.\" $KAME: ipsec_set_policy.3,v 1.14 2001/04/06 07:00:46 itojun Exp $ .\" $FreeBSD$ .\" .\" Copyright (C) 1995, 1996, 1997, 1998, and 1999 WIDE Project. .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the project nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd May 5, 1998 .Dt IPSEC_SET_POLICY 3 .Os .Sh NAME .Nm ipsec_set_policy , .Nm ipsec_get_policylen , .Nm ipsec_dump_policy .Nd manipulate IPsec policy specification structure from readable string .\" .Sh LIBRARY .Lb libipsec .Sh SYNOPSIS .Fd #include .Ft "char *" .Fn ipsec_set_policy "char *policy" "int len" .Ft int .Fn ipsec_get_policylen "char *buf" .Ft "char *" .Fn ipsec_dump_policy "char *buf" "char *delim" .Sh DESCRIPTION .Fn ipsec_set_policy generates IPsec policy specification structure, namely .Li struct sadb_x_policy and/or .Li struct sadb_x_ipsecrequest from human-readable policy specification. policy specification must be given as C string .Fa policy and length .Fa len of .Fa policy . .Fn ipsec_set_policy will return the buffer of IPsec policy specification structure. .Pp You may want the length of the generated buffer such when calling .Xr setsockopt 2 . .Fn ipsec_get_policylen will return the length. .Pp .Fn ipsec_dump_policy converts IPsec policy structure into readable form. Therefore, .Fn ipsec_dump_policy can be regarded as inverse conversion of .Fn ipsec_set_policy . .Fa buf points to a IPsec policy structure, .Li struct sadb_x_policy . .Fa delim is a delimiter string, which is usually a blank character. If you set .Fa delim to .Dv NULL , single whitespace is assumed. .Fn ipsec_dump_policy returns pointer to dynamically allocated string. It is caller's responsibility to reclaim the region, by using .Xr free 3 . .Pp .Fa policy is formatted as either of the following: .Bl -tag -width "discard" .It Ar direction Li discard .Ar direction must be .Li in or .Li out . .Ar direction specifies which direction the policy needs to be applied. With .Li discard policy, packets will be dropped if they match the policy. .It Ar direction Li entrust .Li entrust means to consult to SPD defined by .Xr setkey 8 . .It Ar direction Li bypass .Li bypass means to be bypassed the IPsec processing. .Pq packet will be transmitted in clear . This is for privileged socket. .It Xo .Ar direction .Li ipsec .Ar request ... .Xc .Li ipsec means that the matching packets are subject to IPsec processing. .Li ipsec can be followed by one or more .Ar request string, which is formatted as below: .Bl -tag -width "discard" .It Xo .Ar protocol .Li / .Ar mode .Li / .Ar src .Li - .Ar dst .Op Ar /level .Xc .Ar protocol is either .Li ah , .Li esp or .Li ipcomp . .Pp .Ar mode is either .Li transport or .Li tunnel . .Pp .Ar src and .Ar dst specifies IPsec endpoint. .Ar src always means .Dq sending node and .Ar dst always means .Dq receiving node . Therefore, when .Ar direction is .Li in , .Ar dst is this node and .Ar src is the other node .Pq peer . If .Ar mode is .Li transport , Both .Ar src and .Ar dst can be omited. .Pp .Ar level must be set to one of the following: .Li default , use , require or .Li unique . .Li default means that the kernel should consult the system default policy defined by .Xr sysctl 8 , such as .Li net.inet.ipsec.esp_trans_deflev . See .Xr ipsec 4 regarding the system default. .Li use 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 .Pq when SA is not available , or encrypted .Pq when SA is available . .Li require means that a relevant SA is required, since the kernel must perform IPsec operation against packets. .Li unique is the same as .Li require , 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 .Li unique like .Li unique : number . .Li number must be between 1 and 32767 . If the .Ar request string is kept unambiguous, .Ar level and slash prior to .Ar level can be omitted. However, it is encouraged to specify them explicitly to avoid unintended behaviors. If .Ar level is omitted, it will be interpreted as .Li default . .El .El .Pp Note that there is a bit difference of specification from .Xr setkey 8 . In specification by .Xr setkey 8 , both entrust and bypass are not used. Refer to .Xr setkey 8 for detail. .Pp Here are several examples .Pq long lines are wrapped for readability : .Bd -literal -offset indent 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 .Ed .Sh RETURN VALUES .Fn ipsec_set_policy returns a pointer to the allocated buffer of policy specification if successful; otherwise a NULL pointer is returned. .Fn ipsec_get_policylen returns with positive value .Pq meaning the buffer size on success, and negative value on errors. .Fn ipsec_dump_policy returns a pointer to dynamically allocated region on success, and .Dv NULL on errors. .Sh SEE ALSO .Xr ipsec_strerror 3 , .Xr ipsec 4 , .Xr setkey 8 .Sh HISTORY The functions first appeared in WIDE/KAME IPv6 protocol stack kit. .Pp IPv6 and IPsec support based on the KAME Project (http://www.kame.net/) stack was initially integrated into .Fx 4.0