v4.19.13 snapshot.
diff --git a/include/linux/ppp-comp.h b/include/linux/ppp-comp.h
new file mode 100644
index 0000000..4ea1d37
--- /dev/null
+++ b/include/linux/ppp-comp.h
@@ -0,0 +1,106 @@
+/*
+ * ppp-comp.h - Definitions for doing PPP packet compression.
+ *
+ * Copyright 1994-1998 Paul Mackerras.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+#ifndef _NET_PPP_COMP_H
+#define _NET_PPP_COMP_H
+
+#include <uapi/linux/ppp-comp.h>
+
+
+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 */