Note: for man pages, see the Homa Wiki at: https://homa-transport.atlassian.net/wiki/spaces/HOMA/overview Signed-off-by: John Ousterhout <ouster@xxxxxxxxxxxxxxx> --- include/uapi/linux/homa.h | 165 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 include/uapi/linux/homa.h diff --git a/include/uapi/linux/homa.h b/include/uapi/linux/homa.h new file mode 100644 index 000000000000..d06cfc49c101 --- /dev/null +++ b/include/uapi/linux/homa.h @@ -0,0 +1,165 @@ +/* SPDX-License-Identifier: BSD-2-Clause */ + +/* This file defines the kernel call interface for the Homa + * transport protocol. + */ + +#ifndef _UAPI_LINUX_HOMA_H +#define _UAPI_LINUX_HOMA_H + +#include <linux/types.h> +#ifndef __KERNEL__ +#include <netinet/in.h> +#include <sys/socket.h> +#endif + +#ifdef __cplusplus +extern "C" +{ +#endif + +/* IANA-assigned Internet Protocol number for Homa. */ +#define IPPROTO_HOMA 146 + +/** + * define HOMA_MAX_MESSAGE_LENGTH - Maximum bytes of payload in a Homa + * request or response message. + */ +#define HOMA_MAX_MESSAGE_LENGTH 1000000 + +/** + * define HOMA_BPAGE_SIZE - Number of bytes in pages used for receive + * buffers. Must be power of two. + */ +#define HOMA_BPAGE_SHIFT 16 +#define HOMA_BPAGE_SIZE (1 << HOMA_BPAGE_SHIFT) + +/** + * define HOMA_MAX_BPAGES: The largest number of bpages that will be required + * to store an incoming message. + */ +#define HOMA_MAX_BPAGES ((HOMA_MAX_MESSAGE_LENGTH + HOMA_BPAGE_SIZE - 1) \ + >> HOMA_BPAGE_SHIFT) + +/** + * define HOMA_MIN_DEFAULT_PORT - The 16-bit port space is divided into + * two nonoverlapping regions. Ports 1-32767 are reserved exclusively + * for well-defined server ports. The remaining ports are used for client + * ports; these are allocated automatically by Homa. Port 0 is reserved. + */ +#define HOMA_MIN_DEFAULT_PORT 0x8000 + +/** + * struct homa_sendmsg_args - Provides information needed by Homa's + * sendmsg; passed to sendmsg using the msg_control field. + */ +struct homa_sendmsg_args { + /** + * @id: (in/out) 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. + */ + uint64_t id; + + /** + * @completion_cookie: (in) Used only for request messages; will be + * returned by recvmsg when the RPC completes. Typically used to + * locate app-specific info about the RPC. + */ + uint64_t completion_cookie; +}; + +#if !defined(__cplusplus) +_Static_assert(sizeof(struct homa_sendmsg_args) >= 16, + "homa_sendmsg_args shrunk"); +_Static_assert(sizeof(struct homa_sendmsg_args) <= 16, + "homa_sendmsg_args grew"); +#endif + +/** + * struct homa_recvmsg_args - Provides information needed by Homa's + * recvmsg; passed to recvmsg using the msg_control field. + */ +struct homa_recvmsg_args { + /** + * @id: (in/out) Initially specifies the id of the desired RPC, or 0 + * if any RPC is OK; returns the actual id received. + */ + uint64_t id; + + /** + * @completion_cookie: (out) 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. + */ + uint64_t completion_cookie; + + /** + * @flags: (in) OR-ed combination of bits that control the operation. + * See below for values. + */ + uint32_t flags; + + /** + * @num_bpages: (in/out) Number of valid entries in @bpage_offsets. + * Passes in bpages from previous messages that can now be + * recycled; returns bpages from the new message. + */ + uint32_t num_bpages; + + /** + * @bpage_offsets: (in/out) 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. + */ + uint32_t bpage_offsets[HOMA_MAX_BPAGES]; +}; + +#if !defined(__cplusplus) +_Static_assert(sizeof(struct homa_recvmsg_args) >= 88, + "homa_recvmsg_args shrunk"); +_Static_assert(sizeof(struct homa_recvmsg_args) <= 88, + "homa_recvmsg_args grew"); +#endif + +/* Flag bits for homa_recvmsg_args.flags (see man page for documentation): + */ +#define HOMA_RECVMSG_REQUEST 0x01 +#define HOMA_RECVMSG_RESPONSE 0x02 +#define HOMA_RECVMSG_NONBLOCKING 0x04 +#define HOMA_RECVMSG_VALID_FLAGS 0x07 + +/** define SO_HOMA_SET_BUF: setsockopt option for specifying buffer region. */ +#define SO_HOMA_SET_BUF 10 + +/** struct homa_set_buf - setsockopt argument for SO_HOMA_SET_BUF. */ +struct homa_set_buf_args { + /** @start: First byte of buffer region. */ + void *start; + + /** @length: Total number of bytes available at @start. */ + size_t length; +}; + +/** + * Meanings of the bits in Homa's flag word, which can be set using + * "sysctl /net/homa/flags". + */ + +/** + * Disable the output throttling mechanism: always send all packets + * immediately. + */ +#define HOMA_FLAG_DONT_THROTTLE 2 + +#ifdef __cplusplus +} +#endif + +#endif /* _UAPI_LINUX_HOMA_H */ -- 2.34.1
