web socket RFC6455 frame 打包、解包
2024-10-14 04:23:17
#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{ // 127
LOG(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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