Major overhaul of pseudo-interface cloning. Highlights include:

 - Split the code out into if_clone.[ch].
 - Locked struct if_clone. [1]
 - Add a per-cloner match function rather then simply matching names of
   the form <name><unit> and <name>.
 - Use the match function to allow creation of <interface>.<tag>
   vlan interfaces.  The old way is preserved unchanged!
 - Also the match function to allow creation of stf(4) interfaces named
   stf0, stf, or 6to4.  This is the only major user visible change in
   that "ifconfig stf" creates the interface stf rather then stf0 and
   does not print "stf0" to stdout.
 - Allow destroy functions to fail so they can refuse to delete
   interfaces.  Currently, we forbid the deletion of interfaces which
   were created in the init function, particularly lo0, pflog0, and
   pfsync0.  In the case of lo0 this was a panic implementation so it
   does not count as a user visiable change. :-)
 - Since most interfaces do not need the new functionality, an family of
   wrapper functions, ifc_simple_*(), were created to wrap old style
   cloner functions.
 - The IF_CLONE_INITIALIZER macro is replaced with a new incompatible
   IFC_CLONE_INITIALIZER and ifc_simple consumers use IFC_SIMPLE_DECLARE
   instead.

Submitted by:   Maurycy Pawlowski-Wieronski <maurycy at fouk.org> [1]
Reviewed by:    andre, mlaier
Discussed on:	net

1 files changed, 468 insertions, 0 deletions

diff --git a/sys/net/if_clone.c b/sys/net/if_clone.c
new file mode 100644
index 0000000..37184b2
--- /dev/null
+++ b/sys/net/if_clone.c
@@ -0,0 +1,468 @@
+/*
+ * Copyright (c) 1980, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)if.c	8.5 (Berkeley) 1/9/95
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/malloc.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <net/if.h>
+#include <net/if_clone.h>
+#if 0
+#include <net/if_dl.h>
+#endif
+#include <net/if_types.h>
+#include <net/if_var.h>
+#include <net/radix.h>
+#include <net/route.h>
+
+static void		if_clone_free(struct if_clone *ifc);
+
+static struct mtx	if_cloners_mtx;
+static int		if_cloners_count;
+LIST_HEAD(, if_clone)	if_cloners = LIST_HEAD_INITIALIZER(if_cloners);
+
+#define IF_CLONERS_LOCK_INIT()		\
+    mtx_init(&if_cloners_mtx, "if_cloners lock", NULL, MTX_DEF)
+#define IF_CLONERS_LOCK_ASSERT()	mtx_assert(&if_cloners_mtx, MA_OWNED)
+#define IF_CLONERS_LOCK()		mtx_lock(&if_cloners_mtx)
+#define IF_CLONERS_UNLOCK()		mtx_unlock(&if_cloners_mtx)
+
+#define IF_CLONE_LOCK_INIT(ifc)		\
+    mtx_init(&(ifc)->ifc_mtx, "if_clone lock", NULL, MTX_DEF)
+#define IF_CLONE_LOCK_DESTROY(ifc)	mtx_destroy(&(ifc)->ifc_mtx)
+#define IF_CLONE_LOCK_ASSERT(ifc)	mtx_assert(&(ifc)->ifc_mtx, MA_OWNED)
+#define IF_CLONE_LOCK(ifc)		mtx_lock(&(ifc)->ifc_mtx)
+#define IF_CLONE_UNLOCK(ifc)		mtx_unlock(&(ifc)->ifc_mtx)
+
+#define IF_CLONE_ADDREF(ifc)						\
+	do {								\
+		IF_CLONE_LOCK(ifc);					\
+		IF_CLONE_ADDREF_LOCKED(ifc);				\
+		IF_CLONE_UNLOCK(ifc);					\
+	} while (0)
+#define IF_CLONE_ADDREF_LOCKED(ifc)					\
+	do {								\
+		IF_CLONE_LOCK_ASSERT(ifc);				\
+		KASSERT((ifc)->ifc_refcnt >= 0,				\
+		    ("negative refcnt %ld", (ifc)->ifc_refcnt));	\
+		(ifc)->ifc_refcnt++;					\
+	} while (0)
+#define IF_CLONE_REMREF(ifc)						\
+	do {								\
+		IF_CLONE_LOCK(ifc);					\
+		IF_CLONE_REMREF_LOCKED(ifc);				\
+	} while (0)
+#define IF_CLONE_REMREF_LOCKED(ifc)					\
+	do {								\
+		IF_CLONE_LOCK_ASSERT(ifc);				\
+		KASSERT((ifc)->ifc_refcnt > 0,				\
+		    ("bogus refcnt %ld", (ifc)->ifc_refcnt));		\
+		if (--(ifc)->ifc_refcnt == 0) {				\
+			IF_CLONE_UNLOCK(ifc);				\
+			if_clone_free(ifc);				\
+		}							\
+		/* silently free the lock */				\
+		IF_CLONE_UNLOCK(ifc);					\
+	} while (0)
+
+MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
+
+void
+if_clone_init(void)
+{
+	IF_CLONERS_LOCK_INIT();
+}
+
+/*
+ * Create a clone network interface.
+ */
+int
+if_clone_create(char *name, size_t len)
+{
+	int err;
+	struct if_clone *ifc;
+
+	if (ifunit(name) != NULL)
+		return (EEXIST);
+
+	/* Try to find an applicable cloner for this request */
+	IF_CLONERS_LOCK();
+	LIST_FOREACH(ifc, &if_cloners, ifc_list) {
+		if (ifc->ifc_match(ifc, name)) {
+			IF_CLONE_ADDREF(ifc);
+			break;
+		}
+	}
+	IF_CLONERS_UNLOCK();
+
+	if (ifc == NULL)
+		return (EINVAL);
+
+	err = (*ifc->ifc_create)(ifc, name, len);
+	IF_CLONE_REMREF(ifc);
+	return (err);
+}
+
+/*
+ * Destroy a clone network interface.
+ */
+int
+if_clone_destroy(const char *name)
+{
+	int err;
+	struct if_clone *ifc;
+	struct ifnet *ifp;
+
+	ifp = ifunit(name);
+	if (ifp == NULL)
+		return (ENXIO);
+
+	/* Find the cloner for this interface */
+	IF_CLONERS_LOCK();
+	LIST_FOREACH(ifc, &if_cloners, ifc_list) {
+		if (strcmp(ifc->ifc_name, ifp->if_dname) == 0) {
+			IF_CLONE_ADDREF(ifc);
+			break;
+		}
+	}
+	IF_CLONERS_UNLOCK();
+	if (ifc == NULL)
+		return (EINVAL);
+
+	if (ifc->ifc_destroy == NULL) {
+		err = EOPNOTSUPP;
+		goto done;
+	}
+
+	err =  (*ifc->ifc_destroy)(ifc, ifp);
+
+done:
+	IF_CLONE_REMREF(ifc);
+	return (err);
+}
+
+/*
+ * Register a network interface cloner.
+ */
+void
+if_clone_attach(struct if_clone *ifc)
+{
+	int len, maxclone;
+
+	/*
+	 * Compute bitmap size and allocate it.
+	 */
+	maxclone = ifc->ifc_maxunit + 1;
+	len = maxclone >> 3;
+	if ((len << 3) < maxclone)
+		len++;
+	ifc->ifc_units = malloc(len, M_CLONE, M_WAITOK | M_ZERO);
+	ifc->ifc_bmlen = len;
+	IF_CLONE_LOCK_INIT(ifc);
+	IF_CLONE_ADDREF(ifc);
+
+	IF_CLONERS_LOCK();
+	LIST_INSERT_HEAD(&if_cloners, ifc, ifc_list);
+	if_cloners_count++;
+	IF_CLONERS_UNLOCK();
+
+	if (ifc->ifc_attach != NULL)
+		(*ifc->ifc_attach)(ifc);
+	EVENTHANDLER_INVOKE(if_clone_event, ifc);
+}
+
+/*
+ * Unregister a network interface cloner.
+ */
+void
+if_clone_detach(struct if_clone *ifc)
+{
+
+	IF_CLONERS_LOCK();
+	LIST_REMOVE(ifc, ifc_list);
+	if_cloners_count--;
+	IF_CLONERS_UNLOCK();
+
+	IF_CLONE_REMREF(ifc);
+}
+
+static void
+if_clone_free(struct if_clone *ifc)
+{
+
+	IF_CLONE_LOCK_DESTROY(ifc);
+	free(ifc->ifc_units, M_CLONE);
+}
+
+/*
+ * Provide list of interface cloners to userspace.
+ */
+int
+if_clone_list(struct if_clonereq *ifcr)
+{
+	char outbuf[IFNAMSIZ], *dst;
+	struct if_clone *ifc;
+	int count, err = 0;
+
+	IF_CLONERS_LOCK();
+
+	ifcr->ifcr_total = if_cloners_count;
+	if ((dst = ifcr->ifcr_buffer) == NULL) {
+		/* Just asking how many there are. */
+		goto done;
+	}
+
+	if (ifcr->ifcr_count < 0) {
+		err = EINVAL;
+		goto done;
+	}
+
+	count = (if_cloners_count < ifcr->ifcr_count) ?
+	    if_cloners_count : ifcr->ifcr_count;
+
+	for (ifc = LIST_FIRST(&if_cloners); ifc != NULL && count != 0;
+	     ifc = LIST_NEXT(ifc, ifc_list), count--, dst += IFNAMSIZ) {
+		strlcpy(outbuf, ifc->ifc_name, IFNAMSIZ);
+		err = copyout(outbuf, dst, IFNAMSIZ);
+		if (err)
+			break;
+	}
+
+done:
+	IF_CLONERS_UNLOCK();
+	return (err);
+}
+
+/*
+ * A utility function to extract unit numbers from interface names of
+ * the form name###.
+ *
+ * Returns 0 on success and an error on failure.
+ */
+int
+ifc_name2unit(const char *name, int *unit)
+{
+	const char	*cp;
+
+	for (cp = name; *cp != '\0' && (*cp < '0' || *cp > '9'); cp++);
+	if (*cp == '\0') {
+		*unit = -1;
+	} else {
+		for (*unit = 0; *cp != '\0'; cp++) {
+			if (*cp < '0' || *cp > '9') {
+				/* Bogus unit number. */
+				return (EINVAL);
+			}
+			*unit = (*unit * 10) + (*cp - '0');
+		}
+	}
+
+	return (0);
+}
+
+int
+ifc_alloc_unit(struct if_clone *ifc, int *unit)
+{
+	int wildcard, bytoff, bitoff;
+	int err = 0;
+
+	IF_CLONE_LOCK(ifc);
+
+	bytoff = bitoff = 0;
+	wildcard = (*unit < 0);
+	/*
+	 * Find a free unit if none was given.
+	 */
+	if (wildcard) {
+		while ((bytoff < ifc->ifc_bmlen)
+		    && (ifc->ifc_units[bytoff] == 0xff))
+			bytoff++;
+		if (bytoff >= ifc->ifc_bmlen) {
+			err = ENOSPC;
+			goto done;
+		}
+		while ((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0)
+			bitoff++;
+		*unit = (bytoff << 3) + bitoff;
+	}
+
+	if (*unit > ifc->ifc_maxunit) {
+		err = ENOSPC;
+		goto done;
+	}
+
+	if (!wildcard) {
+		bytoff = *unit >> 3;
+		bitoff = *unit - (bytoff << 3);
+	}
+
+	if((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0) {
+		err = EEXIST;
+		goto done;
+	}
+	/*
+	 * Allocate the unit in the bitmap.
+	 */
+	ifc->ifc_units[bytoff] |= (1 << bitoff);
+
+done:
+	IF_CLONE_UNLOCK(ifc);
+	return (err);
+}
+
+void
+ifc_free_unit(struct if_clone *ifc, int unit)
+{
+	int bytoff, bitoff;
+
+
+	/*
+	 * Compute offset in the bitmap and deallocate the unit.
+	 */
+	bytoff = unit >> 3;
+	bitoff = unit - (bytoff << 3);
+
+	IF_CLONE_LOCK(ifc);
+	KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0,
+	    ("%s: bit is already cleared", __func__));
+	ifc->ifc_units[bytoff] &= ~(1 << bitoff);
+	IF_CLONE_UNLOCK(ifc);
+}
+
+void
+ifc_simple_attach(struct if_clone *ifc)
+{
+	int err;
+	int unit;
+	char name[IFNAMSIZ];
+	struct ifc_simple_data *ifcs = ifc->ifc_data;
+
+	KASSERT(ifcs->ifcs_minifs - 1 <= ifc->ifc_maxunit,
+	    ("%s: %s requested more units then allowed (%d > %d)",
+	    __func__, ifc->ifc_name, ifcs->ifcs_minifs,
+	    ifc->ifc_maxunit + 1));
+
+	for (unit = 0; unit < ifcs->ifcs_minifs; unit++) {
+		snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
+		err = (*ifc->ifc_create)(ifc, name, IFNAMSIZ);
+		KASSERT(err == 0,
+		    ("%s: failed to create required interface %s",
+		    __func__, name));
+	}
+}
+
+int
+ifc_simple_match(struct if_clone *ifc, const char *name)
+{
+	const char *cp;
+	int i;
+	
+	/* Match the name */
+	for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
+		if (ifc->ifc_name[i] != *cp)
+			return (0);
+	}
+
+	/* Make sure there's a unit number or nothing after the name */
+	for (; *cp != '\0'; cp++) {
+		if (*cp < '0' || *cp > '9')
+			return (0);
+	}
+
+	return (1);
+}
+
+int
+ifc_simple_create(struct if_clone *ifc, char *name, size_t len)
+{
+	char *dp;
+	int wildcard;
+	int unit;
+	int err;
+	struct ifc_simple_data *ifcs = ifc->ifc_data;
+
+	err = ifc_name2unit(name, &unit);
+	if (err != 0)
+		return (err);
+
+	wildcard = (unit < 0);
+
+	err = ifc_alloc_unit(ifc, &unit);
+	if (err != 0)
+		return (err);
+
+	err = ifcs->ifcs_create(ifc, unit);
+	if (err != 0) {
+		ifc_free_unit(ifc, unit);
+		return (err);
+	}
+
+	/* In the wildcard case, we need to update the name. */
+	if (wildcard) {
+		for (dp = name; *dp != '\0'; dp++);
+		if (snprintf(dp, len - (dp-name), "%d", unit) >
+		    len - (dp-name) - 1) {
+			/*
+			 * This can only be a programmer error and
+			 * there's no straightforward way to recover if
+			 * it happens.
+			 */
+			panic("if_clone_create(): interface name too long");
+		}
+
+	}
+
+	return (0);
+}
+
+int
+ifc_simple_destroy(struct if_clone *ifc, struct ifnet *ifp)
+{
+	int unit;
+	struct ifc_simple_data *ifcs = ifc->ifc_data;
+
+	unit = ifp->if_dunit;
+
+	if (unit < ifcs->ifcs_minifs) 
+		return (EINVAL);
+
+	ifcs->ifcs_destroy(ifp);
+
+	ifc_free_unit(ifc, unit);
+
+	return (0);
+}