nghttp2/doc/nghttpx.1

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.TH "NGHTTPX" "1" "Mar 07, 2019" "1.37.0" "nghttp2"
.SH NAME
nghttpx \- HTTP/2 proxy
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.SH SYNOPSIS
.sp
\fBnghttpx\fP [OPTIONS]... [<PRIVATE_KEY> <CERT>]
.SH DESCRIPTION
.sp
A reverse proxy for HTTP/2, and HTTP/1.
.INDENT 0.0
.TP
.B <PRIVATE_KEY>
Set  path  to  server\(aqs private  key.   Required  unless
"no\-tls" parameter is used in \fI\%\-\-frontend\fP option.
.UNINDENT
.INDENT 0.0
.TP
.B <CERT>
Set  path  to  server\(aqs  certificate.   Required  unless
"no\-tls"  parameter is  used in  \fI\%\-\-frontend\fP option.   To
make OCSP stapling work, this must be an absolute path.
.UNINDENT
.SH OPTIONS
.sp
The options are categorized into several groups.
.SS Connections
.INDENT 0.0
.TP
.B \-b, \-\-backend=(<HOST>,<PORT>|unix:<PATH>)[;[<PATTERN>[:...]][[;<PARAM>]...]
Set  backend  host  and   port.   The  multiple  backend
addresses are  accepted by repeating this  option.  UNIX
domain socket  can be  specified by prefixing  path name
with "unix:" (e.g., unix:/var/run/backend.sock).
.sp
Optionally, if <PATTERN>s are given, the backend address
is  only  used  if  request matches  the  pattern.   The
pattern  matching is  closely  designed  to ServeMux  in
net/http package of  Go programming language.  <PATTERN>
consists of  path, host +  path or just host.   The path
must start  with "\fI/\fP".  If  it ends with "\fI/\fP",  it matches
all  request path  in  its subtree.   To  deal with  the
request  to the  directory without  trailing slash,  the
path which ends  with "\fI/\fP" also matches  the request path
which  only  lacks  trailing  \(aq\fI/\fP\(aq  (e.g.,  path  "\fI/foo/\fP"
matches request path  "\fI/foo\fP").  If it does  not end with
"\fI/\fP", it  performs exact match against  the request path.
If  host  is given,  it  performs  a match  against  the
request host.   For a  request received on  the frontend
listener with  "sni\-fwd" parameter enabled, SNI  host is
used instead of a request host.  If host alone is given,
"\fI/\fP" is  appended to it,  so that it matches  all request
paths  under the  host  (e.g., specifying  "nghttp2.org"
equals  to "nghttp2.org/").   CONNECT method  is treated
specially.  It  does not have  path, and we  don\(aqt allow
empty path.  To workaround  this, we assume that CONNECT
method has "\fI/\fP" as path.
.sp
Patterns with  host take  precedence over  patterns with
just path.   Then, longer patterns take  precedence over
shorter ones.
.sp
Host  can  include "*"  in  the  left most  position  to
indicate  wildcard match  (only suffix  match is  done).
The "*" must match at least one character.  For example,
host    pattern    "*.nghttp2.org"    matches    against
"www.nghttp2.org"  and  "git.ngttp2.org", but  does  not
match  against  "nghttp2.org".   The exact  hosts  match
takes precedence over the wildcard hosts match.
.sp
If path  part ends with  "*", it is treated  as wildcard
path.  The  wildcard path  behaves differently  from the
normal path.  For normal path,  match is made around the
boundary of path component  separator,"\fI/\fP".  On the other
hand, the wildcard  path does not take  into account the
path component  separator.  All paths which  include the
wildcard  path  without  last  "*" as  prefix,  and  are
strictly longer than wildcard  path without last "*" are
matched.  "*"  must match  at least one  character.  For
example,  the   pattern  "\fI/foo*\fP"  matches   "\fI/foo/\fP"  and
"\fI/foobar\fP".  But it does not match "\fI/foo\fP", or "\fI/fo\fP".
.sp
If <PATTERN> is omitted or  empty string, "\fI/\fP" is used as
pattern,  which  matches  all request  paths  (catch\-all
pattern).  The catch\-all backend must be given.
.sp
When doing  a match, nghttpx made  some normalization to
pattern, request host and path.  For host part, they are
converted to lower case.  For path part, percent\-encoded
unreserved characters  defined in RFC 3986  are decoded,
and any  dot\-segments (".."  and ".")   are resolved and
removed.
.sp
For   example,   \fI\%\-b\fP\(aq127.0.0.1,8080;nghttp2.org/httpbin/\(aq
matches the  request host "nghttp2.org" and  the request
path "\fI/httpbin/get\fP", but does not match the request host
"nghttp2.org" and the request path "\fI/index.html\fP".
.sp
The  multiple <PATTERN>s  can  be specified,  delimiting
them            by           ":".             Specifying
\fI\%\-b\fP\(aq127.0.0.1,8080;nghttp2.org:www.nghttp2.org\(aq  has  the
same  effect  to specify  \fI\%\-b\fP\(aq127.0.0.1,8080;nghttp2.org\(aq
and \fI\%\-b\fP\(aq127.0.0.1,8080;www.nghttp2.org\(aq.
.sp
The backend addresses sharing same <PATTERN> are grouped
together forming  load balancing  group.
.sp
Several parameters <PARAM> are accepted after <PATTERN>.
The  parameters are  delimited  by  ";".  The  available
parameters       are:      "proto=<PROTO>",       "tls",
"sni=<SNI_HOST>",         "fall=<N>",        "rise=<N>",
"affinity=<METHOD>",    "dns",    "redirect\-if\-not\-tls",
"upgrade\-scheme",                        "mruby=<PATH>",
"read\-timeout=<DURATION>",   "write\-timeout=<DURATION>",
"group=<GROUP>",  "group\-weight=<N>", and  "weight=<N>".
The  parameter  consists   of  keyword,  and  optionally
followed by  "=" and value.  For  example, the parameter
"proto=h2"  consists of  the keyword  "proto" and  value
"h2".  The parameter "tls" consists of the keyword "tls"
without value.  Each parameter is described as follows.
.sp
The backend application protocol  can be specified using
optional  "proto"   parameter,  and   in  the   form  of
"proto=<PROTO>".  <PROTO> should be one of the following
list  without  quotes:  "h2", "http/1.1".   The  default
value of <PROTO> is  "http/1.1".  Note that usually "h2"
refers to HTTP/2  over TLS.  But in this  option, it may
mean HTTP/2  over cleartext TCP unless  "tls" keyword is
used (see below).
.sp
TLS  can   be  enabled  by  specifying   optional  "tls"
parameter.  TLS is not enabled by default.
.sp
With "sni=<SNI_HOST>" parameter, it can override the TLS
SNI  field  value  with  given  <SNI_HOST>.   This  will
default to the backend <HOST> name
.sp
The  feature  to detect  whether  backend  is online  or
offline can be enabled  using optional "fall" and "rise"
parameters.   Using  "fall=<N>"  parameter,  if  nghttpx
cannot connect  to a  this backend <N>  times in  a row,
this  backend  is  assumed  to be  offline,  and  it  is
excluded from load balancing.  If <N> is 0, this backend
never  be excluded  from load  balancing whatever  times
nghttpx cannot connect  to it, and this  is the default.
There is  also "rise=<N>" parameter.  After  backend was
excluded from load balancing group, nghttpx periodically
attempts to make a connection to the failed backend, and
if the  connection is made  successfully <N> times  in a
row, the backend is assumed to  be online, and it is now
eligible  for load  balancing target.   If <N>  is 0,  a
backend  is permanently  offline, once  it goes  in that
state, and this is the default behaviour.
.sp
The     session     affinity    is     enabled     using
"affinity=<METHOD>"  parameter.   If  "ip" is  given  in
<METHOD>, client  IP based session affinity  is enabled.
If "cookie"  is given in <METHOD>,  cookie based session
affinity is  enabled.  If  "none" is given  in <METHOD>,
session affinity  is disabled, and this  is the default.
The session  affinity is  enabled per <PATTERN>.   If at
least  one backend  has  "affinity"  parameter, and  its
<METHOD> is not "none",  session affinity is enabled for
all backend  servers sharing the same  <PATTERN>.  It is
advised  to  set  "affinity" parameter  to  all  backend
explicitly if session affinity  is desired.  The session
affinity  may   break  if   one  of  the   backend  gets
unreachable,  or   backend  settings  are   reloaded  or
replaced by API.
.sp
If   "affinity=cookie"    is   used,    the   additional
configuration                is                required.
"affinity\-cookie\-name=<NAME>" must be  used to specify a
name     of     cookie      to     use.      Optionally,
"affinity\-cookie\-path=<PATH>" can  be used to  specify a
path   which   cookie    is   applied.    The   optional
"affinity\-cookie\-secure=<SECURE>"  controls  the  Secure
attribute of a cookie.  The default value is "auto", and
the Secure attribute is  determined by a request scheme.
If a request scheme is "https", then Secure attribute is
set.  Otherwise, it  is not set.  If  <SECURE> is "yes",
the  Secure attribute  is  always set.   If <SECURE>  is
"no", the Secure attribute is always omitted.
.sp
By default, name resolution of backend host name is done
at  start  up,  or reloading  configuration.   If  "dns"
parameter   is  given,   name  resolution   takes  place
dynamically.  This is useful  if backend address changes
frequently.   If  "dns"  is given,  name  resolution  of
backend   host   name   at  start   up,   or   reloading
configuration is skipped.
.sp
If "redirect\-if\-not\-tls" parameter  is used, the matched
backend  requires   that  frontend  connection   is  TLS
encrypted.  If it isn\(aqt, nghttpx responds to the request
with 308  status code, and  https URI the  client should
use instead  is included in Location  header field.  The
port number in  redirect URI is 443 by  default, and can
be  changed using  \fI\%\-\-redirect\-https\-port\fP option.   If at
least one  backend has  "redirect\-if\-not\-tls" parameter,
this feature is enabled  for all backend servers sharing
the   same   <PATTERN>.    It    is   advised   to   set
"redirect\-if\-no\-tls"    parameter   to    all   backends
explicitly if this feature is desired.
.sp
If "upgrade\-scheme"  parameter is used along  with "tls"
parameter, HTTP/2 :scheme pseudo header field is changed
to "https" from "http" when forwarding a request to this
particular backend.  This is  a workaround for a backend
server  which  requires  "https" :scheme  pseudo  header
field on TLS encrypted connection.
.sp
"mruby=<PATH>"  parameter  specifies  a  path  to  mruby
script  file  which  is  invoked when  this  pattern  is
matched.  All backends which share the same pattern must
have the same mruby path.
.sp
"read\-timeout=<DURATION>" and "write\-timeout=<DURATION>"
parameters  specify the  read and  write timeout  of the
backend connection  when this  pattern is  matched.  All
backends which share the same pattern must have the same
timeouts.  If these timeouts  are entirely omitted for a
pattern,            \fI\%\-\-backend\-read\-timeout\fP           and
\fI\%\-\-backend\-write\-timeout\fP are used.
.sp
"group=<GROUP>"  parameter specifies  the name  of group
this backend address belongs to.  By default, it belongs
to  the unnamed  default group.   The name  of group  is
unique   per   pattern.   "group\-weight=<N>"   parameter
specifies the  weight of  the group.  The  higher weight
gets  more frequently  selected  by  the load  balancing
algorithm.  <N> must be  [1, 256] inclusive.  The weight
8 has 4 times more weight  than 2.  <N> must be the same
for  all addresses  which  share the  same <GROUP>.   If
"group\-weight" is  omitted in an address,  but the other
address  which  belongs  to  the  same  group  specifies
"group\-weight",   its    weight   is   used.     If   no
"group\-weight"  is  specified  for  all  addresses,  the
weight of a group becomes 1.  "group" and "group\-weight"
are ignored if session affinity is enabled.
.sp
"weight=<N>"  parameter  specifies  the  weight  of  the
backend  address  inside  a  group  which  this  address
belongs  to.  The  higher  weight  gets more  frequently
selected by  the load balancing algorithm.   <N> must be
[1,  256] inclusive.   The  weight 8  has  4 times  more
weight  than weight  2.  If  this parameter  is omitted,
weight  becomes  1.   "weight"  is  ignored  if  session
affinity is enabled.
.sp
Since ";" and ":" are  used as delimiter, <PATTERN> must
not  contain these  characters.  Since  ";" has  special
meaning in shell, the option value must be quoted.
.sp
Default: \fB127.0.0.1,80\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-f, \-\-frontend=(<HOST>,<PORT>|unix:<PATH>)[[;<PARAM>]...]
Set  frontend  host and  port.   If  <HOST> is  \(aq*\(aq,  it
assumes  all addresses  including  both  IPv4 and  IPv6.
UNIX domain  socket can  be specified by  prefixing path
name  with  "unix:" (e.g.,  unix:/var/run/nghttpx.sock).
This  option can  be used  multiple times  to listen  to
multiple addresses.
.sp
This option  can take  0 or  more parameters,  which are
described  below.   Note   that  "api"  and  "healthmon"
parameters are mutually exclusive.
.sp
Optionally, TLS  can be disabled by  specifying "no\-tls"
parameter.  TLS is enabled by default.
.sp
If "sni\-fwd" parameter is  used, when performing a match
to select a backend server,  SNI host name received from
the client  is used  instead of  the request  host.  See
\fI\%\-\-backend\fP option about the pattern match.
.sp
To  make this  frontend as  API endpoint,  specify "api"
parameter.   This   is  disabled  by  default.    It  is
important  to  limit the  access  to  the API  frontend.
Otherwise, someone  may change  the backend  server, and
break your services,  or expose confidential information
to the outside the world.
.sp
To  make  this  frontend  as  health  monitor  endpoint,
specify  "healthmon"  parameter.   This is  disabled  by
default.  Any  requests which come through  this address
are replied with 200 HTTP status, without no body.
.sp
To  accept   PROXY  protocol   version  1   on  frontend
connection,  specify  "proxyproto" parameter.   This  is
disabled by default.
.sp
Default: \fB*,3000\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backlog=<N>
Set listen backlog size.
.sp
Default: \fB65536\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-address\-family=(auto|IPv4|IPv6)
Specify  address  family  of  backend  connections.   If
"auto" is given, both IPv4  and IPv6 are considered.  If
"IPv4" is  given, only  IPv4 address is  considered.  If
"IPv6" is given, only IPv6 address is considered.
.sp
Default: \fBauto\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-http\-proxy\-uri=<URI>
Specify      proxy       URI      in       the      form
\fI\%http:/\fP/[<USER>:<PASS>@]<PROXY>:<PORT>.    If   a   proxy
requires  authentication,  specify  <USER>  and  <PASS>.
Note that  they must be properly  percent\-encoded.  This
proxy  is used  when the  backend connection  is HTTP/2.
First,  make  a CONNECT  request  to  the proxy  and  it
connects  to the  backend  on behalf  of nghttpx.   This
forms  tunnel.   After  that, nghttpx  performs  SSL/TLS
handshake with  the downstream through the  tunnel.  The
timeouts when connecting and  making CONNECT request can
be     specified    by     \fI\%\-\-backend\-read\-timeout\fP    and
\fI\%\-\-backend\-write\-timeout\fP options.
.UNINDENT
.SS Performance
.INDENT 0.0
.TP
.B \-n, \-\-workers=<N>
Set the number of worker threads.
.sp
Default: \fB1\fP
.UNINDENT
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.TP
.B \-\-single\-thread
Run everything in one  thread inside the worker process.
This   feature   is   provided  for   better   debugging
experience,  or  for  the platforms  which  lack  thread
support.   If  threading  is disabled,  this  option  is
always enabled.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-read\-rate=<SIZE>
Set maximum  average read  rate on  frontend connection.
Setting 0 to this option means read rate is unlimited.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-read\-burst=<SIZE>
Set  maximum read  burst  size  on frontend  connection.
Setting  0  to this  option  means  read burst  size  is
unlimited.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-write\-rate=<SIZE>
Set maximum  average write rate on  frontend connection.
Setting 0 to this option means write rate is unlimited.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-write\-burst=<SIZE>
Set  maximum write  burst size  on frontend  connection.
Setting  0 to  this  option means  write  burst size  is
unlimited.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-worker\-read\-rate=<SIZE>
Set maximum average read rate on frontend connection per
worker.  Setting  0 to  this option  means read  rate is
unlimited.  Not implemented yet.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-worker\-read\-burst=<SIZE>
Set maximum  read burst size on  frontend connection per
worker.  Setting 0 to this  option means read burst size
is unlimited.  Not implemented yet.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-worker\-write\-rate=<SIZE>
Set maximum  average write  rate on  frontend connection
per worker.  Setting  0 to this option  means write rate
is unlimited.  Not implemented yet.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-worker\-write\-burst=<SIZE>
Set maximum write burst  size on frontend connection per
worker.  Setting 0 to this option means write burst size
is unlimited.  Not implemented yet.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-worker\-frontend\-connections=<N>
Set maximum number  of simultaneous connections frontend
accepts.  Setting 0 means unlimited.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-connections\-per\-host=<N>
Set  maximum number  of  backend concurrent  connections
(and/or  streams in  case  of HTTP/2)  per origin  host.
This option  is meaningful when \fI\%\-\-http2\-proxy\fP  option is
used.   The  origin  host  is  determined  by  authority
portion of  request URI (or :authority  header field for
HTTP/2).   To  limit  the   number  of  connections  per
frontend        for       default        mode,       use
\fI\%\-\-backend\-connections\-per\-frontend\fP\&.
.sp
Default: \fB8\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-connections\-per\-frontend=<N>
Set  maximum number  of  backend concurrent  connections
(and/or streams  in case of HTTP/2)  per frontend.  This
option  is   only  used  for  default   mode.   0  means
unlimited.  To limit the  number of connections per host
with          \fI\%\-\-http2\-proxy\fP         option,          use
\fI\%\-\-backend\-connections\-per\-host\fP\&.
.sp
Default: \fB0\fP
.UNINDENT
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.TP
.B \-\-rlimit\-nofile=<N>
Set maximum number of open files (RLIMIT_NOFILE) to <N>.
If 0 is given, nghttpx does not set the limit.
.sp
Default: \fB0\fP
.UNINDENT
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.TP
.B \-\-backend\-request\-buffer=<SIZE>
Set buffer size used to store backend request.
.sp
Default: \fB16K\fP
.UNINDENT
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.TP
.B \-\-backend\-response\-buffer=<SIZE>
Set buffer size used to store backend response.
.sp
Default: \fB128K\fP
.UNINDENT
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.TP
.B \-\-fastopen=<N>
Enables  "TCP Fast  Open" for  the listening  socket and
limits the  maximum length for the  queue of connections
that have not yet completed the three\-way handshake.  If
value is 0 then fast open is disabled.
.sp
Default: \fB0\fP
.UNINDENT
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.TP
.B \-\-no\-kqueue
Don\(aqt use  kqueue.  This  option is only  applicable for
the platforms  which have kqueue.  For  other platforms,
this option will be simply ignored.
.UNINDENT
.SS Timeout
.INDENT 0.0
.TP
.B \-\-frontend\-http2\-read\-timeout=<DURATION>
Specify read timeout for HTTP/2 frontend connection.
.sp
Default: \fB3m\fP
.UNINDENT
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.TP
.B \-\-frontend\-read\-timeout=<DURATION>
Specify read timeout for HTTP/1.1 frontend connection.
.sp
Default: \fB1m\fP
.UNINDENT
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.TP
.B \-\-frontend\-write\-timeout=<DURATION>
Specify write timeout for all frontend connections.
.sp
Default: \fB30s\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-frontend\-keep\-alive\-timeout=<DURATION>
Specify   keep\-alive   timeout   for   frontend   HTTP/1
connection.
.sp
Default: \fB1m\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-stream\-read\-timeout=<DURATION>
Specify  read timeout  for HTTP/2  streams.  0  means no
timeout.
.sp
Default: \fB0\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-stream\-write\-timeout=<DURATION>
Specify write  timeout for  HTTP/2 streams.  0  means no
timeout.
.sp
Default: \fB1m\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-read\-timeout=<DURATION>
Specify read timeout for backend connection.
.sp
Default: \fB1m\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-write\-timeout=<DURATION>
Specify write timeout for backend connection.
.sp
Default: \fB30s\fP
.UNINDENT
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.TP
.B \-\-backend\-connect\-timeout=<DURATION>
Specify  timeout before  establishing TCP  connection to
backend.
.sp
Default: \fB30s\fP
.UNINDENT
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.TP
.B \-\-backend\-keep\-alive\-timeout=<DURATION>
Specify   keep\-alive   timeout    for   backend   HTTP/1
connection.
.sp
Default: \fB2s\fP
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.B \-\-listener\-disable\-timeout=<DURATION>
After accepting  connection failed,  connection listener
is disabled  for a given  amount of time.   Specifying 0
disables this feature.
.sp
Default: \fB30s\fP
.UNINDENT
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.TP
.B \-\-frontend\-http2\-setting\-timeout=<DURATION>
Specify  timeout before  SETTINGS ACK  is received  from
client.
.sp
Default: \fB10s\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-http2\-settings\-timeout=<DURATION>
Specify  timeout before  SETTINGS ACK  is received  from
backend server.
.sp
Default: \fB10s\fP
.UNINDENT
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.TP
.B \-\-backend\-max\-backoff=<DURATION>
Specify  maximum backoff  interval.  This  is used  when
doing health  check against offline backend  (see "fail"
parameter  in \fI\%\-\-backend\fP  option).   It is  also used  to
limit  the  maximum   interval  to  temporarily  disable
backend  when nghttpx  failed to  connect to  it.  These
intervals are calculated  using exponential backoff, and
consecutive failed attempts increase the interval.  This
option caps its maximum value.
.sp
Default: \fB2m\fP
.UNINDENT
.SS SSL/TLS
.INDENT 0.0
.TP
.B \-\-ciphers=<SUITE>
Set allowed  cipher list  for frontend  connection.  The
format of the string is described in OpenSSL ciphers(1).
This option  sets cipher suites for  TLSv1.2 or earlier.
Use \fI\%\-\-tls13\-ciphers\fP for TLSv1.3.
.sp
Default: \fBECDHE\-ECDSA\-AES256\-GCM\-SHA384:ECDHE\-RSA\-AES256\-GCM\-SHA384:ECDHE\-ECDSA\-CHACHA20\-POLY1305:ECDHE\-RSA\-CHACHA20\-POLY1305:ECDHE\-ECDSA\-AES128\-GCM\-SHA256:ECDHE\-RSA\-AES128\-GCM\-SHA256:ECDHE\-ECDSA\-AES256\-SHA384:ECDHE\-RSA\-AES256\-SHA384:ECDHE\-ECDSA\-AES128\-SHA256:ECDHE\-RSA\-AES128\-SHA256\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls13\-ciphers=<SUITE>
Set allowed  cipher list  for frontend  connection.  The
format of the string is described in OpenSSL ciphers(1).
This  option  sets  cipher   suites  for  TLSv1.3.   Use
\fI\%\-\-ciphers\fP for TLSv1.2 or earlier.
.sp
Default: \fBTLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-client\-ciphers=<SUITE>
Set  allowed cipher  list for  backend connection.   The
format of the string is described in OpenSSL ciphers(1).
This option  sets cipher suites for  TLSv1.2 or earlier.
Use \fI\%\-\-tls13\-client\-ciphers\fP for TLSv1.3.
.sp
Default: \fBECDHE\-ECDSA\-AES256\-GCM\-SHA384:ECDHE\-RSA\-AES256\-GCM\-SHA384:ECDHE\-ECDSA\-CHACHA20\-POLY1305:ECDHE\-RSA\-CHACHA20\-POLY1305:ECDHE\-ECDSA\-AES128\-GCM\-SHA256:ECDHE\-RSA\-AES128\-GCM\-SHA256:ECDHE\-ECDSA\-AES256\-SHA384:ECDHE\-RSA\-AES256\-SHA384:ECDHE\-ECDSA\-AES128\-SHA256:ECDHE\-RSA\-AES128\-SHA256\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls13\-client\-ciphers=<SUITE>
Set  allowed cipher  list for  backend connection.   The
format of the string is described in OpenSSL ciphers(1).
This  option  sets  cipher   suites  for  TLSv1.3.   Use
\fI\%\-\-tls13\-client\-ciphers\fP for TLSv1.2 or earlier.
.sp
Default: \fBTLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-ecdh\-curves=<LIST>
Set  supported  curve  list  for  frontend  connections.
<LIST> is a  colon separated list of curve  NID or names
in the preference order.  The supported curves depend on
the  linked  OpenSSL  library.  This  function  requires
OpenSSL >= 1.0.2.
.sp
Default: \fBX25519:P\-256:P\-384:P\-521\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-k, \-\-insecure
Don\(aqt  verify backend  server\(aqs  certificate  if TLS  is
enabled for backend connections.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-cacert=<PATH>
Set path to trusted CA  certificate file.  It is used in
backend  TLS connections  to verify  peer\(aqs certificate.
It is also used to  verify OCSP response from the script
set by \fI\%\-\-fetch\-ocsp\-response\-file\fP\&.  The  file must be in
PEM format.   It can contain multiple  certificates.  If
the  linked OpenSSL  is configured  to load  system wide
certificates, they  are loaded at startup  regardless of
this option.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-private\-key\-passwd\-file=<PATH>
Path  to file  that contains  password for  the server\(aqs
private key.   If none is  given and the private  key is
password protected it\(aqll be requested interactively.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-subcert=<KEYPATH>:<CERTPATH>[[;<PARAM>]...]
Specify  additional certificate  and  private key  file.
nghttpx will  choose certificates based on  the hostname
indicated by client using TLS SNI extension.  If nghttpx
is  built with  OpenSSL  >= 1.0.2,  the shared  elliptic
curves (e.g., P\-256) between  client and server are also
taken into  consideration.  This allows nghttpx  to send
ECDSA certificate  to modern clients, while  sending RSA
based certificate to older  clients.  This option can be
used  multiple  times.   To  make  OCSP  stapling  work,
<CERTPATH> must be absolute path.
.sp
Additional parameter  can be specified in  <PARAM>.  The
available <PARAM> is "sct\-dir=<DIR>".
.sp
"sct\-dir=<DIR>"  specifies the  path to  directory which
contains        *.sct        files        for        TLS
signed_certificate_timestamp extension (RFC 6962).  This
feature   requires   OpenSSL   >=   1.0.2.    See   also
\fI\%\-\-tls\-sct\-dir\fP option.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-dh\-param\-file=<PATH>
Path to file that contains  DH parameters in PEM format.
Without  this   option,  DHE   cipher  suites   are  not
available.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-npn\-list=<LIST>
Comma delimited list of  ALPN protocol identifier sorted
in the  order of preference.  That  means most desirable
protocol comes  first.  This  is used  in both  ALPN and
NPN.  The parameter must be  delimited by a single comma
only  and any  white spaces  are  treated as  a part  of
protocol string.
.sp
Default: \fBh2,h2\-16,h2\-14,http/1.1\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-verify\-client
Require and verify client certificate.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-verify\-client\-cacert=<PATH>
Path  to file  that contains  CA certificates  to verify
client certificate.  The file must be in PEM format.  It
can contain multiple certificates.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-verify\-client\-tolerate\-expired
Accept  expired  client  certificate.   Operator  should
handle  the expired  client  certificate  by some  means
(e.g.,  mruby  script).   Otherwise, this  option  might
cause a security risk.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-client\-private\-key\-file=<PATH>
Path to  file that contains  client private key  used in
backend client authentication.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-client\-cert\-file=<PATH>
Path to  file that  contains client certificate  used in
backend client authentication.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-min\-proto\-version=<VER>
Specify minimum SSL/TLS protocol.   The name matching is
done in  case\-insensitive manner.  The  versions between
\fI\%\-\-tls\-min\-proto\-version\fP and  \fI\%\-\-tls\-max\-proto\-version\fP are
enabled.  If the protocol list advertised by client does
not  overlap  this range,  you  will  receive the  error
message "unknown protocol".  If a protocol version lower
than TLSv1.2 is specified, make sure that the compatible
ciphers are  included in \fI\%\-\-ciphers\fP option.   The default
cipher  list  only   includes  ciphers  compatible  with
TLSv1.2 or above.  The available versions are:
TLSv1.3, TLSv1.2, TLSv1.1, and TLSv1.0
.sp
Default: \fBTLSv1.2\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-max\-proto\-version=<VER>
Specify maximum SSL/TLS protocol.   The name matching is
done in  case\-insensitive manner.  The  versions between
\fI\%\-\-tls\-min\-proto\-version\fP and  \fI\%\-\-tls\-max\-proto\-version\fP are
enabled.  If the protocol list advertised by client does
not  overlap  this range,  you  will  receive the  error
message "unknown protocol".  The available versions are:
TLSv1.3, TLSv1.2, TLSv1.1, and TLSv1.0
.sp
Default: \fBTLSv1.3\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-file=<PATH>
Path to file that contains  random data to construct TLS
session ticket  parameters.  If aes\-128\-cbc is  given in
\fI\%\-\-tls\-ticket\-key\-cipher\fP, the  file must  contain exactly
48    bytes.     If     aes\-256\-cbc    is    given    in
\fI\%\-\-tls\-ticket\-key\-cipher\fP, the  file must  contain exactly
80  bytes.   This  options  can be  used  repeatedly  to
specify  multiple ticket  parameters.  If  several files
are given,  only the  first key is  used to  encrypt TLS
session  tickets.  Other  keys are  accepted but  server
will  issue new  session  ticket with  first key.   This
allows  session  key  rotation.  Please  note  that  key
rotation  does  not  occur automatically.   User  should
rearrange  files or  change options  values and  restart
nghttpx gracefully.   If opening  or reading  given file
fails, all loaded  keys are discarded and  it is treated
as if none  of this option is given.  If  this option is
not given or an error  occurred while opening or reading
a file,  key is  generated every  1 hour  internally and
they are  valid for  12 hours.   This is  recommended if
ticket  key sharing  between  nghttpx  instances is  not
required.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-memcached=<HOST>,<PORT>[;tls]
Specify address  of memcached  server to get  TLS ticket
keys for  session resumption.   This enables  shared TLS
ticket key between  multiple nghttpx instances.  nghttpx
does not set TLS ticket  key to memcached.  The external
ticket key generator is required.  nghttpx just gets TLS
ticket  keys  from  memcached, and  use  them,  possibly
replacing current set  of keys.  It is up  to extern TLS
ticket  key generator  to rotate  keys frequently.   See
"TLS SESSION  TICKET RESUMPTION" section in  manual page
to know the data format in memcached entry.  Optionally,
memcached  connection  can  be  encrypted  with  TLS  by
specifying "tls" parameter.
.UNINDENT
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.TP
.B \-\-tls\-ticket\-key\-memcached\-address\-family=(auto|IPv4|IPv6)
Specify address  family of memcached connections  to get
TLS ticket keys.  If "auto" is given, both IPv4 and IPv6
are considered.   If "IPv4" is given,  only IPv4 address
is considered.  If "IPv6" is given, only IPv6 address is
considered.
.sp
Default: \fBauto\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-memcached\-interval=<DURATION>
Set interval to get TLS ticket keys from memcached.
.sp
Default: \fB10m\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-memcached\-max\-retry=<N>
Set  maximum   number  of  consecutive   retries  before
abandoning TLS ticket key  retrieval.  If this number is
reached,  the  attempt  is considered  as  failure,  and
"failure" count  is incremented by 1,  which contributed
to            the            value            controlled
\fI\%\-\-tls\-ticket\-key\-memcached\-max\-fail\fP option.
.sp
Default: \fB3\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-memcached\-max\-fail=<N>
Set  maximum   number  of  consecutive   failure  before
disabling TLS ticket until next scheduled key retrieval.
.sp
Default: \fB2\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-cipher=<CIPHER>
Specify cipher  to encrypt TLS session  ticket.  Specify
either   aes\-128\-cbc   or  aes\-256\-cbc.    By   default,
aes\-128\-cbc is used.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-memcached\-cert\-file=<PATH>
Path to client certificate  for memcached connections to
get TLS ticket keys.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-ticket\-key\-memcached\-private\-key\-file=<PATH>
Path to client private  key for memcached connections to
get TLS ticket keys.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-fetch\-ocsp\-response\-file=<PATH>
Path to  fetch\-ocsp\-response script file.  It  should be
absolute path.
.sp
Default: \fB/usr/local/share/nghttp2/fetch\-ocsp\-response\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-ocsp\-update\-interval=<DURATION>
Set interval to update OCSP response cache.
.sp
Default: \fB4h\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-ocsp\-startup
Start  accepting connections  after initial  attempts to
get OCSP responses  finish.  It does not  matter some of
the  attempts  fail.  This  feature  is  useful if  OCSP
responses   must    be   available    before   accepting
connections.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-verify\-ocsp
nghttpx does not verify OCSP response.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-ocsp
Disable OCSP stapling.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-session\-cache\-memcached=<HOST>,<PORT>[;tls]
Specify  address of  memcached server  to store  session
cache.   This  enables   shared  session  cache  between
multiple   nghttpx  instances.    Optionally,  memcached
connection can be encrypted with TLS by specifying "tls"
parameter.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-session\-cache\-memcached\-address\-family=(auto|IPv4|IPv6)
Specify address family of memcached connections to store
session cache.  If  "auto" is given, both  IPv4 and IPv6
are considered.   If "IPv4" is given,  only IPv4 address
is considered.  If "IPv6" is given, only IPv6 address is
considered.
.sp
Default: \fBauto\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-session\-cache\-memcached\-cert\-file=<PATH>
Path to client certificate  for memcached connections to
store session cache.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-session\-cache\-memcached\-private\-key\-file=<PATH>
Path to client private  key for memcached connections to
store session cache.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-dyn\-rec\-warmup\-threshold=<SIZE>
Specify the  threshold size for TLS  dynamic record size
behaviour.  During  a TLS  session, after  the threshold
number of bytes  have been written, the  TLS record size
will be increased to the maximum allowed (16K).  The max
record size will  continue to be used on  the active TLS
session.  After  \fI\%\-\-tls\-dyn\-rec\-idle\-timeout\fP has elapsed,
the record size is reduced  to 1300 bytes.  Specify 0 to
always use  the maximum record size,  regardless of idle
period.   This  behaviour  applies   to  all  TLS  based
frontends, and TLS HTTP/2 backends.
.sp
Default: \fB1M\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-dyn\-rec\-idle\-timeout=<DURATION>
Specify TLS dynamic record  size behaviour timeout.  See
\fI\%\-\-tls\-dyn\-rec\-warmup\-threshold\fP  for   more  information.
This behaviour  applies to all TLS  based frontends, and
TLS HTTP/2 backends.
.sp
Default: \fB1s\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-http2\-cipher\-black\-list
Allow  black  listed  cipher suite  on  frontend  HTTP/2
connection.                                          See
\fI\%https://tools.ietf.org/html/rfc7540#appendix\-A\fP  for  the
complete HTTP/2 cipher suites black list.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-client\-no\-http2\-cipher\-black\-list
Allow  black  listed  cipher  suite  on  backend  HTTP/2
connection.                                          See
\fI\%https://tools.ietf.org/html/rfc7540#appendix\-A\fP  for  the
complete HTTP/2 cipher suites black list.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-sct\-dir=<DIR>
Specifies the  directory where  *.sct files  exist.  All
*.sct   files   in  <DIR>   are   read,   and  sent   as
extension_data of  TLS signed_certificate_timestamp (RFC
6962)  to  client.   These   *.sct  files  are  for  the
certificate   specified   in   positional   command\-line
argument <CERT>, or  certificate option in configuration
file.   For   additional  certificates,   use  \fI\%\-\-subcert\fP
option.  This option requires OpenSSL >= 1.0.2.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-psk\-secrets=<PATH>
Read list of PSK identity and secrets from <PATH>.  This
is used for frontend connection.  The each line of input
file  is  formatted  as  <identity>:<hex\-secret>,  where
<identity> is  PSK identity, and <hex\-secret>  is secret
in hex.  An  empty line, and line which  starts with \(aq#\(aq
are skipped.  The default  enabled cipher list might not
contain any PSK cipher suite.  In that case, desired PSK
cipher suites  must be  enabled using  \fI\%\-\-ciphers\fP option.
The  desired PSK  cipher suite  may be  black listed  by
HTTP/2.   To  use  those   cipher  suites  with  HTTP/2,
consider  to  use  \fI\%\-\-no\-http2\-cipher\-black\-list\fP  option.
But be aware its implications.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-client\-psk\-secrets=<PATH>
Read PSK identity and secrets from <PATH>.  This is used
for backend connection.  The each  line of input file is
formatted  as <identity>:<hex\-secret>,  where <identity>
is PSK identity, and <hex\-secret>  is secret in hex.  An
empty line, and line which  starts with \(aq#\(aq are skipped.
The first identity and  secret pair encountered is used.
The default  enabled cipher  list might not  contain any
PSK  cipher suite.   In  that case,  desired PSK  cipher
suites  must be  enabled using  \fI\%\-\-client\-ciphers\fP option.
The  desired PSK  cipher suite  may be  black listed  by
HTTP/2.   To  use  those   cipher  suites  with  HTTP/2,
consider   to  use   \fI\%\-\-client\-no\-http2\-cipher\-black\-list\fP
option.  But be aware its implications.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-tls\-no\-postpone\-early\-data
By default,  nghttpx postpones forwarding  HTTP requests
sent in early data, including those sent in partially in
it, until TLS handshake finishes.  If all backend server
recognizes "Early\-Data" header  field, using this option
makes nghttpx  not postpone  forwarding request  and get
full potential of 0\-RTT data.
.UNINDENT
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.TP
.B \-\-tls\-max\-early\-data=<SIZE>
Sets  the  maximum  amount  of 0\-RTT  data  that  server
accepts.
.sp
Default: \fB16K\fP
.UNINDENT
.SS HTTP/2
.INDENT 0.0
.TP
.B \-c, \-\-frontend\-http2\-max\-concurrent\-streams=<N>
Set the maximum number of  the concurrent streams in one
frontend HTTP/2 session.
.sp
Default: \fB100\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-http2\-max\-concurrent\-streams=<N>
Set the maximum number of  the concurrent streams in one
backend  HTTP/2 session.   This sets  maximum number  of
concurrent opened pushed streams.  The maximum number of
concurrent requests are set by a remote server.
.sp
Default: \fB100\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-frontend\-http2\-window\-size=<SIZE>
Sets  the  per\-stream  initial  window  size  of  HTTP/2
frontend connection.
.sp
Default: \fB65535\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-frontend\-http2\-connection\-window\-size=<SIZE>
Sets the  per\-connection window size of  HTTP/2 frontend
connection.
.sp
Default: \fB65535\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-http2\-window\-size=<SIZE>
Sets  the   initial  window   size  of   HTTP/2  backend
connection.
.sp
Default: \fB65535\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-http2\-connection\-window\-size=<SIZE>
Sets the  per\-connection window  size of  HTTP/2 backend
connection.
.sp
Default: \fB2147483647\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-http2\-no\-cookie\-crumbling
Don\(aqt crumble cookie header field.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-padding=<N>
Add  at most  <N> bytes  to  a HTTP/2  frame payload  as
padding.  Specify 0 to  disable padding.  This option is
meant for debugging purpose  and not intended to enhance
protocol security.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-server\-push
Disable HTTP/2 server push.  Server push is supported by
default mode and HTTP/2  frontend via Link header field.
It is  also supported if  both frontend and  backend are
HTTP/2 in default mode.  In  this case, server push from
backend session is relayed  to frontend, and server push
via Link header field is also supported.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-frontend\-http2\-optimize\-write\-buffer\-size
(Experimental) Enable write  buffer size optimization in
frontend HTTP/2 TLS  connection.  This optimization aims
to reduce  write buffer  size so  that it  only contains
bytes  which can  send immediately.   This makes  server
more responsive to prioritized HTTP/2 stream because the
buffering  of lower  priority stream  is reduced.   This
option is only effective on recent Linux platform.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-frontend\-http2\-optimize\-window\-size
(Experimental)   Automatically  tune   connection  level
window size of frontend  HTTP/2 TLS connection.  If this
feature is  enabled, connection window size  starts with
the   default  window   size,   65535  bytes.    nghttpx
automatically  adjusts connection  window size  based on
TCP receiving  window size.  The maximum  window size is
capped      by      the     value      specified      by
\fI\%\-\-frontend\-http2\-connection\-window\-size\fP\&.     Since   the
stream is subject to stream level window size, it should
be adjusted using \fI\%\-\-frontend\-http2\-window\-size\fP option as
well.   This option  is only  effective on  recent Linux
platform.
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.TP
.B \-\-frontend\-http2\-encoder\-dynamic\-table\-size=<SIZE>
Specify the maximum dynamic  table size of HPACK encoder
in the frontend HTTP/2 connection.  The decoder (client)
specifies  the maximum  dynamic table  size it  accepts.
Then the negotiated dynamic table size is the minimum of
this option value and the value which client specified.
.sp
Default: \fB4K\fP
.UNINDENT
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.TP
.B \-\-frontend\-http2\-decoder\-dynamic\-table\-size=<SIZE>
Specify the maximum dynamic  table size of HPACK decoder
in the frontend HTTP/2 connection.
.sp
Default: \fB4K\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-backend\-http2\-encoder\-dynamic\-table\-size=<SIZE>
Specify the maximum dynamic  table size of HPACK encoder
in the backend HTTP/2 connection.  The decoder (backend)
specifies  the maximum  dynamic table  size it  accepts.
Then the negotiated dynamic table size is the minimum of
this option value and the value which backend specified.
.sp
Default: \fB4K\fP
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.TP
.B \-\-backend\-http2\-decoder\-dynamic\-table\-size=<SIZE>
Specify the maximum dynamic  table size of HPACK decoder
in the backend HTTP/2 connection.
.sp
Default: \fB4K\fP
.UNINDENT
.SS Mode
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.TP
.B (default mode)
Accept  HTTP/2,  and  HTTP/1.1 over  SSL/TLS.   "no\-tls"
parameter is  used in  \fI\%\-\-frontend\fP option,  accept HTTP/2
and HTTP/1.1 over cleartext  TCP.  The incoming HTTP/1.1
connection  can  be  upgraded  to  HTTP/2  through  HTTP
Upgrade.
.UNINDENT
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.TP
.B \-s, \-\-http2\-proxy
Like default mode, but enable forward proxy.  This is so
called HTTP/2 proxy mode.
.UNINDENT
.SS Logging
.INDENT 0.0
.TP
.B \-L, \-\-log\-level=<LEVEL>
Set the severity  level of log output.   <LEVEL> must be
one of INFO, NOTICE, WARN, ERROR and FATAL.
.sp
Default: \fBNOTICE\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-accesslog\-file=<PATH>
Set path to write access log.  To reopen file, send USR1
signal to nghttpx.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-accesslog\-syslog
Send  access log  to syslog.   If this  option is  used,
\fI\%\-\-accesslog\-file\fP option is ignored.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-accesslog\-format=<FORMAT>
Specify  format  string  for access  log.   The  default
format is combined format.   The following variables are
available:
.INDENT 7.0
.IP \(bu 2
$remote_addr: client IP address.
.IP \(bu 2
$time_local: local time in Common Log format.
.IP \(bu 2
$time_iso8601: local time in ISO 8601 format.
.IP \(bu 2
$request: HTTP request line.
.IP \(bu 2
$status: HTTP response status code.
.IP \(bu 2
$body_bytes_sent: the  number of bytes sent  to client
as response body.
.IP \(bu 2
$http_<VAR>: value of HTTP  request header <VAR> where
\(aq_\(aq in <VAR> is replaced with \(aq\-\(aq.
.IP \(bu 2
$remote_port: client  port.
.IP \(bu 2
$server_port: server port.
.IP \(bu 2
$request_time: request processing time in seconds with
milliseconds resolution.
.IP \(bu 2
$pid: PID of the running process.
.IP \(bu 2
$alpn: ALPN identifier of the protocol which generates
the response.   For HTTP/1,  ALPN is  always http/1.1,
regardless of minor version.
.IP \(bu 2
$tls_cipher: cipher used for SSL/TLS connection.
.IP \(bu 2
$tls_client_fingerprint_sha256: SHA\-256 fingerprint of
client certificate.
.IP \(bu 2
$tls_client_fingerprint_sha1:  SHA\-1   fingerprint  of
client certificate.
.IP \(bu 2
$tls_client_subject_name:   subject  name   in  client
certificate.
.IP \(bu 2
$tls_client_issuer_name:   issuer   name   in   client
certificate.
.IP \(bu 2
$tls_client_serial:    serial    number   in    client
certificate.
.IP \(bu 2
$tls_protocol: protocol for SSL/TLS connection.
.IP \(bu 2
$tls_session_id: session ID for SSL/TLS connection.
.IP \(bu 2
$tls_session_reused:  "r"   if  SSL/TLS   session  was
reused.  Otherwise, "."
.IP \(bu 2
$tls_sni: SNI server name for SSL/TLS connection.
.IP \(bu 2
$backend_host:  backend  host   used  to  fulfill  the
request.  "\-" if backend host is not available.
.IP \(bu 2
$backend_port:  backend  port   used  to  fulfill  the
request.  "\-" if backend host is not available.
.UNINDENT
.sp
The  variable  can  be  enclosed  by  "{"  and  "}"  for
disambiguation (e.g., ${remote_addr}).
.sp
Default: \fB$remote_addr \- \- [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent"\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-accesslog\-write\-early
Write  access  log  when   response  header  fields  are
received   from  backend   rather   than  when   request
transaction finishes.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-errorlog\-file=<PATH>
Set path to write error  log.  To reopen file, send USR1
signal  to nghttpx.   stderr will  be redirected  to the
error log file unless \fI\%\-\-errorlog\-syslog\fP is used.
.sp
Default: \fB/dev/stderr\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-errorlog\-syslog
Send  error log  to  syslog.  If  this  option is  used,
\fI\%\-\-errorlog\-file\fP option is ignored.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-syslog\-facility=<FACILITY>
Set syslog facility to <FACILITY>.
.sp
Default: \fBdaemon\fP
.UNINDENT
.SS HTTP
.INDENT 0.0
.TP
.B \-\-add\-x\-forwarded\-for
Append  X\-Forwarded\-For header  field to  the downstream
request.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-strip\-incoming\-x\-forwarded\-for
Strip X\-Forwarded\-For  header field from  inbound client
requests.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-add\-x\-forwarded\-proto
Don\(aqt append  additional X\-Forwarded\-Proto  header field
to  the   backend  request.   If  inbound   client  sets
X\-Forwarded\-Proto,                                   and
\fI\%\-\-no\-strip\-incoming\-x\-forwarded\-proto\fP  option  is  used,
they are passed to the backend.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-strip\-incoming\-x\-forwarded\-proto
Don\(aqt strip X\-Forwarded\-Proto  header field from inbound
client requests.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-add\-forwarded=<LIST>
Append RFC  7239 Forwarded header field  with parameters
specified in comma delimited list <LIST>.  The supported
parameters  are "by",  "for", "host",  and "proto".   By
default,  the value  of  "by" and  "for" parameters  are
obfuscated     string.     See     \fI\%\-\-forwarded\-by\fP    and
\fI\%\-\-forwarded\-for\fP options respectively.  Note that nghttpx
does  not  translate non\-standard  X\-Forwarded\-*  header
fields into Forwarded header field, and vice versa.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-strip\-incoming\-forwarded
Strip  Forwarded   header  field  from   inbound  client
requests.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-forwarded\-by=(obfuscated|ip|<VALUE>)
Specify the parameter value sent out with "by" parameter
of Forwarded  header field.   If "obfuscated"  is given,
the string is randomly generated at startup.  If "ip" is
given,   the  interface   address  of   the  connection,
including port number, is  sent with "by" parameter.  In
case of UNIX domain  socket, "localhost" is used instead
of address and  port.  User can also  specify the static
obfuscated string.  The limitation is that it must start
with   "_",  and   only   consists   of  character   set
[A\-Za\-z0\-9._\-], as described in RFC 7239.
.sp
Default: \fBobfuscated\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-forwarded\-for=(obfuscated|ip)
Specify  the   parameter  value  sent  out   with  "for"
parameter of Forwarded header field.  If "obfuscated" is
given, the string is  randomly generated for each client
connection.  If "ip" is given, the remote client address
of  the connection,  without port  number, is  sent with
"for"  parameter.   In  case   of  UNIX  domain  socket,
"localhost" is used instead of address.
.sp
Default: \fBobfuscated\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-via
Don\(aqt append to  Via header field.  If  Via header field
is received, it is left unaltered.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-strip\-incoming\-early\-data
Don\(aqt strip Early\-Data header  field from inbound client
requests.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-location\-rewrite
Don\(aqt  rewrite location  header field  in default  mode.
When \fI\%\-\-http2\-proxy\fP  is used, location header  field will
not be altered regardless of this option.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-host\-rewrite
Rewrite  host and  :authority header  fields in  default
mode.  When  \fI\%\-\-http2\-proxy\fP is  used, these  headers will
not be altered regardless of this option.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-altsvc=<PROTOID,PORT[,HOST,[ORIGIN]]>
Specify   protocol  ID,   port,  host   and  origin   of
alternative service.  <HOST>  and <ORIGIN> are optional.
They  are advertised  in  alt\-svc header  field only  in
HTTP/1.1  frontend.  This  option can  be used  multiple
times   to   specify  multiple   alternative   services.
Example: \fI\%\-\-altsvc\fP=h2,443
.UNINDENT
.INDENT 0.0
.TP
.B \-\-add\-request\-header=<HEADER>
Specify additional header field to add to request header
set.  This  option just  appends header field  and won\(aqt
replace anything  already set.  This option  can be used
several  times   to  specify  multiple   header  fields.
Example: \fI\%\-\-add\-request\-header\fP="foo: bar"
.UNINDENT
.INDENT 0.0
.TP
.B \-\-add\-response\-header=<HEADER>
Specify  additional  header  field to  add  to  response
header set.   This option just appends  header field and
won\(aqt replace anything already  set.  This option can be
used several  times to  specify multiple  header fields.
Example: \fI\%\-\-add\-response\-header\fP="foo: bar"
.UNINDENT
.INDENT 0.0
.TP
.B \-\-request\-header\-field\-buffer=<SIZE>
Set maximum buffer size for incoming HTTP request header
field list.  This is the sum of header name and value in
bytes.   If  trailer  fields  exist,  they  are  counted
towards this number.
.sp
Default: \fB64K\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-max\-request\-header\-fields=<N>
Set  maximum  number  of incoming  HTTP  request  header
fields.   If  trailer  fields exist,  they  are  counted
towards this number.
.sp
Default: \fB100\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-response\-header\-field\-buffer=<SIZE>
Set  maximum  buffer  size for  incoming  HTTP  response
header field list.   This is the sum of  header name and
value  in  bytes.  If  trailer  fields  exist, they  are
counted towards this number.
.sp
Default: \fB64K\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-max\-response\-header\-fields=<N>
Set  maximum number  of  incoming  HTTP response  header
fields.   If  trailer  fields exist,  they  are  counted
towards this number.
.sp
Default: \fB500\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-error\-page=(<CODE>|*)=<PATH>
Set file path  to custom error page  served when nghttpx
originally  generates  HTTP  error status  code  <CODE>.
<CODE> must be greater than or equal to 400, and at most
599.  If "*"  is used instead of <CODE>,  it matches all
HTTP  status  code.  If  error  status  code comes  from
backend server, the custom error pages are not used.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-server\-name=<NAME>
Change server response header field value to <NAME>.
.sp
Default: \fBnghttpx\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-no\-server\-rewrite
Don\(aqt rewrite server header field in default mode.  When
\fI\%\-\-http2\-proxy\fP is used, these headers will not be altered
regardless of this option.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-redirect\-https\-port=<PORT>
Specify the port number which appears in Location header
field  when  redirect  to  HTTPS  URI  is  made  due  to
"redirect\-if\-not\-tls" parameter in \fI\%\-\-backend\fP option.
.sp
Default: \fB443\fP
.UNINDENT
.SS API
.INDENT 0.0
.TP
.B \-\-api\-max\-request\-body=<SIZE>
Set the maximum size of request body for API request.
.sp
Default: \fB32M\fP
.UNINDENT
.SS DNS
.INDENT 0.0
.TP
.B \-\-dns\-cache\-timeout=<DURATION>
Set duration that cached DNS results remain valid.  Note
that nghttpx caches the unsuccessful results as well.
.sp
Default: \fB10s\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-dns\-lookup\-timeout=<DURATION>
Set timeout that  DNS server is given to  respond to the
initial  DNS  query.  For  the  2nd  and later  queries,
server is  given time based  on this timeout, and  it is
scaled linearly.
.sp
Default: \fB5s\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-dns\-max\-try=<N>
Set the number of DNS query before nghttpx gives up name
lookup.
.sp
Default: \fB2\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-frontend\-max\-requests=<N>
The number  of requests that single  frontend connection
can process.  For HTTP/2, this  is the number of streams
in  one  HTTP/2 connection.   For  HTTP/1,  this is  the
number of keep alive requests.  This is hint to nghttpx,
and it  may allow additional few  requests.  The default
value is unlimited.
.UNINDENT
.SS Debug
.INDENT 0.0
.TP
.B \-\-frontend\-http2\-dump\-request\-header=<PATH>
Dumps request headers received by HTTP/2 frontend to the
file denoted  in <PATH>.  The  output is done  in HTTP/1
header field format and each header block is followed by
an empty line.  This option  is not thread safe and MUST
NOT be used with option \fI\%\-n\fP<N>, where <N> >= 2.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-frontend\-http2\-dump\-response\-header=<PATH>
Dumps response headers sent  from HTTP/2 frontend to the
file denoted  in <PATH>.  The  output is done  in HTTP/1
header field format and each header block is followed by
an empty line.  This option  is not thread safe and MUST
NOT be used with option \fI\%\-n\fP<N>, where <N> >= 2.
.UNINDENT
.INDENT 0.0
.TP
.B \-o, \-\-frontend\-frame\-debug
Print HTTP/2 frames in  frontend to stderr.  This option
is  not thread  safe and  MUST NOT  be used  with option
\fI\%\-n\fP=N, where N >= 2.
.UNINDENT
.SS Process
.INDENT 0.0
.TP
.B \-D, \-\-daemon
Run in a background.  If \fI\%\-D\fP is used, the current working
directory is changed to \(aq\fI/\fP\(aq.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-pid\-file=<PATH>
Set path to save PID of this program.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-user=<USER>
Run this program as <USER>.   This option is intended to
be used to drop root privileges.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-single\-process
Run this program in a  single process mode for debugging
purpose.  Without this option,  nghttpx creates at least
2  processes:  master  and worker  processes.   If  this
option is  used, master  and worker  are unified  into a
single process.  nghttpx still spawns additional process
if neverbleed is used.  In  the single process mode, the
signal handling feature is disabled.
.UNINDENT
.SS Scripting
.INDENT 0.0
.TP
.B \-\-mruby\-file=<PATH>
Set mruby script file
.UNINDENT
.INDENT 0.0
.TP
.B \-\-ignore\-per\-pattern\-mruby\-error
Ignore mruby compile error  for per\-pattern mruby script
file.  If error  occurred, it is treated as  if no mruby
file were specified for the pattern.
.UNINDENT
.SS Misc
.INDENT 0.0
.TP
.B \-\-conf=<PATH>
Load  configuration  from   <PATH>.   Please  note  that
nghttpx always  tries to read the  default configuration
file if \fI\%\-\-conf\fP is not given.
.sp
Default: \fB/etc/nghttpx/nghttpx.conf\fP
.UNINDENT
.INDENT 0.0
.TP
.B \-\-include=<PATH>
Load additional configurations from <PATH>.  File <PATH>
is  read  when  configuration  parser  encountered  this
option.  This option can be used multiple times, or even
recursively.
.UNINDENT
.INDENT 0.0
.TP
.B \-v, \-\-version
Print version and exit.
.UNINDENT
.INDENT 0.0
.TP
.B \-h, \-\-help
Print this help and exit.
.UNINDENT
.sp
The <SIZE> argument is an integer and an optional unit (e.g., 10K is
10 * 1024).  Units are K, M and G (powers of 1024).
.sp
The <DURATION> argument is an integer and an optional unit (e.g., 1s
is 1 second and 500ms is 500 milliseconds).  Units are h, m, s or ms
(hours, minutes, seconds and milliseconds, respectively).  If a unit
is omitted, a second is used as unit.
.SH FILES
.INDENT 0.0
.TP
.B \fI/etc/nghttpx/nghttpx.conf\fP
The default configuration file path nghttpx searches at startup.
The configuration file path can be changed using \fI\%\-\-conf\fP
option.
.sp
Those lines which are staring \fB#\fP are treated as comment.
.sp
The option name in the configuration file is the long command\-line
option name with leading \fB\-\-\fP stripped (e.g., \fBfrontend\fP).  Put
\fB=\fP between option name and value.  Don\(aqt put extra leading or
trailing spaces.
.sp
When specifying arguments including characters which have special
meaning to a shell, we usually use quotes so that shell does not
interpret them.  When writing this configuration file, quotes for
this purpose must not be used.  For example, specify additional
request header field, do this:
.INDENT 7.0
.INDENT 3.5
.sp
.nf
.ft C
add\-request\-header=foo: bar
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
instead of:
.INDENT 7.0
.INDENT 3.5
.sp
.nf
.ft C
add\-request\-header="foo: bar"
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The options which do not take argument in the command\-line \fItake\fP
argument in the configuration file.  Specify \fByes\fP as an argument
(e.g., \fBhttp2\-proxy=yes\fP).  If other string is given, it is
ignored.
.sp
To specify private key and certificate file which are given as
positional arguments in command\-line, use \fBprivate\-key\-file\fP and
\fBcertificate\-file\fP\&.
.sp
\fI\%\-\-conf\fP option cannot be used in the configuration file and
will be ignored if specified.
.TP
.B Error log
Error log is written to stderr by default.  It can be configured
using \fI\%\-\-errorlog\-file\fP\&.  The format of log message is as
follows:
.sp
<datetime> <master\-pid> <current\-pid> <thread\-id> <level> (<filename>:<line>) <msg>
.INDENT 7.0
.TP
.B <datetime>
It is a combination of date and time when the log is written.  It
is in ISO 8601 format.
.TP
.B <master\-pid>
It is a master process ID.
.TP
.B <current\-pid>
It is a process ID which writes this log.
.TP
.B <thread\-id>
It is a thread ID which writes this log.  It would be unique
within <current\-pid>.
.TP
.B <filename> and <line>
They are source file name, and line number which produce this log.
.TP
.B <msg>
It is a log message body.
.UNINDENT
.UNINDENT
.SH SIGNALS
.INDENT 0.0
.TP
.B SIGQUIT
Shutdown gracefully.  First accept pending connections and stop
accepting connection.  After all connections are handled, nghttpx
exits.
.TP
.B SIGHUP
Reload configuration file given in \fI\%\-\-conf\fP\&.
.TP
.B SIGUSR1
Reopen log files.
.UNINDENT
.sp
SIGUSR2
.INDENT 0.0
.INDENT 3.5
Fork and execute nghttpx.  It will execute the binary in the same
path with same command\-line arguments and environment variables.  As
of nghttpx version 1.20.0, the new master process sends SIGQUIT to
the original master process when it is ready to serve requests.  For
the earlier versions of nghttpx, user has to send SIGQUIT to the
original master process.
.sp
The difference between SIGUSR2 (+ SIGQUIT) and SIGHUP is that former
is usually used to execute new binary, and the master process is
newly spawned.  On the other hand, the latter just reloads
configuration file, and the same master process continues to exist.
.UNINDENT
.UNINDENT
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
nghttpx consists of multiple processes: one process for processing
these signals, and another one for processing requests.  The former
spawns the latter.  The former is called master process, and the
latter is called worker process.  If neverbleed is enabled, the
worker process spawns neverbleed daemon process which does RSA key
processing.  The above signal must be sent to the master process.
If the other processes received one of them, it is ignored.  This
behaviour of these processes may change in the future release.  In
other words, in the future release, the processes other than master
process may terminate upon the reception of these signals.
Therefore these signals should not be sent to the processes other
than master process.
.UNINDENT
.UNINDENT
.SH SERVER PUSH
.sp
nghttpx supports HTTP/2 server push in default mode with Link header
field.  nghttpx looks for Link header field (\fI\%RFC 5988\fP) in response headers from
backend server and extracts URI\-reference with parameter
\fBrel=preload\fP (see \fI\%preload\fP)
and pushes those URIs to the frontend client. Here is a sample Link
header field to initiate server push:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
Link: </fonts/font.woff>; rel=preload
Link: </css/theme.css>; rel=preload
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Currently, the following restriction is applied for server push:
.INDENT 0.0
.IP 1. 3
The associated stream must have method "GET" or "POST".  The
associated stream\(aqs status code must be 200.
.UNINDENT
.sp
This limitation may be loosened in the future release.
.sp
nghttpx also supports server push if both frontend and backend are
HTTP/2 in default mode.  In this case, in addition to server push via
Link header field, server push from backend is forwarded to frontend
HTTP/2 session.
.sp
HTTP/2 server push will be disabled if \fI\%\-\-http2\-proxy\fP is
used.
.SH UNIX DOMAIN SOCKET
.sp
nghttpx supports UNIX domain socket with a filename for both frontend
and backend connections.
.sp
Please note that current nghttpx implementation does not delete a
socket with a filename.  And on start up, if nghttpx detects that the
specified socket already exists in the file system, nghttpx first
deletes it.  However, if SIGUSR2 is used to execute new binary and
both old and new configurations use same filename, new binary does not
delete the socket and continues to use it.
.SH OCSP STAPLING
.sp
OCSP query is done using external Python script
\fBfetch\-ocsp\-response\fP, which has been originally developed in Perl
as part of h2o project (\fI\%https://github.com/h2o/h2o\fP), and was
translated into Python.
.sp
The script file is usually installed under
\fB$(prefix)/share/nghttp2/\fP directory.  The actual path to script can
be customized using \fI\%\-\-fetch\-ocsp\-response\-file\fP option.
.sp
If OCSP query is failed, previous OCSP response, if any, is continued
to be used.
.sp
\fI\%\-\-fetch\-ocsp\-response\-file\fP option provides wide range of
possibility to manage OCSP response.  It can take an arbitrary script
or executable.  The requirement is that it supports the command\-line
interface of \fBfetch\-ocsp\-response\fP script, and it must return a
valid DER encoded OCSP response on success.  It must return exit code
0 on success, and 75 for temporary error, and the other error code for
generic failure.  For large cluster of servers, it is not efficient
for each server to perform OCSP query using \fBfetch\-ocsp\-response\fP\&.
Instead, you can retrieve OCSP response in some way, and store it in a
disk or a shared database.  Then specify a program in
\fI\%\-\-fetch\-ocsp\-response\-file\fP to fetch it from those stores.
This could provide a way to share the OCSP response between fleet of
servers, and also any OCSP query strategy can be applied which may be
beyond the ability of nghttpx itself or \fBfetch\-ocsp\-response\fP
script.
.SH TLS SESSION RESUMPTION
.sp
nghttpx supports TLS session resumption through both session ID and
session ticket.
.SS SESSION ID RESUMPTION
.sp
By default, session ID is shared by all worker threads.
.sp
If \fI\%\-\-tls\-session\-cache\-memcached\fP is given, nghttpx will
insert serialized session data to memcached with
\fBnghttpx:tls\-session\-cache:\fP + lowercase hex string of session ID
as a memcached entry key, with expiry time 12 hours.  Session timeout
is set to 12 hours.
.sp
By default, connections to memcached server are not encrypted.  To
enable encryption, use \fBtls\fP keyword in
\fI\%\-\-tls\-session\-cache\-memcached\fP option.
.SS TLS SESSION TICKET RESUMPTION
.sp
By default, session ticket is shared by all worker threads.  The
automatic key rotation is also enabled by default.  Every an hour, new
encryption key is generated, and previous encryption key becomes
decryption only key.  We set session timeout to 12 hours, and thus we
keep at most 12 keys.
.sp
If \fI\%\-\-tls\-ticket\-key\-memcached\fP is given, encryption keys are
retrieved from memcached.  nghttpx just reads keys from memcached; one
has to deploy key generator program to update keys frequently (e.g.,
every 1 hour).  The example key generator tlsticketupdate.go is
available under contrib directory in nghttp2 archive.  The memcached
entry key is \fBnghttpx:tls\-ticket\-key\fP\&.  The data format stored in
memcached is the binary format described below:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
+\-\-\-\-\-\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-+
| VERSION (4)  |LEN (2)|KEY(48 or 80) ...
+\-\-\-\-\-\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-+
               ^                        |
               |                        |
               +\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-+
               (LEN, KEY) pair can be repeated
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
All numbers in the above figure is bytes.  All integer fields are
network byte order.
.sp
First 4 bytes integer VERSION field, which must be 1.  The 2 bytes
integer LEN field gives the length of following KEY field, which
contains key.  If \fI\%\-\-tls\-ticket\-key\-cipher\fP=aes\-128\-cbc is
used, LEN must be 48.  If
\fI\%\-\-tls\-ticket\-key\-cipher\fP=aes\-256\-cbc is used, LEN must be
80.  LEN and KEY pair can be repeated multiple times to store multiple
keys.  The key appeared first is used as encryption key.  All the
remaining keys are used as decryption only.
.sp
By default, connections to memcached server are not encrypted.  To
enable encryption, use \fBtls\fP keyword in
\fI\%\-\-tls\-ticket\-key\-memcached\fP option.
.sp
If \fI\%\-\-tls\-ticket\-key\-file\fP is given, encryption key is read
from the given file.  In this case, nghttpx does not rotate key
automatically.  To rotate key, one has to restart nghttpx (see
SIGNALS).
.SH CERTIFICATE TRANSPARENCY
.sp
nghttpx supports TLS \fBsigned_certificate_timestamp\fP extension (\fI\%RFC
6962\fP).  The relevant options
are \fI\%\-\-tls\-sct\-dir\fP and \fBsct\-dir\fP parameter in
\fI\%\-\-subcert\fP\&.  They takes a directory, and nghttpx reads all
files whose extension is \fB\&.sct\fP under the directory.  The \fB*.sct\fP
files are encoded as \fBSignedCertificateTimestamp\fP struct described
in \fI\%section 3.2 of RFC 69662\fP\&.  This format is
the same one used by \fI\%nginx\-ct\fP and \fI\%mod_ssl_ct\fP\&.
\fI\%ct\-submit\fP can be
used to submit certificates to log servers, and obtain the
\fBSignedCertificateTimestamp\fP struct which can be used with nghttpx.
.SH MRUBY SCRIPTING
.sp
\fBWARNING:\fP
.INDENT 0.0
.INDENT 3.5
The current mruby extension API is experimental and not frozen.  The
API is subject to change in the future release.
.UNINDENT
.UNINDENT
.sp
\fBWARNING:\fP
.INDENT 0.0
.INDENT 3.5
Almost all string value returned from method, or attribute is a
fresh new mruby string, which involves memory allocation, and
copies.  Therefore, it is strongly recommended to store a return
value in a local variable, and use it, instead of calling method or
accessing attribute repeatedly.
.UNINDENT
.UNINDENT
.sp
nghttpx allows users to extend its capability using mruby scripts.
nghttpx has 2 hook points to execute mruby script: request phase and
response phase.  The request phase hook is invoked after all request
header fields are received from client.  The response phase hook is
invoked after all response header fields are received from backend
server.  These hooks allows users to modify header fields, or common
HTTP variables, like authority or request path, and even return custom
response without forwarding request to backend servers.
.sp
There are 2 levels of mruby script invocations: global and
per\-pattern.  The global mruby script is set by \fI\%\-\-mruby\-file\fP
option and is called for all requests.  The per\-pattern mruby script
is set by "mruby" parameter in \fI\%\-b\fP option.  It is invoked for
a request which matches the particular pattern.  The order of hook
invocation is: global request phase hook, per\-pattern request phase
hook, per\-pattern response phase hook, and finally global response
phase hook.  If a hook returns a response, any later hooks are not
invoked.  The global request hook is invoked before the pattern
matching is made and changing request path may affect the pattern
matching.
.sp
Please note that request and response hooks of per\-pattern mruby
script for a single request might not come from the same script.  This
might happen after a request hook is executed, backend failed for some
reason, and at the same time, backend configuration is replaced by API
request, and then the request uses new configuration on retry.  The
response hook from new configuration, if it is specified, will be
invoked.
.sp
The all mruby script will be evaluated once per thread on startup, and
it must instantiate object and evaluate it as the return value (e.g.,
\fBApp.new\fP).  This object is called app object.  If app object
defines \fBon_req\fP method, it is called with \fI\%Nghttpx::Env\fP
object on request hook.  Similarly, if app object defines \fBon_resp\fP
method, it is called with \fI\%Nghttpx::Env\fP object on response
hook.  For each method invocation, user can can access
\fI\%Nghttpx::Request\fP and \fI\%Nghttpx::Response\fP objects
via \fI\%Nghttpx::Env#req\fP and \fI\%Nghttpx::Env#resp\fP
respectively.
.INDENT 0.0
.TP
.B Nghttpx::REQUEST_PHASE
Constant to represent request phase.
.UNINDENT
.INDENT 0.0
.TP
.B Nghttpx::RESPONSE_PHASE
Constant to represent response phase.
.UNINDENT
.INDENT 0.0
.TP
.B class Nghttpx::Env
Object to represent current request specific context.
.INDENT 7.0
.TP
.B attribute [R] req
Return \fI\%Request\fP object.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] resp
Return \fI\%Response\fP object.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] ctx
Return Ruby hash object.  It persists until request finishes.
So values set in request phase hook can be retrieved in
response phase hook.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] phase
Return the current phase.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] remote_addr
Return IP address of a remote client.  If connection is made
via UNIX domain socket, this returns the string "localhost".
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] server_addr
Return address of server that accepted the connection.  This
is a string which specified in \fI\%\-\-frontend\fP option,
excluding port number, and not a resolved IP address.  For
UNIX domain socket, this is a path to UNIX domain socket.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] server_port
Return port number of the server frontend which accepted the
connection from client.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_used
Return true if TLS is used on the connection.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_sni
Return the TLS SNI value which client sent in this connection.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_client_fingerprint_sha256
Return the SHA\-256 fingerprint of a client certificate.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_client_fingerprint_sha1
Return the SHA\-1 fingerprint of a client certificate.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_client_issuer_name
Return the issuer name of a client certificate.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_client_subject_name
Return the subject name of a client certificate.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_client_serial
Return the serial number of a client certificate.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_client_not_before
Return the start date of a client certificate in seconds since
the epoch.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_client_not_after
Return the end date of a client certificate in seconds since
the epoch.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_cipher
Return a TLS cipher negotiated in this connection.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_protocol
Return a TLS protocol version negotiated in this connection.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_session_id
Return a session ID for this connection in hex string.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_session_reused
Return true if, and only if a SSL/TLS session is reused.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] alpn
Return ALPN identifier negotiated in this connection.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] tls_handshake_finished
Return true if SSL/TLS handshake has finished.  If it returns
false in the request phase hook, the request is received in
TLSv1.3 early data (0\-RTT) and might be vulnerable to the
replay attack.  nghttpx will send Early\-Data header field to
backend servers to indicate this.
.UNINDENT
.UNINDENT
.INDENT 0.0
.TP
.B class Nghttpx::Request
Object to represent request from client.  The modification to
Request object is allowed only in request phase hook.
.INDENT 7.0
.TP
.B attribute [R] http_version_major
Return HTTP major version.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] http_version_minor
Return HTTP minor version.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R/W] method
HTTP method.  On assignment, copy of given value is assigned.
We don\(aqt accept arbitrary method name.  We will document them
later, but well known methods, like GET, PUT and POST, are all
supported.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R/W] authority
Authority (i.e., example.org), including optional port
component .  On assignment, copy of given value is assigned.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R/W] scheme
Scheme (i.e., http, https).  On assignment, copy of given
value is assigned.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R/W] path
Request path, including query component (i.e., /index.html).
On assignment, copy of given value is assigned.  The path does
not include authority component of URI.  This may include
query component.  nghttpx makes certain normalization for
path.  It decodes percent\-encoding for unreserved characters
(see \fI\%https://tools.ietf.org/html/rfc3986#section\-2.3\fP), and
resolves ".." and ".".  But it may leave characters which
should be percent\-encoded as is. So be careful when comparing
path against desired string.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] headers
Return Ruby hash containing copy of request header fields.
Changing values in returned hash does not change request
header fields actually used in request processing.  Use
\fI\%Nghttpx::Request#add_header\fP or
\fI\%Nghttpx::Request#set_header\fP to change request
header fields.
.UNINDENT
.INDENT 7.0
.TP
.B add_header(key, value)
Add header entry associated with key.  The value can be single
string or array of string.  It does not replace any existing
values associated with key.
.UNINDENT
.INDENT 7.0
.TP
.B set_header(key, value)
Set header entry associated with key.  The value can be single
string or array of string.  It replaces any existing values
associated with key.
.UNINDENT
.INDENT 7.0
.TP
.B clear_headers()
Clear all existing request header fields.
.UNINDENT
.INDENT 7.0
.TP
.B push(uri)
Initiate to push resource identified by \fIuri\fP\&.  Only HTTP/2
protocol supports this feature.  For the other protocols, this
method is noop.  \fIuri\fP can be absolute URI, absolute path or
relative path to the current request.  For absolute or
relative path, scheme and authority are inherited from the
current request.  Currently, method is always GET.  nghttpx
will issue request to backend servers to fulfill this request.
The request and response phase hooks will be called for pushed
resource as well.
.UNINDENT
.UNINDENT
.INDENT 0.0
.TP
.B class Nghttpx::Response
Object to represent response from backend server.
.INDENT 7.0
.TP
.B attribute [R] http_version_major
Return HTTP major version.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] http_version_minor
Return HTTP minor version.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R/W] status
HTTP status code.  It must be in the range [200, 999],
inclusive.  The non\-final status code is not supported in
mruby scripting at the moment.
.UNINDENT
.INDENT 7.0
.TP
.B attribute [R] headers
Return Ruby hash containing copy of response header fields.
Changing values in returned hash does not change response
header fields actually used in response processing.  Use
\fI\%Nghttpx::Response#add_header\fP or
\fI\%Nghttpx::Response#set_header\fP to change response
header fields.
.UNINDENT
.INDENT 7.0
.TP
.B add_header(key, value)
Add header entry associated with key.  The value can be single
string or array of string.  It does not replace any existing
values associated with key.
.UNINDENT
.INDENT 7.0
.TP
.B set_header(key, value)
Set header entry associated with key.  The value can be single
string or array of string.  It replaces any existing values
associated with key.
.UNINDENT
.INDENT 7.0
.TP
.B clear_headers()
Clear all existing response header fields.
.UNINDENT
.INDENT 7.0
.TP
.B return(body)
Return custom response \fIbody\fP to a client.  When this method
is called in request phase hook, the request is not forwarded
to the backend, and response phase hook for this request will
not be invoked.  When this method is called in response phase
hook, response from backend server is canceled and discarded.
The status code and response header fields should be set
before using this method.  To set status code, use
\fI\%Nghttpx::Response#status\fP\&.  If status code is not
set, 200 is used.  To set response header fields,
\fI\%Nghttpx::Response#add_header\fP and
\fI\%Nghttpx::Response#set_header\fP\&.  When this method is
invoked in response phase hook, the response headers are
filled with the ones received from backend server.  To send
completely custom header fields, first call
\fI\%Nghttpx::Response#clear_headers\fP to erase all
existing header fields, and then add required header fields.
It is an error to call this method twice for a given request.
.UNINDENT
.INDENT 7.0
.TP
.B send_info(status, headers)
Send non\-final (informational) response to a client.  \fIstatus\fP
must be in the range [100, 199], inclusive.  \fIheaders\fP is a
hash containing response header fields.  Its key must be a
string, and the associated value must be either string or
array of strings.  Since this is not a final response, even if
this method is invoked, request is still forwarded to a
backend unless \fI\%Nghttpx::Response#return\fP is called.
This method can be called multiple times.  It cannot be called
after \fI\%Nghttpx::Response#return\fP is called.
.UNINDENT
.UNINDENT
.SS MRUBY EXAMPLES
.sp
Modify request path:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
class App
  def on_req(env)
    env.req.path = "/apps#{env.req.path}"
  end
end

App.new
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Don\(aqt forget to instantiate and evaluate object at the last line.
.sp
Restrict permission of viewing a content to a specific client
addresses:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
class App
  def on_req(env)
    allowed_clients = ["127.0.0.1", "::1"]

    if env.req.path.start_with?("/log/") &&
       !allowed_clients.include?(env.remote_addr) then
      env.resp.status = 404
      env.resp.return "permission denied"
    end
  end
end

App.new
.ft P
.fi
.UNINDENT
.UNINDENT
.SH API ENDPOINTS
.sp
nghttpx exposes API endpoints to manipulate it via HTTP based API.  By
default, API endpoint is disabled.  To enable it, add a dedicated
frontend for API using \fI\%\-\-frontend\fP option with "api"
parameter.  All requests which come from this frontend address, will
be treated as API request.
.sp
The response is normally JSON dictionary, and at least includes the
following keys:
.INDENT 0.0
.TP
.B status
The status of the request processing.  The following values are
defined:
.INDENT 7.0
.TP
.B Success
The request was successful.
.TP
.B Failure
The request was failed.  No change has been made.
.UNINDENT
.TP
.B code
HTTP status code
.UNINDENT
.sp
Additionally, depending on the API endpoint, \fBdata\fP key may be
present, and its value contains the API endpoint specific data.
.sp
We wrote "normally", since nghttpx may return ordinal HTML response in
some cases where the error has occurred before reaching API endpoint
(e.g., header field is too large).
.sp
The following section describes available API endpoints.
.SS POST /api/v1beta1/backendconfig
.sp
This API replaces the current backend server settings with the
requested ones.  The request method should be POST, but PUT is also
acceptable.  The request body must be nghttpx configuration file
format.  For configuration file format, see \fI\%FILES\fP section.  The
line separator inside the request body must be single LF (0x0A).
Currently, only \fI\%backend\fP option is parsed, the
others are simply ignored.  The semantics of this API is replace the
current backend with the backend options in request body.  Describe
the desired set of backend severs, and nghttpx makes it happen.  If
there is no \fI\%backend\fP option is found in request
body, the current set of backend is replaced with the \fI\%backend\fP option\(aqs default value, which is \fB127.0.0.1,80\fP\&.
.sp
The replacement is done instantly without breaking existing
connections or requests.  It also avoids any process creation as is
the case with hot swapping with signals.
.sp
The one limitation is that only numeric IP address is allowed in
\fI\%backend\fP in request body unless "dns" parameter
is used while non numeric hostname is allowed in command\-line or
configuration file is read using \fI\%\-\-conf\fP\&.
.SS GET /api/v1beta1/configrevision
.sp
This API returns configuration revision of the current nghttpx.  The
configuration revision is opaque string, and it changes after each
reloading by SIGHUP.  With this API, an external application knows
that whether nghttpx has finished reloading its configuration by
comparing the configuration revisions between before and after
reloading.  It is recommended to disable persistent (keep\-alive)
connection for this purpose in order to avoid to send a request using
the reused connection which may bound to an old process.
.sp
This API returns response including \fBdata\fP key.  Its value is JSON
object, and it contains at least the following key:
.INDENT 0.0
.TP
.B configRevision
The configuration revision of the current nghttpx
.UNINDENT
.SH SEE ALSO
.sp
\fBnghttp(1)\fP, \fBnghttpd(1)\fP, \fBh2load(1)\fP
.SH AUTHOR
Tatsuhiro Tsujikawa
.SH COPYRIGHT
2012, 2015, 2016, Tatsuhiro Tsujikawa
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