Re: Programming in C with Bluetooth Sockets
凌伟泽
Re: Programming in C with Bluetooth Sockets
This is the function run by the bluetooth device that will recieve the data.
char* BT_Target()
{
int s, client, bytes_read, count = 0;
char * buf;
struct sockaddr_rc loc_addr = { 0 }, rem_addr = { 0 };
int opt = sizeof(rem_addr);
unsigned int max_count;
//attempt to allocate reception buffer
buf = (char *)calloc(MAX_MSG, 1);
if(buf == NULL)
{
perror("No memory!");
return("No memory!");
}
//attempt to allocate socket
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("socket failed to open:");
return("socket failed to open");
}
loc_addr.rc_family = AF_BLUETOOTH;
loc_addr.rc_bdaddr = *BDADDR_ANY;
loc_addr.rc_channel = (uint8_t) RFCOMM_CHANNEL;
//attempt to bind the socket for a maximum number of attempts
for( count = 0; count < MAX_ATTEMPTS && bind(s, (struct sockaddr
*)&loc_addr, sizeof(loc_addr)) < 0; count++);
//if we tried to open the socket but failed
if( count == MAX_ATTEMPTS )
{
perror("unable to bind socket: ");
close(s);
free(buf);
return "unable to bind socket";
}
//attempt to listen
if(listen(s, 1) < 0)
{
perror("listen failed: ");
close(s);
free(buf);
return "listen failed.";
}
//attempt to accept the socket
rem_addr.rc_family = AF_BLUETOOTH;
rem_addr.rc_bdaddr = *BDADDR_ANY;
rem_addr.rc_channel = (uint8_t) RFCOMM_CHANNEL;
client = accept(s, (struct sockaddr *)&rem_addr, &opt);
//if we have created a connection
//we need to recieve the transmission length into max_count
if(client >= 0)
{
count = 0;
fprintf(stderr,"Got a connection\n");
read(client, &max_count, sizeof(unsigned int));
printf( "Message size: %d\n", max_count );
close( client );
}
//the accept has failed
else
{
perror("accept failed: ");
close(s);
free(buf);
return("accept failed");
}
//while we have not recieved the entire message, get the next part
while( count < max_count &&
( client = accept(s, (struct sockaddr*)&rem_addr, &opt) ) >= 0 )
{
bytes_read = read(client, buf + count, sizeof(buf) - count);
fprintf(stderr, "got %d bytes this time\n", bytes_read);
count += bytes_read;
fprintf(stderr, "recieved %d [%s] so far\n", count, buf);
close( client );
if(bytes_read < 0)
{
perror("socket issue.");
fprintf(stderr, "We have socket problems.\n");
close(s);
free(buf);
close(client);
return("We have socket Problems.");
}
}
close(s);
close(client);
return "Success";
}
And this is the function that will send the data.
char* BT_Source(char* fname, int iter, char* tMAC)
{
struct sockaddr_rc addr = { 0 };
int s, status, count = 0, fd;
char* dest = tMAC;
struct stat *stats;
unsigned int len = 0;
char* buf;
//attempt to allocate a socket
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating socket: ");
return "socket creation failed.";
}
// set the connection parameters (who to connect to)
addr.rc_family = AF_BLUETOOTH;
addr.rc_channel = (uint8_t) RFCOMM_CHANNEL;
fprintf(stderr, "The dest addr is now %s\n", dest);
str2ba(dest, &addr.rc_bdaddr);
//attempt to connect the socket for our maximum number of times
status = connect(s, (struct sockaddr *)&addr, sizeof(addr));
for(count = 0; status != 0 && count < MAX_ATTEMPTS;)
{
perror("retrying connection: ");
//if the socket is busy or the host is down, close and reopen
if(!(errno == EBUSY || errno == EHOSTDOWN))
{
close(s);
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating socket: ");
return "socket creation failed.";
}
count++;
}
status = connect(s, (struct sockaddr *)&addr, sizeof(addr));
}
//if the socket was opened properly, send a message
if(status == 0)
{
count = 0;
//get the file size and send it to the client
stat(fname, stats);
len = stats->st_size;
fprintf(stderr, "The length in bytes is %d\n", len);
write(s, &len, sizeof(unsigned int));
//open the file
if((fd = open(fname, O_RDONLY)) == NULL)
{
perror( "Cannot open file for reading" );
close( s );
return "failed";
}
//attempt to allocate reception buffer
buf = (char *)calloc( MAX_MSG + 1, 1 );
if( buf == NULL )
{
perror( "out of memory" );
close( fd );
close( s );
return "failed";
}
//while we still have message to send
while((in = read(fd, buf, MAX_MSG)) > 0)
{
//close previous socket connection to force a flush
close( s );
//allocate a socket
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating socket: ");
return "socket creation failed.";
}
//connect the socket
status = connect(s, (struct sockaddr *)&addr,
sizeof(addr));
for(count = 0; status != 0 && count < MAX_ATTEMPTS;)
{
perror("retrying connection: ");
if(!(errno == EBUSY || errno == EHOSTDOWN))
{
close(s);
s = socket(AF_BLUETOOTH,
SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating
socket: ");
return "socket creation failed.";
}
count++;
sleep( 1 );
}
status = connect(s, (struct sockaddr
*)&addr, sizeof(addr));
}
if( status < 0 )
{
perror("message failed: ");
close(s);
close(fd);
fprintf(stderr, "failed connecting, I
tried %d times.\n", count);
return "uh oh, that message did not go through";
}
//write the next message segment
fprintf(stderr,"data read '%s'\n", buf);
count = write(s, buf, MAX_MSG);
fprintf(stderr,"contents of in: %d, %d bytes
were written\n", in, count);
}
}
else if(status < 0)
{
perror("message failed: ");
close(s);
close(fd);
fprintf(stderr, "failed connecting, I tried %d times.\n", count);
return "uh oh, that message did not go through";
}
fprintf(stderr, "message sent\n");
close(s);
close(fd);
return strdup("Success");
}
This is the latest iteration where the connection is stopped after
each 4 byte transmission and restarted before the next.
-------------------------------------------------------
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Re: Programming in C with Bluetooth Sockets
This is the function run by the bluetooth device that will recieve the data.
char* BT_Target()
{
int s, client, bytes_read, count = 0;
char * buf;
struct sockaddr_rc loc_addr = { 0 }, rem_addr = { 0 };
int opt = sizeof(rem_addr);
unsigned int max_count;
//attempt to allocate reception buffer
buf = (char *)calloc(MAX_MSG, 1);
if(buf == NULL)
{
perror("No memory!");
return("No memory!");
}
//attempt to allocate socket
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("socket failed to open:");
return("socket failed to open");
}
loc_addr.rc_family = AF_BLUETOOTH;
loc_addr.rc_bdaddr = *BDADDR_ANY;
loc_addr.rc_channel = (uint8_t) RFCOMM_CHANNEL;
//attempt to bind the socket for a maximum number of attempts
for( count = 0; count < MAX_ATTEMPTS && bind(s, (struct sockaddr
*)&loc_addr, sizeof(loc_addr)) < 0; count++);
//if we tried to open the socket but failed
if( count == MAX_ATTEMPTS )
{
perror("unable to bind socket: ");
close(s);
free(buf);
return "unable to bind socket";
}
//attempt to listen
if(listen(s, 1) < 0)
{
perror("listen failed: ");
close(s);
free(buf);
return "listen failed.";
}
//attempt to accept the socket
rem_addr.rc_family = AF_BLUETOOTH;
rem_addr.rc_bdaddr = *BDADDR_ANY;
rem_addr.rc_channel = (uint8_t) RFCOMM_CHANNEL;
client = accept(s, (struct sockaddr *)&rem_addr, &opt);
//if we have created a connection
//we need to recieve the transmission length into max_count
if(client >= 0)
{
count = 0;
fprintf(stderr,"Got a connection\n");
read(client, &max_count, sizeof(unsigned int));
printf( "Message size: %d\n", max_count );
close( client );
}
//the accept has failed
else
{
perror("accept failed: ");
close(s);
free(buf);
return("accept failed");
}
//while we have not recieved the entire message, get the next part
while( count < max_count &&
( client = accept(s, (struct sockaddr*)&rem_addr, &opt) ) >= 0 )
{
bytes_read = read(client, buf + count, sizeof(buf) - count);
fprintf(stderr, "got %d bytes this time\n", bytes_read);
count += bytes_read;
fprintf(stderr, "recieved %d [%s] so far\n", count, buf);
close( client );
if(bytes_read < 0)
{
perror("socket issue.");
fprintf(stderr, "We have socket problems.\n");
close(s);
free(buf);
close(client);
return("We have socket Problems.");
}
}
close(s);
close(client);
return "Success";
}
And this is the function that will send the data.
char* BT_Source(char* fname, int iter, char* tMAC)
{
struct sockaddr_rc addr = { 0 };
int s, status, count = 0, fd;
char* dest = tMAC;
struct stat *stats;
unsigned int len = 0;
char* buf;
//attempt to allocate a socket
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating socket: ");
return "socket creation failed.";
}
// set the connection parameters (who to connect to)
addr.rc_family = AF_BLUETOOTH;
addr.rc_channel = (uint8_t) RFCOMM_CHANNEL;
fprintf(stderr, "The dest addr is now %s\n", dest);
str2ba(dest, &addr.rc_bdaddr);
//attempt to connect the socket for our maximum number of times
status = connect(s, (struct sockaddr *)&addr, sizeof(addr));
for(count = 0; status != 0 && count < MAX_ATTEMPTS;)
{
perror("retrying connection: ");
//if the socket is busy or the host is down, close and reopen
if(!(errno == EBUSY || errno == EHOSTDOWN))
{
close(s);
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating socket: ");
return "socket creation failed.";
}
count++;
}
status = connect(s, (struct sockaddr *)&addr, sizeof(addr));
}
//if the socket was opened properly, send a message
if(status == 0)
{
count = 0;
//get the file size and send it to the client
stat(fname, stats);
len = stats->st_size;
fprintf(stderr, "The length in bytes is %d\n", len);
write(s, &len, sizeof(unsigned int));
//open the file
if((fd = open(fname, O_RDONLY)) == NULL)
{
perror( "Cannot open file for reading" );
close( s );
return "failed";
}
//attempt to allocate reception buffer
buf = (char *)calloc( MAX_MSG + 1, 1 );
if( buf == NULL )
{
perror( "out of memory" );
close( fd );
close( s );
return "failed";
}
//while we still have message to send
while((in = read(fd, buf, MAX_MSG)) > 0)
{
//close previous socket connection to force a flush
close( s );
//allocate a socket
s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating socket: ");
return "socket creation failed.";
}
//connect the socket
status = connect(s, (struct sockaddr *)&addr,
sizeof(addr));
for(count = 0; status != 0 && count < MAX_ATTEMPTS;)
{
perror("retrying connection: ");
if(!(errno == EBUSY || errno == EHOSTDOWN))
{
close(s);
s = socket(AF_BLUETOOTH,
SOCK_STREAM, BTPROTO_RFCOMM);
if(s < 0)
{
perror("error creating
socket: ");
return "socket creation failed.";
}
count++;
sleep( 1 );
}
status = connect(s, (struct sockaddr
*)&addr, sizeof(addr));
}
if( status < 0 )
{
perror("message failed: ");
close(s);
close(fd);
fprintf(stderr, "failed connecting, I
tried %d times.\n", count);
return "uh oh, that message did not go through";
}
//write the next message segment
fprintf(stderr,"data read '%s'\n", buf);
count = write(s, buf, MAX_MSG);
fprintf(stderr,"contents of in: %d, %d bytes
were written\n", in, count);
}
}
else if(status < 0)
{
perror("message failed: ");
close(s);
close(fd);
fprintf(stderr, "failed connecting, I tried %d times.\n", count);
return "uh oh, that message did not go through";
}
fprintf(stderr, "message sent\n");
close(s);
close(fd);
return strdup("Success");
}
This is the latest iteration where the connection is stopped after
each 4 byte transmission and restarted before the next.
-------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid0709&bid&3057&dat1642
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