generates an IPsec policy specification structure, namely
and/or
from a human-readable policy specification. The policy specification must be given as a C string
and its length
will return a buffer with the corresponding IPsec policy specification structure. The buffer is dynamically allocated, and must be
by the caller.
You can get the length of the generated buffer with
(i.e. for calling
converts an IPsec policy structure into human-readable form. Therefore,
can be regarded as the inverse function to
points to an IPsec policy structure,
is a delimiter string, which is usually a blank character. If you set
to
a single whitespace is assumed.
returns a pointer to a dynamically allocated string. It is the caller's responsibility to
it.
is formatted as either of the following:
must be
or
specifies in which direction the policy needs to be applied. The non-standard direction
is substituted with
on platforms which do not support forward policies.
is used to control the placement of the policy within the SPD. The policy position is determined by a signed integer where higher priorities indicate the policy is placed closer to the beginning of the list and lower priorities indicate the policy is placed closer to the end of the list. Policies with equal priorities are added at the end of the group of such policies.
Priority can only be specified when libipsec has been compiled against kernel headers that support policy priorities (Linux *[Gt]= 2.6.6). It takes one of the following formats:
is an integer in the range -2147483647..214783648.
is either
or
is an unsigned integer. It can be up to 1073741824 for positive offsets, and up to 1073741823 for negative offsets.
The interpretation of policy priority in these functions and the kernel DOES differ. The relationship between the two can be described as p(kernel) = 0x80000000 - p(func)
With
policy, packets will be dropped if they match the policy.
means to consult the SPD defined by
means to bypass the IPsec processing.
This is for privileged sockets.
means that the matching packets are subject to IPsec processing.
can be followed by one or more
strings, which are formatted as below:
is either
or
is either
or
and
specifies the IPsec endpoint.
always means the
and
always means the
Therefore, when
is
is this node and
is the other node
If
is
Both
and
can be omitted.
must be set to one of the following:
or
means that the kernel should consult the system default policy defined by
such as
See
regarding the system default.
means that a relevant SA can be used when available, since the kernel may perform IPsec operation against packets when possible. In this case, packets can be transmitted in clear
or encrypted
means that a relevant SA is required, since the kernel must perform IPsec operation against packets.
is the same as
but adds the restriction that the SA for outbound traffic is used only for this policy. You may need the identifier in order to relate the policy and the SA when you define the SA by manual keying. You can put the decimal number as the identifier after
like
must be between 1 and 32767 . If the
string is kept unambiguous,
and slash prior to
can be omitted. However, it is encouraged to specify them explicitly to avoid unintended behavior. If
is omitted, it will be interpreted as
Note that there are slight differences to the specification of
In the specification of
both
and
are not used. Refer to
for details.
Here are several examples
in discard out ipsec esp/transport//require in ipsec ah/transport//require out ipsec esp/tunnel/10.1.1.2-10.1.1.1/use in ipsec ipcomp/transport//use esp/transport//use
returns a pointer to the allocated buffer with the policy specification if successful; otherwise a
pointer is returned.
returns a positive value
on success, and a negative value on errors.
returns a pointer to a dynamically allocated region on success, and
on errors.
The functions first appeared in the WIDE/KAME IPv6 protocol stack kit.
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