IPSEC_SPI

When a packet is passed from a higher networking layer through an IPSEC virtual interface, a search in the extended routing table (see ipsec_eroute(8)) yields an effective destination address, a Security Parameters Index (SPI) and a IP protocol number. When an IPSEC packet arrives from the network, its ostensible destination, an SPI and an IP protocol specified by its outermost IPSEC header are used. The destination/SPI/protocol combination is used to select a relevant SA. (See ipsec_spigrp(8) for discussion of how multiple transforms are combined.)

The af, daddr, spi and proto arguments specify the SA to be created or deleted. af is the address family (inet for IPv4, inet6 for IPv6). Daddr is a destination address in dotted-decimal notation for IPv4 or in a coloned hex notation for IPv6. Spi is a number, preceded by '0x' for hexadecimal, between 0x100 and 0xffffffff; values from 0x0 to 0xff are reserved. Proto is an ASCII string, "ah", "esp", "comp" or "tun", specifying the IP protocol. The protocol must agree with the algorithm selected.

Alternatively, the said argument can also specify an SA to be created or deleted. Said combines the three parameters above, such as: "tun.101@1.2.3.4" or "tun:101@1:2::3:4", where the address family is specified by "." for IPv4 and ":" for IPv6. The address family indicators substitute the "0x" for hexadecimal.

The source address, src, must also be provided for the inbound policy check to function. The source address does not need to be included if inbound policy checking has been disabled.

Keys vectors must be entered as hexadecimal or base64 numbers. They should be cryptographically strong random numbers.

All hexadecimal numbers are entered as strings of hexadecimal digits (0-9 and a-f), without spaces, preceded by '0x', where each hexadecimal digit represents 4 bits. All base64 numbers are entered as strings of base64 digits (0-9, A-Z, a-z, '+' and '/'), without spaces, preceded by '0s', where each hexadecimal digit represents 6 bits and '=' is used for padding.

The deletion of an SA that has been grouped will result in the entire chain being deleted.

The form with no additional arguments lists the contents of /proc/net/ipsec_spi. The format of /proc/net/ipsec_spi is discussed in ipsec_spi(5).

The lifetime severity of soft sets a limit when the key management daemons are asked to rekey the SA. The lifetime severity of hard sets a limit when the SA must expire. The lifetime type allocations tells the system when to expire the SA because it is being shared by too many eroutes (not currently used). The lifetime type of bytes tells the system to expire the SA after a certain number of bytes have been processed with that SA. The lifetime type of addtime tells the system to expire the SA a certain number of seconds after the SA was installed. The lifetime type of usetime tells the system to expire the SA a certain number of seconds after that SA has processed its first packet. The lifetime type of packets tells the system to expire the SA after a certain number of packets have been processed with that SA.  

OPTIONS

--af

specifies the address family (inet for IPv4, inet6 for IPv6)

--edst

specifies the effective destination daddr of the Security Association

--spi

specifies the Security Parameters Index spi of the Security Association

--proto

specifies the IP protocol proto of the Security Association

--said

specifies the Security Association in monolithic format

--ah

add an SA for an IPSEC Authentication Header, specified by the following transform identifier (hmac-md5-96 or hmac-sha1-96) (RFC2402, obsoletes RFC1826)

hmac-md5-96

transform following the HMAC and MD5 standards, using a 128-bit key to produce a 96-bit authenticator (RFC2403)

hmac-sha1-96

transform following the HMAC and SHA1 standards, using a 160-bit key to produce a 96-bit authenticator (RFC2404)

--esp

add an SA for an IPSEC Encapsulation Security Payload, specified by the following transform identifier (3des, or 3des-md5-96 (RFC2406, obsoletes RFC1827)

3des

encryption transform following the Triple-DES standard in Cipher-Block-Chaining mode using a 64-bit iv (internally generated) and a 192-bit 3DES ekey (RFC2451)

3des-md5-96

encryption transform following the Triple-DES standard in Cipher-Block-Chaining mode with authentication provided by HMAC and MD5 (96-bit authenticator), using a 64-bit iv (internally generated), a 192-bit 3DES ekey and a 128-bit HMAC-MD5 akey (RFC2451, RFC2403)

3des-sha1-96

encryption transform following the Triple-DES standard in Cipher-Block-Chaining mode with authentication provided by HMAC and SHA1 (96-bit authenticator), using a 64-bit iv (internally generated), a 192-bit 3DES ekey and a 160-bit HMAC-SHA1 akey (RFC2451, RFC2404)

--replay_window replayw

sets the replay window size; valid values are decimal, 1 to 64

--life life_param[,life_param]

sets the lifetime expiry; the format of life_param consists of a comma-separated list of lifetime specifications without spaces; a lifetime specification is comprised of a severity of soft or hard followed by a '-', followed by a lifetime type of allocations, bytes, addtime, usetime or packets followed by an '=' and finally by a value

--comp

add an SA for IPSEC IP Compression, specified by the following transform identifier (deflate) (RFC2393)

deflate

compression transform following the patent-free Deflate compression algorithm (RFC2394)

--ip4

add an SA for an IPv4-in-IPv4 tunnel from encap-src to encap-dst

--ip6

add an SA for an IPv6-in-IPv6 tunnel from encap-src to encap-dst

--src

specify the source end of an IP-in-IP tunnel from encap-src to encap-dst and also specifies the source address of the Security Association to be used in inbound policy checking and must be the same address family as af and edst

--dst

specify the destination end of an IP-in-IP tunnel from encap-src to encap-dst

--del

delete the specified SA

--clear

clears the table of SAs

--help

display synopsis

--version

display version information

EXAMPLES

To keep line lengths down and reduce clutter, some of the long keys in these examples have been abbreviated by replacing part of their text with ``...''. Keys used when the programs are actually run must, of course, be the full length required for the particular algorithm.

ipsec spi --af inet --edst gw2 --spi 0x125 --proto esp \

--src gw1 \

--esp 3des-md5-96 \

   --enckey 0x6630...97ce \

--authkey 0x9941...71df

sets up an SA from gw1 to gw2 with an SPI of 0x125 and protocol ESP (50) using 3DES encryption with integral MD5-96 authentication transform, using an encryption key of 0x6630...97ce and an authentication key of 0x9941...71df (see note above about abbreviated keys).

ipsec spi --af inet6 --edst 3049:9::9000:3100 --spi 0x150 --proto ah \

--src 3049:9::9000:3101 \

--ah hmac-md5-96 \

   --authkey 0x1234...2eda \

sets up an SA from 3049:9::9000:3101 to 3049:9::9000:3100 with an SPI of 0x150 and protocol AH (50) using MD5-96 authentication transform, using an authentication key of 0x1234...2eda (see note above about abbreviated keys).

ipsec spi --said tun.987@192.168.100.100 --del

deletes an SA to 192.168.100.100 with an SPI of 0x987 and protocol IPv4-in-IPv4 (4).

ipsec spi --said tun:500@3049:9::1000:1 --del

deletes an SA to 3049:9::1000:1 with an SPI of 0x500 and protocol IPv6-in-IPv6 (4).  

FILES

/proc/net/ipsec_spi, /usr/local/bin/ipsec  

SEE ALSO

ipsec(8), ipsec_tncfg(8), ipsec_eroute(8), ipsec_spigrp(8), ipsec_klipsdebug(8), ipsec_spi(5)  

HISTORY

Written for the Linux FreeS/WAN project <m[blue]http://www.freeswan.org/m[]> by Richard Guy Briggs.  

BUGS

The syntax is messy and the transform naming needs work.  

AUTHOR

Paul Wouters

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