1.\" $KAME: ipsec.4,v 1.17 2001/06/27 15:25:10 itojun Exp $
2.\"
3.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
4.\" All rights reserved.
5.\"
6.\" Redistribution and use in source and binary forms, with or without
7.\" modification, are permitted provided that the following conditions
8.\" are met:
9.\" 1. Redistributions of source code must retain the above copyright
10.\" notice, this list of conditions and the following disclaimer.
11.\" 2. Redistributions in binary form must reproduce the above copyright
12.\" notice, this list of conditions and the following disclaimer in the
13.\" documentation and/or other materials provided with the distribution.
14.\" 3. Neither the name of the project nor the names of its contributors
15.\" may be used to endorse or promote products derived from this software
16.\" without specific prior written permission.
17.\"
18.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28.\" SUCH DAMAGE.
29.\"
| 1.\" $KAME: ipsec.4,v 1.17 2001/06/27 15:25:10 itojun Exp $
2.\"
3.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
4.\" All rights reserved.
5.\"
6.\" Redistribution and use in source and binary forms, with or without
7.\" modification, are permitted provided that the following conditions
8.\" are met:
9.\" 1. Redistributions of source code must retain the above copyright
10.\" notice, this list of conditions and the following disclaimer.
11.\" 2. Redistributions in binary form must reproduce the above copyright
12.\" notice, this list of conditions and the following disclaimer in the
13.\" documentation and/or other materials provided with the distribution.
14.\" 3. Neither the name of the project nor the names of its contributors
15.\" may be used to endorse or promote products derived from this software
16.\" without specific prior written permission.
17.\"
18.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28.\" SUCH DAMAGE.
29.\"
|
30.\" $FreeBSD: head/share/man/man4/ipsec.4 171696 2007-08-02 08:04:48Z bz $
| 30.\" $FreeBSD: head/share/man/man4/ipsec.4 171732 2007-08-05 16:16:15Z bz $
|
31.\"
| 31.\"
|
32.Dd August 1, 2007
| 32.Dd August 5, 2007
|
33.Dt IPSEC 4
34.Os
35.Sh NAME
36.Nm IPsec
37.Nd Internet Protocol Security protocol
38.Sh SYNOPSIS
39.Cd "options IPSEC"
| 33.Dt IPSEC 4
34.Os
35.Sh NAME
36.Nm IPsec
37.Nd Internet Protocol Security protocol
38.Sh SYNOPSIS
39.Cd "options IPSEC"
|
40.Cd "options IPSEC_FILTERGIF"
| 40.Cd "options IPSEC_FILTERTUNNEL"
|
41.Cd "device crypto"
42.Pp
43.In sys/types.h
44.In netinet/in.h
45.In netipsec/ipsec.h
46.In netipsec/ipsec6.h
47.Sh DESCRIPTION
48.Nm
49is a security protocol implemented within the Internet Protocol layer
50of the networking stack.
51.Nm
52is defined for both IPv4 and IPv6
53.Xr ( inet 4
54and
55.Xr inet6 4 ) .
56.Nm
57is a set of protocols,
58.Tn ESP
59(for Encapsulating Security Payload)
60.Tn AH
61(for Authentication Header),
62and
63.Tn IPComp
64(for IP Payload Compression Protocol)
65that provide security services for IP datagrams.
66AH both authenticates and guarantees the integrity of an IP packet
67by attaching a cryptographic checksum computed using one-way hash functions.
68ESP, in addition, prevents unauthorized parties from reading the payload of
69an IP packet by also encrypting it.
70IPComp tries to increase communication performance by compressing IP payload,
71thus reducing the amount of data sent.
72This will help nodes on slow links but with enough computing power.
73.Nm
74operates in one of two modes: transport mode or tunnel mode.
75Transport mode is used to protect peer-to-peer communication between end nodes.
76Tunnel mode encapsulates IP packets within other IP packets
77and is designed for security gateways such as VPN endpoints.
78.Pp
79System configuration requires the
80.Xr crypto 4
81subsystem.
82.Pp
83The packets can be passed to a virtual
84.Xr enc 4
85interface,
86to perform packet filtering before outbound encryption and after decapsulation
87inbound.
88.Pp
89To properly filter on the inner packets of an
90.Nm
91tunnel with firewalls, add
| 41.Cd "device crypto"
42.Pp
43.In sys/types.h
44.In netinet/in.h
45.In netipsec/ipsec.h
46.In netipsec/ipsec6.h
47.Sh DESCRIPTION
48.Nm
49is a security protocol implemented within the Internet Protocol layer
50of the networking stack.
51.Nm
52is defined for both IPv4 and IPv6
53.Xr ( inet 4
54and
55.Xr inet6 4 ) .
56.Nm
57is a set of protocols,
58.Tn ESP
59(for Encapsulating Security Payload)
60.Tn AH
61(for Authentication Header),
62and
63.Tn IPComp
64(for IP Payload Compression Protocol)
65that provide security services for IP datagrams.
66AH both authenticates and guarantees the integrity of an IP packet
67by attaching a cryptographic checksum computed using one-way hash functions.
68ESP, in addition, prevents unauthorized parties from reading the payload of
69an IP packet by also encrypting it.
70IPComp tries to increase communication performance by compressing IP payload,
71thus reducing the amount of data sent.
72This will help nodes on slow links but with enough computing power.
73.Nm
74operates in one of two modes: transport mode or tunnel mode.
75Transport mode is used to protect peer-to-peer communication between end nodes.
76Tunnel mode encapsulates IP packets within other IP packets
77and is designed for security gateways such as VPN endpoints.
78.Pp
79System configuration requires the
80.Xr crypto 4
81subsystem.
82.Pp
83The packets can be passed to a virtual
84.Xr enc 4
85interface,
86to perform packet filtering before outbound encryption and after decapsulation
87inbound.
88.Pp
89To properly filter on the inner packets of an
90.Nm
91tunnel with firewalls, add
|
92.Cd "options IPSEC_FILTERGIF"
| 92.Cd "options IPSEC_FILTERTUNNEL"
|
93to the kernel configuration file.
94.\"
95.Ss Kernel interface
96.Nm
97is controlled by a key management and policy engine,
98that reside in the operating system kernel.
99Key management
100is the process of associating keys with security associations, also
101know as SAs.
102Policy management dictates when new security
103associations created or destroyed.
104.Pp
105The key management engine can be accessed from userland by using
106.Dv PF_KEY
107sockets.
108The
109.Dv PF_KEY
110socket API is defined in RFC2367.
111.Pp
112The policy engine is controlled by an extension to the
113.Dv PF_KEY
114API,
115.Xr setsockopt 2
116operations, and
117.Xr sysctl 3
118interface.
119The kernel implements
120an extended version of the
121.Dv PF_KEY
122interface and allows the programmer to define IPsec policies
123which are similar to the per-packet filters.
124The
125.Xr setsockopt 2
126interface is used to define per-socket behavior, and
127.Xr sysctl 3
128interface is used to define host-wide default behavior.
129.Pp
130The kernel code does not implement a dynamic encryption key exchange protocol
131such as IKE
132(Internet Key Exchange).
133Key exchange protocols are beyond what is necessary in the kernel and
134should be implemented as daemon processes which call the
135.Nm APIs.
136.\"
137.Ss Policy management
138IPsec policies can be managed in one of two ways, either by
139configuring per-socket policies using the
140.Xr setsockopt 2
141system calls, or by configuring kernel level packet filter-based
142policies using the
143.Dv PF_KEY
144interface, via the
145.Xr setkey 8
146you can define IPsec policies against packets using rules similar to packet
147filtering rules.
148Refer to
149.Xr setkey 8
150on how to use it.
151.Pp
152When setting policies using the
153.Xr setkey 8
154command, the
155.Dq Li default
156option instructs the system to use its default policy, as
157explained below, for processing packets.
158The following sysctl variables are available for configuring the
159system's IPsec behavior.
160The variables can have one of two values.
161A
162.Li 1
163means
164.Dq Li use ,
165which means that if there is a security association then use it but if
166there is not then the packets are not processed by IPsec.
167The value
168.Li 2
169is synonymous with
170.Dq Li require ,
171which requires that a security association must exist for the packets
172to move, and not be dropped.
173These terms are defined in
174.Xr ipsec_set_policy 8 .
175.Bl -column net.inet6.ipsec6.esp_trans_deflev integerxxx
176.It Sy "Name Type Changeable"
177.It "net.inet.ipsec.esp_trans_deflev integer yes"
178.It "net.inet.ipsec.esp_net_deflev integer yes"
179.It "net.inet.ipsec.ah_trans_deflev integer yes"
180.It "net.inet.ipsec.ah_net_deflev integer yes"
181.It "net.inet6.ipsec6.esp_trans_deflev integer yes"
182.It "net.inet6.ipsec6.esp_net_deflev integer yes"
183.It "net.inet6.ipsec6.ah_trans_deflev integer yes"
184.It "net.inet6.ipsec6.ah_net_deflev integer yes"
185.El
186.Pp
187If the kernel does not find a matching, system wide, policy then the
188default value is applied.
189The system wide default policy is specified
190by the following
191.Xr sysctl 8
192variables.
193.Li 0
194means
195.Dq Li discard
196which asks the kernel to drop the packet.
197.Li 1
198means
199.Dq Li none .
200.Bl -column net.inet6.ipsec6.def_policy integerxxx
201.It Sy "Name Type Changeable"
202.It "net.inet.ipsec.def_policy integer yes"
203.It "net.inet6.ipsec6.def_policy integer yes"
204.El
205.\"
206.Ss Miscellaneous sysctl variables
207When the
208.Nm
209protocols are configured for use, all protocols are included in the system.
210To selectively enable/disable protocols, use
211.Xr sysctl 8 .
212.Bl -column net.inet.ipcomp.ipcomp_enable
213.It Sy "Name Default"
214.It "net.inet.esp.esp_enable On"
215.It "net.inet.ah.ah_enable On"
216.It "net.inet.ipcomp.ipcomp_enable Off"
217.El
218.Pp
219In addition the following variables are accessible via
220.Xr sysctl 8 ,
221for tweaking the kernel's IPsec behavior:
222.Bl -column net.inet6.ipsec6.inbonud_call_ike integerxxx
223.It Sy "Name Type Changeable"
224.It "net.inet.ipsec.ah_cleartos integer yes"
225.It "net.inet.ipsec.ah_offsetmask integer yes"
226.It "net.inet.ipsec.dfbit integer yes"
227.It "net.inet.ipsec.ecn integer yes"
228.It "net.inet.ipsec.debug integer yes"
229.It "net.inet6.ipsec6.ecn integer yes"
230.It "net.inet6.ipsec6.debug integer yes"
231.El
232.Pp
233The variables are interpreted as follows:
234.Bl -tag -width 6n
235.It Li ipsec.ah_cleartos
236If set to non-zero, the kernel clears the type-of-service field in the IPv4 header
237during AH authentication data computation.
238This variable is used to get current systems to inter-operate with devices that
239implement RFC1826 AH.
240It should be set to non-zero
241(clear the type-of-service field)
242for RFC2402 conformance.
243.It Li ipsec.ah_offsetmask
244During AH authentication data computation, the kernel will include a
24516bit fragment offset field
246(including flag bits)
247in the IPv4 header, after computing logical AND with the variable.
248The variable is used for inter-operating with devices that
249implement RFC1826 AH.
250It should be set to zero
251(clear the fragment offset field during computation)
252for RFC2402 conformance.
253.It Li ipsec.dfbit
254This variable configures the kernel behavior on IPv4 IPsec tunnel encapsulation.
255If set to 0, the DF bit on the outer IPv4 header will be cleared while
2561 means that the outer DF bit is set regardless from the inner DF bit and
2572 indicates that the DF bit is copied from the inner header to the
258outer one.
259The variable is supplied to conform to RFC2401 chapter 6.1.
260.It Li ipsec.ecn
261If set to non-zero, IPv4 IPsec tunnel encapsulation/decapsulation behavior will
262be friendly to ECN
263(explicit congestion notification),
264as documented in
265.Li draft-ietf-ipsec-ecn-02.txt .
266.Xr gif 4
267talks more about the behavior.
268.It Li ipsec.debug
269If set to non-zero, debug messages will be generated via
270.Xr syslog 3 .
271.El
272.Pp
273Variables under the
274.Li net.inet6.ipsec6
275tree have similar meanings to those described above.
276.\"
277.Sh PROTOCOLS
278The
279.Nm
280protocol acts as a plug-in to the
281.Xr inet 4
282and
283.Xr inet6 4
284protocols and therefore supports most of the protocols defined upon
285those IP-layer protocols.
286The
287.Xr icmp 4
288and
289.Xr icmp6 4
290protocols may behave differently with
291.Nm
292because
293.Nm
294can prevent
295.Xr icmp 4
296or
297.Xr icmp6 4
298routines from looking into the IP payload.
299.\"
300.Sh SEE ALSO
301.Xr ioctl 2 ,
302.Xr socket 2 ,
303.Xr ipsec_set_policy 3 ,
304.Xr crypto 4 ,
305.Xr enc 4 ,
306.Xr icmp6 4 ,
307.Xr intro 4 ,
308.Xr ip6 4 ,
309.Xr setkey 8 ,
310.Xr sysctl 8
311.\".Xr racoon 8
312.Rs
313.%A "S. Kent"
314.%A "R. Atkinson"
315.%T "IP Authentication Header"
316.%O "RFC 2404"
317.Re
318.Rs
319.%A "S. Kent"
320.%A "R. Atkinson"
321.%T "IP Encapsulating Security Payload (ESP)"
322.%O "RFC 2406"
323.Re
324.Sh STANDARDS
325.Rs
326.%A Daniel L. McDonald
327.%A Craig Metz
328.%A Bao G. Phan
329.%T "PF_KEY Key Management API, Version 2"
330.%R RFC
331.%N 2367
332.Re
333.Pp
334.Rs
335.%A "D. L. McDonald"
336.%T "A Simple IP Security API Extension to BSD Sockets"
337.%R internet draft
338.%N "draft-mcdonald-simple-ipsec-api-03.txt"
339.%O work in progress material
340.Re
341.Sh HISTORY
342The original
343.Nm
344implementation appeared in the WIDE/KAME IPv6/IPsec stack.
345.Pp
346For
347.Fx 5.0
348a fully locked IPsec implementation called fast_ipsec was brought in.
349The protocols drew heavily on the
350.Ox
351implementation of the
352.Tn IPsec
353protocols.
354The policy management code was derived from the
355.Tn KAME
356implementation found
357in their
358.Tn IPsec
359protocols.
360The fast_ipsec implementation lacked
361.Xr ip6 4
362support but made use of the
363.Xr crypto 4
364subsystem.
365.Pp
366For
367.Fx 7.0
368.Xr ip6 4
369support was added to fast_ipsec.
370After this the old KAME IPsec implementation was dropped and fast_ipsec
371became what now is the only
372.Nm
373implementation in
374.Fx .
375.Sh BUGS
376There is no single standard for the policy engine API,
377so the policy engine API described herein is just for this implementation.
378.Pp
379AH and tunnel mode encapsulation may not work as you might expect.
380If you configure inbound
381.Dq require
382policy with an AH tunnel or any IPsec encapsulating policy with AH
383(like
384.Dq Li esp/tunnel/A-B/use ah/transport/A-B/require ) ,
385tunnelled packets will be rejected.
386This is because the policy check is enforced on the inner packet on reception,
387and AH authenticates encapsulating
388(outer)
389packet, not the encapsulated
390(inner)
391packet
392(so for the receiving kernel there is no sign of authenticity).
393The issue will be solved when we revamp our policy engine to keep all the
394packet decapsulation history.
395.Pp
396When a large database of security associations or policies is present
397in the kernel the
398.Dv SADB_DUMP
399and
400.Dv SADB_SPDDUMP
401operations on
402.Dv PF_KEY
403sockets may fail due to lack of space.
404Increasing the socket buffer
405size may alleviate this problem.
406.Pp
407The
408.Tn IPcomp
409protocol support is currently broken.
410.Pp
411This documentation needs more review.
| 93to the kernel configuration file.
94.\"
95.Ss Kernel interface
96.Nm
97is controlled by a key management and policy engine,
98that reside in the operating system kernel.
99Key management
100is the process of associating keys with security associations, also
101know as SAs.
102Policy management dictates when new security
103associations created or destroyed.
104.Pp
105The key management engine can be accessed from userland by using
106.Dv PF_KEY
107sockets.
108The
109.Dv PF_KEY
110socket API is defined in RFC2367.
111.Pp
112The policy engine is controlled by an extension to the
113.Dv PF_KEY
114API,
115.Xr setsockopt 2
116operations, and
117.Xr sysctl 3
118interface.
119The kernel implements
120an extended version of the
121.Dv PF_KEY
122interface and allows the programmer to define IPsec policies
123which are similar to the per-packet filters.
124The
125.Xr setsockopt 2
126interface is used to define per-socket behavior, and
127.Xr sysctl 3
128interface is used to define host-wide default behavior.
129.Pp
130The kernel code does not implement a dynamic encryption key exchange protocol
131such as IKE
132(Internet Key Exchange).
133Key exchange protocols are beyond what is necessary in the kernel and
134should be implemented as daemon processes which call the
135.Nm APIs.
136.\"
137.Ss Policy management
138IPsec policies can be managed in one of two ways, either by
139configuring per-socket policies using the
140.Xr setsockopt 2
141system calls, or by configuring kernel level packet filter-based
142policies using the
143.Dv PF_KEY
144interface, via the
145.Xr setkey 8
146you can define IPsec policies against packets using rules similar to packet
147filtering rules.
148Refer to
149.Xr setkey 8
150on how to use it.
151.Pp
152When setting policies using the
153.Xr setkey 8
154command, the
155.Dq Li default
156option instructs the system to use its default policy, as
157explained below, for processing packets.
158The following sysctl variables are available for configuring the
159system's IPsec behavior.
160The variables can have one of two values.
161A
162.Li 1
163means
164.Dq Li use ,
165which means that if there is a security association then use it but if
166there is not then the packets are not processed by IPsec.
167The value
168.Li 2
169is synonymous with
170.Dq Li require ,
171which requires that a security association must exist for the packets
172to move, and not be dropped.
173These terms are defined in
174.Xr ipsec_set_policy 8 .
175.Bl -column net.inet6.ipsec6.esp_trans_deflev integerxxx
176.It Sy "Name Type Changeable"
177.It "net.inet.ipsec.esp_trans_deflev integer yes"
178.It "net.inet.ipsec.esp_net_deflev integer yes"
179.It "net.inet.ipsec.ah_trans_deflev integer yes"
180.It "net.inet.ipsec.ah_net_deflev integer yes"
181.It "net.inet6.ipsec6.esp_trans_deflev integer yes"
182.It "net.inet6.ipsec6.esp_net_deflev integer yes"
183.It "net.inet6.ipsec6.ah_trans_deflev integer yes"
184.It "net.inet6.ipsec6.ah_net_deflev integer yes"
185.El
186.Pp
187If the kernel does not find a matching, system wide, policy then the
188default value is applied.
189The system wide default policy is specified
190by the following
191.Xr sysctl 8
192variables.
193.Li 0
194means
195.Dq Li discard
196which asks the kernel to drop the packet.
197.Li 1
198means
199.Dq Li none .
200.Bl -column net.inet6.ipsec6.def_policy integerxxx
201.It Sy "Name Type Changeable"
202.It "net.inet.ipsec.def_policy integer yes"
203.It "net.inet6.ipsec6.def_policy integer yes"
204.El
205.\"
206.Ss Miscellaneous sysctl variables
207When the
208.Nm
209protocols are configured for use, all protocols are included in the system.
210To selectively enable/disable protocols, use
211.Xr sysctl 8 .
212.Bl -column net.inet.ipcomp.ipcomp_enable
213.It Sy "Name Default"
214.It "net.inet.esp.esp_enable On"
215.It "net.inet.ah.ah_enable On"
216.It "net.inet.ipcomp.ipcomp_enable Off"
217.El
218.Pp
219In addition the following variables are accessible via
220.Xr sysctl 8 ,
221for tweaking the kernel's IPsec behavior:
222.Bl -column net.inet6.ipsec6.inbonud_call_ike integerxxx
223.It Sy "Name Type Changeable"
224.It "net.inet.ipsec.ah_cleartos integer yes"
225.It "net.inet.ipsec.ah_offsetmask integer yes"
226.It "net.inet.ipsec.dfbit integer yes"
227.It "net.inet.ipsec.ecn integer yes"
228.It "net.inet.ipsec.debug integer yes"
229.It "net.inet6.ipsec6.ecn integer yes"
230.It "net.inet6.ipsec6.debug integer yes"
231.El
232.Pp
233The variables are interpreted as follows:
234.Bl -tag -width 6n
235.It Li ipsec.ah_cleartos
236If set to non-zero, the kernel clears the type-of-service field in the IPv4 header
237during AH authentication data computation.
238This variable is used to get current systems to inter-operate with devices that
239implement RFC1826 AH.
240It should be set to non-zero
241(clear the type-of-service field)
242for RFC2402 conformance.
243.It Li ipsec.ah_offsetmask
244During AH authentication data computation, the kernel will include a
24516bit fragment offset field
246(including flag bits)
247in the IPv4 header, after computing logical AND with the variable.
248The variable is used for inter-operating with devices that
249implement RFC1826 AH.
250It should be set to zero
251(clear the fragment offset field during computation)
252for RFC2402 conformance.
253.It Li ipsec.dfbit
254This variable configures the kernel behavior on IPv4 IPsec tunnel encapsulation.
255If set to 0, the DF bit on the outer IPv4 header will be cleared while
2561 means that the outer DF bit is set regardless from the inner DF bit and
2572 indicates that the DF bit is copied from the inner header to the
258outer one.
259The variable is supplied to conform to RFC2401 chapter 6.1.
260.It Li ipsec.ecn
261If set to non-zero, IPv4 IPsec tunnel encapsulation/decapsulation behavior will
262be friendly to ECN
263(explicit congestion notification),
264as documented in
265.Li draft-ietf-ipsec-ecn-02.txt .
266.Xr gif 4
267talks more about the behavior.
268.It Li ipsec.debug
269If set to non-zero, debug messages will be generated via
270.Xr syslog 3 .
271.El
272.Pp
273Variables under the
274.Li net.inet6.ipsec6
275tree have similar meanings to those described above.
276.\"
277.Sh PROTOCOLS
278The
279.Nm
280protocol acts as a plug-in to the
281.Xr inet 4
282and
283.Xr inet6 4
284protocols and therefore supports most of the protocols defined upon
285those IP-layer protocols.
286The
287.Xr icmp 4
288and
289.Xr icmp6 4
290protocols may behave differently with
291.Nm
292because
293.Nm
294can prevent
295.Xr icmp 4
296or
297.Xr icmp6 4
298routines from looking into the IP payload.
299.\"
300.Sh SEE ALSO
301.Xr ioctl 2 ,
302.Xr socket 2 ,
303.Xr ipsec_set_policy 3 ,
304.Xr crypto 4 ,
305.Xr enc 4 ,
306.Xr icmp6 4 ,
307.Xr intro 4 ,
308.Xr ip6 4 ,
309.Xr setkey 8 ,
310.Xr sysctl 8
311.\".Xr racoon 8
312.Rs
313.%A "S. Kent"
314.%A "R. Atkinson"
315.%T "IP Authentication Header"
316.%O "RFC 2404"
317.Re
318.Rs
319.%A "S. Kent"
320.%A "R. Atkinson"
321.%T "IP Encapsulating Security Payload (ESP)"
322.%O "RFC 2406"
323.Re
324.Sh STANDARDS
325.Rs
326.%A Daniel L. McDonald
327.%A Craig Metz
328.%A Bao G. Phan
329.%T "PF_KEY Key Management API, Version 2"
330.%R RFC
331.%N 2367
332.Re
333.Pp
334.Rs
335.%A "D. L. McDonald"
336.%T "A Simple IP Security API Extension to BSD Sockets"
337.%R internet draft
338.%N "draft-mcdonald-simple-ipsec-api-03.txt"
339.%O work in progress material
340.Re
341.Sh HISTORY
342The original
343.Nm
344implementation appeared in the WIDE/KAME IPv6/IPsec stack.
345.Pp
346For
347.Fx 5.0
348a fully locked IPsec implementation called fast_ipsec was brought in.
349The protocols drew heavily on the
350.Ox
351implementation of the
352.Tn IPsec
353protocols.
354The policy management code was derived from the
355.Tn KAME
356implementation found
357in their
358.Tn IPsec
359protocols.
360The fast_ipsec implementation lacked
361.Xr ip6 4
362support but made use of the
363.Xr crypto 4
364subsystem.
365.Pp
366For
367.Fx 7.0
368.Xr ip6 4
369support was added to fast_ipsec.
370After this the old KAME IPsec implementation was dropped and fast_ipsec
371became what now is the only
372.Nm
373implementation in
374.Fx .
375.Sh BUGS
376There is no single standard for the policy engine API,
377so the policy engine API described herein is just for this implementation.
378.Pp
379AH and tunnel mode encapsulation may not work as you might expect.
380If you configure inbound
381.Dq require
382policy with an AH tunnel or any IPsec encapsulating policy with AH
383(like
384.Dq Li esp/tunnel/A-B/use ah/transport/A-B/require ) ,
385tunnelled packets will be rejected.
386This is because the policy check is enforced on the inner packet on reception,
387and AH authenticates encapsulating
388(outer)
389packet, not the encapsulated
390(inner)
391packet
392(so for the receiving kernel there is no sign of authenticity).
393The issue will be solved when we revamp our policy engine to keep all the
394packet decapsulation history.
395.Pp
396When a large database of security associations or policies is present
397in the kernel the
398.Dv SADB_DUMP
399and
400.Dv SADB_SPDDUMP
401operations on
402.Dv PF_KEY
403sockets may fail due to lack of space.
404Increasing the socket buffer
405size may alleviate this problem.
406.Pp
407The
408.Tn IPcomp
409protocol support is currently broken.
410.Pp
411This documentation needs more review.
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