1 /* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ 2 3 #ifndef _LIBMCTP_H 4 #define _LIBMCTP_H 5 6 #ifdef __cplusplus 7 extern "C" { 8 #endif 9 10 #include <stdarg.h> 11 #include <stdbool.h> 12 #include <stdint.h> 13 #include <stddef.h> 14 15 typedef uint8_t mctp_eid_t; 16 17 /* Special Endpoint ID values */ 18 #define MCTP_EID_NULL 0 19 #define MCTP_EID_BROADCAST 0xff 20 21 /* MCTP packet definitions */ 22 struct mctp_hdr { 23 uint8_t ver; 24 uint8_t dest; 25 uint8_t src; 26 uint8_t flags_seq_tag; 27 }; 28 29 /* Definitions for flags_seq_tag field */ 30 #define MCTP_HDR_FLAG_SOM (1 << 7) 31 #define MCTP_HDR_FLAG_EOM (1 << 6) 32 #define MCTP_HDR_FLAG_TO (1 << 3) 33 #define MCTP_HDR_TO_SHIFT (3) 34 #define MCTP_HDR_TO_MASK (1) 35 #define MCTP_HDR_SEQ_SHIFT (4) 36 #define MCTP_HDR_SEQ_MASK (0x3) 37 #define MCTP_HDR_TAG_SHIFT (0) 38 #define MCTP_HDR_TAG_MASK (0x7) 39 40 #define MCTP_MESSAGE_TO_SRC true 41 #define MCTP_MESSAGE_TO_DST false 42 #define MCTP_MESSAGE_CAPTURE_OUTGOING true 43 #define MCTP_MESSAGE_CAPTURE_INCOMING false 44 45 /* Baseline Transmission Unit and packet size */ 46 #define MCTP_BTU 64 47 #define MCTP_PACKET_SIZE(unit) ((unit) + sizeof(struct mctp_hdr)) 48 #define MCTP_BODY_SIZE(unit) ((unit) - sizeof(struct mctp_hdr)) 49 50 /* packet buffers */ 51 52 struct mctp_pktbuf { 53 size_t start, end, size; 54 size_t mctp_hdr_off; 55 struct mctp_pktbuf *next; 56 unsigned char data[]; 57 }; 58 59 struct mctp_binding; 60 61 struct mctp_pktbuf *mctp_pktbuf_alloc(struct mctp_binding *hw, size_t len); 62 void mctp_pktbuf_free(struct mctp_pktbuf *pkt); 63 struct mctp_hdr *mctp_pktbuf_hdr(struct mctp_pktbuf *pkt); 64 void *mctp_pktbuf_data(struct mctp_pktbuf *pkt); 65 size_t mctp_pktbuf_size(struct mctp_pktbuf *pkt); 66 void *mctp_pktbuf_alloc_start(struct mctp_pktbuf *pkt, size_t size); 67 void *mctp_pktbuf_alloc_end(struct mctp_pktbuf *pkt, size_t size); 68 int mctp_pktbuf_push(struct mctp_pktbuf *pkt, void *data, size_t len); 69 void *mctp_pktbuf_pop(struct mctp_pktbuf *pkt, size_t len); 70 71 /* MCTP core */ 72 struct mctp; 73 struct mctp_bus; 74 75 struct mctp *mctp_init(void); 76 void mctp_set_max_message_size(struct mctp *mctp, size_t message_size); 77 typedef void (*mctp_capture_fn)(struct mctp_pktbuf *pkt, bool outgoing, 78 void *user); 79 void mctp_set_capture_handler(struct mctp *mctp, mctp_capture_fn fn, 80 void *user); 81 void mctp_destroy(struct mctp *mctp); 82 83 /* Register a binding to the MCTP core, and creates a bus (populating 84 * binding->bus). 85 * 86 * If this function is called, the MCTP stack is initialised as an 'endpoint', 87 * and will deliver local packets to a RX callback - see `mctp_set_rx_all()` 88 * below. 89 */ 90 int mctp_register_bus(struct mctp *mctp, struct mctp_binding *binding, 91 mctp_eid_t eid); 92 93 void mctp_unregister_bus(struct mctp *mctp, struct mctp_binding *binding); 94 95 /* Create a simple bidirectional bridge between busses. 96 * 97 * In this mode, the MCTP stack is initialised as a bridge. There is no EID 98 * defined, so no packets are considered local. Instead, all messages from one 99 * binding are forwarded to the other. 100 */ 101 int mctp_bridge_busses(struct mctp *mctp, struct mctp_binding *b1, 102 struct mctp_binding *b2); 103 104 typedef void (*mctp_rx_fn)(uint8_t src_eid, bool tag_owner, uint8_t msg_tag, 105 void *data, void *msg, size_t len); 106 107 int mctp_set_rx_all(struct mctp *mctp, mctp_rx_fn fn, void *data); 108 109 int mctp_message_tx(struct mctp *mctp, mctp_eid_t eid, bool tag_owner, 110 uint8_t msg_tag, void *msg, size_t msg_len); 111 112 /* hardware bindings */ 113 114 /** 115 * @tx: Binding function to transmit one packet on the interface 116 * Return: 117 * * 0 - Success, pktbuf can be released 118 * * -EMSGSIZE - Packet exceeds binding MTU, pktbuf must be dropped 119 * * -EBUSY - Packet unable to be transmitted, pktbuf must be retained 120 */ 121 struct mctp_binding { 122 const char *name; 123 uint8_t version; 124 struct mctp_bus *bus; 125 struct mctp *mctp; 126 size_t pkt_size; 127 size_t pkt_header; 128 size_t pkt_trailer; 129 int (*start)(struct mctp_binding *binding); 130 int (*tx)(struct mctp_binding *binding, struct mctp_pktbuf *pkt); 131 mctp_rx_fn control_rx; 132 void *control_rx_data; 133 }; 134 135 void mctp_binding_set_tx_enabled(struct mctp_binding *binding, bool enable); 136 137 /* 138 * Receive a packet from binding to core. Takes ownership of pkt, free()-ing it 139 * after use. 140 */ 141 void mctp_bus_rx(struct mctp_binding *binding, struct mctp_pktbuf *pkt); 142 143 /* environment-specific allocation */ 144 void mctp_set_alloc_ops(void *(*alloc)(size_t), void (*free)(void *), 145 void *(realloc)(void *, size_t)); 146 147 /* environment-specific logging */ 148 149 void mctp_set_log_stdio(int level); 150 void mctp_set_log_syslog(void); 151 void mctp_set_log_custom(void (*fn)(int, const char *, va_list)); 152 153 /* these should match the syslog-standard LOG_* definitions, for 154 * easier use with syslog */ 155 #define MCTP_LOG_ERR 3 156 #define MCTP_LOG_WARNING 4 157 #define MCTP_LOG_NOTICE 5 158 #define MCTP_LOG_INFO 6 159 #define MCTP_LOG_DEBUG 7 160 161 #ifdef __cplusplus 162 } 163 #endif 164 165 #endif /* _LIBMCTP_H */ 166