New netgraph node ng_patch(4). It performs data modification of packets

passing through. Modifications are restricted to a subset of C language
operations on unsigned integers of 8, 16, 32 or 64 bit size.
These are: set to new value (=), addition (+=), subtraction (-=),
multiplication (*=), division (/=), negation (= -), bitwise AND (&=),
bitwise OR (|=), bitwise eXclusive OR (^=), shift left (<<=),
shift right (>>=). Several operations are all applied to a packet
sequentially in order they were specified by user.

Submitted by:	Maxim Ignatenko <gelraen.ua at gmail.com>
		Vadim Goncharov <vadimnuclight at tpu.ru>
Discussed with:	net@
Approved by:	mav (mentor)
MFC after:	1 month

1 files changed, 107 insertions, 0 deletions

diff --git a/sys/netgraph/ng_patch.h b/sys/netgraph/ng_patch.h
new file mode 100644
index 0000000..fedde07
--- /dev/null
+++ b/sys/netgraph/ng_patch.h
@@ -0,0 +1,107 @@
+/*-
+ * Copyright (C) 2010 by Maxim Ignatenko <gelraen.ua@gmail.com>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _NETGRAPH_NG_PATCH_H_
+#define _NETGRAPH_NG_PATCH_H_
+
+/* Node type name. */
+#define NG_PATCH_NODE_TYPE	"patch"
+
+/* Node type cookie. */
+#define NGM_PATCH_COOKIE	1262445509
+
+/* Hook names */
+#define NG_PATCH_HOOK_IN	"in"
+#define NG_PATCH_HOOK_OUT	"out"
+
+/* Netgraph commands understood by this node type */
+enum {
+	NGM_PATCH_SETCONFIG = 1,
+	NGM_PATCH_GETCONFIG,
+	NGM_PATCH_GET_STATS,
+	NGM_PATCH_CLR_STATS,
+	NGM_PATCH_GETCLR_STATS
+};
+
+/* Patching modes */
+enum {
+	NG_PATCH_MODE_SET = 1,
+	NG_PATCH_MODE_ADD = 2,
+	NG_PATCH_MODE_SUB = 3,
+	NG_PATCH_MODE_MUL = 4,
+	NG_PATCH_MODE_DIV = 5,
+	NG_PATCH_MODE_NEG = 6,
+	NG_PATCH_MODE_AND = 7,
+	NG_PATCH_MODE_OR = 8,
+	NG_PATCH_MODE_XOR = 9,
+	NG_PATCH_MODE_SHL = 10,
+	NG_PATCH_MODE_SHR = 11
+};
+
+struct ng_patch_op {
+	uint64_t	value;
+	uint32_t	offset;
+	uint16_t	length;	/* 1,2,4 or 8 (bytes) */
+	uint16_t	mode;
+};
+
+#define NG_PATCH_OP_TYPE_INFO	{	\
+		{ "value",	&ng_parse_uint64_type	},	\
+		{ "offset",	&ng_parse_uint32_type	},	\
+		{ "length",	&ng_parse_uint16_type	},	\
+		{ "mode",	&ng_parse_uint16_type	},	\
+		{ NULL } \
+}
+
+struct ng_patch_config {
+	uint32_t	count;
+	uint32_t	csum_flags;
+	struct ng_patch_op ops[];
+};
+
+#define NG_PATCH_CONFIG_TYPE_INFO	{	\
+		{ "count",	&ng_parse_uint32_type	},	\
+		{ "csum_flags",	&ng_parse_uint32_type	},	\
+		{ "ops",	&ng_patch_confarr_type	},	\
+		{ NULL } \
+}
+
+struct ng_patch_stats {
+	uint64_t	received;
+	uint64_t	patched;
+	uint64_t	dropped;
+};
+
+#define NG_PATCH_STATS_TYPE_INFO {	\
+		{ "received",	&ng_parse_uint64_type	},	\
+		{ "patched",	&ng_parse_uint64_type	},	\
+		{ "dropped",	&ng_parse_uint64_type	},	\
+		{ NULL } \
+}
+
+#endif /* _NETGRAPH_NG_PATCH_H_ */