socket.c

minix操作系统最新版本（3.1.1）的源代码

#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>

#include <net/netlib.h>
#include <netinet/in.h>

#define DEBUG 0

static int _tcp_socket(int protocol);
static int _udp_socket(int protocol);

int socket(int domain, int type, int protocol)
{
#if DEBUG
	fprintf(stderr, "socket: domain %d, type %d, protocol %d\n",
		domain, type, protocol);
#endif
	if (domain != AF_INET)
	{
#if DEBUG
		fprintf(stderr, "socket: bad domain %d\n", domain);
#endif
		errno= EAFNOSUPPORT;
		return -1;
	}
	if (type == SOCK_STREAM)
		return _tcp_socket(protocol);

	if (type == SOCK_DGRAM)
		return _udp_socket(protocol);

#if DEBUG
	fprintf(stderr, "socket: nothing for domain %d, type %d, protocol %d\n",
		domain, type, protocol);
#endif
	errno= EPROTOTYPE;
	return -1;
}

static int _tcp_socket(int protocol)
{
	int fd;
	if (protocol != 0 && protocol != IPPROTO_TCP)
	{
#if DEBUG
		fprintf(stderr, "socket(tcp): bad protocol %d\n", protocol);
#endif
		errno= EPROTONOSUPPORT;
		return -1;
	}
	fd= open(TCP_DEVICE, O_RDWR);
	return fd;
}

static int _udp_socket(int protocol)
{
	int r, fd, t_errno;
	struct sockaddr_in sin;

	if (protocol != 0 && protocol != IPPROTO_UDP)
	{
#if DEBUG
		fprintf(stderr, "socket(udp): bad protocol %d\n", protocol);
#endif
		errno= EPROTONOSUPPORT;
		return -1;
	}
	fd= open(UDP_DEVICE, O_RDWR);
	if (fd == -1)
		return fd;

	/* Bind is implict for UDP sockets? */
	sin.sin_family= AF_INET;
	sin.sin_addr.s_addr= INADDR_ANY;
	sin.sin_port= 0;
	r= bind(fd, (struct sockaddr *)&sin, sizeof(sin));
	if (r != 0)
	{
		t_errno= errno;
		close(fd);
		errno= t_errno;
		return -1;
	}
	return fd;
}