Xin Zhang / azure-iot-c-sdk-f767zi

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Dependents:   samplemqtt

c-utility/src/uws_frame_encoder.c@0:f7f1f0d76dd6, 2018-08-23 (annotated)

Committer:
XinZhangMS
Date:
Thu Aug 23 06:52:14 2018 +0000
Revision:
0:f7f1f0d76dd6
azure-c-sdk for mbed os supporting NUCLEO_F767ZI

Who changed what in which revision?

UserRevisionLine numberNew contents of line
XinZhangMS 0:f7f1f0d76dd6 1 // Copyright (c) Microsoft. All rights reserved.
XinZhangMS 0:f7f1f0d76dd6 2 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
XinZhangMS 0:f7f1f0d76dd6 3
XinZhangMS 0:f7f1f0d76dd6 4 #include <stdlib.h>
XinZhangMS 0:f7f1f0d76dd6 5 #include <stdint.h>
XinZhangMS 0:f7f1f0d76dd6 6 #include <stddef.h>
XinZhangMS 0:f7f1f0d76dd6 7 #include <stdbool.h>
XinZhangMS 0:f7f1f0d76dd6 8 #include "azure_c_shared_utility/gballoc.h"
XinZhangMS 0:f7f1f0d76dd6 9 #include "azure_c_shared_utility/gb_rand.h"
XinZhangMS 0:f7f1f0d76dd6 10 #include "azure_c_shared_utility/uws_frame_encoder.h"
XinZhangMS 0:f7f1f0d76dd6 11 #include "azure_c_shared_utility/xlogging.h"
XinZhangMS 0:f7f1f0d76dd6 12 #include "azure_c_shared_utility/buffer_.h"
XinZhangMS 0:f7f1f0d76dd6 13 #include "azure_c_shared_utility/uniqueid.h"
XinZhangMS 0:f7f1f0d76dd6 14
XinZhangMS 0:f7f1f0d76dd6 15 BUFFER_HANDLE uws_frame_encoder_encode(WS_FRAME_TYPE opcode, const unsigned char* payload, size_t length, bool is_masked, bool is_final, unsigned char reserved)
XinZhangMS 0:f7f1f0d76dd6 16 {
XinZhangMS 0:f7f1f0d76dd6 17 BUFFER_HANDLE result;
XinZhangMS 0:f7f1f0d76dd6 18
XinZhangMS 0:f7f1f0d76dd6 19 if (reserved > 7)
XinZhangMS 0:f7f1f0d76dd6 20 {
XinZhangMS 0:f7f1f0d76dd6 21 /* Codes_SRS_UWS_FRAME_ENCODER_01_052: [ If `reserved` has any bits set except the lowest 3 then `uws_frame_encoder_encode` shall fail and return NULL. ]*/
XinZhangMS 0:f7f1f0d76dd6 22 LogError("Bad reserved value: 0x%02x", reserved);
XinZhangMS 0:f7f1f0d76dd6 23 result = NULL;
XinZhangMS 0:f7f1f0d76dd6 24 }
XinZhangMS 0:f7f1f0d76dd6 25 else if (opcode > 0x0F)
XinZhangMS 0:f7f1f0d76dd6 26 {
XinZhangMS 0:f7f1f0d76dd6 27 /* Codes_SRS_UWS_FRAME_ENCODER_01_006: [ If an unknown opcode is received, the receiving endpoint MUST _Fail the WebSocket Connection_. ]*/
XinZhangMS 0:f7f1f0d76dd6 28 LogError("Invalid opcode: 0x%02x", opcode);
XinZhangMS 0:f7f1f0d76dd6 29 result = NULL;
XinZhangMS 0:f7f1f0d76dd6 30 }
XinZhangMS 0:f7f1f0d76dd6 31 else if ((length > 0) &&
XinZhangMS 0:f7f1f0d76dd6 32 (payload == NULL))
XinZhangMS 0:f7f1f0d76dd6 33 {
XinZhangMS 0:f7f1f0d76dd6 34 /* Codes_SRS_UWS_FRAME_ENCODER_01_054: [ If `length` is greater than 0 and payload is NULL, then `uws_frame_encoder_encode` shall fail and return NULL. ]*/
XinZhangMS 0:f7f1f0d76dd6 35 LogError("Invalid arguments: NULL payload and length=%u", (unsigned int)length);
XinZhangMS 0:f7f1f0d76dd6 36 result = NULL;
XinZhangMS 0:f7f1f0d76dd6 37 }
XinZhangMS 0:f7f1f0d76dd6 38 else
XinZhangMS 0:f7f1f0d76dd6 39 {
XinZhangMS 0:f7f1f0d76dd6 40 size_t needed_bytes = 2;
XinZhangMS 0:f7f1f0d76dd6 41 size_t header_bytes;
XinZhangMS 0:f7f1f0d76dd6 42
XinZhangMS 0:f7f1f0d76dd6 43 /* Codes_SRS_UWS_FRAME_ENCODER_01_044: [ On success `uws_frame_encoder_encode` shall return a non-NULL handle to the result buffer. ]*/
XinZhangMS 0:f7f1f0d76dd6 44 /* Codes_SRS_UWS_FRAME_ENCODER_01_048: [ The newly created buffer shall be created by calling `BUFFER_new`. ]*/
XinZhangMS 0:f7f1f0d76dd6 45 result = BUFFER_new();
XinZhangMS 0:f7f1f0d76dd6 46 if (result == NULL)
XinZhangMS 0:f7f1f0d76dd6 47 {
XinZhangMS 0:f7f1f0d76dd6 48 /* Codes_SRS_UWS_FRAME_ENCODER_01_049: [ If `BUFFER_new` fails then `uws_frame_encoder_encode` shall fail and return NULL. ]*/
XinZhangMS 0:f7f1f0d76dd6 49 LogError("Cannot create new buffer");
XinZhangMS 0:f7f1f0d76dd6 50 }
XinZhangMS 0:f7f1f0d76dd6 51 else
XinZhangMS 0:f7f1f0d76dd6 52 {
XinZhangMS 0:f7f1f0d76dd6 53 /* Codes_SRS_UWS_FRAME_ENCODER_01_001: [ `uws_frame_encoder_encode` shall encode the information given in `opcode`, `payload`, `length`, `is_masked`, `is_final` and `reserved` according to the RFC6455 into a new buffer.]*/
XinZhangMS 0:f7f1f0d76dd6 54 if (length > 65535)
XinZhangMS 0:f7f1f0d76dd6 55 {
XinZhangMS 0:f7f1f0d76dd6 56 needed_bytes += 8;
XinZhangMS 0:f7f1f0d76dd6 57 }
XinZhangMS 0:f7f1f0d76dd6 58 else if (length > 125)
XinZhangMS 0:f7f1f0d76dd6 59 {
XinZhangMS 0:f7f1f0d76dd6 60 needed_bytes += 2;
XinZhangMS 0:f7f1f0d76dd6 61 }
XinZhangMS 0:f7f1f0d76dd6 62
XinZhangMS 0:f7f1f0d76dd6 63 if (is_masked)
XinZhangMS 0:f7f1f0d76dd6 64 {
XinZhangMS 0:f7f1f0d76dd6 65 needed_bytes += 4;
XinZhangMS 0:f7f1f0d76dd6 66 }
XinZhangMS 0:f7f1f0d76dd6 67
XinZhangMS 0:f7f1f0d76dd6 68 header_bytes = needed_bytes;
XinZhangMS 0:f7f1f0d76dd6 69 needed_bytes += length;
XinZhangMS 0:f7f1f0d76dd6 70
XinZhangMS 0:f7f1f0d76dd6 71 /* Codes_SRS_UWS_FRAME_ENCODER_01_046: [ The result buffer shall be resized accordingly using `BUFFER_enlarge`. ]*/
XinZhangMS 0:f7f1f0d76dd6 72 if (BUFFER_enlarge(result, needed_bytes) != 0)
XinZhangMS 0:f7f1f0d76dd6 73 {
XinZhangMS 0:f7f1f0d76dd6 74 /* Codes_SRS_UWS_FRAME_ENCODER_01_047: [ If `BUFFER_enlarge` fails then `uws_frame_encoder_encode` shall fail and return NULL. ]*/
XinZhangMS 0:f7f1f0d76dd6 75 LogError("Cannot allocate memory for encoded frame");
XinZhangMS 0:f7f1f0d76dd6 76 BUFFER_delete(result);
XinZhangMS 0:f7f1f0d76dd6 77 result = NULL;
XinZhangMS 0:f7f1f0d76dd6 78 }
XinZhangMS 0:f7f1f0d76dd6 79 else
XinZhangMS 0:f7f1f0d76dd6 80 {
XinZhangMS 0:f7f1f0d76dd6 81 /* Codes_SRS_UWS_FRAME_ENCODER_01_050: [ The allocated memory shall be accessed by calling `BUFFER_u_char`. ]*/
XinZhangMS 0:f7f1f0d76dd6 82 unsigned char* buffer = BUFFER_u_char(result);
XinZhangMS 0:f7f1f0d76dd6 83 if (buffer == NULL)
XinZhangMS 0:f7f1f0d76dd6 84 {
XinZhangMS 0:f7f1f0d76dd6 85 /* Codes_SRS_UWS_FRAME_ENCODER_01_051: [ If `BUFFER_u_char` fails then `uws_frame_encoder_encode` shall fail and return a NULL. ]*/
XinZhangMS 0:f7f1f0d76dd6 86 LogError("Cannot get encoded buffer pointer");
XinZhangMS 0:f7f1f0d76dd6 87 BUFFER_delete(result);
XinZhangMS 0:f7f1f0d76dd6 88 result = NULL;
XinZhangMS 0:f7f1f0d76dd6 89 }
XinZhangMS 0:f7f1f0d76dd6 90 else
XinZhangMS 0:f7f1f0d76dd6 91 {
XinZhangMS 0:f7f1f0d76dd6 92 /* Codes_SRS_UWS_FRAME_ENCODER_01_007: [ * %x0 denotes a continuation frame ]*/
XinZhangMS 0:f7f1f0d76dd6 93 /* Codes_SRS_UWS_FRAME_ENCODER_01_008: [ * %x1 denotes a text frame ]*/
XinZhangMS 0:f7f1f0d76dd6 94 /* Codes_SRS_UWS_FRAME_ENCODER_01_009: [ * %x2 denotes a binary frame ]*/
XinZhangMS 0:f7f1f0d76dd6 95 /* Codes_SRS_UWS_FRAME_ENCODER_01_010: [ * %x3-7 are reserved for further non-control frames ]*/
XinZhangMS 0:f7f1f0d76dd6 96 /* Codes_SRS_UWS_FRAME_ENCODER_01_011: [ * %x8 denotes a connection close ]*/
XinZhangMS 0:f7f1f0d76dd6 97 /* Codes_SRS_UWS_FRAME_ENCODER_01_012: [ * %x9 denotes a ping ]*/
XinZhangMS 0:f7f1f0d76dd6 98 /* Codes_SRS_UWS_FRAME_ENCODER_01_013: [ * %xA denotes a pong ]*/
XinZhangMS 0:f7f1f0d76dd6 99 /* Codes_SRS_UWS_FRAME_ENCODER_01_014: [ * %xB-F are reserved for further control frames ]*/
XinZhangMS 0:f7f1f0d76dd6 100 buffer[0] = (unsigned char)opcode;
XinZhangMS 0:f7f1f0d76dd6 101
XinZhangMS 0:f7f1f0d76dd6 102 /* Codes_SRS_UWS_FRAME_ENCODER_01_002: [ Indicates that this is the final fragment in a message. ]*/
XinZhangMS 0:f7f1f0d76dd6 103 /* Codes_SRS_UWS_FRAME_ENCODER_01_003: [ The first fragment MAY also be the final fragment. ]*/
XinZhangMS 0:f7f1f0d76dd6 104 if (is_final)
XinZhangMS 0:f7f1f0d76dd6 105 {
XinZhangMS 0:f7f1f0d76dd6 106 buffer[0] |= 0x80;
XinZhangMS 0:f7f1f0d76dd6 107 }
XinZhangMS 0:f7f1f0d76dd6 108
XinZhangMS 0:f7f1f0d76dd6 109 /* Codes_SRS_UWS_FRAME_ENCODER_01_004: [ MUST be 0 unless an extension is negotiated that defines meanings for non-zero values. ]*/
XinZhangMS 0:f7f1f0d76dd6 110 buffer[0] |= reserved << 4;
XinZhangMS 0:f7f1f0d76dd6 111
XinZhangMS 0:f7f1f0d76dd6 112 /* Codes_SRS_UWS_FRAME_ENCODER_01_022: [ Note that in all cases, the minimal number of bytes MUST be used to encode the length, for example, the length of a 124-byte-long string can't be encoded as the sequence 126, 0, 124. ]*/
XinZhangMS 0:f7f1f0d76dd6 113 /* Codes_SRS_UWS_FRAME_ENCODER_01_018: [ The length of the "Payload data", in bytes: ]*/
XinZhangMS 0:f7f1f0d76dd6 114 /* Codes_SRS_UWS_FRAME_ENCODER_01_023: [ The payload length is the length of the "Extension data" + the length of the "Application data". ]*/
XinZhangMS 0:f7f1f0d76dd6 115 /* Codes_SRS_UWS_FRAME_ENCODER_01_042: [ The payload length, indicated in the framing as frame-payload-length, does NOT include the length of the masking key. ]*/
XinZhangMS 0:f7f1f0d76dd6 116 if (length > 65535)
XinZhangMS 0:f7f1f0d76dd6 117 {
XinZhangMS 0:f7f1f0d76dd6 118 /* Codes_SRS_UWS_FRAME_ENCODER_01_020: [ If 127, the following 8 bytes interpreted as a 64-bit unsigned integer (the most significant bit MUST be 0) are the payload length. ]*/
XinZhangMS 0:f7f1f0d76dd6 119 buffer[1] = 127;
XinZhangMS 0:f7f1f0d76dd6 120
XinZhangMS 0:f7f1f0d76dd6 121 /* Codes_SRS_UWS_FRAME_ENCODER_01_021: [ Multibyte length quantities are expressed in network byte order. ]*/
XinZhangMS 0:f7f1f0d76dd6 122 buffer[2] = (unsigned char)((uint64_t)length >> 56) & 0xFF;
XinZhangMS 0:f7f1f0d76dd6 123 buffer[3] = (unsigned char)((uint64_t)length >> 48) & 0xFF;
XinZhangMS 0:f7f1f0d76dd6 124 buffer[4] = (unsigned char)((uint64_t)length >> 40) & 0xFF;
XinZhangMS 0:f7f1f0d76dd6 125 buffer[5] = (unsigned char)((uint64_t)length >> 32) & 0xFF;
XinZhangMS 0:f7f1f0d76dd6 126 buffer[6] = (unsigned char)((uint64_t)length >> 24) & 0xFF;
XinZhangMS 0:f7f1f0d76dd6 127 buffer[7] = (unsigned char)((uint64_t)length >> 16) & 0xFF;
XinZhangMS 0:f7f1f0d76dd6 128 buffer[8] = (unsigned char)((uint64_t)length >> 8) & 0xFF;
XinZhangMS 0:f7f1f0d76dd6 129 buffer[9] = (unsigned char)(length & 0xFF);
XinZhangMS 0:f7f1f0d76dd6 130 }
XinZhangMS 0:f7f1f0d76dd6 131 else if (length > 125)
XinZhangMS 0:f7f1f0d76dd6 132 {
XinZhangMS 0:f7f1f0d76dd6 133 /* Codes_SRS_UWS_FRAME_ENCODER_01_019: [ If 126, the following 2 bytes interpreted as a 16-bit unsigned integer are the payload length. ]*/
XinZhangMS 0:f7f1f0d76dd6 134 buffer[1] = 126;
XinZhangMS 0:f7f1f0d76dd6 135
XinZhangMS 0:f7f1f0d76dd6 136 /* Codes_SRS_UWS_FRAME_ENCODER_01_021: [ Multibyte length quantities are expressed in network byte order. ]*/
XinZhangMS 0:f7f1f0d76dd6 137 buffer[2] = (unsigned char)(length >> 8);
XinZhangMS 0:f7f1f0d76dd6 138 buffer[3] = (unsigned char)(length & 0xFF);
XinZhangMS 0:f7f1f0d76dd6 139 }
XinZhangMS 0:f7f1f0d76dd6 140 else
XinZhangMS 0:f7f1f0d76dd6 141 {
XinZhangMS 0:f7f1f0d76dd6 142 /* Codes_SRS_UWS_FRAME_ENCODER_01_043: [ if 0-125, that is the payload length. ]*/
XinZhangMS 0:f7f1f0d76dd6 143 buffer[1] = (unsigned char)length;
XinZhangMS 0:f7f1f0d76dd6 144 }
XinZhangMS 0:f7f1f0d76dd6 145
XinZhangMS 0:f7f1f0d76dd6 146 if (is_masked)
XinZhangMS 0:f7f1f0d76dd6 147 {
XinZhangMS 0:f7f1f0d76dd6 148 /* Codes_SRS_UWS_FRAME_ENCODER_01_015: [ Defines whether the "Payload data" is masked. ]*/
XinZhangMS 0:f7f1f0d76dd6 149 /* Codes_SRS_UWS_FRAME_ENCODER_01_033: [ A masked frame MUST have the field frame-masked set to 1, as defined in Section 5.2. ]*/
XinZhangMS 0:f7f1f0d76dd6 150 buffer[1] |= 0x80;
XinZhangMS 0:f7f1f0d76dd6 151
XinZhangMS 0:f7f1f0d76dd6 152 /* Codes_SRS_UWS_FRAME_ENCODER_01_053: [ In order to obtain a 32 bit value for masking, `gb_rand` shall be used 4 times (for each byte). ]*/
XinZhangMS 0:f7f1f0d76dd6 153 /* Codes_SRS_UWS_FRAME_ENCODER_01_016: [ If set to 1, a masking key is present in masking-key, and this is used to unmask the "Payload data" as per Section 5.3. ]*/
XinZhangMS 0:f7f1f0d76dd6 154 /* Codes_SRS_UWS_FRAME_ENCODER_01_026: [ This field is present if the mask bit is set to 1 and is absent if the mask bit is set to 0. ]*/
XinZhangMS 0:f7f1f0d76dd6 155 /* Codes_SRS_UWS_FRAME_ENCODER_01_034: [ The masking key is contained completely within the frame, as defined in Section 5.2 as frame-masking-key. ]*/
XinZhangMS 0:f7f1f0d76dd6 156 /* Codes_SRS_UWS_FRAME_ENCODER_01_036: [ The masking key is a 32-bit value chosen at random by the client. ]*/
XinZhangMS 0:f7f1f0d76dd6 157 /* Codes_SRS_UWS_FRAME_ENCODER_01_037: [ When preparing a masked frame, the client MUST pick a fresh masking key from the set of allowed 32-bit values. ]*/
XinZhangMS 0:f7f1f0d76dd6 158 /* Codes_SRS_UWS_FRAME_ENCODER_01_038: [ The masking key needs to be unpredictable; thus, the masking key MUST be derived from a strong source of entropy, and the masking key for a given frame MUST NOT make it simple for a server/proxy to predict the masking key for a subsequent frame. ]*/
XinZhangMS 0:f7f1f0d76dd6 159 buffer[header_bytes - 4] = (unsigned char)gb_rand();
XinZhangMS 0:f7f1f0d76dd6 160 buffer[header_bytes - 3] = (unsigned char)gb_rand();
XinZhangMS 0:f7f1f0d76dd6 161 buffer[header_bytes - 2] = (unsigned char)gb_rand();
XinZhangMS 0:f7f1f0d76dd6 162 buffer[header_bytes - 1] = (unsigned char)gb_rand();
XinZhangMS 0:f7f1f0d76dd6 163 }
XinZhangMS 0:f7f1f0d76dd6 164
XinZhangMS 0:f7f1f0d76dd6 165 if (length > 0)
XinZhangMS 0:f7f1f0d76dd6 166 {
XinZhangMS 0:f7f1f0d76dd6 167 if (is_masked)
XinZhangMS 0:f7f1f0d76dd6 168 {
XinZhangMS 0:f7f1f0d76dd6 169 size_t i;
XinZhangMS 0:f7f1f0d76dd6 170
XinZhangMS 0:f7f1f0d76dd6 171 /* Codes_SRS_UWS_FRAME_ENCODER_01_035: [ It is used to mask the "Payload data" defined in the same section as frame-payload-data, which includes "Extension data" and "Application data". ]*/
XinZhangMS 0:f7f1f0d76dd6 172 /* Codes_SRS_UWS_FRAME_ENCODER_01_039: [ To convert masked data into unmasked data, or vice versa, the following algorithm is applied. ]*/
XinZhangMS 0:f7f1f0d76dd6 173 /* Codes_SRS_UWS_FRAME_ENCODER_01_040: [ The same algorithm applies regardless of the direction of the translation, e.g., the same steps are applied to mask the data as to unmask the data. ]*/
XinZhangMS 0:f7f1f0d76dd6 174 for (i = 0; i < length; i++)
XinZhangMS 0:f7f1f0d76dd6 175 {
XinZhangMS 0:f7f1f0d76dd6 176 /* Codes_SRS_UWS_FRAME_ENCODER_01_041: [ Octet i of the transformed data ("transformed-octet-i") is the XOR of octet i of the original data ("original-octet-i") with octet at index i modulo 4 of the masking key ("masking-key-octet-j"): ]*/
XinZhangMS 0:f7f1f0d76dd6 177 buffer[header_bytes + i] = ((unsigned char*)payload)[i] ^ buffer[header_bytes - 4 + (i % 4)];
XinZhangMS 0:f7f1f0d76dd6 178 }
XinZhangMS 0:f7f1f0d76dd6 179 }
XinZhangMS 0:f7f1f0d76dd6 180 else
XinZhangMS 0:f7f1f0d76dd6 181 {
XinZhangMS 0:f7f1f0d76dd6 182 (void)memcpy(buffer + header_bytes, payload, length);
XinZhangMS 0:f7f1f0d76dd6 183 }
XinZhangMS 0:f7f1f0d76dd6 184 }
XinZhangMS 0:f7f1f0d76dd6 185 }
XinZhangMS 0:f7f1f0d76dd6 186 }
XinZhangMS 0:f7f1f0d76dd6 187 }
XinZhangMS 0:f7f1f0d76dd6 188 }
XinZhangMS 0:f7f1f0d76dd6 189
XinZhangMS 0:f7f1f0d76dd6 190 return result;
XinZhangMS 0:f7f1f0d76dd6 191 }