ntp_io.c

网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下

/*
 * ntp_io.c - input/output routines for ntpd.	The socket-opening code
 *		   was shamelessly stolen from ntpd.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "ntp_machine.h"
#include "ntpd.h"
#include "ntp_io.h"
#include "iosignal.h"
#include "ntp_refclock.h"
#include "ntp_stdlib.h"
#include "ntp.h"

/* Don't include ISC's version of IPv6 variables and structures */
#define ISC_IPV6_H 1
#include <isc/interfaceiter.h>
#include <isc/list.h>
#include <isc/result.h>

#ifdef SIM
#include "ntpsim.h"
#endif

#include <stdio.h>
#include <signal.h>
#ifdef HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif /* HAVE_SYS_PARAM_H */
#ifdef HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_SOCKIO_H	/* UXPV: SIOC* #defines (Frank Vance <[e-mail]>) */
# include <sys/sockio.h>
#endif


/* 
 * Set up some macros to look for IPv6 and IPv6 multicast
 */

#if defined(ISC_PLATFORM_HAVEIPV6) && !defined(DISABLE_IPV6)

#define INCLUDE_IPV6_SUPPORT

#if defined(INCLUDE_IPV6_SUPPORT) && defined(IPV6_JOIN_GROUP) && defined(IPV6_LEAVE_GROUP)
#define INCLUDE_IPV6_MULTICAST_SUPPORT

#endif	/* IPV6 Multicast Support */
#endif  /* IPv6 Support */

extern int listen_to_virtual_ips;
extern const char *specific_interface;

#if defined(SYS_WINNT)
#include <transmitbuff.h>
#include <isc/win32os.h>
/*
 * Define this macro to control the behavior of connection
 * resets on UDP sockets.  See Microsoft KnowledgeBase Article Q263823
 * for details.
 * NOTE: This requires that Windows 2000 systems install Service Pack 2
 * or later.
 */
#ifndef SIO_UDP_CONNRESET 
#define SIO_UDP_CONNRESET _WSAIOW(IOC_VENDOR,12) 
#endif

#endif

/*
 * We do asynchronous input using the SIGIO facility.  A number of
 * recvbuf buffers are preallocated for input.	In the signal
 * handler we poll to see which sockets are ready and read the
 * packets from them into the recvbuf's along with a time stamp and
 * an indication of the source host and the interface it was received
 * through.  This allows us to get as accurate receive time stamps
 * as possible independent of other processing going on.
 *
 * We watch the number of recvbufs available to the signal handler
 * and allocate more when this number drops below the low water
 * mark.  If the signal handler should run out of buffers in the
 * interim it will drop incoming frames, the idea being that it is
 * better to drop a packet than to be inaccurate.
 */


/*
 * Other statistics of possible interest
 */
volatile u_long packets_dropped;	/* total number of packets dropped on reception */
volatile u_long packets_ignored;	/* packets received on wild card interface */
volatile u_long packets_received;	/* total number of packets received */
u_long packets_sent;	/* total number of packets sent */
u_long packets_notsent; /* total number of packets which couldn't be sent */

volatile u_long handler_calls;	/* number of calls to interrupt handler */
volatile u_long handler_pkts;	/* number of pkts received by handler */
u_long io_timereset;		/* time counters were reset */

/*
 * Interface stuff
 */
struct interface *any_interface;	/* default ipv4 interface */
struct interface *any6_interface;	/* default ipv6 interface */
struct interface *loopback_interface;	/* loopback ipv4 interface */
struct interface *loopback6_interface;	/* loopback ipv6 interface */
struct interface inter_list[MAXINTERFACES]; /* Interface list */
int ninterfaces;			/* Total number of interfaces */
int nwilds;				/* Total number of wildcard intefaces */
int wildipv4 = -1;			/* Index into inter_list for IPv4 wildcard */
int wildipv6 = -1;			/* Index into inter_list for IPv6 wildcard */

#ifdef REFCLOCK
/*
 * Refclock stuff.	We keep a chain of structures with data concerning
 * the guys we are doing I/O for.
 */
static	struct refclockio *refio;
#endif /* REFCLOCK */


/*
 * Define what the possible "soft" errors can be.  These are non-fatal returns
 * of various network related functions, like recv() and so on.
 *
 * For some reason, BSDI (and perhaps others) will sometimes return <0
 * from recv() but will have errno==0.  This is broken, but we have to
 * work around it here.
 */
#define SOFT_ERROR(e)	((e) == EAGAIN || \
			 (e) == EWOULDBLOCK || \
			 (e) == EINTR || \
			 (e) == 0)

/*
 * File descriptor masks etc. for call to select
 * Not needed for I/O Completion Ports
 */
fd_set activefds;
int maxactivefd;

static	int create_sockets	P((u_short));
static	SOCKET	open_socket	P((struct sockaddr_storage *, int, int, struct interface *, int));
static	void	close_socket	P((SOCKET));
#ifdef REFCLOCK
static	void	close_file	P((SOCKET));
#endif
static	char *	fdbits		P((int, fd_set *));
static	void	set_reuseaddr	P((int));
static	isc_boolean_t	socket_broadcast_enable	 P((struct interface *, SOCKET, struct sockaddr_storage *));
static	isc_boolean_t	socket_broadcast_disable P((struct interface *, int, struct sockaddr_storage *));
/*
 * Multicast functions
 */
static	isc_boolean_t	addr_ismulticast	 P((struct sockaddr_storage *));
/*
 * Not all platforms support multicast
 */
#ifdef MCAST
static	isc_boolean_t	socket_multicast_enable	 P((struct interface *, int, int, struct sockaddr_storage *));
static	isc_boolean_t	socket_multicast_disable P((struct interface *, int, struct sockaddr_storage *));
#endif

#ifdef DEBUG
static void print_interface	P((int));
#endif

typedef struct vsock vsock_t;

struct vsock {
	SOCKET				fd;
	ISC_LINK(vsock_t)		link;
};

ISC_LIST(vsock_t)	sockets_list;

typedef struct remaddr remaddr_t;

struct remaddr {
      struct sockaddr_storage	addr;
      int			if_index;
      int			flags;
      ISC_LINK(remaddr_t)	link;
};

ISC_LIST(remaddr_t)       remoteaddr_list;

void	add_socket_to_list	P((SOCKET));
void	delete_socket_from_list	P((SOCKET));
void	add_addr_to_list	P((struct sockaddr_storage *, int, int));
int     modify_addr_in_list	P((struct sockaddr_storage *, int));
void	delete_addr_from_list	P((struct sockaddr_storage *));
int     find_addr_in_list	P((struct sockaddr_storage *));
int     find_flagged_addr_in_list P((struct sockaddr_storage *, int));
int	create_wildcards	P((u_short));
isc_boolean_t address_okay	P((isc_interface_t *));
void	convert_isc_if		P((isc_interface_t *, struct interface *, u_short));
int	findlocalinterface	P((struct sockaddr_storage *));
int	findlocalcastinterface	P((struct sockaddr_storage *, int));

/*
 * Routines to read the ntp packets
 */
#if !defined(HAVE_IO_COMPLETION_PORT)
static inline int     read_network_packet	P((SOCKET, struct interface *, l_fp));
static inline int     read_refclock_packet	P((SOCKET, struct refclockio *, l_fp));
#endif

#ifdef SYS_WINNT
/*
 * Windows 2000 systems incorrectly cause UDP sockets using WASRecvFrom
 * to not work correctly, returning a WSACONNRESET error when a WSASendTo
 * fails with an "ICMP port unreachable" response and preventing the
 * socket from using the WSARecvFrom in subsequent operations.
 * The function below fixes this, but requires that Windows 2000
 * Service Pack 2 or later be installed on the system.  NT 4.0
 * systems are not affected by this and work correctly.
 * See Microsoft Knowledge Base Article Q263823 for details of this.
 */
isc_result_t
connection_reset_fix(SOCKET fd) {
	DWORD dwBytesReturned = 0;
	BOOL  bNewBehavior = FALSE;
	DWORD status;

	if(isc_win32os_majorversion() < 5)
		return (ISC_R_SUCCESS); /*  NT 4.0 has no problem */

	/* disable bad behavior using IOCTL: SIO_UDP_CONNRESET */
	status = WSAIoctl(fd, SIO_UDP_CONNRESET, &bNewBehavior,
			  sizeof(bNewBehavior), NULL, 0,
			  &dwBytesReturned, NULL, NULL);
	if (status != SOCKET_ERROR)
		return (ISC_R_SUCCESS);
	else
		return (ISC_R_UNEXPECTED);
}
#endif
/*
 * init_io - initialize I/O data structures and call socket creation routine
 */
void
init_io(void)
{
#ifdef SYS_WINNT
	if (!Win32InitSockets())
	{
		netsyslog(LOG_ERR, "No useable winsock.dll: %m");
		exit(1);
	}
	init_transmitbuff();
#endif /* SYS_WINNT */

	/*
	 * Init buffer free list and stat counters
	 */
	init_recvbuff(RECV_INIT);

	packets_dropped = packets_received = 0;
	packets_ignored = 0;
	packets_sent = packets_notsent = 0;
	handler_calls = handler_pkts = 0;
	io_timereset = 0;
	loopback_interface = NULL;
	loopback6_interface = NULL;
	any_interface = NULL;
	any6_interface = NULL;

#ifdef REFCLOCK
	refio = 0;
#endif

#if defined(HAVE_SIGNALED_IO)
	(void) set_signal();
#endif

	ISC_LIST_INIT(sockets_list);

        ISC_LIST_INIT(remoteaddr_list);

	/*
	 * Create the sockets
	 */
	BLOCKIO();
	(void) create_sockets(htons(NTP_PORT));
	UNBLOCKIO();

#ifdef DEBUG
	if (debug)
	    printf("init_io: maxactivefd %d\n", maxactivefd);
#endif
}

/*
 * Function to dump the contents of the interface structure
 * For debugging use only.
 */
#ifdef DEBUG
void
interface_dump(struct interface *itf)
{
	u_char* cp;
	int i;
	/* Limit the size of the sockaddr_storage hex dump */
	int maxsize = min(32, sizeof(struct sockaddr_storage));

	printf("Dumping interface: %p\n", itf);
	printf("fd = %d\n", itf->fd);
	printf("bfd = %d\n", itf->bfd);
	printf("sin = %s,\n", stoa(&(itf->sin)));
	cp = (u_char*) &(itf->sin);
	for(i = 0; i < maxsize; i++)
	{
		printf("%02x", *cp++);
		if((i+1)%4 == 0)
			printf(" ");
	}
	printf("\n");
	printf("bcast = %s,\n", stoa(&(itf->bcast)));
	cp = (u_char*) &(itf->bcast);
	for(i = 0; i < maxsize; i++)
	{
		printf("%02x", *cp++);
		if((i+1)%4 == 0)
			printf(" ");
	}
	printf("\n");
	printf("mask = %s,\n", stoa(&(itf->mask)));
	cp = (u_char*) &(itf->mask);
	for(i = 0; i < maxsize; i++)
	{
		printf("%02x", *cp++);
		if((i+1)%4 == 0)
			printf(" ");
	}
	printf("\n");
	printf("name = %s\n", itf->name);
	printf("flags = 0x%08x\n", itf->flags);
	printf("last_ttl = %d\n", itf->last_ttl);
	printf("addr_refid = %08x\n", itf->addr_refid);
	printf("num_mcast = %d\n", itf->num_mcast);
	printf("received = %ld\n", itf->received);
	printf("sent = %ld\n", itf->sent);
	printf("notsent = %ld\n", itf->notsent);
	printf("ifindex = %u\n", itf->ifindex);
	printf("scopeid = %u\n", itf->scopeid);

}

static void
print_interface(int ind) {

	printf("interface %d:  fd=%d,  bfd=%d,  name=%s,  flags=0x%x,  scope=%d\n",
	       ind,
	       inter_list[ind].fd,
	       inter_list[ind].bfd,
	       inter_list[ind].name,
	       inter_list[ind].flags,
	       inter_list[ind].scopeid);
	/* Leave these as three printf calls. */
	printf("              sin=%s", stoa((&inter_list[ind].sin)));
	if (inter_list[ind].flags & INT_BROADCAST)
	    printf("  bcast=%s", stoa((&inter_list[ind].bcast)));
	/* Only IPv4 has a network mask */
	if(inter_list[ind].family == AF_INET)
		printf(",  mask=%s", stoa((&inter_list[ind].mask)));

	printf(" %s\n", inter_list[ind].ignore_packets == ISC_FALSE ? "Enabled": "Disabled");
	if (debug > 4)	/* in-depth debugging only */
		interface_dump(&inter_list[ind]);
}
#endif

int
create_wildcards(u_short port) {

	int idx = 0;
	isc_boolean_t okipv4 = ISC_TRUE;
	/*
	 * create pseudo-interface with wildcard IPv4 address
	 */
#ifdef IPV6_V6ONLY
	if(isc_net_probeipv4() != ISC_R_SUCCESS)
		okipv4 = ISC_FALSE;
#endif

	if(okipv4 == ISC_TRUE) {
		inter_list[idx].family = AF_INET;
		inter_list[idx].sin.ss_family = AF_INET;
		((struct sockaddr_in*)&inter_list[idx].sin)->sin_addr.s_addr = htonl(INADDR_ANY);
		((struct sockaddr_in*)&inter_list[idx].sin)->sin_port = port;
		(void) strncpy(inter_list[idx].name, "wildcard", sizeof(inter_list[idx].name));
		inter_list[idx].mask.ss_family = AF_INET;
		((struct sockaddr_in*)&inter_list[idx].mask)->sin_addr.s_addr = htonl(~(u_int32)0);
		inter_list[idx].bfd = INVALID_SOCKET;
		inter_list[idx].num_mcast = 0;
		inter_list[idx].received = 0;
		inter_list[idx].sent = 0;
		inter_list[idx].notsent = 0;
		inter_list[idx].flags = INT_BROADCAST | INT_UP;
		inter_list[idx].ignore_packets = ISC_TRUE;
#if defined(MCAST)
	/*
	 * enable possible multicast reception on the broadcast socket
	 */
		inter_list[idx].bcast.ss_family = AF_INET;
		((struct sockaddr_in*)&inter_list[idx].bcast)->sin_port = port;
		((struct sockaddr_in*)&inter_list[idx].bcast)->sin_addr.s_addr = htonl(INADDR_ANY);
#endif /* MCAST */
		any_interface = &inter_list[idx];
		wildipv4 = idx;
		idx++;
	}

#ifdef INCLUDE_IPV6_SUPPORT
	/*
	 * create pseudo-interface with wildcard IPv6 address
	 */
	if (isc_net_probeipv6() == ISC_R_SUCCESS) {
		inter_list[idx].family = AF_INET6;
		inter_list[idx].sin.ss_family = AF_INET6;
		((struct sockaddr_in6*)&inter_list[idx].sin)->sin6_addr = in6addr_any;
		((struct sockaddr_in6*)&inter_list[idx].sin)->sin6_port = port;
# ifdef ISC_PLATFORM_HAVESCOPEID
		((struct sockaddr_in6*)&inter_list[idx].sin)->sin6_scope_id = 0;
# endif
		(void) strncpy(inter_list[idx].name, "wildcard", sizeof(inter_list[idx].name));
		inter_list[idx].mask.ss_family = AF_INET6;
		memset(&((struct sockaddr_in6*)&inter_list[idx].mask)->sin6_addr.s6_addr, 0xff, sizeof(struct in6_addr));
		inter_list[idx].bfd = INVALID_SOCKET;
		inter_list[idx].num_mcast = 0;
		inter_list[idx].received = 0;
		inter_list[idx].sent = 0;
		inter_list[idx].notsent = 0;
		inter_list[idx].flags = INT_UP;
		inter_list[idx].ignore_packets = ISC_TRUE;
		any6_interface = &inter_list[idx];
		wildipv6 = idx;
		idx++;
	}
#endif
	return (idx);
}

isc_boolean_t
address_okay(isc_interface_t *isc_if) {

#ifdef DEBUG
	if (debug > 2)
	    printf("address_okay: listen Virtual: %d, IF name: %s, Up Flag: %d\n", 
		    listen_to_virtual_ips, isc_if->name, (isc_if->flags & INTERFACE_F_UP));
#endif
	/*
	 * Always allow the loopback
	 */
	if((isc_if->flags & INTERFACE_F_LOOPBACK) != 0)
		return (ISC_TRUE);

	/*
	 * Check if the interface is specified
	 */
	if (specific_interface != NULL) {
		if (strcasecmp(isc_if->name, specific_interface) == 0)
			return (ISC_TRUE);
		else
			return (ISC_FALSE);
	}
	else {
		if (listen_to_virtual_ips == 0  && 
		   (strchr(isc_if->name, (int)':') != NULL))
			return (ISC_FALSE);
	}

	/* XXXPDM This should be fixed later, but since we may not have set
	 * the UP flag, we at least get to use the interface.
	 * The UP flag is not always set so we don't do this right now.
	 */
/*	if ((isc_if->flags & INTERFACE_F_UP) == 0)
		return (ISC_FALSE);
*/
	return (ISC_TRUE);
}
void
convert_isc_if(isc_interface_t *isc_if, struct interface *itf, u_short port) {

	itf->scopeid = 0;
	itf->family = (short) isc_if->af;
	if(isc_if->af == AF_INET) {
		itf->sin.ss_family = (u_short) isc_if->af;
		strcpy(itf->name, isc_if->name);
		memcpy(&(((struct sockaddr_in*)&itf->sin)->sin_addr),
		       &(isc_if->address.type.in),
		       sizeof(struct in_addr));
		((struct sockaddr_in*)&itf->sin)->sin_port = port;

		if((isc_if->flags & INTERFACE_F_BROADCAST) != 0) {
			itf->flags |= INT_BROADCAST;
			itf->bcast.ss_family = itf->sin.ss_family;
			memcpy(&(((struct sockaddr_in*)&itf->bcast)->sin_addr),
			       &(isc_if->broadcast.type.in),
				 sizeof(struct in_addr));
			((struct sockaddr_in*)&itf->bcast)->sin_port = port;
		}

		itf->mask.ss_family = itf->sin.ss_family;
		memcpy(&(((struct sockaddr_in*)&itf->mask)->sin_addr),
		       &(isc_if->netmask.type.in),
		       sizeof(struct in_addr));
		((struct sockaddr_in*)&itf->mask)->sin_port = port;

		if (((isc_if->flags & INTERFACE_F_LOOPBACK) != 0) && (loopback_interface == NULL))
		{
			loopback_interface = itf;
		}
	}
#ifdef INCLUDE_IPV6_SUPPORT
	else if (isc_if->af == AF_INET6) {
		itf->sin.ss_family = (u_short) isc_if->af;
		strcpy(itf->name, isc_if->name);
		memcpy(&(((struct sockaddr_in6 *)&itf->sin)->sin6_addr),
		       &(isc_if->address.type.in6),