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/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
#ifndef _LIBMCTP_H
#define _LIBMCTP_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stddef.h>
typedef uint8_t mctp_eid_t;
/* Special Endpoint ID values */
#define MCTP_EID_NULL 0
#define MCTP_EID_BROADCAST 0xff
/* MCTP packet definitions */
struct mctp_hdr {
uint8_t ver;
uint8_t dest;
uint8_t src;
uint8_t flags_seq_tag;
};
/* Definitions for flags_seq_tag field */
#define MCTP_HDR_FLAG_SOM (1 << 7)
#define MCTP_HDR_FLAG_EOM (1 << 6)
#define MCTP_HDR_FLAG_TO (1 << 3)
#define MCTP_HDR_TO_SHIFT (3)
#define MCTP_HDR_TO_MASK (1)
#define MCTP_HDR_SEQ_SHIFT (4)
#define MCTP_HDR_SEQ_MASK (0x3)
#define MCTP_HDR_TAG_SHIFT (0)
#define MCTP_HDR_TAG_MASK (0x7)
#define MCTP_MESSAGE_TO_SRC true
#define MCTP_MESSAGE_TO_DST false
#define MCTP_MESSAGE_CAPTURE_OUTGOING true
#define MCTP_MESSAGE_CAPTURE_INCOMING false
/* Baseline Transmission Unit and packet size */
#define MCTP_BTU 64
#define MCTP_PACKET_SIZE(unit) ((unit) + sizeof(struct mctp_hdr))
#define MCTP_BODY_SIZE(unit) ((unit) - sizeof(struct mctp_hdr))
/* packet buffers */
struct mctp_pktbuf {
size_t start, end, size;
size_t mctp_hdr_off;
struct mctp_pktbuf *next;
unsigned char data[];
};
struct mctp_binding;
struct mctp_pktbuf *mctp_pktbuf_alloc(struct mctp_binding *hw, size_t len);
void mctp_pktbuf_free(struct mctp_pktbuf *pkt);
struct mctp_hdr *mctp_pktbuf_hdr(struct mctp_pktbuf *pkt);
void *mctp_pktbuf_data(struct mctp_pktbuf *pkt);
size_t mctp_pktbuf_size(struct mctp_pktbuf *pkt);
void *mctp_pktbuf_alloc_start(struct mctp_pktbuf *pkt, size_t size);
void *mctp_pktbuf_alloc_end(struct mctp_pktbuf *pkt, size_t size);
int mctp_pktbuf_push(struct mctp_pktbuf *pkt, void *data, size_t len);
void *mctp_pktbuf_pop(struct mctp_pktbuf *pkt, size_t len);
/* MCTP core */
struct mctp;
struct mctp_bus;
struct mctp *mctp_init(void);
void mctp_set_max_message_size(struct mctp *mctp, size_t message_size);
typedef void (*mctp_capture_fn)(struct mctp_pktbuf *pkt, bool outgoing,
void *user);
void mctp_set_capture_handler(struct mctp *mctp, mctp_capture_fn fn,
void *user);
void mctp_destroy(struct mctp *mctp);
/* Register a binding to the MCTP core, and creates a bus (populating
* binding->bus).
*
* If this function is called, the MCTP stack is initialised as an 'endpoint',
* and will deliver local packets to a RX callback - see `mctp_set_rx_all()`
* below.
*/
int mctp_register_bus(struct mctp *mctp, struct mctp_binding *binding,
mctp_eid_t eid);
void mctp_unregister_bus(struct mctp *mctp, struct mctp_binding *binding);
/* Create a simple bidirectional bridge between busses.
*
* In this mode, the MCTP stack is initialised as a bridge. There is no EID
* defined, so no packets are considered local. Instead, all messages from one
* binding are forwarded to the other.
*/
int mctp_bridge_busses(struct mctp *mctp, struct mctp_binding *b1,
struct mctp_binding *b2);
typedef void (*mctp_rx_fn)(uint8_t src_eid, bool tag_owner, uint8_t msg_tag,
void *data, void *msg, size_t len);
int mctp_set_rx_all(struct mctp *mctp, mctp_rx_fn fn, void *data);
int mctp_message_tx(struct mctp *mctp, mctp_eid_t eid, bool tag_owner,
uint8_t msg_tag, void *msg, size_t msg_len);
/* hardware bindings */
/**
* @tx: Binding function to transmit one packet on the interface
* Return:
* * 0 - Success, pktbuf can be released
* * -EMSGSIZE - Packet exceeds binding MTU, pktbuf must be dropped
* * -EBUSY - Packet unable to be transmitted, pktbuf must be retained
*/
struct mctp_binding {
const char *name;
uint8_t version;
struct mctp_bus *bus;
struct mctp *mctp;
size_t pkt_size;
size_t pkt_header;
size_t pkt_trailer;
int (*start)(struct mctp_binding *binding);
int (*tx)(struct mctp_binding *binding, struct mctp_pktbuf *pkt);
mctp_rx_fn control_rx;
void *control_rx_data;
};
enum mctp_bus_state {
mctp_bus_state_constructed = 0,
mctp_bus_state_tx_enabled,
mctp_bus_state_tx_disabled,
};
void mctp_binding_set_tx_enabled(struct mctp_binding *binding, bool enable);
enum mctp_bus_state mctp_bus_get_state(struct mctp_bus *bus);
/*
* Receive a packet from binding to core. Takes ownership of pkt, free()-ing it
* after use.
*/
void mctp_bus_rx(struct mctp_binding *binding, struct mctp_pktbuf *pkt);
/* environment-specific allocation */
void mctp_set_alloc_ops(void *(*alloc)(size_t), void (*free)(void *),
void *(realloc)(void *, size_t));
/* environment-specific logging */
void mctp_set_log_stdio(int level);
void mctp_set_log_syslog(void);
void mctp_set_log_custom(void (*fn)(int, const char *, va_list));
/* these should match the syslog-standard LOG_* definitions, for
* easier use with syslog */
#define MCTP_LOG_ERR 3
#define MCTP_LOG_WARNING 4
#define MCTP_LOG_NOTICE 5
#define MCTP_LOG_INFO 6
#define MCTP_LOG_DEBUG 7
#ifdef __cplusplus
}
#endif
#endif /* _LIBMCTP_H */
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