web socket RFC6455 frame 打包、解包

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#ifndef __APP_WEBSOCKET_FRAME_H__#define __APP_WEBSOCKET_FRAME_H__#include "memory.hpp"class buffer;struct websocket_frame{websocket_frame();~websocket_frame();static const unsigned int fix_min_len = 2;static const unsigned int fix_masking_len = 4;static const unsigned int fix_126_len = 2;static const unsigned int fix_127_len = 8;bool fin;bool rsv1;bool rsv2;bool rsv3;unsigned char opcode;bool mask;unsigned char payload_len ;unsigned short payload_126_len;unsigned long long payload_127_len;unsigned char ??masking_key[4];shared_ptr<buffer> payload;unsigned int get_head_len() const ;unsigned int get_total_len() const ;unsigned int get_payload_len() const ;//解包int unpakcage( const shared_ptr<buffer> & buf );//打包unsigned int package_size() ;shared_ptr<buffer> package() ;protected:void set_masking_key( unsigned char * data, int offset);void get_masking_key( unsigned char * data, int offset);};#endif

#include "websocket_frame.hpp"#include "buffer_pool.hpp"#include <cstring>#include <glog/logging.h>#include <cstdlib>websocket_frame::websocket_frame():fin(false),rsv1(false),rsv2(false),rsv3(false),mask(false),opcode(0),payload_len(0),payload_126_len(0),payload_127_len(0){int rand_var = rand();masking_key[0] = (rand_var & 0xff000000)>>24;masking_key[1] = (rand_var & 0x00ff0000) >> 16;masking_key[2] = ( rand_var & 0x0000ff00) >> 8;masking_key[3] = rand_var & 0x000000ff;}websocket_frame::~websocket_frame(){if( payload ){recycle_buffer(payload);}}void websocket_frame::set_masking_key( unsigned char * data, int offset){masking_key[0] = data[0+offset];masking_key[1] = data[1+offset];masking_key[2] = data[2+offset];masking_key[3] = data[3+offset];}void websocket_frame:: get_masking_key( unsigned char * data, int offset){ data[0+offset] = masking_key[0]; data[1+offset] = masking_key[1] ; data[2+offset] = masking_key[2]; data[3+offset] = masking_key[3] ;}unsigned int websocket_frame::get_head_len() const {return get_total_len() - get_payload_len();}unsigned int websocket_frame::get_total_len() const {if( mask ){if( payload_len < 126 ){return payload_len + fix_min_len + fix_masking_len;}else if( payload_len == 126 ){return payload_126_len + fix_min_len + fix_masking_len + fix_126_len;}else {return payload_127_len +fix_min_len + fix_masking_len + fix_127_len;}}else{if( payload_len < 126 ){return payload_len + fix_min_len;}else if( payload_len == 126 ){return payload_126_len + fix_min_len + fix_126_len;}else {return payload_127_len + fix_min_len + fix_127_len;}}}unsigned int websocket_frame::get_payload_len() const {if( payload_len < 126 ){return payload_len;}else if( payload_len == 126 ){return payload_126_len;}else {return payload_127_len;}}int websocket_frame::unpakcage( const shared_ptr<buffer> & buf ){if( buf->length() == 0 ){return 2;}unsigned char * data = buf->data();fin = data[0] & 0x80;rsv1 = data[0] & (0x40 ?);rsv2 = data[0] & ( 0x20);rsv3 = data[0] & ( 0x10);opcode = (data[0] & 0x0f) ;mask = data[1] & 0x80;payload_len = data[1] & 0x7f;if( payload_len < 126 ){if( buf->length() < get_total_len() ){return get_total_len() - buf->length();}payload = get_buffer( get_payload_len());unsigned char * pdata = payload->data();if( mask ){set_masking_key(data,2);int i;for( i = 0 ; i < payload_len; i ++ ){pdata[i] = data[6+i] ^ masking_key[i%4];}}else{memcpy(pdata, data+2, get_payload_len());}payload->size(get_payload_len());}else if( payload_len == 126 ){if( buf->length() < 4 ){return 4 - buf->length();}payload_126_len = (data[2] << 8 )| data[3];if( buf->length() < get_total_len() ){return get_total_len() - buf->length();}payload = get_buffer( get_payload_len());unsigned char * pdata = payload->data();if( mask ){set_masking_key(data,4);int i;for( i = 0 ; i < payload_126_len; i ++ ){pdata[i] = data[8+i] ^ masking_key[i%4];}}else{memcpy(pdata, data+4, get_payload_len());}payload->size(get_payload_len());}else{ // 127LOG(FATAL)<<"un support big frame for websocket.";}return 0;}unsigned int websocket_frame::package_size() {if( payload->length() < 126 ){payload_len = payload->length();}else if( payload->length() < 0xffff ){payload_len = 126;payload_126_len = payload->length();}else{payload_len = 127;payload_127_len = payload->length();}return get_total_len();}shared_ptr<buffer> websocket_frame::package() {shared_ptr<buffer> buf = get_buffer( package_size());buf->size(package_size());unsigned char * data = buf->data();data[0] = 0;if( fin ){data[0] |= 0x80;}if( rsv1 ){data[0] |= 0x40;}if( rsv2 ){data[0] |= 0x20;}if( rsv3 ) {data[0] |= 0x10;}data[0] |= (opcode & 0x0f);data[1] = 0;if( mask ){data[1] |= 0x80;}data[1] |=( payload_len & 0x7f);unsigned char * pdata = payload->data();if( payload_len < 126 ){if( mask ){//get_masking_key(data,2);data[2] = masking_key[0];data[3] = masking_key[1];data[4] = masking_key[2];data[5] = masking_key[3];int i = 0;for( i = 0 ; i < payload_len; i ++ ){data[6+i] = pdata[i] ^ masking_key[i%4];}}else{memcpy(data+2, pdata,payload_len);}}else if( payload_len == 126 ){data[2] =(unsigned char)( (payload_126_len & 0xff00) >> 8);data[3] =(unsigned char) (payload_126_len & 0x00ff);if( mask ){data[4] = masking_key[0];data[5] = masking_key[1];data[6] = masking_key[2];data[7] = masking_key[3];int i = 0;for( i = 0 ; i < payload_126_len; i ++ ){data[8+i] = pdata[i] ^ masking_key[i%4];}}else{memcpy(data+4, pdata,payload_126_len);}}else if( payload_len == 127 ){LOG(FATAL)<<"no support 127 web socket frame.";}return buf;}

重点在unpakcage方法，该方法在解包成功时，返回0。失败时，返回还须要多少字节才干够解析一个完整的包。

另外临时没有计算payload_len=127情况下，主要是大部分环境下不须要用到那么大。解包成功后。get_head_len、get_total_len、get_payload_len调用时，都能够返回正确的数据，假设unpackage返回大于0时，调用关于len的函数是属于非法的。。

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