/* * coap_pdu_internal.h -- CoAP PDU structure * * Copyright (C) 2010-2021 Olaf Bergmann * * SPDX-License-Identifier: BSD-2-Clause * * This file is part of the CoAP library libcoap. Please see README for terms * of use. */ /** * @file coap_pdu_internal.h * @brief CoAP PDU internal information */ #ifndef COAP_COAP_PDU_INTERNAL_H_ #define COAP_COAP_PDU_INTERNAL_H_ #ifdef WITH_LWIP #include #endif #include /** * @defgroup pdu_internal PDU (Internal) * CoAP PDU Structures, Enums and Functions that are not exposed to * applications * @{ */ #define COAP_DEFAULT_VERSION 1 /* version of CoAP supported */ /* TCP Message format constants, do not modify */ #define COAP_MESSAGE_SIZE_OFFSET_TCP8 13 #define COAP_MESSAGE_SIZE_OFFSET_TCP16 269 /* 13 + 256 */ #define COAP_MESSAGE_SIZE_OFFSET_TCP32 65805 /* 269 + 65536 */ /* Derived message size limits */ #define COAP_MAX_MESSAGE_SIZE_TCP0 (COAP_MESSAGE_SIZE_OFFSET_TCP8-1) /* 12 */ #define COAP_MAX_MESSAGE_SIZE_TCP8 (COAP_MESSAGE_SIZE_OFFSET_TCP16-1) /* 268 */ #define COAP_MAX_MESSAGE_SIZE_TCP16 (COAP_MESSAGE_SIZE_OFFSET_TCP32-1) /* 65804 */ #define COAP_MAX_MESSAGE_SIZE_TCP32 (COAP_MESSAGE_SIZE_OFFSET_TCP32+0xFFFFFFFF) #ifndef COAP_DEBUG_BUF_SIZE #if defined(WITH_CONTIKI) || defined(WITH_LWIP) #define COAP_DEBUG_BUF_SIZE 128 #else /* defined(WITH_CONTIKI) || defined(WITH_LWIP) */ /* 1024 derived from RFC7252 4.6. Message Size max payload */ #define COAP_DEBUG_BUF_SIZE (8 + 1024 * 2) #endif /* defined(WITH_CONTIKI) || defined(WITH_LWIP) */ #endif /* COAP_DEBUG_BUF_SIZE */ #ifndef COAP_DEFAULT_MAX_PDU_RX_SIZE #if defined(WITH_CONTIKI) || defined(WITH_LWIP) #define COAP_DEFAULT_MAX_PDU_RX_SIZE (COAP_MAX_MESSAGE_SIZE_TCP16+4UL) #else /* 8 MiB max-message-size plus some space for options */ #define COAP_DEFAULT_MAX_PDU_RX_SIZE (8UL*1024*1024+256) #endif #endif /* COAP_DEFAULT_MAX_PDU_RX_SIZE */ /** * Indicates that a response is suppressed. This will occur for error * responses if the request was received via IP multicast. */ #define COAP_DROPPED_RESPONSE -2 #define COAP_PDU_DELAYED -3 #define COAP_PAYLOAD_START 0xFF /* payload marker */ #define COAP_PDU_IS_EMPTY(pdu) ((pdu)->code == 0) #define COAP_PDU_IS_REQUEST(pdu) (!COAP_PDU_IS_EMPTY(pdu) && (pdu)->code < 32) #define COAP_PDU_IS_RESPONSE(pdu) ((pdu)->code >= 64 && (pdu)->code < 224) #define COAP_PDU_IS_SIGNALING(pdu) ((pdu)->code >= 224) #define COAP_PDU_MAX_UDP_HEADER_SIZE 4 #define COAP_PDU_MAX_TCP_HEADER_SIZE 6 /** * structure for CoAP PDUs * token, if any, follows the fixed size header, then options until * payload marker (0xff), then the payload if stored inline. * Memory layout is: * <---header--->|<---token---><---options--->0xff<---payload---> * header is addressed with a negative offset to token, its maximum size is * max_hdr_size. * options starts at token + token_length * payload starts at data, its length is used_size - (data - token) */ struct coap_pdu_t { coap_pdu_type_t type; /**< message type */ coap_pdu_code_t code; /**< request method (value 1--31) or response code (value 64-255) */ coap_mid_t mid; /**< message id, if any, in regular host byte order */ uint8_t max_hdr_size; /**< space reserved for protocol-specific header */ uint8_t hdr_size; /**< actual size used for protocol-specific header */ uint8_t token_length; /**< length of Token */ uint16_t max_opt; /**< highest option number in PDU */ size_t alloc_size; /**< allocated storage for token, options and payload */ size_t used_size; /**< used bytes of storage for token, options and payload */ size_t max_size; /**< maximum size for token, options and payload, or zero for variable size pdu */ uint8_t *token; /**< first byte of token, if any, or options */ uint8_t *data; /**< first byte of payload, if any */ #ifdef WITH_LWIP struct pbuf *pbuf; /**< lwIP PBUF. The package data will always reside * inside the pbuf's payload, but this pointer * has to be kept because no exact offset can be * given. This field must not be accessed from * outside, because the pbuf's reference count * is checked to be 1 when the pbuf is assigned * to the pdu, and the pbuf stays exclusive to * this pdu. */ #endif const uint8_t *body_data; /**< Holds ptr to re-assembled data or NULL */ size_t body_length; /**< Holds body data length */ size_t body_offset; /**< Holds body data offset */ size_t body_total; /**< Holds body data total size */ coap_lg_xmit_t *lg_xmit; /**< Holds ptr to lg_xmit if sending a set of blocks */ }; /** * Dynamically grows the size of @p pdu to @p new_size. The new size * must not exceed the PDU's configure maximum size. On success, this * function returns 1, otherwise 0. * * @param pdu The PDU to resize. * @param new_size The new size in bytes. * @return 1 if the operation succeeded, 0 otherwise. */ int coap_pdu_resize(coap_pdu_t *pdu, size_t new_size); /** * Dynamically grows the size of @p pdu to @p new_size if needed. The new size * must not exceed the PDU's configured maximum size. On success, this * function returns 1, otherwise 0. * * @param pdu The PDU to resize. * @param new_size The new size in bytes. * @return 1 if the operation succeeded, 0 otherwise. */ int coap_pdu_check_resize(coap_pdu_t *pdu, size_t new_size); /** * Interprets @p data to determine the number of bytes in the header. * This function returns @c 0 on error or a number greater than zero on success. * * @param proto Session's protocol * @param data The first byte of raw data to parse as CoAP PDU. * * @return A value greater than zero on success or @c 0 on error. */ size_t coap_pdu_parse_header_size(coap_proto_t proto, const uint8_t *data); /** * Parses @p data to extract the message size. * @p length must be at least coap_pdu_parse_header_size(proto, data). * This function returns @c 0 on error or a number greater than zero on success. * * @param proto Session's protocol * @param data The raw data to parse as CoAP PDU. * @param length The actual size of @p data. * * @return A value greater than zero on success or @c 0 on error. */ size_t coap_pdu_parse_size(coap_proto_t proto, const uint8_t *data, size_t length); /** * Decode the protocol specific header for the specified PDU. * @param pdu A newly received PDU. * @param proto The target wire protocol. * @return 1 for success or 0 on error. */ int coap_pdu_parse_header(coap_pdu_t *pdu, coap_proto_t proto); /** * Verify consistency in the given CoAP PDU structure and locate the data. * This function returns @c 0 on error or a number greater than zero on * success. * This function only parses the token and options, up to the payload start * marker. * * @param pdu The PDU structure to check. * * @return 1 on success or @c 0 on error. */ int coap_pdu_parse_opt(coap_pdu_t *pdu); /** * Parses @p data into the CoAP PDU structure given in @p result. * The target pdu must be large enough to * This function returns @c 0 on error or a number greater than zero on success. * * @param proto Session's protocol * @param data The raw data to parse as CoAP PDU. * @param length The actual size of @p data. * @param pdu The PDU structure to fill. Note that the structure must * provide space to hold at least the token and options * part of the message. * * @return 1 on success or @c 0 on error. */ int coap_pdu_parse(coap_proto_t proto, const uint8_t *data, size_t length, coap_pdu_t *pdu); /** * Clears any contents from @p pdu and resets @c used_size, * and @c data pointers. @c max_size is set to @p size, any * other field is set to @c 0. Note that @p pdu must be a valid * pointer to a coap_pdu_t object created e.g. by coap_pdu_init(). * * @param pdu The PDU to clear. * @param size The maximum size of the PDU. */ void coap_pdu_clear(coap_pdu_t *pdu, size_t size); /** * Removes (first) option of given number from the @p pdu. * * @param pdu The PDU to remove the option from. * @param number The number of the CoAP option to remove (first only removed). * * @return @c 1 if success else @c 0 if error. */ int coap_remove_option(coap_pdu_t *pdu, coap_option_num_t number); /** * Inserts option of given number in the @p pdu with the appropriate data. * The option will be inserted in the appropriate place in the options in * the pdu. * * @param pdu The PDU where the option is to be inserted. * @param number The number of the new option. * @param len The length of the new option. * @param data The data of the new option. * * @return The overall length of the option or @c 0 on failure. */ size_t coap_insert_option(coap_pdu_t *pdu, coap_option_num_t number, size_t len, const uint8_t *data); /** * Updates existing first option of given number in the @p pdu with the new * data. * * @param pdu The PDU where the option is to be updated. * @param number The number of the option to update (first only updated). * @param len The length of the updated option. * @param data The data of the updated option. * * @return The overall length of the updated option or @c 0 on failure. */ size_t coap_update_option(coap_pdu_t *pdu, coap_option_num_t number, size_t len, const uint8_t *data); /** * Compose the protocol specific header for the specified PDU. * * @param pdu A newly composed PDU. * @param proto The target wire protocol. * * @return Number of header bytes prepended before pdu->token or 0 on error. */ size_t coap_pdu_encode_header(coap_pdu_t *pdu, coap_proto_t proto); /** * Updates token in @p pdu with length @p len and @p data. * This function returns @c 0 on error or a value greater than zero on success. * * @param pdu The PDU where the token is to be updated. * @param len The length of the new token. * @param data The token to add. * * @return A value greater than zero on success, or @c 0 on error. */ int coap_update_token(coap_pdu_t *pdu, size_t len, const uint8_t *data); /** @} */ #endif /* COAP_COAP_PDU_INTERNAL_H_ */