1c167b9c7SMaximilian Luz /* SPDX-License-Identifier: GPL-2.0+ */
2c167b9c7SMaximilian Luz /*
3c167b9c7SMaximilian Luz * SSH message parser.
4c167b9c7SMaximilian Luz *
5*221756e6SMaximilian Luz * Copyright (C) 2019-2022 Maximilian Luz <luzmaximilian@gmail.com>
6c167b9c7SMaximilian Luz */
7c167b9c7SMaximilian Luz
8c167b9c7SMaximilian Luz #ifndef _SURFACE_AGGREGATOR_SSH_PARSER_H
9c167b9c7SMaximilian Luz #define _SURFACE_AGGREGATOR_SSH_PARSER_H
10c167b9c7SMaximilian Luz
11c167b9c7SMaximilian Luz #include <linux/device.h>
12c167b9c7SMaximilian Luz #include <linux/kfifo.h>
13c167b9c7SMaximilian Luz #include <linux/slab.h>
14c167b9c7SMaximilian Luz #include <linux/types.h>
15c167b9c7SMaximilian Luz
16c167b9c7SMaximilian Luz #include <linux/surface_aggregator/serial_hub.h>
17c167b9c7SMaximilian Luz
18c167b9c7SMaximilian Luz /**
19c167b9c7SMaximilian Luz * struct sshp_buf - Parser buffer for SSH messages.
20c167b9c7SMaximilian Luz * @ptr: Pointer to the beginning of the buffer.
21c167b9c7SMaximilian Luz * @len: Number of bytes used in the buffer.
22c167b9c7SMaximilian Luz * @cap: Maximum capacity of the buffer.
23c167b9c7SMaximilian Luz */
24c167b9c7SMaximilian Luz struct sshp_buf {
25c167b9c7SMaximilian Luz u8 *ptr;
26c167b9c7SMaximilian Luz size_t len;
27c167b9c7SMaximilian Luz size_t cap;
28c167b9c7SMaximilian Luz };
29c167b9c7SMaximilian Luz
30c167b9c7SMaximilian Luz /**
31c167b9c7SMaximilian Luz * sshp_buf_init() - Initialize a SSH parser buffer.
32c167b9c7SMaximilian Luz * @buf: The buffer to initialize.
33c167b9c7SMaximilian Luz * @ptr: The memory backing the buffer.
34c167b9c7SMaximilian Luz * @cap: The length of the memory backing the buffer, i.e. its capacity.
35c167b9c7SMaximilian Luz *
36c167b9c7SMaximilian Luz * Initializes the buffer with the given memory as backing and set its used
37c167b9c7SMaximilian Luz * length to zero.
38c167b9c7SMaximilian Luz */
sshp_buf_init(struct sshp_buf * buf,u8 * ptr,size_t cap)39c167b9c7SMaximilian Luz static inline void sshp_buf_init(struct sshp_buf *buf, u8 *ptr, size_t cap)
40c167b9c7SMaximilian Luz {
41c167b9c7SMaximilian Luz buf->ptr = ptr;
42c167b9c7SMaximilian Luz buf->len = 0;
43c167b9c7SMaximilian Luz buf->cap = cap;
44c167b9c7SMaximilian Luz }
45c167b9c7SMaximilian Luz
46c167b9c7SMaximilian Luz /**
47c167b9c7SMaximilian Luz * sshp_buf_alloc() - Allocate and initialize a SSH parser buffer.
48c167b9c7SMaximilian Luz * @buf: The buffer to initialize/allocate to.
49c167b9c7SMaximilian Luz * @cap: The desired capacity of the buffer.
50c167b9c7SMaximilian Luz * @flags: The flags used for allocating the memory.
51c167b9c7SMaximilian Luz *
52c167b9c7SMaximilian Luz * Allocates @cap bytes and initializes the provided buffer struct with the
53c167b9c7SMaximilian Luz * allocated memory.
54c167b9c7SMaximilian Luz *
55c167b9c7SMaximilian Luz * Return: Returns zero on success and %-ENOMEM if allocation failed.
56c167b9c7SMaximilian Luz */
sshp_buf_alloc(struct sshp_buf * buf,size_t cap,gfp_t flags)57c167b9c7SMaximilian Luz static inline int sshp_buf_alloc(struct sshp_buf *buf, size_t cap, gfp_t flags)
58c167b9c7SMaximilian Luz {
59c167b9c7SMaximilian Luz u8 *ptr;
60c167b9c7SMaximilian Luz
61c167b9c7SMaximilian Luz ptr = kzalloc(cap, flags);
62c167b9c7SMaximilian Luz if (!ptr)
63c167b9c7SMaximilian Luz return -ENOMEM;
64c167b9c7SMaximilian Luz
65c167b9c7SMaximilian Luz sshp_buf_init(buf, ptr, cap);
66c167b9c7SMaximilian Luz return 0;
67c167b9c7SMaximilian Luz }
68c167b9c7SMaximilian Luz
69c167b9c7SMaximilian Luz /**
70c167b9c7SMaximilian Luz * sshp_buf_free() - Free a SSH parser buffer.
71c167b9c7SMaximilian Luz * @buf: The buffer to free.
72c167b9c7SMaximilian Luz *
73c167b9c7SMaximilian Luz * Frees a SSH parser buffer by freeing the memory backing it and then
74c167b9c7SMaximilian Luz * resetting its pointer to %NULL and length and capacity to zero. Intended to
75c167b9c7SMaximilian Luz * free a buffer previously allocated with sshp_buf_alloc().
76c167b9c7SMaximilian Luz */
sshp_buf_free(struct sshp_buf * buf)77c167b9c7SMaximilian Luz static inline void sshp_buf_free(struct sshp_buf *buf)
78c167b9c7SMaximilian Luz {
79c167b9c7SMaximilian Luz kfree(buf->ptr);
80c167b9c7SMaximilian Luz buf->ptr = NULL;
81c167b9c7SMaximilian Luz buf->len = 0;
82c167b9c7SMaximilian Luz buf->cap = 0;
83c167b9c7SMaximilian Luz }
84c167b9c7SMaximilian Luz
85c167b9c7SMaximilian Luz /**
86c167b9c7SMaximilian Luz * sshp_buf_drop() - Drop data from the beginning of the buffer.
87c167b9c7SMaximilian Luz * @buf: The buffer to drop data from.
88c167b9c7SMaximilian Luz * @n: The number of bytes to drop.
89c167b9c7SMaximilian Luz *
90c167b9c7SMaximilian Luz * Drops the first @n bytes from the buffer. Re-aligns any remaining data to
91c167b9c7SMaximilian Luz * the beginning of the buffer.
92c167b9c7SMaximilian Luz */
sshp_buf_drop(struct sshp_buf * buf,size_t n)93c167b9c7SMaximilian Luz static inline void sshp_buf_drop(struct sshp_buf *buf, size_t n)
94c167b9c7SMaximilian Luz {
95c167b9c7SMaximilian Luz memmove(buf->ptr, buf->ptr + n, buf->len - n);
96c167b9c7SMaximilian Luz buf->len -= n;
97c167b9c7SMaximilian Luz }
98c167b9c7SMaximilian Luz
99c167b9c7SMaximilian Luz /**
100c167b9c7SMaximilian Luz * sshp_buf_read_from_fifo() - Transfer data from a fifo to the buffer.
101c167b9c7SMaximilian Luz * @buf: The buffer to write the data into.
102c167b9c7SMaximilian Luz * @fifo: The fifo to read the data from.
103c167b9c7SMaximilian Luz *
104c167b9c7SMaximilian Luz * Transfers the data contained in the fifo to the buffer, removing it from
105c167b9c7SMaximilian Luz * the fifo. This function will try to transfer as much data as possible,
106c167b9c7SMaximilian Luz * limited either by the remaining space in the buffer or by the number of
107c167b9c7SMaximilian Luz * bytes available in the fifo.
108c167b9c7SMaximilian Luz *
109c167b9c7SMaximilian Luz * Return: Returns the number of bytes transferred.
110c167b9c7SMaximilian Luz */
sshp_buf_read_from_fifo(struct sshp_buf * buf,struct kfifo * fifo)111c167b9c7SMaximilian Luz static inline size_t sshp_buf_read_from_fifo(struct sshp_buf *buf,
112c167b9c7SMaximilian Luz struct kfifo *fifo)
113c167b9c7SMaximilian Luz {
114c167b9c7SMaximilian Luz size_t n;
115c167b9c7SMaximilian Luz
116c167b9c7SMaximilian Luz n = kfifo_out(fifo, buf->ptr + buf->len, buf->cap - buf->len);
117c167b9c7SMaximilian Luz buf->len += n;
118c167b9c7SMaximilian Luz
119c167b9c7SMaximilian Luz return n;
120c167b9c7SMaximilian Luz }
121c167b9c7SMaximilian Luz
122c167b9c7SMaximilian Luz /**
123c167b9c7SMaximilian Luz * sshp_buf_span_from() - Initialize a span from the given buffer and offset.
124c167b9c7SMaximilian Luz * @buf: The buffer to create the span from.
125c167b9c7SMaximilian Luz * @offset: The offset in the buffer at which the span should start.
126c167b9c7SMaximilian Luz * @span: The span to initialize (output).
127c167b9c7SMaximilian Luz *
128c167b9c7SMaximilian Luz * Initializes the provided span to point to the memory at the given offset in
129c167b9c7SMaximilian Luz * the buffer, with the length of the span being capped by the number of bytes
130c167b9c7SMaximilian Luz * used in the buffer after the offset (i.e. bytes remaining after the
131c167b9c7SMaximilian Luz * offset).
132c167b9c7SMaximilian Luz *
133c167b9c7SMaximilian Luz * Warning: This function does not validate that @offset is less than or equal
134c167b9c7SMaximilian Luz * to the number of bytes used in the buffer or the buffer capacity. This must
135c167b9c7SMaximilian Luz * be guaranteed by the caller.
136c167b9c7SMaximilian Luz */
sshp_buf_span_from(struct sshp_buf * buf,size_t offset,struct ssam_span * span)137c167b9c7SMaximilian Luz static inline void sshp_buf_span_from(struct sshp_buf *buf, size_t offset,
138c167b9c7SMaximilian Luz struct ssam_span *span)
139c167b9c7SMaximilian Luz {
140c167b9c7SMaximilian Luz span->ptr = buf->ptr + offset;
141c167b9c7SMaximilian Luz span->len = buf->len - offset;
142c167b9c7SMaximilian Luz }
143c167b9c7SMaximilian Luz
144c167b9c7SMaximilian Luz bool sshp_find_syn(const struct ssam_span *src, struct ssam_span *rem);
145c167b9c7SMaximilian Luz
146c167b9c7SMaximilian Luz int sshp_parse_frame(const struct device *dev, const struct ssam_span *source,
147c167b9c7SMaximilian Luz struct ssh_frame **frame, struct ssam_span *payload,
148c167b9c7SMaximilian Luz size_t maxlen);
149c167b9c7SMaximilian Luz
150c167b9c7SMaximilian Luz int sshp_parse_command(const struct device *dev, const struct ssam_span *source,
151c167b9c7SMaximilian Luz struct ssh_command **command,
152c167b9c7SMaximilian Luz struct ssam_span *command_data);
153c167b9c7SMaximilian Luz
154c167b9c7SMaximilian Luz #endif /* _SURFACE_AGGREGATOR_SSH_PARSER_h */
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