[peerdist] Add individual block download mechanism

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/fault.h

@@ -17,6 +17,18 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 /* Drop every N transmitted or received PeerDist discovery packets */
 #define PEERDISC_DISCARD_RATE 0
 
+/* Annul every N PeerDist download attempts */
+#define PEERBLK_ANNUL_RATE 0
+
+/* Stall every N PeerDist download attempts */
+#define PEERBLK_STALL_RATE 0
+
+/* Abort every N PeerDist download attempts */
+#define PEERBLK_ABORT_RATE 0
+
+/* Corrupt every N received PeerDist packets */
+#define PEERBLK_CORRUPT_RATE 0
+
 #include <config/local/fault.h>
 
 #endif /* CONFIG_FAULT_H */

src/include/ipxe/errfile.h

@@ -253,6 +253,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_httpbasic		( ERRFILE_NET | 0x00430000 )
 #define ERRFILE_httpdigest		( ERRFILE_NET | 0x00440000 )
 #define ERRFILE_peerdisc		( ERRFILE_NET | 0x00450000 )
+#define ERRFILE_peerblk			( ERRFILE_NET | 0x00460000 )
 
 #define ERRFILE_image		      ( ERRFILE_IMAGE | 0x00000000 )
 #define ERRFILE_elf		      ( ERRFILE_IMAGE | 0x00010000 )

src/include/ipxe/peerblk.h

@@ -0,0 +1,144 @@
+#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 );
+
+#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;
+	/** 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;
+};
+
+/** 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 */