At Tue, 23 Jul 2019 21:14:21 -0700 (PDT) [email protected] wrote:
>
>
>
> Hi,
>
> I am using beagle bone black board in Linux ubuntu 16.04LTS, i need to work
> on Ethernet .
>
> requirement is like enabling Ethernet between the Board and PC and i need
> to send the data from PC and need to receive the data on beagle bone black
> using Ethernet communication and once data collected that data i need to
> pass to the other PC using Uart..
>
> Uart enabling and transmitting the data i understood...
>
> please tell me how to configure Ethernet and C program to receive the data
> from Ethernet....
>
> please suggest me any related link for this....
Well... You probably don't want to delve into raw Ethernet. What you want to
do is implement some sort of Tcp/Ip data transfer and let the kernel(s) sweat
the details.
Tcp/Ip uses a client / server model: one side is the "server" and the other is
the "client". The server is a little more complicated than the client.
To implement a "server" process, you need to creating a socket, bind it to a
port [number] and then listen on it and when someone connects to the port (the
client), you then start communicating.
In C you would use these functions:
socket() -- create a socket
bind() -- bind it to an address & port
listen() -- listen for connections
accept() -- accept a connection to the client
Then:
read() and write() to actually transfer data, then close() when done.
Minimial C program would look something like this:
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <string.h>
#include <sys/poll.h>
#define ERRORCHECK(funcall,message) \
if ((funcall) < 0) { \
int err = errno; \
perror(message); \
exit(err); \
}
#define PORT 10000 /* Port we will be listening on. */
int do_dataTransfer(int connection,struct sockaddr_in *fromAddress);
int main(int argc, char *argv[])
{
int listenSock, connectSock, pstatus;
struct sockaddr_in my_addr, peer_addr;
socklen_t peer_addr_size;
struct pollfd ufd;
/* Create a socket */
listenSock = socket(AF_INET, SOCK_STREAM|SOCK_NONBLOCK,0);
ERRORCHECK(listenSock,"Failed to create socket")
memset(&my_addr,0,sizeof(my_addr)); /* clear out the address */
my_addr.sin_addr.s_addr = htonl(INADDR_ANY); /* listen on all addresses */
my_addr.sin_port = htons(PORT);
my_addr.sin_family = AF_INET;
/* Bind the address to a port */
ERRORCHECK(bind(listenSock,(const struct
sockaddr*)&my_addr,sizeof(my_addr)))
/* Listen for clients */
ERRORCHECK(listen(listenSock,1) /* backlog of one: only one client at a
time */
/* Check to see if anyone wants to talk to us */
while (1) {
ufd.fd = listenSock;
ufd.events = POLLIN;
pstatus = poll(&ufd,1,10);
ERRORCHECK(pstatus,"Poll failed");
if (pstatus > 0) {
/* Someone wants to talk, connect to his socket */
connectSock = accept(listenSock,(struct
sockaddr*)&peer_addr,&peer_addr_size);
ERRORCHECK(connectSock,"Accept failed");
if (connectSock > 0) {
/* We are connected. Now we can talk to each other. */
do_dataTransfer(connectSock,&peer_addr);
}
}
usleep(50000); /* sleep 50 ms */
}
}
The client program would use socket() to create the socket, then connect() to
connect it to a server. And then read() and write() to transfer data and
finally close() to close the connection.
On most Linux machines, there are man pages for all of these functions (in
section 2). There are probably zillions of example programs out on the
Internet as well.
--
Robert Heller -- 978-544-6933
Deepwoods Software -- Custom Software Services
http://www.deepsoft.com/ -- Linux Administration Services
[email protected] -- Webhosting Services
--
For more options, visit http://beagleboard.org/discuss
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