connection.c

DHCP服务器源码

/* connection.c

   Subroutines for dealing with connections. */

/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1999-2003 by Internet Software Consortium
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 *   Internet Systems Consortium, Inc.
 *   950 Charter Street
 *   Redwood City, CA 94063
 *   <[e-mail]>
 *   http://www.isc.org/
 *
 * This software has been written for Internet Systems Consortium
 * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
 * To learn more about Internet Systems Consortium, see
 * ``http://www.isc.org/''.  To learn more about Vixie Enterprises,
 * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
 * ``http://www.nominum.com''.
 */

#include <omapip/omapip_p.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>


#if defined (TRACING)
static void trace_connect_input (trace_type_t *, unsigned, char *);
static void trace_connect_stop (trace_type_t *);
static void trace_disconnect_input (trace_type_t *, unsigned, char *);
static void trace_disconnect_stop (trace_type_t *);
trace_type_t *trace_connect;
trace_type_t *trace_disconnect;
extern omapi_array_t *trace_listeners;
#endif
static isc_result_t omapi_connection_connect_internal (omapi_object_t *);

OMAPI_OBJECT_ALLOC (omapi_connection,
		    omapi_connection_object_t, omapi_type_connection)

isc_result_t omapi_connect (omapi_object_t *c,
			    const char *server_name,
			    unsigned port)
{
	struct hostent *he;
	unsigned i, hix;
	omapi_addr_list_t *addrs = (omapi_addr_list_t *)0;
	struct in_addr foo;
	isc_result_t status;

#ifdef DEBUG_PROTOCOL
	log_debug ("omapi_connect(%s, port=%d)", server_name, port);
#endif

	if (!inet_aton (server_name, &foo)) {
		/* If we didn't get a numeric address, try for a domain
		   name.  It's okay for this call to block. */
		he = gethostbyname (server_name);
		if (!he)
			return ISC_R_HOSTUNKNOWN;
		for (i = 0; he -> h_addr_list [i]; i++)
			;
		if (i == 0)
			return ISC_R_HOSTUNKNOWN;
		hix = i;

		status = omapi_addr_list_new (&addrs, hix, MDL);
		if (status != ISC_R_SUCCESS)
			return status;
		for (i = 0; i < hix; i++) {
			addrs -> addresses [i].addrtype = he -> h_addrtype;
			addrs -> addresses [i].addrlen = he -> h_length;
			memcpy (addrs -> addresses [i].address,
				he -> h_addr_list [i],
				(unsigned)he -> h_length);
			addrs -> addresses [i].port = port;
		}
	} else {
		status = omapi_addr_list_new (&addrs, 1, MDL);
		if (status != ISC_R_SUCCESS)
			return status;
		addrs -> addresses [0].addrtype = AF_INET;
		addrs -> addresses [0].addrlen = sizeof foo;
		memcpy (addrs -> addresses [0].address, &foo, sizeof foo);
		addrs -> addresses [0].port = port;
		hix = 1;
	}
	status = omapi_connect_list (c, addrs, (omapi_addr_t *)0);
	omapi_addr_list_dereference (&addrs, MDL);
	return status;
}

isc_result_t omapi_connect_list (omapi_object_t *c,
				 omapi_addr_list_t *remote_addrs,
				 omapi_addr_t *local_addr)
{
	isc_result_t status;
	omapi_connection_object_t *obj;
	int flag;
	struct sockaddr_in local_sin;
#if defined (TRACING)
	trace_addr_t *addrs;
	u_int16_t naddrs;
#endif

	obj = (omapi_connection_object_t *)0;
	status = omapi_connection_allocate (&obj, MDL);
	if (status != ISC_R_SUCCESS)
		return status;

	status = omapi_object_reference (&c -> outer, (omapi_object_t *)obj,
					 MDL);
	if (status != ISC_R_SUCCESS) {
		omapi_connection_dereference (&obj, MDL);
		return status;
	}
	status = omapi_object_reference (&obj -> inner, c, MDL);
	if (status != ISC_R_SUCCESS) {
		omapi_connection_dereference (&obj, MDL);
		return status;
	}

	/* Store the address list on the object. */
	omapi_addr_list_reference (&obj -> connect_list, remote_addrs, MDL);
	obj -> cptr = 0;
	obj -> state = omapi_connection_unconnected;

#if defined (TRACING)
	/* If we're playing back, don't actually try to connect - just leave
	   the object available for a subsequent connect or disconnect. */
	if (!trace_playback ()) {
#endif
		/* Create a socket on which to communicate. */
		obj -> socket =
			socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
		if (obj -> socket < 0) {
			omapi_connection_dereference (&obj, MDL);
			if (errno == EMFILE || errno == ENFILE
			    || errno == ENOBUFS)
				return ISC_R_NORESOURCES;
			return ISC_R_UNEXPECTED;
		}

		/* Set up the local address, if any. */
		if (local_addr) {
			/* Only do TCPv4 so far. */
			if (local_addr -> addrtype != AF_INET) {
				omapi_connection_dereference (&obj, MDL);
				return ISC_R_INVALIDARG;
			}
			local_sin.sin_port = htons (local_addr -> port);
			memcpy (&local_sin.sin_addr,
				local_addr -> address,
				local_addr -> addrlen);
#if defined (HAVE_SA_LEN)
			local_sin.sin_len = sizeof local_addr;
#endif
			local_sin.sin_family = AF_INET;
			memset (&local_sin.sin_zero, 0,
				sizeof local_sin.sin_zero);
			
			if (bind (obj -> socket, (struct sockaddr *)&local_sin,
				  sizeof local_sin) < 0) {
				omapi_object_dereference ((omapi_object_t **)
							  &obj, MDL);
				if (errno == EADDRINUSE)
					return ISC_R_ADDRINUSE;
				if (errno == EADDRNOTAVAIL)
					return ISC_R_ADDRNOTAVAIL;
				if (errno == EACCES)
					return ISC_R_NOPERM;
				return ISC_R_UNEXPECTED;
			}
			obj -> local_addr = local_sin;
		}

#if defined (HAVE_SETFD)
		if (fcntl (obj -> socket, F_SETFD, 1) < 0) {
			close (obj -> socket);
			omapi_connection_dereference (&obj, MDL);
			return ISC_R_UNEXPECTED;
		}
#endif

		/* Set the SO_REUSEADDR flag (this should not fail). */
		flag = 1;
		if (setsockopt (obj -> socket, SOL_SOCKET, SO_REUSEADDR,
				(char *)&flag, sizeof flag) < 0) {
			omapi_connection_dereference (&obj, MDL);
			return ISC_R_UNEXPECTED;
		}
	
		/* Set the file to nonblocking mode. */
		if (fcntl (obj -> socket, F_SETFL, O_NONBLOCK) < 0) {
			omapi_connection_dereference (&obj, MDL);
			return ISC_R_UNEXPECTED;
		}

		status = (omapi_register_io_object
			  ((omapi_object_t *)obj,
			   0, omapi_connection_writefd,
			   0, omapi_connection_connect,
			   omapi_connection_reaper));
		if (status != ISC_R_SUCCESS)
			goto out;
		status = omapi_connection_connect_internal ((omapi_object_t *)
							    obj);
#if defined (TRACING)
	}
	omapi_connection_register (obj, MDL);
#endif

      out:
	omapi_connection_dereference (&obj, MDL);
	return status;
}

#if defined (TRACING)
omapi_array_t *omapi_connections;

OMAPI_ARRAY_TYPE(omapi_connection, omapi_connection_object_t)

void omapi_connection_trace_setup (void) {
	trace_connect = trace_type_register ("connect", (void *)0,
					     trace_connect_input,
					     trace_connect_stop, MDL);
	trace_disconnect = trace_type_register ("disconnect", (void *)0,
						trace_disconnect_input,
						trace_disconnect_stop, MDL);
}

void omapi_connection_register (omapi_connection_object_t *obj,
				const char *file, int line)
{
	isc_result_t status;
	trace_iov_t iov [6];
	int iov_count = 0;
	int32_t connect_index, listener_index;
	static int32_t index;

	if (!omapi_connections) {
		status = omapi_connection_array_allocate (&omapi_connections,
							  file, line);
		if (status != ISC_R_SUCCESS)
			return;
	}

	status = omapi_connection_array_extend (omapi_connections, obj,
						(int *)0, file, line);
	if (status != ISC_R_SUCCESS) {
		obj -> index = -1;
		return;
	}

#if defined (TRACING)
	if (trace_record ()) {
		/* Connection registration packet:
		   
		     int32_t index
		     int32_t listener_index [-1 means no listener]
		   u_int16_t remote_port
		   u_int16_t local_port
		   u_int32_t remote_addr
		   u_int32_t local_addr */

		connect_index = htonl (index);
		index++;
		if (obj -> listener)
			listener_index = htonl (obj -> listener -> index);
		else
			listener_index = htonl (-1);
		iov [iov_count].buf = (char *)&connect_index;
		iov [iov_count++].len = sizeof connect_index;
		iov [iov_count].buf = (char *)&listener_index;
		iov [iov_count++].len = sizeof listener_index;
		iov [iov_count].buf = (char *)&obj -> remote_addr.sin_port;
		iov [iov_count++].len = sizeof obj -> remote_addr.sin_port;
		iov [iov_count].buf = (char *)&obj -> local_addr.sin_port;
		iov [iov_count++].len = sizeof obj -> local_addr.sin_port;
		iov [iov_count].buf = (char *)&obj -> remote_addr.sin_addr;
		iov [iov_count++].len = sizeof obj -> remote_addr.sin_addr;
		iov [iov_count].buf = (char *)&obj -> local_addr.sin_addr;
		iov [iov_count++].len = sizeof obj -> local_addr.sin_addr;

		status = trace_write_packet_iov (trace_connect,
						 iov_count, iov, file, line);
	}
#endif
}

static void trace_connect_input (trace_type_t *ttype,
				 unsigned length, char *buf)
{
	struct sockaddr_in remote, local;
	int32_t connect_index, listener_index;
	char *s = buf;
	omapi_connection_object_t *obj;
	isc_result_t status;
	int i;

	if (length != ((sizeof connect_index) +
		       (sizeof remote.sin_port) +
		       (sizeof remote.sin_addr)) * 2) {
		log_error ("Trace connect: invalid length %d", length);
		return;
	}

	memset (&remote, 0, sizeof remote);
	memset (&local, 0, sizeof local);
	memcpy (&connect_index, s, sizeof connect_index);
	s += sizeof connect_index;
	memcpy (&listener_index, s, sizeof listener_index);
	s += sizeof listener_index;
	memcpy (&remote.sin_port, s, sizeof remote.sin_port);
	s += sizeof remote.sin_port;
	memcpy (&local.sin_port, s, sizeof local.sin_port);
	s += sizeof local.sin_port;
	memcpy (&remote.sin_addr, s, sizeof remote.sin_addr);
	s += sizeof remote.sin_addr;
	memcpy (&local.sin_addr, s, sizeof local.sin_addr);
	s += sizeof local.sin_addr;

	connect_index = ntohl (connect_index);
	listener_index = ntohl (listener_index);

	/* If this was a connect to a listener, then we just slap together
	   a new connection. */
	if (listener_index != -1) {
		omapi_listener_object_t *listener;
		listener = (omapi_listener_object_t *)0;
		omapi_array_foreach_begin (trace_listeners,
					   omapi_listener_object_t, lp) {
			if (lp -> address.sin_port == local.sin_port) {
				omapi_listener_reference (&listener, lp, MDL);
				omapi_listener_dereference (&lp, MDL);
				break;
			} 
		} omapi_array_foreach_end (trace_listeners,
					   omapi_listener_object_t, lp);
		if (!listener) {
			log_error ("%s%ld, addr %s, port %d",
				   "Spurious traced listener connect - index ",
				   (long int)listener_index,
				   inet_ntoa (local.sin_addr),
				   ntohs (local.sin_port));
			return;
		}
		obj = (omapi_connection_object_t *)0;
		status = omapi_listener_connect (&obj, listener, -1, &remote);
		if (status != ISC_R_SUCCESS) {
			log_error ("traced listener connect: %s",
				   isc_result_totext (status));
		}
		if (obj)
			omapi_connection_dereference (&obj, MDL);
		omapi_listener_dereference (&listener, MDL);
		return;
	}

	/* Find the matching connect object, if there is one. */
	omapi_array_foreach_begin (omapi_connections,
				   omapi_connection_object_t, lp) {
	    for (i = 0; (lp -> connect_list &&
			 i < lp -> connect_list -> count); i++) {
		    if (!memcmp (&remote.sin_addr,
				 &lp -> connect_list -> addresses [i].address,
				 sizeof remote.sin_addr) &&
			(ntohs (remote.sin_port) ==
			 lp -> connect_list -> addresses [i].port))
			lp -> state = omapi_connection_connected;
			lp -> remote_addr = remote;
			lp -> remote_addr.sin_family = AF_INET;
#if defined (HAVE_SIN_LEN)
			lp -> remote_addr.sin_len = sizeof remote;
#endif
			omapi_addr_list_dereference (&lp -> connect_list, MDL);
			lp -> index = connect_index;
			status = omapi_signal_in ((omapi_object_t *)lp,
						  "connect");
			omapi_connection_dereference (&lp, MDL);
			return;
		}
	} omapi_array_foreach_end (omapi_connections,
				   omapi_connection_object_t, lp);
						 
	log_error ("Spurious traced connect - index %ld, addr %s, port %d",
		   (long int)connect_index, inet_ntoa (remote.sin_addr),
		   ntohs (remote.sin_port));
	return;
}

static void trace_connect_stop (trace_type_t *ttype) { }

static void trace_disconnect_input (trace_type_t *ttype,
				    unsigned length, char *buf)
{
	int32_t *index;
	if (length != sizeof *index) {
		log_error ("trace disconnect: wrong length %d", length);
		return;
	}
	
	index = (int32_t *)buf;

	omapi_array_foreach_begin (omapi_connections,
				   omapi_connection_object_t, lp) {
		if (lp -> index == ntohl (*index)) {
			omapi_disconnect ((omapi_object_t *)lp, 1);
			omapi_connection_dereference (&lp, MDL);
			return;
		}
	} omapi_array_foreach_end (omapi_connections,
				   omapi_connection_object_t, lp);

	log_error ("trace disconnect: no connection matching index %ld",
		   (long int)ntohl (*index));
}

static void trace_disconnect_stop (trace_type_t *ttype) { }
#endif

/* Disconnect a connection object from the remote end.   If force is nonzero,
   close the connection immediately.   Otherwise, shut down the receiving end
   but allow any unsent data to be sent before actually closing the socket. */

isc_result_t omapi_disconnect (omapi_object_t *h,
			       int force)
{
	omapi_connection_object_t *c;
	isc_result_t status;

#ifdef DEBUG_PROTOCOL
	log_debug ("omapi_disconnect(%s)", force ? "force" : "");
#endif

	c = (omapi_connection_object_t *)h;
	if (c -> type != omapi_type_connection)
		return ISC_R_INVALIDARG;

#if defined (TRACING)
	if (trace_record ()) {
		int32_t index;

		index = htonl (c -> index);
		status = trace_write_packet (trace_disconnect,
					     sizeof index, (char *)&index,
					     MDL);
		if (status != ISC_R_SUCCESS) {
			trace_stop ();
			log_error ("trace_write_packet: %s",
				   isc_result_totext (status));
		}
	}
	if (!trace_playback ()) {
#endif
		if (!force) {
			/* If we're already disconnecting, we don't have to do
			   anything. */
			if (c -> state == omapi_connection_disconnecting)
				return ISC_R_SUCCESS;

			/* Try to shut down the socket - this sends a FIN to
			   the remote end, so that it won't send us any more
			   data.   If the shutdown succeeds, and we still
			   have bytes left to write, defer closing the socket
			   until that's done. */
			if (!shutdown (c -> socket, SHUT_RD)) {
				if (c -> out_bytes > 0) {
					c -> state =
						omapi_connection_disconnecting;
					return ISC_R_SUCCESS;
				}
			}
		}
		close (c -> socket);
#if defined (TRACING)
	}
#endif
	c -> state = omapi_connection_closed;

	/* Disconnect from I/O object, if any. */
	if (h -> outer) {
		if (h -> outer -> inner)
			omapi_object_dereference (&h -> outer -> inner, MDL);
		omapi_object_dereference (&h -> outer, MDL);
	}

	/* If whatever created us registered a signal handler, send it
	   a disconnect signal. */
	omapi_signal (h, "disconnect", h);
	return ISC_R_SUCCESS;
}

isc_result_t omapi_connection_require (omapi_object_t *h, unsigned bytes)
{
	omapi_connection_object_t *c;