1 files changed, 103 insertions, 0 deletions
diff --git a/include/linux/ppp-comp.h b/include/linux/ppp-comp.h
new file mode 100644
index 000000000..fb847e47f
--- /dev/null
+++ b/include/linux/ppp-comp.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * ppp-comp.h - Definitions for doing PPP packet compression.
+ *
+ * Copyright 1994-1998 Paul Mackerras.
+ */
+#ifndef _NET_PPP_COMP_H
+#define _NET_PPP_COMP_H
+
+#include <uapi/linux/ppp-comp.h>
+
+struct compstat;
+struct module;
+
+/*
+ * The following symbols control whether we include code for
+ * various compression methods.
+ */
+
+#ifndef DO_BSD_COMPRESS
+#define DO_BSD_COMPRESS	1	/* by default, include BSD-Compress */
+#endif
+#ifndef DO_DEFLATE
+#define DO_DEFLATE	1	/* by default, include Deflate */
+#endif
+#define DO_PREDICTOR_1	0
+#define DO_PREDICTOR_2	0
+
+/*
+ * Structure giving methods for compression/decompression.
+ */
+
+struct compressor {
+	int	compress_proto;	/* CCP compression protocol number */
+
+	/* Allocate space for a compressor (transmit side) */
+	void	*(*comp_alloc) (unsigned char *options, int opt_len);
+
+	/* Free space used by a compressor */
+	void	(*comp_free) (void *state);
+
+	/* Initialize a compressor */
+	int	(*comp_init) (void *state, unsigned char *options,
+			      int opt_len, int unit, int opthdr, int debug);
+
+	/* Reset a compressor */
+	void	(*comp_reset) (void *state);
+
+	/* Compress a packet */
+	int     (*compress) (void *state, unsigned char *rptr,
+			      unsigned char *obuf, int isize, int osize);
+
+	/* Return compression statistics */
+	void	(*comp_stat) (void *state, struct compstat *stats);
+
+	/* Allocate space for a decompressor (receive side) */
+	void	*(*decomp_alloc) (unsigned char *options, int opt_len);
+
+	/* Free space used by a decompressor */
+	void	(*decomp_free) (void *state);
+
+	/* Initialize a decompressor */
+	int	(*decomp_init) (void *state, unsigned char *options,
+				int opt_len, int unit, int opthdr, int mru,
+				int debug);
+
+	/* Reset a decompressor */
+	void	(*decomp_reset) (void *state);
+
+	/* Decompress a packet. */
+	int	(*decompress) (void *state, unsigned char *ibuf, int isize,
+				unsigned char *obuf, int osize);
+
+	/* Update state for an incompressible packet received */
+	void	(*incomp) (void *state, unsigned char *ibuf, int icnt);
+
+	/* Return decompression statistics */
+	void	(*decomp_stat) (void *state, struct compstat *stats);
+
+	/* Used in locking compressor modules */
+	struct module *owner;
+	/* Extra skb space needed by the compressor algorithm */
+	unsigned int comp_extra;
+};
+
+/*
+ * The return value from decompress routine is the length of the
+ * decompressed packet if successful, otherwise DECOMP_ERROR
+ * or DECOMP_FATALERROR if an error occurred.
+ * 
+ * We need to make this distinction so that we can disable certain
+ * useful functionality, namely sending a CCP reset-request as a result
+ * of an error detected after decompression.  This is to avoid infringing
+ * a patent held by Motorola.
+ * Don't you just lurve software patents.
+ */
+
+#define DECOMP_ERROR		-1	/* error detected before decomp. */
+#define DECOMP_FATALERROR	-2	/* error detected after decomp. */
+
+extern int ppp_register_compressor(struct compressor *);
+extern void ppp_unregister_compressor(struct compressor *);
+#endif /* _NET_PPP_COMP_H */