NAME
relayd.conf
—
relay daemon configuration
file
DESCRIPTION
relayd.conf
is the configuration file for
the relay daemon,
relayd(8).
SECTIONS
relayd.conf
is divided into seven main
sections:
- Macros
- User-defined variables may be defined and used later, simplifying the configuration file.
- Global Configuration
- Global settings for relayd(8). Do note that the config file allows global settings to be added after defining tables in the config file, but those tables will use the built-in defaults instead of the global settings below them.
- Tables
- Table definitions describe a list of hosts, in a similar fashion to pf(4) tables. They are used for relay, redirection, and router target selection with the described options and health checking on the host they contain.
- Redirections
- Redirections are translated to pf(4) rdr-to rules for stateful forwarding to a target host from a health-checked table on layer 3.
- Relays
- Relays allow application layer load balancing, TLS acceleration, and general purpose TCP proxying on layer 7.
- Protocols
- Protocols are predefined settings and filter rules for relays.
- Routers
- Routers are used to insert routes with health-checked gateways for (WAN) link balancing.
Within the sections, a host address can be specified by IPv4 address, IPv6 address, interface name, interface group, or DNS hostname. If the address is an interface name, relayd(8) will look up the first IPv4 address and any other IPv4 and IPv6 addresses of the specified network interface. A port can be specified by number or name. The port name to number mappings are found in the file /etc/services; see services(5) for details.
The current line can be extended over multiple lines using a backslash (‘\’). Comments can be put anywhere in the file using a hash mark (‘#’), and extend to the end of the current line. Care should be taken when commenting out multi-line text: the comment is effective until the end of the entire block.
Argument names not beginning with a letter, digit, or underscore must be quoted.
Additional configuration files can be included with the
include
keyword, for example:
include "/etc/relayd.conf.local"
MACROS
Macros can be defined that will later be expanded in context.
Macro names must start with a letter, digit, or underscore, and may contain
any of those characters. Macro names may not be reserved words (for example,
table
, relay
, or
timeout
). Macros are not expanded inside quotes.
For example:
www1="10.0.0.1" www2="10.0.0.2" table <webhosts> { $www1 $www2 }
GLOBAL CONFIGURATION
Here are the settings that can be set globally:
interval
number- Set the interval in seconds at which the hosts will be checked. The default interval is 10 seconds.
log
(updates
|all
)- Log state notifications after completed host checks. Either only log the
updates
to new states or logall
state notifications, even if the state didn't change. The host state can be “up” (the health check completed successfully), “down” (the host is down or didn't match the check criteria), or “unknown” (the host is disabled or has not been checked yet). prefork
number- When using relays, run the specified number of processes to handle relayed connections. This increases the performance and prevents delays when connecting to a relay. relayd(8) runs 3 relay processes by default and every process will handle all configured relays.
snmp
[trap
] ["path"]- Send an SNMP trap when the state of a host changes. relayd(8) will try to connect to snmpd(8) over the AgentX SNMP socket specified by path and request it send a trap to the registered trap receivers. If path is not specified, a default path of /var/run/agentx.sock will be used. See snmpd.conf(5) for more information about SNMP configuration.
timeout
number- Set the global timeout in milliseconds for checks. This can be overridden by the timeout value in the table definitions. The default interval is 200 milliseconds and it must not exceed the global interval. Please note that the default value is optimized for checks within the same collision domain – use a higher timeout, such as 1000 milliseconds, for checks of hosts in other subnets. If this option is to be set, it should be placed before overrides in tables.
TABLES
Tables are used to group a set of hosts as the target for redirections or relays; they will be mapped to a pf(4) table for redirections. Tables may be defined with the following attribute:
disable
- Start the table disabled – no hosts will be checked in this table. The table can be later enabled through relayctl(8).
Each table must contain at least one host address; multiple hosts are separated by newline, comma, or whitespace. Host entries may be defined with the following attributes:
ip ttl
number- Change the default time-to-live value in the IP headers for host checks.
parent
number- The optional parent option inherits the state from a parent host with the
specified identifier. The check will be skipped for this host and copied
from the parent host. This can be used to prevent multiple checks on hosts
with multiple IP addresses for the same service. The host identifiers are
sequentially assigned to the configured hosts starting with 1; it can be
shown with the
relayctl(8)
show summary
commands. priority
number- Change the route priority used when adding a route. If not specified, the
kernel will set a priority of 8 (
RTP_STATIC
). In ordinary use, a fallback route should be added statically with a very high (e.g. 52) priority. Unused in all other modes. retry
number- The optional retry option adds a tolerance for failed host checks; the check will be retried for number more times before setting the host state to down. If this table is used by a relay, it will also specify the number of retries for outgoing connection attempts.
For example:
table <service> { 192.168.1.1, 192.168.1.2, 192.168.2.3 } table <fallback> disable { 10.1.5.1 retry 2 } redirect "www" { listen on www.example.com port 80 forward to <service> check http "/" code 200 forward to <fallback> check http "/" code 200 }
Tables are used by forward to
directives
in redirections or relays with a set of general options, health-checking
rules, and timings; see the
REDIRECTIONS and
RELAYS sections for more information about
the forward context. Table specific configuration directives are described
below. Multiple options can be appended to forward
to
directives, separated by whitespaces.
The following options will configure the health-checking method for the table, and is mandatory for redirections:
check http
path [host
hostname]code
number- For each host in the table, verify that retrieving the URL
path gives the HTTP return code
number. If hostname is
specified, it is used as the “Host:” header to query a
specific hostname at the target host. To validate the HTTP return code,
use this shell command:
$ echo -n "HEAD <path> HTTP/1.0\r\n\r\n" | \ nc <host> <port> | head -n1
This prints the status header including the actual return code:
HTTP/1.1 200 OK
check https
path [host
hostname]code
number- This has the same effect as above but wraps the HTTP request in TLS.
check http
path [host
hostname]digest
string- For each host in the table, verify that retrieving the URL
path produces non-binary content whose message
digest matches the defined string. The algorithm used is determined by the
string length of the digest argument, either SHA1
(40 characters) or MD5 (32 characters). If hostname
is specified, it is used as the “Host:” header to query a
specific hostname at the target host. The digest does not take the HTTP
headers into account. Do not specify a binary object (such as a graphic)
as the target of the request, as
relayd.conf
expects the data returned to be a string. To compute the digest, use this simple command:$ ftp -o - http://host[:port]/path | sha1
This gives a digest that can be used as-is in a digest statement:
a9993e36476816aba3e25717850c26c9cd0d89d
check https
path [host
hostname]digest
string- This has the same effect as above but wraps the HTTP request in TLS.
check icmp
- Ping hosts in this table to determine whether they are up or not. This method will automatically use ICMP or ICMPV6 depending on the address family of each host.
check script
path- Execute an external program to check the host state. The program will be
executed for each host by specifying the hostname on the command line:
/usr/local/bin/checkload.pl front-www1.private.example.com
relayd(8) expects a positive return value on success and zero on failure. Note that the script will be executed with the privileges of the "_relayd" user and terminated after timeout milliseconds.
check send
dataexpect
pattern [tls
]- For each host in the table, a TCP connection is established on the port
specified, then data is sent. Incoming data is then
read and is expected to match against pattern using
shell globbing rules. If data is an empty string or
nothing
then nothing is sent on the connection and data is immediately read. This can be useful with protocols that output a banner like SMTP, NNTP, and FTP. If thetls
keyword is present, the transaction will occur in a TLS tunnel. check tcp
- Use a simple TCP connect to check that hosts are up.
check tls
- Perform a complete TLS handshake with each host to check their availability.
The following general table options are available:
demote
group- Enable the per-table
carp(4) demotion option. This will increment the carp demotion
counter for the specified interface group if all hosts in the table are
down. For more information on interface groups, see the
group
keyword in ifconfig(8). interval
number- Override the global interval and specify one for this table. It must be a multiple of the global interval.
timeout
number- Set the timeout in milliseconds for each host that is checked using TCP as the transport. This will override the global timeout, which is 200 milliseconds by default.
The following options will set the scheduling algorithm to select a host from the specified table:
mode hash
[key]- Balances the outgoing connections across the active hosts based on the key, IP address and port of the relay. Additional input can be fed into the hash by looking at HTTP headers and GET variables; see the PROTOCOLS section below. This mode is only supported by relays.
mode least-states
- Forward each outgoing connection to the active host with the least active pf(4) states. This mode is only supported by redirections.
mode loadbalance
[key]- Balances the outgoing connections across the active hosts based on the key, the source IP address of the client, and the IP address and port of the relay. This mode is only supported by relays.
mode random
- Distributes the outgoing connections randomly through all active hosts. This mode is supported by redirections and relays.
mode roundrobin
- Distributes the outgoing connections using a round-robin scheduler through all active hosts. This is the default mode and will be used if no option has been specified. This mode is supported by redirections and relays.
mode source-hash
[key]- Balances the outgoing connections across the active hosts based on the key and the source IP address of the client. This mode is supported by redirections and relays.
The optional key argument can be specified
for the hash
, loadbalance
,
and source-hash
modes as either a hex value with a
leading ‘0x
’ or as a string. If
omitted, relayd(8) generates a random key when the configuration is
loaded.
REDIRECTIONS
Redirections represent a
pf(4)
rdr-to rule. They are used for stateful redirections to the hosts in the
specified tables. pf(4) rewrites the target IP addresses and ports of the
incoming connections, operating on layer 3. The configuration directives
that are valid in the redirect
context are described
below:
disable
- The redirection is initially disabled. It can be later enabled through relayctl(8).
forward to
<table> [port
number] options ...- Specify the tables of target hosts to be used; see the
TABLES section above for information
about table options. If the
port
option is not specified, the first port from thelisten on
directive will be used. This directive can be specified twice – the second entry will be used as the backup table if all hosts in the main table are down. At least one entry for the main table is mandatory. listen on
address [ip-proto]port
port [interface
name]- Specify an address and a port
to listen on. pf(4) will redirect incoming connections for the specified
target to the hosts in the main or backup table. The
port argument can optionally specify a port range
instead of a single port; the format is
min-port:max-port. The
optional argument ip-proto can be used to specify an
IP protocol like
tcp
orudp
; it defaults totcp
. The rule can be optionally restricted to a given interface name. route to
<table> [port
number] options ...- Like the
forward to
directive, but directly routes the packets to the target host without modifying the target address using a pf(4) route-to rule. This can be used for “direct server return” to force the target host to respond via a different gateway. Note that hosts have to accept sessions for the same address as the gateway, which is typically done by configuring a loopback interface on the host with this address. session timeout
seconds- Specify the inactivity timeout in seconds for established redirections. The default timeout is 600 seconds (10 minutes). The maximum is 2147483647 seconds (68 years).
sticky-address
- This has the same effect as specifying sticky-address for an rdr-to rule in pf.conf(5). It will ensure that multiple connections from the same source are mapped to the same redirection address.
- [
match
]pftag
name - Automatically tag packets passing through the
pf(4) rdr-to rule with the name supplied. This allows simpler
filter rules. The optional
match
keyword will change the default rule action from ‘pass in quick
’ to ‘match in
’ to allow further evaluation in the pf ruleset using thetagged
name rule option.
RELAYS
Relays will forward traffic between a client and a target server. In contrast to redirections and IP forwarding in the network stack, a relay will accept incoming connections from remote clients as a server, open an outgoing connection to a target host, and forward any traffic between the target host and the remote client, operating on layer 7. A relay is also called an application layer gateway or layer 7 proxy.
The main purpose of a relay is to provide advanced load balancing functionality based on specified protocol characteristics, such as HTTP headers, to provide TLS acceleration and to allow basic handling of the underlying application protocol.
The relay
configuration directives are
described below:
disable
- Start the relay but immediately close any accepted connections.
- [
transparent
]forward
[with tls
]to
address [port
port] options ... - Specify the address and port of the target host to connect to. If the
port
option is not specified, the port from thelisten on
directive will be used. Use thetransparent
keyword to enable fully-transparent mode; the source address of the client will be retained in this case.The
with tls
directive enables client-side TLS mode to connect to the remote host. Verification of server certificates can be enabled by setting theca file
option in the protocol section.The following options may be specified for forward directives:
retry
number- The optional host
retry
option will be used as a tolerance for failed host connections; the connection will be retried for number more times. inet
- If the requested destination is an IPv6 address, relayd(8) will forward the connection to an IPv4 address which is determined by the last 4 octets of the original IPv6 destination. For example, if the original IPv6 destination address is 2001:db8:7395:ffff::a01:101, the session is relayed to the IPv4 address 10.1.1.1 (a01:101).
inet6
address-prefix- If the requested destination is an IPv4 address, relayd(8) will forward the connection to an IPv6 address which is determined by setting the last 4 octets of the specified IPv6 address-prefix to the 4 octets of the original IPv4 destination. For example, if the original IPv4 destination address is 10.1.1.1 and the specified address prefix is 2001:db8:7395:ffff::, the session is relayed to the IPv6 address 2001:db8:7395:ffff::a01:101.
forward to
<table> [port
port] options ...- Like the previous directive, but connect to a host from the specified
table; see the TABLES section above for
information about table options. This directive can be specified multiple
times – subsequent entries will be used as the backup table if all
hosts in the previous table are down. At least one entry for the main
table is mandatory. As above, use the
with tls
directive to enable client-side TLS mode when connecting to the remote host. forward to
destination
options ...- When redirecting connections with a divert-to rule in
pf.conf(5) to a relay listening on localhost, this directive will
look up the real destination address of the intended target host, allowing
the relay to be run as a transparent proxy. If an additional
forward to
directive to a specified address or table is present, it will be used as a backup if the lookup failed. As above, use thewith tls
directive to enable client-side TLS mode when connecting to the remote host. forward to
nat lookup
options ...- Like the previous directive, but for redirections with rdr-to in pf.conf(5).
listen on
addressport
port [tls
]- Specify the address and port for the relay to listen on. The relay will
accept incoming connections to the specified address.
If the
tls
keyword is present, the relay will accept connections using the encrypted TLS protocol. The relay will attempt to look up a private key in /etc/ssl/private/address:port.key and a public certificate in /etc/ssl/address:port.crt, where address is the specified IP address and port is the specified port that the relay listens on. If these files are not present, the relay will continue to look in /etc/ssl/private/address.key and /etc/ssl/address.crt. See ssl(8) for details about SSL/TLS server certificates. protocol
name- Use the specified protocol definition for the relay. The generic TCP protocol options will be used by default; see the PROTOCOLS section below.
session timeout
seconds- Specify the inactivity timeout in seconds for accepted sessions. The default timeout is 600 seconds (10 minutes). The maximum is 2147483647 seconds (68 years).
TLS RELAYS
In addition to plain TCP, relayd(8) supports the Transport Layer Security (TLS) cryptographic protocol for authenticated and encrypted relays. TLS is the successor of the original Secure Sockets Layer (SSL) protocol, but the term SSL is sometimes still used in modern TLS-based applications. relayd(8) can operate as a TLS client or server to offer a variety of options for different use cases related to TLS.
TLS client
- When configuring the relay
forward
statements with thewith tls
directive, relayd(8) will enable client-side TLS to connect to the remote host. This is commonly used for TLS tunneling and transparent encapsulation of plain TCP connections. See theforward to
description in the RELAYS section for more details. TLS server
- When specifying the
tls
keyword in the relaylisten
statements, relayd(8) will accept connections from clients as a TLS server. This mode is also known as “SSL/TLS acceleration”. See thelisten on
description in the RELAYS section for more details. TLS client and server
- When combining both modes, TLS server and client,
relayd(8) can filter TLS connections as a man-in-the-middle. This
combined mode is also called “TLS inspection”. The
configuration requires additional X.509 certificate settings; see the
ca key
description in the PROTOCOLS section for more details.
When configured for “TLS inspection” mode, relayd(8) will listen for incoming connections which have been diverted to the local socket by PF. Before accepting and negotiating the incoming TLS connection as a server, it will look up the original destination address on the diverted socket, and pre-connect to the target server as a TLS client to obtain the remote TLS certificate. It will update or patch the obtained TLS certificate by replacing the included public key with its local server key because it doesn't have the private key of the remote server certificate. It also updates the X.509 issuer name to the local CA subject name and signs the certificate with its local CA key. This way it keeps all the other X.509 attributes that are already present in the server certificate, including the "green bar" extended validation attributes. Now it finally accepts the TLS connection from the diverted client using the updated certificate and continues to handle the connection and to connect to the remote server.
PROTOCOLS
Protocols are templates defining settings and rules for relays. They allow setting generic TCP options, TLS settings, and rules for the selected application layer protocol.
The protocol directive is available for a number of different application layer protocols. There is no generic handler for UDP-based protocols because it is a stateless datagram-based protocol which has to look into the application layer protocol to find any possible state information.
dns protocol
- (UDP) Domain Name System (DNS) protocol. The requested IDs in the DNS header will be used to match the state. relayd(8) replaces these IDs with random values to compensate for predictable values generated by some hosts.
http protocol
- Handle the HyperText Transfer Protocol (HTTP, or "HTTPS" if encapsulated in a TLS tunnel).
- [
tcp
]protocol
- Generic handler for TCP-based protocols. This is the default.
The available configuration directives are described below:
- (
block
|pass
|match
) [rule] - Specify one or more rules to filter connections based on their network or application layer headers; see the FILTER RULES section for more details.
return error
[option]- Return an error response to the client if an internal operation or the
forward connection to the client failed. By default, the connection will
be silently dropped. The effect of this option depends on the protocol:
HTTP will send an error header and page to the client before closing the
connection. Additional valid options are:
style
string- Specify a Cascading Style Sheet (CSS) to be used for the returned HTTP
error pages, for example:
body { background: #a00000; color: white; }
tcp
option- Enable or disable the specified TCP/IP options; see
tcp(4) and ip(4) for more information about the options. Valid options
are:
backlog
number- Set the maximum length the queue of pending connections may grow to.
The backlog option is 10 by default and is limited by the
kern.somaxconn
sysctl(8) variable. ip minttl
number- This option for the underlying IP connection may be used to discard packets with a TTL lower than the specified value. This can be used to implement the Generalized TTL Security Mechanism (GTSM) according to RFC 5082.
ip ttl
number- Change the default time-to-live value in the IP headers.
- [
no
]nodelay
- Enable the TCP NODELAY option for this connection. This is recommended to avoid delays in the relayed data stream, e.g. for SSH connections.
- [
no
]sack
- Use selective acknowledgements for this connection.
socket buffer
number- Set the socket-level buffer size for input and output for this connection. This will affect the TCP window size.
- [
no
]splice
- Use socket splicing for zero-copy data transfer. This option is enabled by default.
tls
option- Set the TLS options and session settings. This is only used if TLS is
enabled in the relay. Valid options are:
ca cert
path- Specify a CA certificate for TLS inspection. For more information, see
the
ca key
option below. ca file
path- This option enables CA verification in TLS client mode. The daemon will load the CA (Certificate Authority) certificates from the specified path to verify the server certificates. OpenBSD provides a default CA bundle in /etc/ssl/cert.pem.
ca key
pathpassword
password- Specify a CA key for TLS inspection. The
password argument will specify the password to
decrypt the CA key (typically an RSA key). This option will enable TLS
inspection if the following conditions are true:
- TLS server mode is enabled by the
listen
directive:listen on ... tls
. - TLS client mode and divert lookups are enabled by the
forward
directive:forward with tls to destination
. - The
ca cert
option is specified. - The
ca key
option is specified.
- TLS server mode is enabled by the
ciphers
string- Set the string defining the TLS cipher suite. If not specified, the
default value ‘
HIGH:!aNULL
’ will be used (strong crypto cipher suites without anonymous DH). See the CIPHERS section of openssl(1) for information about SSL/TLS cipher suites and preference lists. - [
no
]cipher-server-preference
- Prefer the server's cipher list over the client's preferences when choosing a cipher for the connection; enabled by default.
- [
no
]client-renegotiation
- Allow client-initiated renegotiation; enabled by default. Disable to mitigate a potential DoS risk.
ecdh
[curve
name]- Set a named curve to use when generating EC keys for ECDHE-based
cipher suites with Perfect Forward Secrecy (PFS). If the curve
name is not specified, the default curve
prime256v1
will be used. ECDHE is enabled by default. no ecdh
- Disable ECDHE support.
edh
[params
maximum]- Enable EDH-based cipher suites with Perfect Forward Secrecy (PFS) for older clients that do not support ECDHE. If the maximum length of the DH params for EDH is not specified, the default value of 1024 bits will be used. Other possible values are numbers between 1024 and 8192, including 1024, 1536, 2048, 4096, or 8192. Values higher than 1024 bits can cause incompatibilities with older TLS clients.
no edh
- Disable EDH support. This is the default.
session cache
value- Set the maximum size of the TLS session cache. If the
value is zero, the default size defined by the
TLS library will be used. A positive number will set the maximum size
in bytes and the keyword
disable
will disable the TLS session cache. - [
no
]sslv3
- Enable the SSLv3 protocol; disabled by default.
- [
no
]tlsv1
- Enable all TLSv1 protocols. This is an alias that includes
tlsv1.0
,tlsv1.1
, andtlsv1.2
. - [
no
]tlsv1.0
- Enable the TLSv1.0 protocol; disabled by default.
- [
no
]tlsv1.1
- Enable the TLSv1.1 protocol; disabled by default.
- [
no
]tlsv1.2
- Disable the TLSv1.2 protocol; enabled by default.
FILTER RULES
Relays have the ability to filter connections based on their network or application layer headers. Filter rules apply options to connections based on the specified filter parameters.
For each connection that is processed by a relay, the filter rules
are evaluated in sequential order, from first to last. For
block
and pass
, the last
matching rule decides what action is taken; if no rule matches the
connection, the default action is to establish the connection without any
additional action. For match
, rules are evaluated
every time they match; the pass/block state of a connection remains
unchanged.
The filter action may be one of the following:
block
- The connection is blocked. If a
block
rule matches a new connection attempt, it will not be established.block
rules can also trigger for existing connections after evaluating application layer parameters; any connection of the relay session will be instantly dropped. match
- The connection is matched. This action does not alter the connection state, but allows additional parameters to the connection.
pass
- The connection is passed; relayd(8) will continue to process the relay session normally.
These filter parameters can be used in the rules:
request
orresponse
- A relay session always consists of two connections: the
request
, a client initiating a new connection to a server via the relay, and theresponse
, the server accepting the connection. Depending on the protocol, an established session can be purely request/response-based (like HTTP), exchange data in a bidirectional way (like arbitrary TCP sessions), or just contain a single datagram and an optional response (like UDP-based protocols). But the client always requests to communicate with a remote peer; the server. quick
- If a connection is matched by a rule with the
quick
option set, the rule is considered to be the last matching rule and any further evaluation is skipped. inet
orinet6
- Only match connections with the specified address family, either of type IPv4 or IPv6.
label
string- The label will be printed as part of the error message if the
return error
option is set and may contain HTML tags, for example:block request url digest 5c1e03f58f8ce0b457474ffb371fd1ef \ label "<a href='http://example.com/adv.pl?id=7359'>\ Advisory provided by example.com</a>"
no
parameter- Reset a sticky parameter that was previously set by a matching rule. The
parameter is a keyword that can be either
label
ortag
. tag
string- Add a "sticky" tag to connections matching this filter rule.
Tags can be used to filter the connection by further rules using the
tagged
option. Only one tag is assigned per connection; the tag will be replaced if the connection is already tagged. tagged
string- Match the connection if it is already tagged with a given tag by a previous rule.
forward to
<table>- Forward the request to a server in the specified table. With this option,
requests can be passed to specific backend servers. A corresponding
forward to
declaration in the RELAYS section is required.
The following parameters are available when using the
http
protocol:
method
name- Match the HTTP request method. The method is specified by
name and can be either
CONNECT
,COPY
,DELETE
,GET
,HEAD
,LOCK
,MKCOL
,MOVE
,OPTIONS
,PATCH
,POST
,PROPFIND
,PROPPATCH
,PUT
,TRACE
, orUNLOCK
. - type option
[[
digest
] (key|file
path) [value
value]] - Match a specified HTTP header entity and an optional
key
andvalue
. Anoption
can be specified to modify the matched entity or to trigger an event. The entity is extracted from the HTTP request or response header and can be either of typecookie
,header
,path
,query
, orurl
.Instead of a single key, multiple keys can be loaded from a
file
specified by path that contains one key per line. Lines will be stripped at the first whitespace or newline character and any empty lines or lines beginning with a hash mark (‘#
’) will be ignored.If the
digest
keyword is specified, compare the message digest of the key against the defined string. The algorithm used is determined by the string length of the key argument, either SHA1 (40 characters) or MD5 (32 characters). To compute the digest, for example for aurl
, use this simple command:$ echo -n "example.com/path/?args" | sha1
[type] may be one of:
- Look up the entity as a value in the Cookie header. This type is only
available with the direction
request
. header
option [key [value
value]]- Look up the entity in the application protocol headers, like HTTP headers
in
http
mode. path
option [key [value
value]]- Look up the entity as a value in the URL path when using the
http
protocol. This type is only available with the directionrequest
. The key will match the path of the requested URL without the hostname and query and the value will match the complete query, for example:block path "/index.html" block path "/cgi-bin/t.cgi" value "foo=bar*"
query
option [key [value
value]]- Look up the entity as a query variable in the URL when using the
http
protocol. This type is only available with the directionrequest
, for example:# Will match /cgi-bin/example.pl?foo=bar&ok=yes request query expect "bar" from "foo"
url
option [[digest
] key [value
value]]- Look up the entity as a URL suffix/prefix expression consisting of a
canonicalized hostname without port or suffix and a path name or prefix
when using the
http
protocol. This type is only available with the directionrequest
, for example:block url "example.com/index.html" block url "example.com/test.cgi?val=1"
relayd(8) will match the full URL and different possible suffix/prefix combinations by stripping subdomains and path components (up to 5 levels), and the query string. For example, the following lookups will be done for http://www.example.com:81/1/2/3/4/5.html?query=yes:
www.example.com/1/2/3/4/5.html?query=yes www.example.com/1/2/3/4/5.html www.example.com/ www.example.com/1/ www.example.com/1/2/ www.example.com/1/2/3/ example.com/1/2/3/4/5.html?query=yes example.com/1/2/3/4/5.html example.com/ example.com/1/ example.com/1/2/ example.com/1/2/3/
[option] may be one of:
append
- Append the specified value to a protocol entity with
the selected key name. If it does not exist, it will
be created with the new value.
The value string may contain predefined macros that will be expanded at runtime:
$REMOTE_ADDR
- The IP address of the connected client.
$REMOTE_PORT
- The TCP source port of the connected client.
$SERVER_ADDR
- The configured IP address of the relay.
$SERVER_PORT
- The configured TCP server port of the relay.
$SERVER_NAME
- The server software name of relayd(8).
$TIMEOUT
- The configured session timeout of the relay.
hash
- Feed the value of the selected entity into the load
balancing hash to select the target host. See the
table
keyword in the RELAYS section above. log
- Log the key name and the value of the entity.
remove
- Remove the entity with the selected key name.
set
- Like the
append
directive above, but change the contents of the specified entity. If key does not exist in the request, it will be created with the new value.The value string may contain predefined macros that will be expanded at runtime, as detailed for the
append
directive above.
ROUTERS
Routers represent routing table entries in the kernel forwarding database, see route(4), and a table of associated gateways. They are used to dynamically insert or remove routes with gateways based on their availability and health-check results. A router can include multiple network statements and a single forward statement with a table of one or more gateways. All entries in a single router directive must match the same address family, either IPv4 or IPv6.
The kernel supports multipath routing when multiple gateways exist to the same destination address. The multipath routing behaviour can be changed globally using the sysctl(8) variables net.inet.ip.multipath and net.inet6.ip6.multipath. With the default setting of 0, the first route selected will be used for subsequent packets to that destination regardless of source. Setting it to 1 will enable load balancing based on the packet source address across gateways; multiple routes with the same priority are used equally. The kernel will also check the link state of the related network interface and try a different route if it is not active.
The configuration directives that are valid in the
routers
context are described below:
forward to
<table>port
number options ...- Specify the table of target gateways to be used; see the TABLES section above for information about table options. This entry is mandatory and must be specified once.
route
address/
prefix- Specify the network address and prefix length of a route destination that is reachable via the active gateways. This entry must be specified at least once in a router directive.
rtable
id- Add the routes to the kernel routing table with the specified id.
rtlabel
label- Add the routes with the specified label to the kernel routing table.
FILES
- /etc/relayd.conf
- relayd(8) configuration file.
- /etc/services
- Service name database.
- /etc/ssl/address.crt
- /etc/ssl/address:port.crt
- /etc/ssl/private/address.key
- /etc/ssl/private/address:port.key
- Location of the relay TLS server certificates, where address is the configured IP address and port is the configured port number of the relay.
- /etc/ssl/cert.pem
- Default location of the CA bundle that can be used with relayd(8).
EXAMPLES
This configuration file would create a redirection service “www” which load balances four hosts and falls back to one host containing a “sorry page”:
www1=front-www1.private.example.com www2=front-www2.private.example.com www3=front-www3.private.example.com www4=front-www4.private.example.com interval 5 table <phphosts> { $www1, $www2, $www3, $www4 } table <sorryhost> disable { sorryhost.private.example.com } redirect "www" { listen on www.example.com port 8080 interface trunk0 listen on www6.example.com port 80 interface trunk0 pftag REDIRECTED forward to <phphosts> port 8080 timeout 300 \ check http "/" digest "630aa3c2f..." forward to <sorryhost> port 8080 timeout 300 check icmp }
It is possible to specify multiple listen directives with different IP protocols in a single redirection configuration:
redirect "dns" { listen on dns.example.com tcp port 53 listen on dns.example.com udp port 53 forward to <dnshosts> port 53 check tcp }
The following configuration would add a relay to forward secure
HTTPS connections to a pool of HTTP webservers using the
loadbalance
mode (TLS acceleration and layer 7 load
balancing). The HTTP protocol definition will add two HTTP headers
containing address information of the client and the server, set the
“Keep-Alive” header value to the configured session timeout,
and include the “sessid” variable in the hash to calculate the
target host:
http protocol "https" { match header append "X-Forwarded-For" \ value "$REMOTE_ADDR" match header append "X-Forwarded-By" \ value "$REMOTE_ADDR:$SERVER_PORT" match header set "Keep-Alive" value "$TIMEOUT" match query hash "sessid" match hash "sessid" pass block path "/cgi-bin/index.cgi" value "*command=*" tls { no tlsv1.0, ciphers "HIGH" } } relay "tlsaccel" { listen on www.example.com port 443 tls protocol "https" forward to <phphosts> port 8080 mode loadbalance check tcp }
The second relay example will accept incoming connections to port
2222 and forward them to a remote SSH server. The TCP
nodelay
option will allow a “smooth”
SSH session without delays between keystrokes or displayed output on the
terminal:
protocol "myssh" { tcp { nodelay, socket buffer 65536 } } relay "sshforward" { listen on www.example.com port 2222 protocol "myssh" forward to shell.example.com port 22 }
The following relay example will configure “TLS inspection” as described in the TLS RELAYS section. To start, first generate a new local CA key and certificate:
# openssl req -x509 -days 365 -newkey rsa:2048 \ -keyout /etc/ssl/private/ca.key -out /etc/ssl/ca.crt
A TLS server key and self-signed cert for 127.0.0.1 are also
required; see listen on
in the
RELAYS section for more details about
certificate locations. Configure the packet filter with a matching divert
rule in pf.conf(5):
# Divert incoming HTTPS traffic to relayd pass in on vlan1 inet proto tcp to port 443 \ divert-to localhost port 8443
And finally configure the TLS inspection in
relayd.conf
:
http protocol httpfilter { return error pass match label "Prohibited!" block url "social.network.example.com/" # New configuration directives for SSL/TLS Interception tls ca key "/etc/ssl/private/ca.key" password "password123" tls ca cert "/etc/ssl/ca.crt" } relay tlsinspect { listen on 127.0.0.1 port 8443 tls protocol httpfilter forward with tls to destination }
The next simple router configuration example can be used to run redundant, health-checked WAN links:
table <gateways> { $gw1 ip ttl 1, $gw2 ip ttl 1 } router "uplinks" { route 0.0.0.0/0 forward to <gateways> check icmp }
SEE ALSO
HISTORY
The relayd.conf
file format, formerly
known as hoststated.conf
, first appeared in
OpenBSD 4.1. It was renamed to
relayd.conf
in OpenBSD
4.3.
AUTHORS
The relayd(8) program was written by Pierre-Yves Ritschard <pyr@openbsd.org> and Reyk Floeter <reyk@openbsd.org>.
CAVEATS
relayd(8) Verification of TLS server certificates is based on a static CA bundle and relayd(8) currently does not support CRLs (Certificate Revocation Lists).