The
utility adds, updates, dumps, or flushes
Security Association Database (SAD) entries
as well as Security Policy Database (SPD) entries in the kernel.
The
utility takes a series of operations from the standard input
(if invoked with
-c
or the file named
filename
(if invoked with
-f filename
-D
Dump the SAD entries.
If with
-P
the SPD entries are dumped.
-F
Flush the SAD entries.
If with
-P
the SPD entries are flushed.
-a
The
utility
usually does not display dead SAD entries with
-D
If with
-a
the dead SAD entries will be displayed as well.
A dead SAD entry means that
it has been expired but remains in the system
because it is referenced by some SPD entries.
-h
Add hexadecimal dump on
-x
mode.
-l
Loop forever with short output on
-D
-v
Be verbose.
The program will dump messages exchanged on
PF_KEY
socket, including messages sent from other processes to the kernel.
-x
Loop forever and dump all the messages transmitted to
PF_KEY
socket.
-xx
makes each timestamps unformatted.
Configuration syntax
With
-c
or
-f
on the command line,
accepts the following configuration syntax.
Lines starting with hash signs
(`#'
)
are treated as comment lines.
Clear all SPD entries.
-FP
on the command line achieves the same functionality.
spddump;
Dumps all SPD entries.
-DP
on the command line achieves the same functionality.
Meta-arguments are as follows:
src
dst
Source/destination of the secure communication is specified as
IPv4/v6 address.
The
utility
can resolve a FQDN into numeric addresses.
If the FQDN resolves into multiple addresses,
will install multiple SAD/SPD entries into the kernel
by trying all possible combinations.
-4
-6
and
-n
restricts the address resolution of FQDN in certain ways.
-4
and
-6
restrict results into IPv4/v6 addresses only, respectively.
-n
avoids FQDN resolution and requires addresses to be numeric addresses.
protocol
protocol
is one of following:
esp
ESP based on rfc2406
esp-old
ESP based on rfc1827
ah
AH based on rfc2402
ah-old
AH based on rfc1826
ipcomp
IPComp
tcp
TCP-MD5 based on rfc2385
spi
Security Parameter Index
(SPI)
for the SAD and the SPD.
spi
must be a decimal number, or a hexadecimal number with
`0x'
prefix.
SPI values between 0 and 255 are reserved for future use by IANA
and they cannot be used.
TCP-MD5 associations must use 0x1000 and therefore only have per-host
granularity at this time.
extensions
take some of the following:
-m mode
Specify a security protocol mode for use.
mode
is one of following:
transport , tunnel
or
any
The default value is
any
-r size
Specify window size of bytes for replay prevention.
size
must be decimal number in 32-bit word.
If
size
is zero or not specified, replay check does not take place.
-u id
Specify the identifier of the policy entry in SPD.
See
policy
-f pad_option
defines the content of the ESP padding.
pad_option
is one of following:
zero-pad
All of the padding are zero.
random-pad
A series of randomized values are set.
seq-pad
A series of sequential increasing numbers started from 1 are set.
-f nocyclic-seq
Do not allow cyclic sequence number.
-lh time
-ls time
Specify hard/soft life time duration of the SA.
algorithm
-E ealgo key
Specify an encryption algorithm
ealgo
for ESP.
-E ealgo key
-A aalgo key
Specify a encryption algorithm
ealgo
as well as a payload authentication algorithm
aalgo
for ESP.
-A aalgo key
Specify an authentication algorithm for AH.
-C calgo [-R
]
Specify a compression algorithm for IPComp.
If
-R
is specified, the
spi
field value will be used as the IPComp CPI
(compression parameter index)
on wire as is.
If
-R
is not specified,
the kernel will use well-known CPI on wire, and
spi
field will be used only as an index for kernel internal usage.
key
must be double-quoted character string, or a series of hexadecimal digits
preceded by
`0x'
Possible values for
ealgoaalgo
and
calgo
are specified in separate section.
src_range
dst_range
These are selections of the secure communication specified as
IPv4/v6 address or IPv4/v6 address range, and it may accompany
TCP/UDP port specification.
This takes the following form:
prefixlen
and
port
must be a decimal number.
The square brackets around
port
are necessary and are not manpage metacharacters.
For FQDN resolution, the rules applicable to
src
and
dst
apply here as well.
upperspec
The upper layer protocol to be used.
You can use one of the words in
/etc/protocols
as
upperspec
as well as
icmp6ip4
or
any
The word
any
stands for
``any protocol''
The protocol number may also be used to specify the
upperspec
A type and code related to ICMPv6 may also be specified as an
upperspec
The type is specified first, followed by a comma and then the relevant
code.
The specification must be placed after
icmp6
The kernel considers a zero to be a wildcard but
cannot distinguish between a wildcard and an ICMPv6
type which is zero.
The following example shows a policy where IPSec is not required for
inbound Neighbor Solicitations:
"spdadd ::/0 ::/0 icmp6 135,0 -P in none;"
NOTE:
upperspec
does not work in the forwarding case at this moment,
as it requires extra reassembly at forwarding node,
which is not implemented at this moment.
Although there are many protocols in
/etc/protocols
protocols other than TCP, UDP and ICMP may not be suitable to use with IPsec.
policy
policy
is expressed in one of the following three formats:
-P direction discard
-P direction none
-P direction ipsecprotocol/mode/src-dst/level [...]
The direction of a policy must be specified as
one of:
outindiscardnone
or
ipsec
The
discard
direction
means that packets matching the supplied indices will be discarded
while
none
means that IPsec operations will not take place on the packet and
ipsec
means that IPsec operation will take place onto the packet.
The
protocol/mode/src-dst/level
statement gives the rule for how to process the packet.
The
protocol
is specified as
ahesp
or
ipcomp
The
mode
is either
transport
or
tunnel
If
mode
is
tunnel
you must specify the end-point addresses of the SA as
src
and
dst
with a dash,
`-'
between the addresses.
If
mode
is
transport
both
src
and
dst
can be omitted.
The
level
is one of the following:
default , use , require
or
unique
If the SA is not available in every level, the kernel will request
the SA from the key exchange daemon.
A value of
default
tells the kernel to use the system wide default protocol
e.g. the one from the
esp_trans_deflev
sysctl variable, when the kernel processes the packet.
A value of
use
means that the kernel will use an SA if it is available,
otherwise the kernel will pass the packet as it would normally.
A value of
require
means that an SA is required whenever the kernel sends a packet matched
that matches the policy.
The
unique
level is the same as
require
but, in addition, it allows the policy to bind with the unique out-bound SA.
For example, if you specify the policy level
uniqueracoon(8)
will configure the SA for the policy.
If you configure the SA by manual keying for that policy,
you can put the decimal number as the policy identifier after
unique
separated by colon
`:'
as in the following example:
unique:number
In order to bind this policy to the SA,
number
must be between 1 and 32767,
which corresponds to
extensions -u
of manual SA configuration.
When you want to use an SA bundle, you can define multiple rules.
For
example, if an IP header was followed by an AH header followed by an
ESP header followed by an upper layer protocol header, the rule would
be:
esp/transport//require ah/transport//require
The rule order is very important.
Note that
``discard
''
and
``none
''
are not in the syntax described in
ipsec_set_policy3.
There are small, but important, differences in the syntax.
See
ipsec_set_policy3
for details.
ALGORITHMS
The following list shows the supported algorithms.
The
protocol
and
algorithm
are almost completely orthogonal.
The following list of authentication algorithms can be used as
aalgo
in the
-A aalgo
of the
protocol
parameter:
algorithm keylen (bits) comment
hmac-md5 128 ah: rfc2403
128 ah-old: rfc2085
hmac-sha1 160 ah: rfc2404
160 ah-old: 128bit ICV (no document)
keyed-md5 128 ah: 96bit ICV (no document)
128 ah-old: rfc1828
keyed-sha1 160 ah: 96bit ICV (no document)
160 ah-old: 128bit ICV (no document)
null 0 to 2048 for debugging
hmac-sha2-256 256 ah: 96bit ICV
(draft-ietf-ipsec-ciph-sha-256-00)
256 ah-old: 128bit ICV (no document)
hmac-sha2-384 384 ah: 96bit ICV (no document)
384 ah-old: 128bit ICV (no document)
hmac-sha2-512 512 ah: 96bit ICV (no document)
512 ah-old: 128bit ICV (no document)
hmac-ripemd160 160 ah: 96bit ICV (RFC2857)
ah-old: 128bit ICV (no document)
aes-xcbc-mac 128 ah: 96bit ICV (RFC3566)
128 ah-old: 128bit ICV (no document)
tcp-md5 8 to 640 tcp: rfc2385
The following is the list of encryption algorithms that can be used as the
ealgo
in the
-E ealgo
of the
protocol
parameter:
The
utility first appeared in WIDE Hydrangea IPv6 protocol stack kit.
The utility was completely re-designed in June 1998.
BUGS
The
utility
should report and handle syntax errors better.
For IPsec gateway configuration,
src_range
and
dst_range
with TCP/UDP port number do not work, as the gateway does not reassemble
packets
(cannot inspect upper-layer headers).
