ntee.c

#include <sys/types.h>
#include <sys/sendfile.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <fcntl.h>

#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#define PORT	8080

int
main(int argc, char **argv)
{
	int			 listen_sock, client, file, sock2;
	unsigned short		 bind_port = PORT;
	struct sockaddr_in	 in_addr, client_addr;
#if 0
	char			 buf[256];
#endif
	char			*filename = "file.out";
	int			 sockopt = 1;
	socklen_t		 addrlen;

	int			 pipe_file[2], pipe_socket[2];

	listen_sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	assert(listen_sock >= 0);
	setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &sockopt, sizeof(sockopt));

	memset(&in_addr, 0, sizeof(in_addr));
	in_addr.sin_family = AF_INET;
	in_addr.sin_port = htons(bind_port);

	assert(bind(listen_sock, &in_addr, sizeof(in_addr)) == 0);
	assert(listen(listen_sock, 16) == 0);

	client = accept(listen_sock, &client_addr, &addrlen);
	assert(client >= 0);

	sock2 = socket(AF_INET, SOCK_DGRAM, 0);
	assert(sock2 >= 0);
	client_addr.sin_port = htons(8181);
	connect(sock2, &client_addr, addrlen);

	int		opt;
	socklen_t	olen = sizeof(opt);

	getsockopt(sock2, SOL_SOCKET, SO_SNDLOWAT, &opt, &olen); 
	printf("lowat: %d\n", opt);
	getsockopt(sock2, SOL_SOCKET, SO_SNDBUF, &opt, &olen); 
	printf("sndbuf: %d\n", opt);

	file = open(filename, O_CREAT|O_RDWR, 0664);
	if (file == -1) {
		perror("open");
		return 1;
	}

	pipe(pipe_file);
	pipe(pipe_socket);

	ssize_t len;
	int flags = 0; /* SPLICE_F_NONBLOCK */

	len = splice(client, NULL, pipe_file[1], NULL, INT_MAX, flags);
	printf("splice client->file pipe: %ld\n", len);

	len = tee(pipe_file[0], pipe_socket[1], INT_MAX, flags);
	printf("tee file->socket: %ld\n", len);

	len = splice(pipe_file[0], NULL, file, NULL, INT_MAX, flags);
	printf("splice pipe->file: %ld\n", len);

	len = splice(pipe_socket[0], NULL, sock2, NULL, INT_MAX, flags);
	printf("splice pipe->socket: %ld\n", len);

#if 0
	char buf[] = "otherdata";
	write(sock2, buf, sizeof(buf) - 1);
#endif

	close(pipe_file[0]);
	close(pipe_file[1]);
	close(pipe_socket[0]);
	close(pipe_socket[1]);
	close(sock2);
	close(file);
	close(client);
	close(listen_sock);

	return 0;
}