b215ec0af5
The attempts made to have _libssh2_channel_write() accept larger pieces of data and split up the data by itself into 32700 byte chunks and pass them on to channel_write() in a loop as a way to do faster operations on larger data blocks was a failed attempt. The reason why it is difficult: The API only allows EAGAIN or a length to be returned. When looping over multiple blocks to get sent, one block can get sent and the next might not. And yet: when transport_send() has returned EAGAIN we must not call it again with new data until it has returned OK on the existing data it is still working on. This makes it a mess and we do get a much easier job by simply returning the bytes or EAGAIN at once, as in the EAGAIN case we can assume that we will be called with the same arguments again and transport_send() will be happy. Unfortunately, I think we take a small performance hit by not being able to do this.
libssh2 - SSH2 library ====================== libssh2 is a library implementing the SSH2 protocol, available under the revised BSD license. Web site: http://www.libssh2.org/ Mailing list: http://cool.haxx.se/mailman/listinfo/libssh2-devel Generic installation instructions are in INSTALL. Some ./configure options deserve additional comments: * --enable-crypt-none The SSH2 Transport allows for unencrypted data transmission using the "none" cipher. Because this is such a huge security hole, it is typically disabled on SSH2 implementations and is disabled in libssh2 by default as well. Enabling this option will allow for "none" as a negotiable method, however it still requires that the method be advertized by the remote end and that no more-preferable methods are available. * --enable-mac-none The SSH2 Transport also allows implementations to forego a message authentication code. While this is less of a security risk than using a "none" cipher, it is still not recommended as disabling MAC hashes removes a layer of security. Enabling this option will allow for "none" as a negotiable method, however it still requires that the method be advertized by the remote end and that no more-preferable methods are available. * --disable-gex-new The diffie-hellman-group-exchange-sha1 (dh-gex) key exchange method originally defined an exchange negotiation using packet type 30 to request a generation pair based on a single target value. Later refinement of dh-gex provided for range and target values. By default libssh2 will use the newer range method. If you experience trouble connecting to an old SSH server using dh-gex, try this option to fallback on the older more reliable method. * --with-libgcrypt * --without-libgcrypt * --with-libgcrypt-prefix=DIR libssh2 can use the Libgcrypt library (http://www.gnupg.org/) for cryptographic operations. Either Libgcrypt or OpenSSL is required. Configure will attempt to locate Libgcrypt automatically. If your installation of Libgcrypt is in another location, specify it using --with-libgcrypt-prefix. * --with-openssl * --without-openssl * --with-libssl-prefix=[DIR] libssh2 can use the OpenSSL library (http://www.openssl.org) for cryptographic operations. Either Libgcrypt or OpenSSL is required. Configure will attempt to locate OpenSSL in the default location. If your installation of OpenSSL is in another location, specify it using --with-libssl-prefix. * --with-libz * --without-libz * --with-libz-prefix=[DIR] If present, libssh2 will attempt to use the zlib (http://www.zlib.org) for payload compression, however zlib is not required. If your installation of Libz is in another location, specify it using --with-libz-prefix. * --enable-debug Will make the build use more pedantic and strict compiler options as well as enable the libssh2_trace() function (for showing debug traces).