2  * Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.
19  * Byte-wise ring buffer which supports pushing and popping blocks of multiple
45 #define MAX_OFFSET   (((uint64_t)1) << 62) /* QUIC-imposed limit */  in OSSL_SAFE_MATH_UNSIGNED()
47 static ossl_inline int ring_buf_init(struct ring_buf *r)  in OSSL_SAFE_MATH_UNSIGNED()
49     r->start = NULL;  in OSSL_SAFE_MATH_UNSIGNED()
50     r->alloc = 0;  in OSSL_SAFE_MATH_UNSIGNED()
51     r->head_offset = r->ctail_offset = 0;  in OSSL_SAFE_MATH_UNSIGNED()
55 static ossl_inline void ring_buf_destroy(struct ring_buf *r, int cleanse)  in ring_buf_destroy()  argument
58         OPENSSL_clear_free(r->start, r->alloc);  in ring_buf_destroy()
60         OPENSSL_free(r->start);  in ring_buf_destroy()
61     r->start = NULL;  in ring_buf_destroy()
62     r->alloc = 0;  in ring_buf_destroy()
65 static ossl_inline size_t ring_buf_used(struct ring_buf *r)  in ring_buf_used()  argument
67     return (size_t)(r->head_offset - r->ctail_offset);  in ring_buf_used()
70 static ossl_inline size_t ring_buf_avail(struct ring_buf *r)  in ring_buf_avail()  argument
72     return r->alloc - ring_buf_used(r);  in ring_buf_avail()
75 static ossl_inline int ring_buf_write_at(struct ring_buf *r,  in ring_buf_write_at()  argument
81     unsigned char *start = r->start;  in ring_buf_write_at()
84     avail = ring_buf_avail(r);  in ring_buf_write_at()
85     if (logical_offset < r->ctail_offset  in ring_buf_write_at()
87            > safe_add_u64(r->head_offset, avail, &err)  in ring_buf_write_at()
88         || safe_add_u64(r->head_offset, buf_len, &err)  in ring_buf_write_at()
94         idx = logical_offset % r->alloc;  in ring_buf_write_at()
95         l = r->alloc - idx;  in ring_buf_write_at()
100         if (r->head_offset < logical_offset + l)  in ring_buf_write_at()
101             r->head_offset = logical_offset + l;  in ring_buf_write_at()
105         buf_len -= l;  in ring_buf_write_at()
113 static ossl_inline size_t ring_buf_push(struct ring_buf *r,  in ring_buf_push()  argument
118     unsigned char *start = r->start;  in ring_buf_push()
121         avail = ring_buf_avail(r);  in ring_buf_push()
125         if (buf_len > MAX_OFFSET - r->head_offset)  in ring_buf_push()
126             buf_len = (size_t)(MAX_OFFSET - r->head_offset);  in ring_buf_push()
131         idx = r->head_offset % r->alloc;  in ring_buf_push()
132         l = r->alloc - idx;  in ring_buf_push()
137         r->head_offset  += l;  in ring_buf_push()
139         buf_len         -= l;  in ring_buf_push()
146 static ossl_inline const unsigned char *ring_buf_get_ptr(const struct ring_buf *r,  in ring_buf_get_ptr()  argument
150     unsigned char *start = r->start;  in ring_buf_get_ptr()
153     if (logical_offset >= r->head_offset || logical_offset < r->ctail_offset)  in ring_buf_get_ptr()
155     idx = logical_offset % r->alloc;  in ring_buf_get_ptr()
156     *max_len = r->alloc - idx;  in ring_buf_get_ptr()
172 static ossl_inline int ring_buf_get_buf_at(const struct ring_buf *r,  in ring_buf_get_buf_at()  argument
177     const unsigned char *start = r->start;  in ring_buf_get_buf_at()
180     if (logical_offset > r->head_offset || logical_offset < r->ctail_offset)  in ring_buf_get_buf_at()
183     if (r->alloc == 0) {  in ring_buf_get_buf_at()
189     idx = logical_offset % r->alloc;  in ring_buf_get_buf_at()
190     l   = (size_t)(r->head_offset - logical_offset);  in ring_buf_get_buf_at()
191     if (l > r->alloc - idx)  in ring_buf_get_buf_at()
192         l = r->alloc - idx;  in ring_buf_get_buf_at()
199 static ossl_inline void ring_buf_cpop_range(struct ring_buf *r,  in ring_buf_cpop_range()  argument
205     if (start > r->ctail_offset || end >= MAX_OFFSET)  in ring_buf_cpop_range()
208     if (cleanse && r->alloc > 0 && end > r->ctail_offset) {  in ring_buf_cpop_range()
209         size_t idx = r->ctail_offset % r->alloc;  in ring_buf_cpop_range()
213         if (cleanse_end > r->head_offset)  in ring_buf_cpop_range()
214             cleanse_end = r->head_offset;  in ring_buf_cpop_range()
215         l = (size_t)(cleanse_end - r->ctail_offset);  in ring_buf_cpop_range()
216         if (l > r->alloc - idx) {  in ring_buf_cpop_range()
217             OPENSSL_cleanse((unsigned char *)r->start + idx, r->alloc - idx);  in ring_buf_cpop_range()
218             l -= r->alloc - idx;  in ring_buf_cpop_range()
222             OPENSSL_cleanse((unsigned char *)r->start + idx, l);  in ring_buf_cpop_range()
225     r->ctail_offset = end + 1;  in ring_buf_cpop_range()
227     if (r->head_offset < r->ctail_offset)  in ring_buf_cpop_range()
228         r->head_offset = r->ctail_offset;  in ring_buf_cpop_range()
231 static ossl_inline int ring_buf_resize(struct ring_buf *r, size_t num_bytes,  in ring_buf_resize()  argument
238     if (num_bytes == r->alloc)  in ring_buf_resize()
241     if (num_bytes < ring_buf_used(r))  in ring_buf_resize()
249     rnew.head_offset    = r->head_offset - ring_buf_used(r);  in ring_buf_resize()
253         if (!ring_buf_get_buf_at(r, r->ctail_offset + copied, &src, &src_len)) {  in ring_buf_resize()
269     assert(rnew.head_offset == r->head_offset);  in ring_buf_resize()
270     rnew.ctail_offset = r->ctail_offset;  in ring_buf_resize()
272     ring_buf_destroy(r, cleanse);  in ring_buf_resize()
273     memcpy(r, &rnew, sizeof(*r));  in ring_buf_resize()