ant-http/plugins/ws.c

186 lines
4.5 KiB
C
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#include "ws.h"
/**
* Read a frame header
* based on this header, we'll decide
* the appropriate handle for frame data
*/
ws_msg_header_t * ws_read_header(int client)
{
uint8_t byte;
uint8_t bytes[8];
ws_msg_header_t* header = (ws_msg_header_t*) malloc(sizeof(*header));
// get first byte
if(recv(client, &byte, sizeof(byte), 0) <0) goto fail;
if(BITV(byte,6) || BITV(byte,5) || BITV(byte,4)) goto fail;// all RSV bit must be 0
//printf("FIN: %d, RSV1: %d, RSV2: %d, RSV3:%d, opcode:%d\n", BITV(byte,7), BITV(byte,6), BITV(byte,5), BITV(byte,4),(byte & 0x0F) );
// find and opcode
header->fin = BITV(byte,7);
header->opcode = (byte & 0x0F);
// get next byte
if(recv(client, &byte, sizeof(byte), 0) <0) goto fail;
//printf("MASK: %d paylen:%d\n", BITV(byte,7), (byte & 0x7F));
// check mask bit, should be 1
if(!BITV(byte,7))
{
// close the connection with protocol error
ws_close(client, 1002);
goto fail;
}
// get the data length of the frame
int len = (byte & 0x7F);
if(len <= 125)
{
header->plen = len;
} else if(len == 126)
{
if(recv(client,bytes, 2*sizeof(uint8_t), 0) <0) goto fail;
header->plen = (bytes[0]<<8) + bytes[1];
} else
{
//read only last 4 byte
if(recv(client,bytes, 8*sizeof(uint8_t), 0) <0) goto fail;
header->plen = (bytes[4]<<24) + (bytes[5]<<16) + (bytes[6] << 8) + bytes[7] ;
}
//printf("len: %d\n", header->plen);
// last step is to get the maskey
if(recv(client,header->mask_key, 4*sizeof(uint8_t), 0) <0) goto fail;
//printf("key 0: %d key 1: %d key2:%d, key3: %d\n",header->mask_key[0],header->mask_key[1],header->mask_key[2], header->mask_key[3] );
// check wheather it is a ping or a close message
// process it and return NULL
//otherwise return the header
//return the header
switch(header->opcode){
case WS_CLOSE: // client requests to close the connection
// send back a close message
ws_close(client,1000);
//goto fail;
break;
case WS_PING: // client send a ping
// send back a pong message
pong(client,header->plen);
break;
default: break;
}
return header;
fail:
free(header);
return NULL;
}
/**
* Read data from client
* and unmask data using the key
*/
int ws_read_data(int client, ws_msg_header_t* header, int len, uint8_t* data)
{
// if len == -1 ==> read all remaining data to 'data';
if(header->plen == 0) return 0;
int dlen = (len==-1 || len > header->plen)?header->plen:len;
if((dlen = recv(client,data, dlen, 0)) <0) return -1;
header->plen = header->plen - dlen;
// unmask received data
for(int i = 0; i < dlen; ++i)
data[i] = data[i]^ header->mask_key[i%4];
return dlen;
}
void _send_header(int client, ws_msg_header_t header)
{
uint8_t byte = 0;
uint8_t bytes[8];
for(int i=0; i< 8; i++) bytes[i] = 0;
//first byte |FIN|000|opcode|
byte = (header.fin << 7) + header.opcode;
send(client, &byte, 1, 0);
// second byte, payload length
// mask = 0
if(header.plen <= 125)
{
byte = header.plen;
send(client, &byte, 1, 0);
}
else if(header.plen < 65536) // 16 bits
{
byte = 126;
bytes[0] = (header.plen) >> 8;
bytes[1] = (header.plen) & 0x00FF;
send(client, &byte, 1, 0);
send(client, &bytes, 2, 0);
}
else // > 16 bits
{
byte = 127;
bytes[4] = (header.plen) >> 24;
bytes[5] = ((header.plen)>>16) & 0x00FF;
bytes[6] = ((header.plen)>>8) & 0x00FF;
bytes[7] = (header.plen) & 0x00FF;
send(client, &byte, 1, 0);
send(client, &bytes, 8, 0);
}
}
/**
* send a text data frame to client
*/
void ws_t(int client, const char* data)
{
ws_msg_header_t header;
header.fin = 1;
header.opcode = WS_TEXT;
header.plen = strlen(data);
_send_header(client,header);
send(client, data, header.plen,0);
}
/**
* send a binary data fram to client
* not tested yet, but should work
*/
void ws_b(int client, uint8_t* data, int l)
{
ws_msg_header_t header;
header.fin = 1;
header.opcode = WS_BIN;
header.plen = l;
_send_header(client,header);
send(client, data, header.plen,0);
}
/**
* Not tested yet
* but should work
*/
void pong(int client, int len)
{
ws_msg_header_t pheader;
pheader.fin = 1;
pheader.opcode = WS_PONG;
pheader.plen = len;
uint8_t data[len];
if(recv(client,data, len, 0) < 0) return;
_send_header(client, pheader);
send(client, data, len, 0);
}
/*
* Not tested yet, but should work
*/
void ws_close(int client, unsigned int status)
{
ws_msg_header_t header;
header.fin = 1;
header.opcode = WS_CLOSE;
header.plen = 2;
uint8_t bytes[2];
bytes[0] = status >> 8;
bytes[1] = status & 0xFF;
_send_header(client, header);
send(client,bytes,2,0);
}