<File>; MAX_QUEUE_NUM],
+    pub kick_fd: [Option<File>; MAX_QUEUE_NUM],
+    pub err_fd: [Option<File>; MAX_QUEUE_NUM],
+    pub vring_started: [bool; MAX_QUEUE_NUM],
+    pub vring_enabled: [bool; MAX_QUEUE_NUM],
+    pub inflight_file: Option<File>,
+}
+
+impl DummySlaveReqHandler {
+    pub fn new() -> Self {
+        DummySlaveReqHandler {
+            queue_num: MAX_QUEUE_NUM,
+            ..Default::default()
+        }
+    }
+
+    /// Helper to check if VirtioFeature enabled
+    fn check_feature(&self, feat: VhostUserVirtioFeatures) -> Result<()> {
+        if self.acked_features & feat.bits() != 0 {
+            Ok(())
+        } else {
+            Err(Error::InactiveFeature(feat))
+        }
+    }
+
+    /// Helper to check is VhostUserProtocolFeatures enabled
+    fn check_proto_feature(&self, feat: VhostUserProtocolFeatures) -> Result<()> {
+        if self.acked_protocol_features & feat.bits() != 0 {
+            Ok(())
+        } else {
+            Err(Error::InactiveOperation(feat))
+        }
+    }
+}
+
+impl VhostUserSlaveReqHandlerMut for DummySlaveReqHandler {
+    fn set_owner(&mut self) -> Result<()> {
+        if self.owned {
+            return Err(Error::InvalidOperation("already claimed"));
+        }
+        self.owned = true;
+        Ok(())
+    }
+
+    fn reset_owner(&mut self) -> Result<()> {
+        self.owned = false;
+        self.features_acked = false;
+        self.acked_features = 0;
+        self.acked_protocol_features = 0;
+        Ok(())
+    }
+
+    fn get_features(&mut self) -> Result<u64> {
+        Ok(VIRTIO_FEATURES)
+    }
+
+    fn set_features(&mut self, features: u64) -> Result<()> {
+        if !self.owned {
+            return Err(Error::InvalidOperation("not owned"));
+        } else if self.features_acked {
+            return Err(Error::InvalidOperation("features already set"));
+        } else if (features & !VIRTIO_FEATURES) != 0 {
+            return Err(Error::InvalidParam);
+        }
+
+        self.acked_features = features;
+        self.features_acked = true;
+
+        // If VHOST_USER_F_PROTOCOL_FEATURES has not been negotiated,
+        // the ring is initialized in an enabled state.
+        // If VHOST_USER_F_PROTOCOL_FEATURES has been negotiated,
+        // the ring is initialized in a disabled state. Client must not
+        // pass data to/from the backend until ring is enabled by
+        // VHOST_USER_SET_VRING_ENABLE with parameter 1, or after it has
+        // been disabled by VHOST_USER_SET_VRING_ENABLE with parameter 0.
+        let vring_enabled =
+            self.acked_features & VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits() == 0;
+        for enabled in &mut self.vring_enabled {
+            *enabled = vring_enabled;
+        }
+
+        Ok(())
+    }
+
+    fn set_mem_table(&mut self, _ctx: &[VhostUserMemoryRegion], _files: Vec<File>) -> Result<()> {
+        Ok(())
+    }
+
+    fn set_vring_num(&mut self, index: u32, num: u32) -> Result<()> {
+        if index as usize >= self.queue_num || num == 0 || num as usize > MAX_VRING_NUM {
+            return Err(Error::InvalidParam);
+        }
+        self.vring_num[index as usize] = num;
+        Ok(())
+    }
+
+    fn set_vring_addr(
+        &mut self,
+        index: u32,
+        _flags: VhostUserVringAddrFlags,
+        _descriptor: u64,
+        _used: u64,
+        _available: u64,
+        _log: u64,
+    ) -> Result<()> {
+        if index as usize >= self.queue_num {
+            return Err(Error::InvalidParam);
+        }
+        Ok(())
+    }
+
+    fn set_vring_base(&mut self, index: u32, base: u32) -> Result<()> {
+        if index as usize >= self.queue_num || base as usize >= MAX_VRING_NUM {
+            return Err(Error::InvalidParam);
+        }
+        self.vring_base[index as usize] = base;
+        Ok(())
+    }
+
+    fn get_vring_base(&mut self, index: u32) -> Result<VhostUserVringState> {
+        if index as usize >= self.queue_num {
+            return Err(Error::InvalidParam);
+        }
+        // Quotation from vhost-user spec:
+        // Client must start ring upon receiving a kick (that is, detecting
+        // that file descriptor is readable) on the descriptor specified by
+        // VHOST_USER_SET_VRING_KICK, and stop ring upon receiving
+        // VHOST_USER_GET_VRING_BASE.
+        self.vring_started[index as usize] = false;
+        Ok(VhostUserVringState::new(
+            index,
+            self.vring_base[index as usize],
+        ))
+    }
+
+    fn set_vring_kick(&mut self, index: u8, fd: Option<File>) -> Result<()> {
+        if index as usize >= self.queue_num || index as usize > self.queue_num {
+            return Err(Error::InvalidParam);
+        }
+        self.kick_fd[index as usize] = fd;
+
+        // Quotation from vhost-user spec:
+        // Client must start ring upon receiving a kick (that is, detecting
+        // that file descriptor is readable) on the descriptor specified by
+        // VHOST_USER_SET_VRING_KICK, and stop ring upon receiving
+        // VHOST_USER_GET_VRING_BASE.
+        //
+        // So we should add fd to event monitor(select, poll, epoll) here.
+        self.vring_started[index as usize] = true;
+        Ok(())
+    }
+
+    fn set_vring_call(&mut self, index: u8, fd: Option<File>) -> Result<()> {
+        if index as usize >= self.queue_num || index as usize > self.queue_num {
+            return Err(Error::InvalidParam);
+        }
+        self.call_fd[index as usize] = fd;
+        Ok(())
+    }
+
+    fn set_vring_err(&mut self, index: u8, fd: Option<File>) -> Result<()> {
+        if index as usize >= self.queue_num || index as usize > self.queue_num {
+            return Err(Error::InvalidParam);
+        }
+        self.err_fd[index as usize] = fd;
+        Ok(())
+    }
+
+    fn get_protocol_features(&mut self) -> Result<VhostUserProtocolFeatures> {
+        Ok(VhostUserProtocolFeatures::all())
+    }
+
+    fn set_protocol_features(&mut self, features: u64) -> Result<()> {
+        // Note: slave that reported VHOST_USER_F_PROTOCOL_FEATURES must
+        // support this message even before VHOST_USER_SET_FEATURES was
+        // called.
+        // What happens if the master calls set_features() with
+        // VHOST_USER_F_PROTOCOL_FEATURES cleared after calling this
+        // interface?
+        self.acked_protocol_features = features;
+        Ok(())
+    }
+
+    fn get_queue_num(&mut self) -> Result<u64> {
+        Ok(MAX_QUEUE_NUM as u64)
+    }
+
+    fn set_vring_enable(&mut self, index: u32, enable: bool) -> Result<()> {
+        // This request should be handled only when VHOST_USER_F_PROTOCOL_FEATURES
+        // has been negotiated.
+        self.check_feature(VhostUserVirtioFeatures::PROTOCOL_FEATURES)?;
+
+        if index as usize >= self.queue_num || index as usize > self.queue_num {
+            return Err(Error::InvalidParam);
+        }
+
+        // Slave must not pass data to/from the backend until ring is
+        // enabled by VHOST_USER_SET_VRING_ENABLE with parameter 1,
+        // or after it has been disabled by VHOST_USER_SET_VRING_ENABLE
+        // with parameter 0.
+        self.vring_enabled[index as usize] = enable;
+        Ok(())
+    }
+
+    fn get_config(
+        &mut self,
+        offset: u32,
+        size: u32,
+        _flags: VhostUserConfigFlags,
+    ) -> Result<Vec<u8>> {
+        self.check_proto_feature(VhostUserProtocolFeatures::CONFIG)?;
+
+        if !(VHOST_USER_CONFIG_OFFSET..VHOST_USER_CONFIG_SIZE).contains(&offset)
+            || size > VHOST_USER_CONFIG_SIZE - VHOST_USER_CONFIG_OFFSET
+            || size + offset > VHOST_USER_CONFIG_SIZE
+        {
+            return Err(Error::InvalidParam);
+        }
+        assert_eq!(offset, 0x100);
+        assert_eq!(size, 4);
+        Ok(vec![0xa5; size as usize])
+    }
+
+    fn set_config(&mut self, offset: u32, buf: &[u8], _flags: VhostUserConfigFlags) -> Result<()> {
+        let size = buf.len() as u32;
+        self.check_proto_feature(VhostUserProtocolFeatures::CONFIG)?;
+
+        if !(VHOST_USER_CONFIG_OFFSET..VHOST_USER_CONFIG_SIZE).contains(&offset)
+            || size > VHOST_USER_CONFIG_SIZE - VHOST_USER_CONFIG_OFFSET
+            || size + offset > VHOST_USER_CONFIG_SIZE
+        {
+            return Err(Error::InvalidParam);
+        }
+        assert_eq!(offset, 0x100);
+        assert_eq!(buf.len(), 4);
+        assert_eq!(buf, &[0xa5; 4]);
+        Ok(())
+    }
+
+    fn get_inflight_fd(
+        &mut self,
+        inflight: &VhostUserInflight,
+    ) -> Result<(VhostUserInflight, File)> {
+        let file = tempfile::tempfile().unwrap();
+        self.inflight_file = Some(file.try_clone().unwrap());
+        Ok((
+            VhostUserInflight {
+                mmap_size: 0x1000,
+                mmap_offset: 0,
+                num_queues: inflight.num_queues,
+                queue_size: inflight.queue_size,
+            },
+            file,
+        ))
+    }
+
+    fn set_inflight_fd(&mut self, _inflight: &VhostUserInflight, _file: File) -> Result<()> {
+        Ok(())
+    }
+
+    fn get_max_mem_slots(&mut self) -> Result<u64> {
+        Ok(MAX_MEM_SLOTS as u64)
+    }
+
+    fn add_mem_region(&mut self, _region: &VhostUserSingleMemoryRegion, _fd: File) -> Result<()> {
+        Ok(())
+    }
+
+    fn remove_mem_region(&mut self, _region: &VhostUserSingleMemoryRegion) -> Result<()> {
+        Ok(())
+    }
+}