README
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go-homa
A Go Client For The Homa Transport Protocol.
Usage
For a simple example of how to use this library, see the examples directory.
Documentation
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Index ¶
- Constants
- Variables
- type AbortArgs
- type BufferPool
- type Message
- type RecvmsgArgs
- type SendmsgArgs
- type SetBufArgs
- type SockaddrInUnion
- type Socket
- func (s *Socket) Abort(id uint64, errorCode int32) error
- func (s *Socket) Close() error
- func (s *Socket) LocalAddr() net.Addr
- func (s *Socket) Recv() (*Message, error)
- func (s *Socket) Reply(dstAddr net.Addr, id uint64, message []byte) error
- func (s *Socket) Send(dstAddr net.Addr, message []byte, completionCookie uint64) (uint64, error)
Constants ¶
const ( // Homa's protocol number within the IP protocol space (this is not an officially allocated slot). IPPROTO_HOMA = 0xFD // Option for specifying buffer region. SO_HOMA_SET_BUF = 10 // Disable the output throttling mechanism: always send all packets immediately. HOMA_FLAG_DONT_THROTTLE = 2 )
const ( // Maximum bytes of payload in a Homa request or response message. HOMA_MAX_MESSAGE_LENGTH = 1000000 // Number of bytes in pages used for receive buffers. Must be power of two. HOMA_BPAGE_SHIFT = 16 HOMA_BPAGE_SIZE = 1 << HOMA_BPAGE_SHIFT // The largest number of bpages that will be required to store an incoming message. HOMA_MAX_BPAGES = (HOMA_MAX_MESSAGE_LENGTH + HOMA_BPAGE_SIZE - 1) >> HOMA_BPAGE_SHIFT )
const ( HOMA_RECVMSG_REQUEST = 0x01 HOMA_RECVMSG_RESPONSE = 0x02 HOMA_RECVMSG_NONBLOCKING = 0x04 HOMA_RECVMSG_VALID_FLAGS = 0x07 )
Flag bits for homa_recvmsg_args.flags (see man page for documentation).
Variables ¶
var ( HOMAIOCREPLY = ioctl.IOWR(0x89, 0xe2, unsafe.Sizeof(SendmsgArgs{})) HOMAIOCABORT = ioctl.IOWR(0x89, 0xe3, unsafe.Sizeof(AbortArgs{})) HOMAIOCFREEZE = ioctl.IO(0x89, 0xef) )
I/O control calls on Homa sockets. These are mapped into the SIOCPROTOPRIVATE range of 0x89e0 through 0x89ef.
Functions ¶
This section is empty.
Types ¶
type AbortArgs ¶
type AbortArgs struct {
// ID of RPC to abort, or zero to abort all RPCs on socket.
ID uint64
// Zero means destroy and free RPCs; nonzero means complete
// them with this error (recvmsg will return the RPCs).
ErrorCode int32
// Unused padding.
Pad1 int32
Pad2 [2]uint64
}
Structure that passes arguments and results between user space and the HOMAIOCABORT ioctl.
type BufferPool ¶
type BufferPool struct {
// contains filtered or unexported fields
}
func NewBufferPool ¶
func NewBufferPool() (*BufferPool, error)
NewBufferPool allocates a new buffer pool.
func (*BufferPool) Base ¶
func (bp *BufferPool) Base() unsafe.Pointer
Base returns the base address of the buffer pool.
func (*BufferPool) Close ¶
func (bp *BufferPool) Close() error
Close frees the buffer pools allocated memory.
func (*BufferPool) Size ¶
func (bp *BufferPool) Size() int
Size returns the size of the buffer pool (in bytes).
type Message ¶
type Message struct {
// contains filtered or unexported fields
}
Message is a Homa RPC message.
func NewMessage ¶
func NewMessage(bp *BufferPool, args RecvmsgArgs, length int64) *Message
NewMessage creates a new message from the given buffer pool and receive message arguments.
func (*Message) CompletionCookie ¶
CompletionCookie returns the completion cookie for the message.
type RecvmsgArgs ¶
type RecvmsgArgs struct {
// Initially specifies the id of the desired RPC,
// or 0 if any RPC is OK; returns the actual id received.
ID uint64
// If the incoming message is a response, this will return
// the completion cookie specified when the request was sent.
// For requests this will always be zero.
CompletionCookie uint64
// OR-ed combination of bits that control the operation.
Flags int32
// The address of the peer is stored here when available.
// This field is different from the msg_name field in struct msghdr
// in that the msg_name field isn't set after errors. This field will
// always be set when peer information is available, which includes
// some error cases.
PeerAddr SockaddrInUnion
// Number of valid entries in @bpage_offsets.
// Passes in bpages from previous messages that can now be
// recycled; returns bpages from the new message.
NumBPages uint32
// Unused padding.
Pad1 [4]byte
// Each entry is an offset into the buffer region for the socket pool.
// When returned from recvmsg, the offsets indicate where fragments of
// the new message are stored. All entries but the last refer to full
// buffer pages (HOMA_BPAGE_SIZE bytes) and are bpage-aligned. The last
// entry may refer to a bpage fragment and is not necessarily aligned.
// The application now owns these bpages and must eventually return them
// to Homa, using bpage_offsets in a future recvmsg invocation.
BPageOffsets [HOMA_MAX_BPAGES]uint32
}
RecvmsgArgs - Provides information needed by Homa's recvmsg.
type SendmsgArgs ¶
type SendmsgArgs struct {
// ID of the message being sent.
// An initial value of 0 means a new request is being sent; nonzero means the message is a reply to the given id.
// If the message is a request, then the value is modified to hold the id of the new RPC.
ID uint64
// Used only for request messages; will be returned by recvmsg when the RPC completes.
// Typically used to locate app-specific info about the RPC.
CompletionCookie uint64
}
Provides information needed by Homa's sendmsg.
type SetBufArgs ¶
type SetBufArgs struct {
Start unsafe.Pointer // Pointer to the first byte of the buffer region
Length uint64 // Total number of bytes in the buffer
}
setsockopt argument for SO_HOMA_SET_BUF.
type SockaddrInUnion ¶
type SockaddrInUnion [28]byte
Enough space to hold any kind of sockaddr_in or sockaddr_in6.
type Socket ¶
type Socket struct {
// contains filtered or unexported fields
}
func (*Socket) Abort ¶
Abort terminates the execution of an RPC associated with this socket. It takes an RPC ID and an error code as arguments. If the ID is 0, it aborts all client RPCs on this socket. The error code specifies how aborted RPCs should be handled. On success, it returns nil; on failure, it returns the encountered error.
func (*Socket) LocalAddr ¶
LocalAddr returns the local network address of the socket. This is useful if the socket was bound to port 0, which causes the kernel to assign an available port number. It returns the local network address of the socket, or nil if the socket is not bound.
func (*Socket) Recv ¶
Recv waits for an incoming RPC and returns a message containing the RPC's data. It returns a message containing the RPC's data, or an error if the operation failed.
func (*Socket) Reply ¶
Reply sends a response message for an RPC previously received with a call to recvmsg. ID is the unique identifier for the request, as returned by recvmsg when the request was received.
Source Files
Directories