[peerdist] Start block download timers from within opener methods
Move the responsibility for starting the block download timers from
peerblk_expired() to peerblk_raw_open() and peerblk_retrieval_open(),
in preparation for adding the ability to defer calls to
peerblk_raw_open() via a block download queue.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[peerdist] Gather and report peer statistics during download
Record and report the number of peers (calculated as the maximum
number of peers discovered for a block's segment at the time that the
block download is complete), and the percentage of blocks retrieved
from peers rather than from the origin server.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[peerdist] Avoid NULL pointer dereference for plaintext blocks
Avoid accidentally dereferencing a NULL cipher context pointer for
plaintext blocks (which are usually messages with a block length of
zero, indicating a missing block).
Signed-off-by: Michael Brown <mcb30@ipxe.org>