1 /*
2 * Copyright (c) 2018-2021 mcumgr authors
3 * Copyright (c) 2023 Nordic Semiconductor ASA
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 /**
9 * @file
10 * @brief SMP - Simple Management Protocol.
11 *
12 * SMP is a basic protocol that sits on top of the mgmt layer. SMP requests
13 * and responses have the following format:
14 *
15 * [Offset 0]: Mgmt header
16 * [Offset 8]: CBOR map of command-specific key-value pairs.
17 *
18 * SMP request packets may contain multiple concatenated requests. Each
19 * request must start at an offset that is a multiple of 4, so padding should
20 * be inserted between requests as necessary. Requests are processed
21 * sequentially from the start of the packet to the end. Each response is sent
22 * individually in its own packet. If a request elicits an error response,
23 * processing of the packet is aborted.
24 */
25
26 #ifndef H_SMP_
27 #define H_SMP_
28
29 #include <zephyr/net/buf.h>
30 #include <zephyr/mgmt/mcumgr/transport/smp.h>
31
32 #include <zcbor_common.h>
33
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
37
38 /** SMP MCUmgr protocol version, part of the SMP header */
39 enum smp_mcumgr_version_t {
40 /** Version 1: the original protocol */
41 SMP_MCUMGR_VERSION_1 = 0,
42
43 /** Version 2: adds more detailed error reporting capabilities */
44 SMP_MCUMGR_VERSION_2,
45 };
46
47 struct cbor_nb_reader {
48 struct net_buf *nb;
49 /* CONFIG_MCUMGR_SMP_CBOR_MAX_DECODING_LEVELS + 2 translates to minimal
50 * zcbor backup states.
51 */
52 zcbor_state_t zs[CONFIG_MCUMGR_SMP_CBOR_MAX_DECODING_LEVELS + 2];
53 };
54
55 struct cbor_nb_writer {
56 struct net_buf *nb;
57 zcbor_state_t zs[CONFIG_MCUMGR_SMP_CBOR_MAX_ENCODING_LEVELS + 2];
58
59 #if IS_ENABLED(CONFIG_MCUMGR_SMP_SUPPORT_ORIGINAL_PROTOCOL)
60 uint16_t error_group;
61 uint16_t error_ret;
62 #endif
63 };
64
65 /**
66 * @brief Allocates a net_buf for holding an mcumgr request or response.
67 *
68 * @return A newly-allocated buffer net_buf on success;
69 * NULL on failure.
70 */
71 struct net_buf *smp_packet_alloc(void);
72
73 /**
74 * @brief Frees an mcumgr net_buf
75 *
76 * @param nb The net_buf to free.
77 */
78 void smp_packet_free(struct net_buf *nb);
79
80 /**
81 * @brief Decodes, encodes, and transmits SMP packets.
82 */
83 struct smp_streamer {
84 struct smp_transport *smpt;
85 struct cbor_nb_reader *reader;
86 struct cbor_nb_writer *writer;
87
88 #ifdef CONFIG_MCUMGR_SMP_VERBOSE_ERR_RESPONSE
89 const char *rc_rsn;
90 #endif
91 };
92
93 /**
94 * @brief Processes a single SMP request packet and sends all corresponding responses.
95 *
96 * Processes all SMP requests in an incoming packet. Requests are processed
97 * sequentially from the start of the packet to the end. Each response is sent
98 * individually in its own packet. If a request elicits an error response,
99 * processing of the packet is aborted. This function consumes the supplied
100 * request buffer regardless of the outcome.
101 *
102 * @param streamer The streamer providing the required SMP callbacks.
103 * @param req The request packet to process.
104 *
105 * @return 0 on success, #mcumgr_err_t code on failure.
106 */
107 int smp_process_request_packet(struct smp_streamer *streamer, void *req);
108
109 /**
110 * @brief Appends an "err" response
111 *
112 * This appends an err response to a pending outgoing response which contains a
113 * result code for a specific group. Note that error codes are specific to the
114 * command group they are emitted from).
115 *
116 * @param zse The zcbor encoder to use.
117 * @param group The group which emitted the error.
118 * @param ret The command result code to add.
119 *
120 * @return true on success, false on failure (memory error).
121 */
122 bool smp_add_cmd_err(zcbor_state_t *zse, uint16_t group, uint16_t ret);
123
124 /** @deprecated Deprecated after Zephyr 3.4, use smp_add_cmd_err() instead */
smp_add_cmd_ret(zcbor_state_t * zse,uint16_t group,uint16_t ret)125 __deprecated inline bool smp_add_cmd_ret(zcbor_state_t *zse, uint16_t group, uint16_t ret)
126 {
127 return smp_add_cmd_err(zse, group, ret);
128 }
129
130 #if IS_ENABLED(CONFIG_MCUMGR_SMP_SUPPORT_ORIGINAL_PROTOCOL)
131 /** @typedef smp_translate_error_fn
132 * @brief Translates a SMP version 2 error response to a legacy SMP version 1 error code.
133 *
134 * @param ret The SMP version 2 group error value.
135 *
136 * @return #enum mcumgr_err_t Legacy SMP version 1 error code to return to client.
137 */
138 typedef int (*smp_translate_error_fn)(uint16_t err);
139 #endif
140
141 #ifdef __cplusplus
142 }
143 #endif
144
145 #endif /* H_SMP_ */
146
