setkey - manually manipulate the IPsec SA/SP database
setkey [-nvrk] file ...
setkey [-nvrk] -c
setkey [-vrk] -f filename
setkey [-aPlvrk] -D
setkey [-Pv] -F
setkey [-H] -x
setkey [-h] [-V]
setkey adds, updates, dumps, or flushes Security Association Database (SAD) entries as well as Security Policy Database (SPD) entries in the kernel.
setkey takes a series of operations from the standard input (if invoked with -c) or the file named filename (if invoked with -f filename).
(no flag)
Dump the SAD entries or SPD entries contained in the specified
file.
Configuration syntax
With -c or -f on the command line, setkey accepts the following configuration
syntax. Lines starting with hash signs (’#’) are treated as comment
lines.
add [-46n] src dst protocol spi [extensions] algorithm ... ; Add an SAD entry. add can fail with multiple reasons, including when the key length does not match the specified algorithm.
get [-46n] src dst protocol spi ;
Show an SAD entry.
delete [-46n] src dst protocol spi ;
Remove an SAD entry.
deleteall [-46n] src dst protocol ;
Remove all SAD entries that match the specification.
flush [protocol] ;
Clear all SAD entries matched by the options. -F on the command
line achieves the same functionality.
dump [protocol] ;
Dumps all SAD entries matched by the options. -D on the command
line achieves the same functionality.
spdadd [-46n] src_range dst_range upperspec policy ; Add an SPD entry.
spdadd tagged tag policy ;
Add an SPD entry based on PF tag. tag must be a string surrounded
by doublequote.
spddelete [-46n] src_range dst_range upperspec -P direction ; Delete an SPD entry.
spdflush ;
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
protocol
protocol is one of following:
extensions
take some of the following:
algorithm
-E ealgo key
Specify a 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, 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 ealgo, aalgo 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:
address
address/prefixlen
address[port]
address/prefixlen[port]
prefixlen and port must be decimal number. The square bracket around port is really necessary. They are not manpage metacharacters. For FQDN resolution, the rules applicable to src and dst apply here as well.
upperspec
Upper-layer protocol to be used. You can use one of words in
/etc/protocols as upperspec. Or icmp6, ip4, and any can be specified.
any stands for ‘‘any protocol’’. Also you can use the
protocol number. You can specify a type and/or a code of ICMPv6
when Upper-layer protocol is ICMPv6. the specification can be
placed after icmp6. A type is separated with a code by single
comma. A code must be specified anytime. When a zero is specified,
the kernel deals with it as a wildcard. Note that the kernel
can not distinguish a wildcard from that a type of ICMPv6 is
zero. For example, the following means the policy doesn’t
require IPsec for any inbound Neighbor Solicitation.
spdadd ::/0 ::/0 icmp6 135,0 -P in none;
NOTE: upperspec does not work against forwarding case at this moment, as it requires extra reassembly at forwarding node (not implemented at this moment). We have many protocols in /etc/protocols, but protocols except of TCP, UDP and ICMP may not be suitable to use with IPsec. You have to consider and be careful to use them.
policy policy is the one of the following three formats:
You must specify the direction of its policy as direction. Either out , in or fwd are used.
priority specification is used to control the placement of the policy within the SPD. 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 setkey has been compiled against kernel headers that support policy priorities (>= 2.6.6). If the kernel does not support priorities, a warning message will be printed the first time a priority specification is used. Policy priority takes one of the following formats:
{priority,prio} offset
offset is an integer in ranges -2147483647 .. 214783648.
{priority,prio} base {+,-} offset
base is either low (-1073741824), def (0), or high
(1073741824)
offset is an unsigned integer. It can be up to 1073741824 for positive offsets, and up to 1073741823 for negative offsets.
discard means the packet matching indexes will be discarded.
none means that IPsec operation will not take place onto the
packet. ipsec means that IPsec operation will take place onto
the packet. The part of protocol/mode/src-dst/level specifies
the rule how to process the packet. Either ah, esp or ipcomp is
to be set as protocol. mode is either transport or tunnel. If
mode is tunnel, you must specify the end-points addresses of the
SA as src and dst with ‘-’ between these addresses which is used
to specify the SA to use. If mode is transport, both src and dst
can be omitted. level is to be one of the following: default,
use, require or unique. If the SA is not available in every
level, the kernel will request getting SA to the key exchange
daemon. default means the kernel consults to the system wide
default against protocol you specified, e.g. esp_trans_deflev
sysctl variable, when the kernel processes the packet. use means
that the kernel use a SA if it’s available, otherwise the kernel
keeps normal operation. require means SA is required whenever
the kernel sends a packet matched with the policy. unique is the
same to require, in addition, it allows the policy to bind with
the unique out-bound SA. You just specify the policy level
unique, racoon(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 ‘:’ like the following; unique:number. in order
to bind this policy to the SA. number must be between 1 and
32767. It corresponds to extensions -u of the manual SA configuration.
When you want to use SA bundle, you can define multiple
rules. For example, if an IP header was followed by AH header
followed by 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_policy(3) . There are little differences in the syntax. See ipsec_set_policy(3) for detail.
Algorithms
The following list shows the supported algorithms. protocol and
algorithm are almost orthogonal. Followings are the list of authentication
algorithms that can be used as aalgo in -A aalgo of protocol parameter:
Followings are the list of encryption algorithms that can be used as ealgo in -E ealgo of protocol parameter:
Note that the first 128 bits of a key for aes-ctr will be used as AES key, and remaining 32 bits will be used as nonce.
Followings are the list of compression algorithms that can be used as calgo in -C calgo of protocol parameter:
algorithm
RFC vs Linux kernel semantics
Linux kernel uses fwd policy instead of in policy for packets what are
forwarded through that particular box.
In kernel mode setkey manages and shows policies and SAs exactly as they are stored in the kernel.
In RFC mode setkey
creates fwd policies for every in policy inserted. (not implemented yet) filters out all fwd policies
The command exits with 0 on success, and non-zero on errors.
add 3ffe:501:4819::1 3ffe:501:481d::1 esp 123457 -E des-cbc 0x3ffe05014819ffff ;
add -6 myhost.example.com yourhost.example.com ah 123456 -A hmac-sha1 “AH SA configuration!” ;
add 10.0.11.41 10.0.11.33 esp 0x10001
-E des-cbc 0x3ffe05014819ffff
-A hmac-md5 “authentication!!” ;
get 3ffe:501:4819::1 3ffe:501:481d::1 ah 123456 ;
flush ;
dump esp ;
spdadd 10.0.11.41/32[21] 10.0.11.33/32[any] any -P out ipsec esp/tunnel/192.168.0.1-192.168.1.2/require ;
ipsec_set_policy(3) , racoon(8) , sysctl(8)
Changed manual key configuration for IPsec, October 1999, http://www.kame.net/newsletter/19991007/.
The setkey command first appeared in WIDE Hydrangea IPv6 protocol stack kit. The command was completely re-designed in June 1998.
setkey 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).