1 files changed, 76 insertions, 0 deletions
diff --git a/src/plugins/http/http2/hpack.h b/src/plugins/http/http2/hpack.h
new file mode 100644
index 00000000000..6bd6a3c25f1
--- /dev/null
+++ b/src/plugins/http/http2/hpack.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2025 Cisco Systems, Inc.
+ */
+
+#ifndef SRC_PLUGINS_HTTP_HPACK_H_
+#define SRC_PLUGINS_HTTP_HPACK_H_
+
+#include <vppinfra/types.h>
+
+#define HPACK_INVALID_INT CLIB_UWORD_MAX
+#if uword_bits == 64
+#define HPACK_ENCODED_INT_MAX_LEN 10
+#else
+#define HPACK_ENCODED_INT_MAX_LEN 6
+#endif
+
+/**
+ * Decode unsigned variable-length integer (RFC7541 section 5.1)
+ *
+ * @param src        Pointer to source buffer which will be advanced
+ * @param end        End of the source buffer
+ * @param prefix_len Number of bits of the prefix (between 1 and 8)
+ *
+ * @return Decoded integer or @c HPACK_INVALID_INT in case of error
+ */
+uword hpack_decode_int (u8 **src, u8 *end, u8 prefix_len);
+
+/**
+ * Encode given value as unsigned variable-length integer (RFC7541 section 5.1)
+ *
+ * @param dst        Pointer to destination buffer, should have enough space
+ * @param value      Integer value to encode (up to @c CLIB_WORD_MAX)
+ * @param prefix_len Number of bits of the prefix (between 1 and 8)
+ *
+ * @return Advanced pointer to the destination buffer
+ *
+ * @note Encoded integer will take maximum @c HPACK_ENCODED_INT_MAX_LEN bytes
+ */
+u8 *hpack_encode_int (u8 *dst, uword value, u8 prefix_len);
+
+/**
+ * Decode
+ *
+ * @param src Pointer to source buffer which will be advanced
+ * @param end End of the source buffer
+ * @param buf     Pointer to the buffer where string is decoded which will be
+ *                advanced by number of written bytes
+ * @param buf_len Length the buffer, will be decreased
+ *
+ * @return @c 0 on success.
+ */
+int hpack_decode_huffman (u8 **src, u8 *end, u8 **buf, uword *buf_len);
+
+/**
+ * Encode given string in Huffman codes.
+ *
+ * @param dst       Pointer to destination buffer, should have enough space
+ * @param value     String to encode
+ * @param value_len Length of the string
+ *
+ * @return Advanced pointer to the destination buffer
+ */
+u8 *hpack_encode_huffman (u8 *dst, const u8 *value, uword value_len);
+
+/**
+ * Number of bytes required to encode given string in Huffman codes
+ *
+ * @param value     Pointer to buffer with string to encode
+ * @param value_len Length of the string
+ *
+ * @return number of bytes required to encode string in Huffman codes, round up
+ * to byte boundary
+ */
+uword hpack_huffman_encoded_len (const u8 *value, uword value_len);
+
+#endif /* SRC_PLUGINS_HTTP_HPACK_H_ */