added network interface iterator

lib/isc/Makefile.in

@@ -30,7 +30,7 @@ OBJS =		@ISC_EXTRA_OBJS@ \
 		result.o rwlock.o symtab.o str.o event.o task.o timer.o \
 		version.o \
 		unix/app.o unix/time.o unix/stdtime.o unix/socket.o \
-		pthreads/condition.o
+		pthreads/condition.o unix/interfaceiter.o
 
 SUBDIRS =	include unix pthreads
 TARGETS =	timestamp

lib/isc/include/isc/interfaceiter.h

@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 1999  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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM 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.
+ */
+
+#ifndef ISC_INTERFACEITER_H
+#define ISC_INTERFACEITER_H 1
+
+/*****
+ ***** Module Info
+ *****/
+
+/*
+ * Interface iterator
+ *
+ * Iterate over the list of network interfaces.
+ *
+ * Interfaces whose address family is not supported are ignored and never
+ * returned by the iterator.  Interfaces whose netmask, interface flags,
+ * or similar cannot be obtained are also ignored, and the failure is logged.
+ *
+ * Standards:
+ *	The API for scanning varies greatly among operating systems.
+ *	This module attempts to hide the differences.
+ */
+
+/***
+ *** Imports
+ ***/
+
+#include <isc/result.h>
+#include <isc/mem.h>
+#include <isc/sockaddr.h>
+
+/***
+ *** Types
+ ***/
+
+typedef struct isc_interfaceiter isc_interfaceiter_t;
+
+/*
+ * Public structure describing a network interface.
+ * 
+ * In 'address', 'netmask', and 'dstaddress', 
+ * only the network address field (for IPv4, type.sin.sin_addr)
+ * is used.  Other fields including the port and address family
+ * have undefined values.
+ */
+
+typedef struct {
+	char name[32];			/* Interface name, null-terminated. */
+	unsigned int af;		/* Address family. */ 
+	isc_sockaddr_t address;		/* Local address. */
+	isc_sockaddr_t netmask;		/* Network mask
+					   (non-point-to-point only). */
+	isc_sockaddr_t dstaddress; 	/* Destination address
+					   (point-to-point only). */
+	isc_uint32_t flags;		/* Flags; see below. */
+} isc_interface_t;
+
+/* Interface flags. */
+
+#define INTERFACE_F_UP			0x00000001U
+#define INTERFACE_F_POINTTOPOINT	0x00000002U
+#define INTERFACE_F_LOOPBACK		0x00000004U
+
+/***
+ *** Functions
+ ***/
+
+isc_result_t
+isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp);
+/*
+ * Create an iterator for traversing the operating system's list
+ * of network interfaces.
+ *
+ * Returns:
+ *	ISC_R_SUCCESS
+ * 	ISC_R_NOMEMORY
+ *	Various network-related errors
+ */
+
+isc_result_t
+isc_interfaceiter_first(isc_interfaceiter_t *iter);
+/*
+ * Position the iterator on the first interface.
+ *
+ * Returns:
+ *	ISC_R_SUCCESS		Success.
+ *	ISC_R_NOMORE		There are no interfaces.
+ */
+     
+isc_result_t
+isc_interfaceiter_current(isc_interfaceiter_t *iter,
+			  isc_interface_t *ifdata);
+/*
+ * Get information about the interface the iterator is currently
+ * positioned at and store it at *ifdata.
+ *
+ * Requires:
+ * 	The iterator has been successfully positioned using
+ * 	isc_interface_iter_first() / isc_interface_iter_next().
+ *
+ * Returns:
+ *	ISC_R_SUCCESS		Success.
+ */
+     
+isc_result_t
+isc_interfaceiter_next(isc_interfaceiter_t *iter);
+/*
+ * Position the iterator on the next interface.
+ *
+ * Requires:
+ * 	The iterator has been successfully positioned using
+ * 	isc_interface_iter_first() / isc_interface_iter_next().
+ *
+ * Returns:
+ *	ISC_R_SUCCESS		Success.
+ *	ISC_R_NOMORE		There are no more interfaces.
+ */
+
+void
+isc_interfaceiter_destroy(isc_interfaceiter_t **iterp);
+/*
+ * Destroy the iterator.
+ */
+
+#endif /* ISC_INTERFACEITER_H */

lib/isc/unix/Makefile.in

@@ -24,7 +24,7 @@ CINCLUDES =	-I${srcdir}/.. \
 CDEFINES =
 CWARNINGS =
 
-OBJS =		app.o time.o stdtime.o socket.o
+OBJS =		app.o time.o stdtime.o socket.o interfaceiter.o
 
 SUBDIRS =	include
 TARGETS =	${OBJS}

lib/isc/unix/interfaceiter.c

@@ -0,0 +1,351 @@
+/*
+ * Copyright (C) 1999  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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM 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.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+
+#include <isc/assertions.h>
+#include <isc/error.h>
+#include <isc/mem.h>
+#include <isc/result.h>
+#include <isc/types.h>
+#include <isc/inet.h>
+#include <isc/interfaceiter.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+
+#include <net/if.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+
+#define IFITER_MAGIC		0x49464954U	/* IFIT. */	
+#define VALID_IFITER(t)		((t) != NULL && (t)->magic == IFITER_MAGIC)
+
+struct isc_interfaceiter {
+	unsigned int		magic;		/* Magic number. */
+	isc_mem_t		*mctx;
+	int			socket;
+	struct ifconf 		ifc;
+	unsigned int		bufsize;
+	unsigned int		pos;		/* Current offset in
+						   SIOGCONF data */
+	isc_interface_t		current;	/* Current interface data. */
+	isc_result_t		result;		/* Last result code. */
+};
+
+
+/*
+ * Size of buffer for SIOCGIFCONF, in bytes.  We assume no sane system
+ * will have more than a megabyte of interface configuration data.
+ */
+#define IFCONF_BUFSIZE_INITIAL	4096
+#define IFCONF_BUFSIZE_MAX	1048576
+
+isc_result_t
+isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp)
+{
+	isc_interfaceiter_t *iter;
+	isc_result_t result;
+	char *buf;
+	REQUIRE(mctx != NULL);
+	REQUIRE(iterp != NULL);
+	REQUIRE(*iterp == NULL);
+	
+	iter = isc_mem_get(mctx, sizeof(*iter));
+	if (iter == NULL)
+		return (ISC_R_NOMEMORY);
+
+	iter->mctx = mctx;
+
+	/* Create an unbound datagram socket to do the SIOCGIFADDR ioctl on. */
+	if ((iter->socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "making interface scan socket: %s",
+				 strerror(errno));
+		result = ISC_R_UNEXPECTED;
+		goto socket_failure;
+	}
+	
+	/*
+	 * Get the interface configuration, allocating more memory if
+	 * necessary.
+	 */
+	iter->bufsize = IFCONF_BUFSIZE_INITIAL;
+
+	for (;;) {
+		buf = isc_mem_get(mctx, iter->bufsize);
+		if (buf == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto alloc_failure;
+		}
+		
+		iter->ifc.ifc_len = iter->bufsize;
+		iter->ifc.ifc_buf = buf;
+		if (ioctl(iter->socket, SIOCGIFCONF, (char *) &iter->ifc) >= 0)
+			break;
+		if (errno != EINVAL) {
+			UNEXPECTED_ERROR(__FILE__, __LINE__,
+					 "get interface configuration: %s",
+					 strerror(errno));
+			result = ISC_R_UNEXPECTED;
+			goto ioctl_failure;
+		}
+
+		if (iter->bufsize >= IFCONF_BUFSIZE_MAX) {
+			UNEXPECTED_ERROR(__FILE__, __LINE__, 
+					 "get interface configuration: "
+					 "maximum buffer size exceeded");
+			result = ISC_R_UNEXPECTED;
+			goto ioctl_failure;
+		}
+		isc_mem_put(mctx, buf, iter->bufsize);
+		
+		iter->bufsize *= 2;
+	}
+
+	/*
+	 * A newly created iterator has an undefined position
+	 * until isc_interfaceiter_first() is called.
+	 */
+	iter->pos = (unsigned int) -1;
+	iter->result = ISC_R_FAILURE;
+	
+	iter->magic = IFITER_MAGIC;
+	*iterp = iter;
+	return (ISC_R_SUCCESS);
+
+ ioctl_failure:
+	isc_mem_put(mctx, buf, iter->bufsize);
+
+ alloc_failure:
+	(void) close(iter->socket);
+	
+ socket_failure:
+	isc_mem_put(mctx, iter, sizeof *iter);
+	return (result);
+}
+
+/*
+ * Copy a socket address.  The address family is given explicity
+ * instead of using src->sa_family, because the latter does not work
+ * for copying the network mask as obtained by SIOCGIFNETMASK.
+ */
+static void 
+copy_sockaddr(int family, isc_sockaddr_t *dst, struct sockaddr *src) {
+	switch (family) {
+	case AF_INET:
+		dst->type.sin.sin_family = AF_INET;
+		memcpy(&dst->type.sin.sin_addr,
+		       &((struct sockaddr_in *) src)->sin_addr,
+		       sizeof(struct in_addr));
+		break;
+	/* XXX IPv6 */
+	default:
+		INSIST(0);
+		break;
+	}
+}
+	       
+/*
+ * Get information about the current interface to iter->current.
+ * If successful, return ISC_R_SUCCESS.
+ * If the interface has an unsupported address family,
+ * return ISC_R_FAILURE.  In case of other failure,
+ * return ISC_R_UNEXPECTED.
+ */
+
+static isc_result_t
+internal_current(isc_interfaceiter_t *iter) {
+	struct ifreq *ifrp;
+	struct ifreq ifreq;
+	int family;
+	
+	REQUIRE(VALID_IFITER(iter));
+	REQUIRE (iter->pos < (unsigned int) iter->ifc.ifc_len);
+	
+	ifrp = (struct ifreq *)((char *) iter->ifc.ifc_req + iter->pos);
+	
+	memcpy(&ifreq, ifrp, sizeof ifreq);
+
+	family = ifreq.ifr_addr.sa_family;
+	if (family != AF_INET) /* XXX IPv6 */	
+		return (ISC_R_FAILURE); 
+	
+	memset(&iter->current, 0, sizeof(iter->current));
+	
+	INSIST(sizeof(ifreq.ifr_name) <= sizeof(iter->current.name));
+	memcpy(iter->current.name, ifreq.ifr_name, sizeof(ifreq.ifr_name));
+	
+	copy_sockaddr(family, &iter->current.address, &ifreq.ifr_addr);
+
+	/* Get interface flags. */
+
+	iter->current.flags = 0;
+	
+	if (ioctl(iter->socket, SIOCGIFFLAGS, (char *) &ifreq) < 0) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__, 
+				 "%s: getting interface flags: %s",
+				 ifreq.ifr_name,
+				 strerror(errno));
+		return (ISC_R_UNEXPECTED);
+	}
+	
+	if ((ifreq.ifr_flags & IFF_UP) != 0)
+		iter->current.flags |= INTERFACE_F_UP;
+
+	if ((ifreq.ifr_flags & IFF_POINTOPOINT) != 0)
+		iter->current.flags |= INTERFACE_F_POINTTOPOINT;
+
+	if ((ifreq.ifr_flags & IFF_LOOPBACK) != 0)
+		iter->current.flags |= INTERFACE_F_LOOPBACK;
+
+	/*
+	 * If point-to-point, get the destination address;
+	 * otherwise, get the network mask.
+	 */
+	if ((iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0) {
+		if (ioctl(iter->socket, SIOCGIFDSTADDR, (char *) &ifreq) < 0) {
+			UNEXPECTED_ERROR(__FILE__, __LINE__, 
+					 "%s: getting destination address: %s",
+					 ifreq.ifr_name,
+					 strerror(errno));
+			return (ISC_R_UNEXPECTED);
+		}
+		copy_sockaddr(family, &iter->current.dstaddress,
+			      &ifreq.ifr_dstaddr);
+	} else {
+		if (ioctl(iter->socket, SIOCGIFNETMASK, (char *) &ifreq) < 0) {
+			UNEXPECTED_ERROR(__FILE__, __LINE__,
+					 "%s: getting netmask: %s",
+					 ifreq.ifr_name,
+					 strerror(errno));
+			return (ISC_R_UNEXPECTED);
+		}
+		copy_sockaddr(family, &iter->current.netmask,
+			      &ifreq.ifr_addr);		
+	}
+	
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Step the iterator to the next interface.  Unlike 
+ * isc_interfaceiter_next(), this may leave the iterator
+ * positioned on an interface that will ultimately
+ * be ignored.  Return ISC_R_NOMORE if there are no more
+ * interfaces, otherwise ISC_R_SUCCESS.
+ */
+static isc_result_t
+internal_next(isc_interfaceiter_t *iter) {
+	struct ifreq *ifrp;
+
+	REQUIRE (iter->pos < (unsigned int) iter->ifc.ifc_len);
+	
+	ifrp = (struct ifreq *)((char *) iter->ifc.ifc_req + iter->pos);
+		
+#ifdef HAVE_SA_LEN
+	if (ifrp->ifr_addr.sa_len > sizeof(struct sockaddr))
+		iter->pos += sizeof(ifrp->ifr_name) + ifrp->ifr_addr.sa_len;
+	else
+#endif
+		iter->pos += sizeof *ifrp;
+
+	if (iter->pos >= (unsigned int) iter->ifc.ifc_len)
+		return (ISC_R_NOMORE);
+	
+	return (ISC_R_SUCCESS);
+}
+
+
+isc_result_t
+isc_interfaceiter_current(isc_interfaceiter_t *iter,
+			  isc_interface_t *ifdata)
+{
+	REQUIRE(iter->result == ISC_R_SUCCESS);
+	memcpy(ifdata, &iter->current, sizeof(*ifdata));
+	return ISC_R_SUCCESS;
+}
+
+/*
+ * Position the iterator on the first user-visible interface.
+ */
+isc_result_t
+isc_interfaceiter_first(isc_interfaceiter_t *iter) {
+	isc_result_t result;
+
+	REQUIRE(VALID_IFITER(iter));	
+
+	iter->pos = 0;
+	for (;;) {
+		result = internal_current(iter);
+		if (result == ISC_R_SUCCESS)
+			break;
+		result = internal_next(iter);
+		if (result == ISC_R_NOMORE)
+			break;
+		INSIST(result == ISC_R_SUCCESS);
+	}
+	iter->result = result;
+	return (result);
+}
+
+/*
+ * Position the iterator on the next user-visible interface.
+ */
+isc_result_t
+isc_interfaceiter_next(isc_interfaceiter_t *iter) {
+	isc_result_t result;
+		
+	REQUIRE(VALID_IFITER(iter));
+	REQUIRE(iter->result == ISC_R_SUCCESS);
+
+	for (;;) {
+		result = internal_next(iter);
+		if (result == ISC_R_NOMORE)
+			break;
+		INSIST(result == ISC_R_SUCCESS);
+		result = internal_current(iter);
+		if (result == ISC_R_SUCCESS)
+			break;
+	}
+	iter->result = result;
+	return (result);
+}
+
+void
+isc_interfaceiter_destroy(isc_interfaceiter_t **iterp)
+{
+	isc_interfaceiter_t *iter;
+	REQUIRE(iterp != NULL);
+	iter = *iterp;
+	REQUIRE(VALID_IFITER(iter));
+
+	(void) close(iter->socket);
+	isc_mem_put(iter->mctx, iter->ifc.ifc_buf, iter->bufsize);
+
+	iter->magic = 0;
+	isc_mem_put(iter->mctx, iter, sizeof *iter);
+	*iterp = NULL;
+}