Add pfil(9) subroutines and manpage from NetBSD.

1 files changed, 176 insertions, 0 deletions

diff --git a/sys/net/pfil.c b/sys/net/pfil.c
new file mode 100644
index 0000000..67501ee
--- /dev/null
+++ b/sys/net/pfil.c
@@ -0,0 +1,176 @@
+/*	$FreeBSD$	*/
+
+/*
+ * Copyright (c) 1996 Matthew R. Green
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+
+#include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/malloc.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/queue.h>
+
+#include <net/if.h>
+#include <net/pfil.h>
+
+static void pfil_init __P((struct pfil_head *));
+static int pfil_list_add(pfil_list_t *,
+    int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)), int);
+static int pfil_list_remove(pfil_list_t *,
+    int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)));
+
+static void
+pfil_init(ph)
+	 struct pfil_head *ph;
+{
+
+	TAILQ_INIT(&ph->ph_in);
+	TAILQ_INIT(&ph->ph_out);
+	ph->ph_init = 1;
+}
+
+/*
+ * pfil_add_hook() adds a function to the packet filter hook.  the
+ * flags are:
+ *	PFIL_IN		call me on incoming packets
+ *	PFIL_OUT	call me on outgoing packets
+ *	PFIL_ALL	call me on all of the above
+ *	PFIL_WAITOK	OK to call malloc with M_WAITOK.
+ */
+int
+pfil_add_hook(func, flags, ph)
+	int	(*func) __P((void *, int, struct ifnet *, int,
+			     struct mbuf **));
+	int	flags;
+	struct	pfil_head	*ph;
+{
+	int err = 0;
+
+	if (ph->ph_init == 0)
+		pfil_init(ph);
+
+	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;
+	}
+	return 0;
+}
+
+static int
+pfil_list_add(list, func, flags)
+	pfil_list_t *list;
+	int	(*func) __P((void *, int, struct ifnet *, int,
+			     struct mbuf **));
+	int flags;
+{
+	struct packet_filter_hook *pfh;
+
+	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;
+}
+
+/*
+ * pfil_remove_hook removes a specific function from the packet filter
+ * hook list.
+ */
+int
+pfil_remove_hook(func, flags, ph)
+	int	(*func) __P((void *, int, struct ifnet *, int,
+			     struct mbuf **));
+	int	flags;
+	struct	pfil_head	*ph;
+{
+	int err = 0;
+
+	if (ph->ph_init == 0)
+		pfil_init(ph);
+
+	if (flags & PFIL_IN)
+		err = pfil_list_remove(&ph->ph_in, func);
+	if ((err == 0) && (flags & PFIL_OUT))
+		err = pfil_list_remove(&ph->ph_out, func);
+	return err;
+}
+
+/*
+ * 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) __P((void *, int, struct ifnet *, int,
+			     struct mbuf **));
+{
+	struct packet_filter_hook *pfh;
+
+	for (pfh = list->tqh_first; pfh; pfh = pfh->pfil_link.tqe_next)
+		if (pfh->pfil_func == func) {
+			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 (ph->ph_in.tqh_first);
+		case PFIL_OUT:
+			return (ph->ph_out.tqh_first);
+		}
+	return NULL;
+}