Ubuntu Manpage: uftp - Encrypted UDP based ftp with multicast

NAME

       uftp - Encrypted UDP based ftp with multicast - server

SYNOPSIS

       uftp [ -R txrate ] [ -L logfile ] [ -B udp_buf_size ]
           [ -g max_log_size ] [ -n max_log_count ]
           [ -Y keytype ] [ -h hashtype ] [ -w sigtype ]
           [ -e keyextype[:curve] ] [ -c ] [ -m max_nak_count ]
           [ -k key_file ] [ -K key_length | curve ] [ -l ] [ -T ]
           [ -b block_size ] [ -t ttl ] [ -Q dscp ] [ -z | -Z ]
           [ -I interface ] [ -p port ] [ -u source_port ]
           [ -j proxylist_file ] [ -q ] [ -f ] [ -y ] [ -U UID ]
           [ -a max_passes ] [ -x log_level ] [ -W txweight ]
           [ -H host[,host...] | -H @hostlist_file
           | -F restart_file ] [ -X exclude_file ]
           [ -M pub_multicast_addr ] [ -P priv_multicast_addr ]
           [ -N max_nak_pct ] [ -C cc_type ] [ -o ][ -D dest_name ]
           [ -E base_dir[,base_dir... ] ] [ -S status_file ]
           [ -r init_grtt[:min_grtt:max_grtt] ] [ -s robust ]
           { -i list_file | file [ file... ] }

DESCRIPTION

       uftp  is  the server process of the UFTP suite.  It sends one or more files to one or more
       receivers via multicast with optional encryption.

OPTIONS

The following options are supported:

-R txrate
The transmission speed in Kbps. Specifying -1 for this value results in data being
sent as fast as the network interface will allow. Using a value of -1 is
recommended only if the network path between the server and all clients is as fast
as the server's local interface, and works best in a gigabit environment. Default
is 1000 Kbps. Ignored if -C is given any value other than "none".

-L logfile
Specifies the log file. Default is to write to stderr.

-B buf_size
The size in bytes of the UDP send buffer and receive buffer to use. Valid values
are 65536-104857600 (64KB-100MB). Defaults to 262144.

-g max_log_size
Specifies the maximum log file size in MB. Once the log file reaches this size,
the file is renamed with a .1 extension and a new log file is opened. For example,
if the log file is /tmp/uftp.log, it will be renamed /tmp/uftp.log.1 and a new
/tmp/uftp.log will be created. Ignored if -L is not specified. Valid values are
1-1024. Default is no log rolling.

-n max_log_count
Specifies the maximum number of archive log files to keep when log rolling is
active. When the log file rolls, archive logs are renamed with an incrementing
numerical extension until the max is reached. Archive log files beyond the maximum
are deleted. Ignored if -L and -g are not specified. Valid values are 1-1000.
Default is 5.

-Y keytype
The symmetric encryption algorithm to use. Valid values are "des" for DES in CBC
mode, "3des" for three key Triple DES in CBC mode, "aes128-cbc", "aes256-cbc",
"aes128-gcm", "aes256-gcm", "aes128-ccm", "aes256-ccm", or "none" to not set up
encryption at all. The GCM and CCM modes are authenticated encryption modes which
applies a signatures at the same time as encryption. If one of these modes are
specifies, the value of -w is ignored. Default is "none". Not all installations
may support all of these algorithms.

-h hashtype
The hashing algorithm to use for key derivation and HMAC signatures. Valid values
are "sha1" for SHA-1, "sha256" for SHA-256, "sha384" for SHA-384, and "sha512" for
SHA-512. Defaults to "sha1". Ignored if -Y is "none". Not all installations may
support all of these algorithms.

-w sigtype
Specifies the type of signature to be applied to encrypted messages. Valid values
are "hmac" to apply an HMAC to the encrypted message, and "keyex" to apply either
an RSA or ECDSA signature depending on the key exchange algorithm chosen via -e.
HMAC signatures are based off the group master key and ensure the sender of a
message is a valid member of the group, but does not guarantee that the message
came from a specific group member. RSA and ECDSA signatures ensure that messages
come from a particular member, but is much much slower to calculate than HMAC and
creates a larger per-packet overhead. If the keytype specified by -Y is an
authentication mode cipher (i.e. AES in GCM or CCM mode), this field is ignored and
signatures will instead be generated at the same time data is encrypted. This also
has the lowest size overhead and is the fastest. Default is "hmac". Ignored if -Y
is "none".

-e keyextype[:curve]
Specifies the key exchange algorithm to use. Valid values are "rsa" for an RSA key
exchange, "ecdh_rsa" for an Elliptic Curve Diffie-Hellman (ECDH) key exchange with
RSA signatures, and "ecdh_ecdsa" for an ECDH key exchange with ECDSA signatures.
Using one of the ECDH schemes provides perfect forward security, while using just
RSA is slightly more resilient to replay attacks. If ecdh_rsa or ecdh_ecdsa are
chosen, the named EC curve that the ECDH key is based on may optionally be
selected, with prime256v1 as the default (See -k and -K for the list of available
EC curves). Default key exchange scheme is "rsa". Ignored if -Y is "none".

-c If specified, forces clients to authenticate by sending their RSA public key in a
CLIENT_KEY message. Client key fingerprints and proxy key fingerprints specified
by -H and -j respectively will NOT be checked unless -c is specified. Ignored if
-Y is "none".

-m max_nak_count
Specifies the number of times a client reports naks beyond the maximum percentage
before getting dropped. Valid values are 1-10. Default is 1.

-k key_file

-K key_length | curve
These two options are used to read and/or write the server's RSA/ECDSA private key.
Both are ignored if -Y is "none".

The type of private key read/written depend on the key exchange algorithm chosen
via the -e option. If -e is "rsa" or "ecdh_rsa", -K specifies the key length in
bits of an RSA public/private keypair to generate, and -k expects an RSA key. If
-e is "ecdh_ecdsa", -K specifies a named EC curve on which an EC public/private
keypair is generated, and -k expects an EC key.

The list of supported EC curves is as follows (availability may vary depending on
system settings and crypto library used):

sect163k1 sect163r1 sect163r2 sect193r1 sect193r2 sect233k1 sect233r1 sect239k1
sect283k1 sect283r1 sect409k1 sect409r1 sect571k1 sect571r1 secp160k1 secp160r1
secp160r2 secp192k1 prime192v1 secp224k1 secp224r1 secp256k1 prime256v1 secp384r1
secp521r1

If neither -k nor -K are specified, either an RSA private key 512 bits in length or
an EC private key on curve prime256p1 (depending on the value of -e) is generated
but not persisted.

If -k is specified but not -K, the RSA or ECDSA private key is read from key_file.

If -k is not specified but -K is, an RSA or ECDSA private key is generated but not
persisted.

If both -k and -K are specified, an RSA or ECDSA private key is generated and
stored in key_file.

The definition of key_file is dependent on the crypto library UFTP is compiled to
use.

On Windows systems, UFTP can built to use either CNG, which is the new API
supported by Windows Vista and Windows 7, or CryptoAPI, which is the legacy API and
the only one available to Windows XP.

Under CryptoAPI, all RSA private keys must be stored in a key container
(technically only keys used to sign data, but for UFTP's purposes this is the
case). Key containers are internal to Windows, and each user (and the system) has
its own set of key containers. In this case, key_file is actually the name of the
key container. When -k is not specified, the generated key is not persisted.
Elliptic Curve algorithms are not supported under CryptoAPI.

Under CNG, RSA and ECDSA private keys are also stored in key containers, and RSA
keys created by CrypoAPI may be read by CNG. Like CryptoAPI, key_file also
specifies the key container name, and the generated key is not persisted if -k is
not specified. CNG only supports 3 named EC curves: prime256v1, secp384r1, and
secp521r1.

All other systems use OpenSSL for the crypto library (although under Windows UFTP
can be also be built to use it). In this case, key_file specifies a file name
where the RSA private key is stored unencrypted in PEM format (the OS is expected
to protect this file). When both -k and -K are specified, the file is only written
to if it does not currently exist. If the file does exist, an error message will
be returned and the server will exit. When -k is not specified, the generated key
is not persisted. These PEM files may also be manipulated via the openssl(1)
command line tool.

Keys can also be generated and viewed via the uftp_keymgt(1) utility.

-l Follow symbolic links. By default, if the server encounters a symbolic link, it
will send the link itself instead of the file it points to. Specifying this flag
causes the server to send the file the link points to.

-T Print the timestamp on each line of output. If -L is specified, this option is
implied.

-b block_size
Specifies the size of a data block. This value should be around 100-200 bytes less
that the path MTU to provide ample room for all headers and extensions, up to and
including the IP and UDP headers. Prior to version 4.0, this option specified the
MTU and calculated the block size based on that. Default is 1300.

-t ttl Specifies the time-to-live for multicast packets. Default is 1.

-Q dscp
Specifies the Differentiated Services Code Point (DSCP), formerly Type of Service
(TOS), in the IP header for all outgoing packets. Valid values are 0-63 and may be
specified in either decimal or hexadecimal. Default is 0.

On Windows XP systems, the OS doesn't allow this parameter to be changed by
default. To change this, add/modify the following DWORD registry value, set to 0,
and reboot:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\DisableUserTOSSetting

Not currently supported on Windows Vista or later.

-z Enables sync mode. Clients will check if an incoming file exists. If so, the
client will decline the incoming file if it either older than the existing file or
the same age and the same size as the existing file.

As of version 4.1, parsable output that was previously generated by this option is
now enabled separately via the -S option.

-Z Sync preview mode. Works like sync mode, except no files are actually transmitted,
and the RESULT and STATS lines reflect the status of each file had they actually
been sent. The "time" and "speed" datapoints are approximated based on the
transmission speed.

-I interface
The interface to send the data from. Can be specified either by interface name, by
hostname, or by IP. If not specified, the default system interface is used.

-p port
The UDP port number to send to. Default is 1044.

-u source_port
The UDP port number to send from. Default is 0, which uses a random port number.

-j proxylist_file
A file containing a list of proxies the server is expecting to hear from. The file
should contain the ID of a proxy optionally followed by the proxy's public key
fingerprint, with one on each line. If a key fingerprint is given, the key
specified by the proxy must match the fingerprint. This option should not be used
without -H. If -H is specified, -j must also be specified if proxies are expected
to respond, otherwise the server will reject the proxies.

Example contents:
0x00001111|66:1E:C9:1D:FC:99:DB:60:B0:1A:F0:8F:CA:F4:28:27:A6:BE:94:BC
0x00002222

-q Quit-on-error flag. Normally, the server will continue with a session as long as
at least one client is still active. With this flag, the server will quit if any
client aborts, drops out, or never responds. Most useful in conjunction with
clients using the temp directory option (-T) so that clients that successfully
receive at least one file before being told to abort don't have files from an
aborted session in the destination directory.

-f Restartable flag. If specified, and at least one client fails to receive all
files, the server will write a restart file named "_group_{group ID}_restart in the
current directory to save the current state, which includes the group ID, list of
files, and list of failed clients. This file can then be passed to -F to restart
the failed transfer.

-y For Windows systems using CryptoAPI or CNG, private keys are normally stored in the
key container of the running user. Specifying this option stores keys in the
system key container. On non-Windows systems, this option has no effect.

-U UID The unique ID for this server, specified as an 8 digit hexadecimal number
(0xnnnnnnnn). The default value is based on the IP address of the outgoing
multicast address as specified by -I. If this address is IPv4, the UID is the
address. If it is IPv6, the UID is the last 4 bytes of the address.

-a max_passes
The maximum number of passes that are made through the file for transmission before
any clients that have not yet fully received the current file are aborted. Valid
values are 0-65535. Default is 65535.

-x log_level
Specifies current logging level. Valid values are 0-5, with 0 being the least
verbose and 5 being the most verbose. Default is 2, which is consistent with
logging prior to version 3.5.

-W txweight
Sets the maximum file transfer time, expressed as a percentage of the optimal time.
Valid values are 110-10000. Ignored if congestion control is enabled. Default is
no maximum time.

-H { host[,host...] | @hostlist_file }
Specifies the clients for closed group membership. Can be specified as either a
comma separated list of client IDs, or can be read from hostlist_file. This file
is in the same format as proxylist_file. Note that key fingerprints cannot be
specified using the comma separated syntax. Clients that are behind a proxy do not
need key fingerprints specified, since the proxy's key fingerprint will be checked
instead. If unspecified, open group membership is used, and any client may
register.

-F restart_file
Specifies the name of a restart file to use to resume a failed transfer. If
specified, -H may not be specified and all files listed to send will be ignored,
since the restart file contains both of these. All other command line options
specified on the first attempt are not automatically applied, so you can alter then
for the next attempt if need be.

-X exclude_file
A file containing the names of files/paths to be excluded from the session, one per
line. For example, if you send a directory called d1 containing subdirectories d2,
d3, and d4, and you don't want to send the contents of d4, the exclude_file should
contain a line reading "d1/d4".

-M pub_multicast_addr
The public address to announce on. May be either a multicast address or a unicast
address, and either IPv4 or IPv6. If a unicast address is specified, the -P option
is ignored and all data moves over the specified unicast address. If a multicast
IPv6 address is specified, -P must also be specified. Default is 230.4.4.1.

-P priv_multicast_addr
The private multicast address that the data is transferred to. One or more parts
of the IP address (other that the first) may be replaced with the letter 'x',
resulting in a random number being chosen for that part, either 0-255 for IPv4 or
0-0xFFFF for IPv6. Default value is 230.5.5.x. If clients are using source
specific multicast (SSM), this and -M must specify valid SSM addresses, which fall
in the range 232.0.0.0/8 for IPv4 and ff3x::/32 for IPv6 (here x specifies the
multicast scope). The values for -M and -P must both be the same IP version.

-N max_nak_pct
Specifies the maximum percentage of NAKs that a client can report for a particular
section. This option works with the -m option, which specifies the number of times
a client may exceed this limit before getting dropped. This allows the server to
keep a very slow client from stalling the session for others. Valid values are
0-100. Default is 100.

-C cc_type
Specifies the congestion control mode to use. Currently supported values are
"none" and "tfmcc". Specifying "none" means data will be sent at a fixed rate as
specified by the -R option. Specifying "tfmcc" will use the TCP Friendly Multicast
Congestion Control scheme as specified in RFC 4654. Normally TFMCC will limit the
rate based strictly on loss, however a minimum, maximum, and initial rate in Kbps
may each be optionally specified for TFMCC mode as
"tfmcc:min=min_rate:init=init_rate:max=max_rate", and any or all of these may be
applied and in any order. Default value is "none".

TFMCC will make use of the Explicit Congestion Notification (ECN) bits in the IP
header on systems that support it natively. Known supported systems are Linux,
FreeBSD, Windows XP (sender only), Windows Vista and later (receiver only), and
Solaris (sender only).

-o

-D dest_name
These options specify the name given to the sent file(s) on the client side. If
only one file/directory is specified to send and -o is not specified, the name
specified by -D is given to that file/directory, and the effects of -E are ignored.
If more than one file/directory is specified to send, or if -o is specified, they
are placed in a subdirectory with the name specified by -D.

This option may also specify an absolute path name. If so, clients must be either
all Windows or all UNIX-like, since they have differing filesystem structures,
otherwise the behavior is undefined. The server, however, need not be the same OS
as the clients. When specifying an absolute path name, the path must be contained
in one of a client's destination directories, otherwise the client will reject the
file. When sending to Windows clients, an absolute path may be either local
(drive:\path\to\file) or remote (\\host\share\path\to\file).

-E base_dir[,base_dir...]
Specifies one or more "base" directories for files. Normally, for any
file/directory specified, any leading path elements are stripped from the name
before sending. If the specified file/directory name matches one of the base
directories, only the path elements of the base directory are stripped, and the
remainder is sent as the file name. Any specified file/directory that does not
match a base directory is skipped.

For example, without -E, if you pass /path/to/file to send, the transmitted
filename is file. If you pass in -E /path, the transmitted file name is to/file.

-S status_file
Prints easily parsable status information to a file. This information was
previously only available in sync mode (-z) and was mixed with the normal logging
output. Setting this option to @LOG results in status info being mixed with normal
logging output.

The following is printed for each client after all have registered:

CONNECT;status;target

Where "status" is either "success" or "failed", and "target" is the name of the
client.

The following is printed after each file:

RESULT;target;filename;size;status;speed

Where "target" is the name of the client, "filename" is the name of the current
file, "size" is the size of the file in kilobytes (i.e. 1234KB), "speed" is the
transmission speed for that file in KB/s, and status is:

copy: The file was sent.

overwrite: The file was sent, and overwrote an existing file. Only generated in
sync mode.

skipped: The file was declined by the client because it is older that the existing
file. Only generated in sync mode.

rejected: The file was rejected, because the file was sent with an absolute
pathname and either the client is using a temp directory or the filename doesn't
match one of the client's destination directories.

The following is printed at the end of the session:

STATS;target;num_copy;num_overwrite;num_skip;total_size;time;speed

Where "target" is the name of the client, "num_copy" is the number of files sent
with "copy" status, "num_overwrite" is the number of files sent with "overwrite"
status, "num_skip" is the number of files sent with "skipped" status, "total_size"
is the total size of all files sent in kilobytes, "time" is the total transmission
time for all files, and "speed" is the overall transmission speed for all files.

Also, the following line is printed verbatim prior to the STATS lines for ease of
reading:

HSTATS;target;copy;overwrite;skip;totalKB;time;speedKB/s

-r init_grtt[:min_grtt:max_grtt]
Specifies the initial value, and optionally the min and max values, of the Group
Round Trip Time (GRTT) used in timing calculations. The GRTT changes dynamically
based on the network conditions. This option is useful if the initial connection
period is too short or long, if receivers are getting bogged down and cannot
respond to the server quick enough before timing out, or if receivers are getting
flagged with too high of an RTT and take too long to recover to a reasonable value.
Valid values are 0.001 to 1000. Defaults are 0.5 for init_grtt, 0.01 for min_grtt,
and 15.0 for max_grtt.

-s robust
Specifies the robustness factor for message retransmission. The server will resend
particular messages up to robust times while waiting for client responses. Valid
values are 10-50. Default is 20.

-i list_file
Name of a file containing a list of files to send, one per line. Empty lines are
ignored. Passing in '-' for list_file reads files from stdin. Other files
specified on the command line are ignored if -i is given.

file [file...]
The file(s) or directory(ies) to send. Any special files (block/character devices,
pipes, sockets, etc.) are skipped. By default, any symbolic links are sent as
links (see -l). Any Windows client will silently refuse to create them. If -F or
-i is specified, any files listed will be ignored.

There are also special metafile names that can send commands to the clients. The
@DELETE:{filename} metafile instructs the client to delete the given filename. nhe
usual rules regarding which of the client's destination directories to use also
applies here. The @FREESPACE metafile will cause the client to report back the
amount of free disk space in the primary destination directory.

EXAMPLES

       Starting with the default options:

            uftp the_file

       The server sends the_file with no encryption at  1000  Kbps,  sending  announcements  over
       230.4.4.1  and  later  messages  over 230.5.5.x (x is randomly selected).  Any client that
       responds to the announcement will be accepted.  The payload portion of the packets will be
       1300 bytes.

       To send at 50 Mbps:

            uftp -R 50000 the_file

       Or to allow the transmission rate to be determined dynamically:

            uftp -C tfmcc the_file

       To send multiple files:

            uftp file_1 file_2 file_3

       or:

            uftp dir_1 dir_2 file_3

       To send multiple files that all land in a certain subdirectory on each client:

            uftp -D dest_dir file_1 file_2

       To send announcements over multicast address 224.1.2.3 and later messages over 224.4.5.6:

            uftp -M 224.1.2.3 -P 224.4.5.6 file

       Or for IPv6:

            uftp -M ff02::1:2:3 -P ff02::4:5:6 file

       Or in unicast mode:

            uftp -M host_or_ip file

       Where host_or_ip is the hostname or unicast IP address of the host to send to.

       To send only to certain hosts:

            uftp -H client_id_1,client_id_2,client_id_3 file_to_send

       or:

            uftp -H @file_containing_list_of_clients file_to_send

       If  you  want  to  use jumbo ethernet frames of 9000 bytes (leaving 200 bytes of space for
       headers):

            uftp -b 8800 file_to_send

       To  send  /path/to/file1  and  /path/to/file2,  and  have  them  appear  on   clients   as
       /remote/dir/to/file1 and /remote/dir/to/file2:

            uftp -E /path -D /remote/dir /path/to/file1 /path/to/file2

       To  send  a  file  encrypted  with  AES-256-CBC  and SHA-1 hashing, using an autogenerated
       512-bit RSA key to negotiate the session:

            uftp -Y aes256-cbc -h sha1 file_to_send

       To do the above with a previously generated RSA key stored in key_file_or_container (under
       Windows,  the  name  of an internal key container, otherwise the name of a file containing
       the key in PEM format):

            uftp -Y aes256-cbc -h sha1 -k key_file_or_container file_to_send

EXIT STATUS

       The following exit values are returned:

       0      The file transfer session finished with at least one client receiving at least  one
              file.

       1      An invalid command line parameter was specified.

       2      An error occurred while attempting to initialize network connections.

       3      An error occurred while reading or generating cryptographic key data.

       4      An error occurred while opening or rolling the log file.

       5      A memory allocation error occurred.

       6      The server was interrupted by the user.

       7      No client responded to the ANNOUNCE message.

       8      No client responded to a FILEINFO message.

       9      All  client  either  dropped  out  of the session or aborted.  Also returned if one
              client drops out or aborts when -q is specified.

       10     The session completed, but none of the specified files were received by any client.

NOTES

       The latest version of UFTP can be found at http://uftp-multicast.sourceforge.net.  UFTP is
       covered  by the GNU General Public License.  Commercial licenses and support are available
       from Dennis Bush (bush@tcnj.edu).