1 files changed, 280 insertions, 76 deletions

diff --git a/sys/net/pfil.c b/sys/net/pfil.c
index 2ed40b2..c995ec2 100644
--- a/sys/net/pfil.c
+++ b/sys/net/pfil.c
@@ -1,4 +1,5 @@
-/*	$FreeBSD$	*/
+/*	$FreeBSD$ */
+/*	$NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $	*/
 
 /*
  * Copyright (c) 1996 Matthew R. Green
@@ -29,30 +30,198 @@
  */
 
 #include <sys/param.h>
+#include <sys/kernel.h>
 #include <sys/errno.h>
 #include <sys/malloc.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/systm.h>
+#include <sys/condvar.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/proc.h>
 #include <sys/queue.h>
 
 #include <net/if.h>
 #include <net/pfil.h>
 
-static void pfil_init(struct pfil_head *);
-static int pfil_list_add(pfil_list_t *,
-    int (*)(void *, int, struct ifnet *, int, struct mbuf **), int);
+static struct mtx pfil_global_lock;
+
+MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock", MTX_DEF);
+
+static int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int);
+
 static int pfil_list_remove(pfil_list_t *,
-    int (*)(void *, int, struct ifnet *, int, struct mbuf **));
+    int (*)(void *, struct mbuf **, struct ifnet *, int), void *);
+
+LIST_HEAD(, pfil_head) pfil_head_list =
+    LIST_HEAD_INITIALIZER(&pfil_head_list);
+
+static __inline void
+PFIL_RLOCK(struct pfil_head *ph)
+{
+	mtx_lock(&ph->ph_mtx);
+	ph->ph_busy_count++;
+	mtx_unlock(&ph->ph_mtx);
+}
+
+static __inline void
+PFIL_RUNLOCK(struct pfil_head *ph)
+{
+	mtx_lock(&ph->ph_mtx);
+	ph->ph_busy_count--;
+	if (ph->ph_busy_count == 0 && ph->ph_want_write)
+		cv_signal(&ph->ph_cv);
+	mtx_unlock(&ph->ph_mtx);
+}
+
+static __inline void
+PFIL_WLOCK(struct pfil_head *ph)
+{
+	mtx_lock(&ph->ph_mtx);
+	ph->ph_want_write = 1;
+	while (ph->ph_busy_count > 0)
+		cv_wait(&ph->ph_cv, &ph->ph_mtx);
+}
+
+static __inline int
+PFIL_TRY_WLOCK(struct pfil_head *ph)
+{
+	mtx_lock(&ph->ph_mtx);
+	ph->ph_want_write = 1;
+	if (ph->ph_busy_count > 0) {
+		ph->ph_want_write = 0;
+		mtx_unlock(&ph->ph_mtx);
+		return EBUSY;
+	}
+	return 0;
+}
+
+static __inline void
+PFIL_WUNLOCK(struct pfil_head *ph)
+{
+	ph->ph_want_write = 0;				\
+	mtx_unlock(&ph->ph_mtx);
+	cv_signal(&ph->ph_cv);
+}
 
-static void
-pfil_init(ph)
-	 struct pfil_head *ph;
+#define PFIL_LIST_LOCK() mtx_lock(&pfil_global_lock)
+#define PFIL_LIST_UNLOCK() mtx_unlock(&pfil_global_lock)
+
+/*
+ * pfil_run_hooks() runs the specified packet filter hooks.
+ */
+int
+pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
+    int dir)
 {
+	struct packet_filter_hook *pfh;
+	struct mbuf *m = *mp;
+	int rv = 0;
+
+	if (ph->ph_busy_count == -1 || ph->ph_want_write)
+		return (0);
+
+	PFIL_RLOCK(ph);
+	for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
+	     pfh = TAILQ_NEXT(pfh, pfil_link)) {
+		if (pfh->pfil_func != NULL) {
+			rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir);
+			if (rv != 0 || m == NULL)
+				break;
+		}
+	}
+	PFIL_RUNLOCK(ph);
+	
+	*mp = m;
+	return (rv);
+}
+
+/*
+ * pfil_head_register() registers a pfil_head with the packet filter
+ * hook mechanism.
+ */
+int
+pfil_head_register(struct pfil_head *ph)
+{
+	struct pfil_head *lph;
+
+	PFIL_LIST_LOCK();
+	LIST_FOREACH(lph, &pfil_head_list, ph_list)
+		if (ph->ph_type == lph->ph_type &&
+		    ph->ph_un.phu_val == lph->ph_un.phu_val) {
+			PFIL_LIST_UNLOCK();
+			return EEXIST;
+		}
+	PFIL_LIST_UNLOCK();
+
+	if (mtx_initialized(&ph->ph_mtx)) {	/* should not happen */
+		KASSERT((0), ("%s: allready initialized!", __func__));
+		return EBUSY;
+	} else {
+		ph->ph_busy_count = -1;
+		ph->ph_want_write = 1;
+		mtx_init(&ph->ph_mtx, "pfil_head_mtx", NULL, MTX_DEF);
+		cv_init(&ph->ph_cv, "pfil_head_cv");
+		mtx_lock(&ph->ph_mtx);			/* XXX: race? */
+	}
 
 	TAILQ_INIT(&ph->ph_in);
 	TAILQ_INIT(&ph->ph_out);
-	ph->ph_init = 1;
+
+	PFIL_LIST_LOCK();
+	LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
+	PFIL_LIST_UNLOCK();
+	
+	PFIL_WUNLOCK(ph);
+	
+	return (0);
+}
+
+/*
+ * pfil_head_unregister() removes a pfil_head from the packet filter
+ * hook mechanism.
+ */
+int
+pfil_head_unregister(struct pfil_head *ph)
+{
+	struct packet_filter_hook *pfh, *pfnext;
+		
+	PFIL_LIST_LOCK();
+	/* 
+	 * LIST_REMOVE is safe for unlocked pfil_heads in ph_list.
+	 * No need to WLOCK all of them.
+	 */
+	LIST_REMOVE(ph, ph_list);
+	PFIL_LIST_UNLOCK();
+
+	PFIL_WLOCK(ph);			/* XXX: may sleep (cv_wait)! */
+	
+	TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext)
+		free(pfh, M_IFADDR);
+	TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext)
+		free(pfh, M_IFADDR);
+	cv_destroy(&ph->ph_cv);
+	mtx_destroy(&ph->ph_mtx);
+	
+	return (0);
+}
+
+/*
+ * pfil_head_get() returns the pfil_head for a given key/dlt.
+ */
+struct pfil_head *
+pfil_head_get(int type, u_long val)
+{
+	struct pfil_head *ph;
+
+	PFIL_LIST_LOCK();
+	LIST_FOREACH(ph, &pfil_head_list, ph_list)
+		if (ph->ph_type == type && ph->ph_un.phu_val == val)
+			break;
+	PFIL_LIST_UNLOCK();
+	
+	return (ph);
 }
 
 /*
@@ -64,53 +233,71 @@ pfil_init(ph)
  *	PFIL_WAITOK	OK to call malloc with M_WAITOK.
  */
 int
-pfil_add_hook(func, flags, ph)
-	int	(*func)(void *, int, struct ifnet *, int, struct mbuf **);
-	int	flags;
-	struct	pfil_head	*ph;
+pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
+    void *arg, int flags, struct pfil_head *ph)
 {
-	int err = 0;
+	struct packet_filter_hook *pfh1 = NULL;
+	struct packet_filter_hook *pfh2 = NULL;
+	int err;
 
-	if (ph->ph_init == 0)
-		pfil_init(ph);
+	/* Get memory */
+	if (flags & PFIL_IN) {
+		pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1), 
+		    M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
+		if (pfh1 == NULL) {
+			err = ENOMEM;
+			goto error;
+		}
+	}
+	if (flags & PFIL_OUT) {
+		pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
+		    M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
+		if (pfh2 == NULL) {
+			err = ENOMEM;
+			goto error;
+		}
+	}
 
-	if (flags & PFIL_IN)
-		err = pfil_list_add(&ph->ph_in, func, flags & ~PFIL_OUT);
-	if (err)
-		return err;
-	if (flags & PFIL_OUT)
-		err = pfil_list_add(&ph->ph_out, func, flags & ~PFIL_IN);
-	if (err) {
-		if (flags & PFIL_IN)
-			pfil_list_remove(&ph->ph_in, func);
-		return err;
+	/* Lock */
+	if (flags & PFIL_WAITOK)
+		PFIL_WLOCK(ph);
+	else {
+		err = PFIL_TRY_WLOCK(ph);
+		if (err)
+			goto error;
 	}
-	return 0;
-}
 
-static int
-pfil_list_add(list, func, flags)
-	pfil_list_t *list;
-	int	(*func)(void *, int, struct ifnet *, int, struct mbuf **);
-	int flags;
-{
-	struct packet_filter_hook *pfh;
+	/* Add */
+	if (flags & PFIL_IN) {
+		pfh1->pfil_func = func;
+		pfh1->pfil_arg = arg;
+		err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
+		if (err)
+			goto done;
+	}
+	if (flags & PFIL_OUT) {
+		pfh2->pfil_func = func;
+		pfh2->pfil_arg = arg;
+		err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
+		if (err) {
+			if (flags & PFIL_IN)
+				pfil_list_remove(&ph->ph_in, func, arg);
+			goto done;
+		}
+	}
+
+	ph->ph_busy_count = 0;
+	PFIL_WUNLOCK(ph);
 
-	pfh = (struct packet_filter_hook *)malloc(sizeof(*pfh), M_IFADDR,
-	    flags & PFIL_WAITOK ? M_WAITOK : M_NOWAIT);
-	if (pfh == NULL)
-		return ENOMEM;
-	pfh->pfil_func = func;
-	/*
-	 * insert the input list in reverse order of the output list
-	 * so that the same path is followed in or out of the kernel.
-	 */
-	
-	if (flags & PFIL_IN)
-		TAILQ_INSERT_HEAD(list, pfh, pfil_link);
-	else
-		TAILQ_INSERT_TAIL(list, pfh, pfil_link);
 	return 0;
+done:
+	PFIL_WUNLOCK(ph);
+error:
+	if (pfh1 != NULL)
+		free(pfh1, M_IFADDR);
+	if (pfh2 != NULL)
+		free(pfh2, M_IFADDR);
+	return err;
 }
 
 /*
@@ -118,54 +305,71 @@ pfil_list_add(list, func, flags)
  * hook list.
  */
 int
-pfil_remove_hook(func, flags, ph)
-	int	(*func)(void *, int, struct ifnet *, int, struct mbuf **);
-	int	flags;
-	struct	pfil_head	*ph;
+pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
+    void *arg, int flags, struct pfil_head *ph)
 {
 	int err = 0;
 
-	if (ph->ph_init == 0)
-		pfil_init(ph);
+	if (flags & PFIL_WAITOK)
+		PFIL_WLOCK(ph);
+	else {
+		err = PFIL_TRY_WLOCK(ph);
+		if (err)
+			return err;
+	}
 
 	if (flags & PFIL_IN)
-		err = pfil_list_remove(&ph->ph_in, func);
+		err = pfil_list_remove(&ph->ph_in, func, arg);
 	if ((err == 0) && (flags & PFIL_OUT))
-		err = pfil_list_remove(&ph->ph_out, func);
+		err = pfil_list_remove(&ph->ph_out, func, arg);
+
+	if (TAILQ_EMPTY(&ph->ph_in) && TAILQ_EMPTY(&ph->ph_out))
+		ph->ph_busy_count = -1;
+
+	PFIL_WUNLOCK(ph);
+	
 	return err;
 }
 
+static int
+pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
+{
+	struct packet_filter_hook *pfh;
+
+	/*
+	 * First make sure the hook is not already there.
+	 */
+	TAILQ_FOREACH(pfh, list, pfil_link)
+		if (pfh->pfil_func == pfh1->pfil_func &&
+		    pfh->pfil_arg == pfh1->pfil_arg)
+			return EEXIST;
+	/*
+	 * insert the input list in reverse order of the output list
+	 * so that the same path is followed in or out of the kernel.
+	 */
+	if (flags & PFIL_IN)
+		TAILQ_INSERT_HEAD(list, pfh1, pfil_link);
+	else
+		TAILQ_INSERT_TAIL(list, pfh1, pfil_link);
+
+	return 0;
+}
+
 /*
  * pfil_list_remove is an internal function that takes a function off the
  * specified list.
  */
 static int
-pfil_list_remove(list, func)
-	pfil_list_t *list;
-	int	(*func)(void *, int, struct ifnet *, int, struct mbuf **);
+pfil_list_remove(pfil_list_t *list,
+    int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg)
 {
 	struct packet_filter_hook *pfh;
 
 	TAILQ_FOREACH(pfh, list, pfil_link)
-		if (pfh->pfil_func == func) {
+		if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
 			TAILQ_REMOVE(list, pfh, pfil_link);
 			free(pfh, M_IFADDR);
 			return 0;
 		}
 	return ENOENT;
 }
-
-struct packet_filter_hook *
-pfil_hook_get(flag, ph)
-	int flag;
-	struct	pfil_head	*ph;
-{
-	if (ph->ph_init != 0)
-		switch (flag) {
-		case PFIL_IN:
-			return (TAILQ_FIRST(&ph->ph_in));
-		case PFIL_OUT:
-			return (TAILQ_FIRST(&ph->ph_out));
-		}
-	return NULL;
-}