peerblk.h

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#ifndef _IPXE_PEERBLK_H
#define _IPXE_PEERBLK_H

/** @file
 *
 * Peer Content Caching and Retrieval (PeerDist) protocol block downloads
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#include <stdint.h>
#include <ipxe/refcnt.h>
#include <ipxe/interface.h>
#include <ipxe/crypto.h>
#include <ipxe/aes.h>
#include <ipxe/xferbuf.h>
#include <ipxe/retry.h>
#include <ipxe/process.h>
#include <ipxe/pccrc.h>
#include <ipxe/peerdisc.h>

/** A PeerDist retrieval protocol decryption buffer descriptor */
struct peerdist_block_decrypt {
        /** Data transfer buffer */
        struct xfer_buffer *xferbuf;
        /** Offset within data transfer buffer */
        size_t offset;
        /** Length to use from data transfer buffer */
        size_t len;
};

/** PeerDist retrieval protocol decryption data transfer buffer indices */
enum peerdist_block_decrypt_index {
        /** Data before the trimmed content */
        PEERBLK_BEFORE = 0,
        /** Data within the trimmed content */
        PEERBLK_DURING,
        /** Data after the trimmed content */
        PEERBLK_AFTER,
        /** Number of decryption buffers */
        PEERBLK_NUM_BUFFERS
};

/** A PeerDist block download */
struct peerdist_block {
        /** Reference count */
        struct refcnt refcnt;
        /** Data transfer interface */
        struct interface xfer;
        /** Raw data interface */
        struct interface raw;
        /** Retrieval protocol interface */
        struct interface retrieval;

        /** Original URI */
        struct uri *uri;
        /** Content range of this block */
        struct peerdist_range range;
        /** Trimmed range of this block */
        struct peerdist_range trim;
        /** Offset of first byte in trimmed range within overall download */
        size_t offset;

        /** Digest algorithm */
        struct digest_algorithm *digest;
        /** Digest size
         *
         * Note that this may be shorter than the digest size of the
         * digest algorithm.
         */
        size_t digestsize;
        /** Digest context (statically allocated at instantiation time) */
        void *digestctx;

        /** Cipher algorithm */
        struct cipher_algorithm *cipher;
        /** Cipher context (dynamically allocated as needed) */
        void *cipherctx;

        /** Segment index */
        unsigned int segment;
        /** Segment identifier */
        uint8_t id[PEERDIST_DIGEST_MAX_SIZE];
        /** Segment secret */
        uint8_t secret[PEERDIST_DIGEST_MAX_SIZE];
        /** Block index */
        unsigned int block;
        /** Block hash */
        uint8_t hash[PEERDIST_DIGEST_MAX_SIZE];

        /** Current position (relative to incoming data stream) */
        size_t pos;
        /** Start of trimmed content (relative to incoming data stream) */
        size_t start;
        /** End of trimmed content (relative to incoming data stream) */
        size_t end;
        /** Data buffer */
        struct xfer_buffer buffer;

        /** Decryption process */
        struct process process;
        /** Decryption data buffer descriptors */
        struct peerdist_block_decrypt decrypt[PEERBLK_NUM_BUFFERS];
        /** Remaining decryption length */
        size_t cipher_remaining;
        /** Remaining digest length (excluding AES padding bytes) */
        size_t digest_remaining;

        /** Discovery client */
        struct peerdisc_client discovery;
        /** Current position in discovered peer list */
        struct peerdisc_peer *peer;
        /** Block download queue */
        struct peerdist_block_queue *queue;
        /** List of queued block downloads */
        struct list_head queued;
        /** Retry timer */
        struct retry_timer timer;
        /** Number of full attempt cycles completed */
        unsigned int cycles;
        /** Most recent attempt failure */
        int rc;

        /** Time at which block download was started */
        unsigned long started;
        /** Time at which most recent attempt was started */
        unsigned long attempted;
};

/** PeerDist block download queue */
struct peerdist_block_queue {
        /** Download opening process */
        struct process process;
        /** List of queued downloads */
        struct list_head list;

        /** Number of open downloads */
        unsigned int count;
        /** Maximum number of open downloads */
        unsigned int max;

        /** Open block download
         *
         * @v peerblk           PeerDist block download
         * @ret rc              Return status code
         */
        int ( * open ) ( struct peerdist_block *peerblk );
};

/** Retrieval protocol block fetch response (including transport header)
 *
 * @v digestsize        Digest size
 * @v len               Data block length
 * @v vrf_len           Length of uselessness
 * @v blksize           Cipher block size
 */
#define peerblk_msg_blk_t( digestsize, len, vrf_len, blksize )          \
        struct {                                                        \
                struct peerdist_msg_transport_header hdr;               \
                peerdist_msg_blk_t ( digestsize, len, vrf_len,          \
                                     blksize ) msg;                     \
        } __attribute__ (( packed ))

extern int peerblk_open ( struct interface *xfer, struct uri *uri,
                          struct peerdist_info_block *block );

#endif /* _IPXE_PEERBLK_H */