.\" $NetBSD: OSSL_HTTP_transfer.3,v 1.2.2.3 2023/11/02 19:32:25 sborrill Exp $ .\" .\" Automatically generated by Pod::Man 4.14 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. 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No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "OSSL_HTTP_transfer 3" .TH OSSL_HTTP_transfer 3 "2023-10-25" "3.0.12" "OpenSSL" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" OSSL_HTTP_open, OSSL_HTTP_bio_cb_t, OSSL_HTTP_proxy_connect, OSSL_HTTP_set1_request, OSSL_HTTP_exchange, OSSL_HTTP_get, OSSL_HTTP_transfer, OSSL_HTTP_close \&\- HTTP client high\-level functions .SH "LIBRARY" libcrypto, -lcrypto .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& #include \& \& typedef BIO *(*OSSL_HTTP_bio_cb_t)(BIO *bio, void *arg, \& int connect, int detail); \& OSSL_HTTP_REQ_CTX *OSSL_HTTP_open(const char *server, const char *port, \& const char *proxy, const char *no_proxy, \& int use_ssl, BIO *bio, BIO *rbio, \& OSSL_HTTP_bio_cb_t bio_update_fn, void *arg, \& int buf_size, int overall_timeout); \& int OSSL_HTTP_proxy_connect(BIO *bio, const char *server, const char *port, \& const char *proxyuser, const char *proxypass, \& int timeout, BIO *bio_err, const char *prog); \& int OSSL_HTTP_set1_request(OSSL_HTTP_REQ_CTX *rctx, const char *path, \& const STACK_OF(CONF_VALUE) *headers, \& const char *content_type, BIO *req, \& const char *expected_content_type, int expect_asn1, \& size_t max_resp_len, int timeout, int keep_alive); \& BIO *OSSL_HTTP_exchange(OSSL_HTTP_REQ_CTX *rctx, char **redirection_url); \& BIO *OSSL_HTTP_get(const char *url, const char *proxy, const char *no_proxy, \& BIO *bio, BIO *rbio, \& OSSL_HTTP_bio_cb_t bio_update_fn, void *arg, \& int buf_size, const STACK_OF(CONF_VALUE) *headers, \& const char *expected_content_type, int expect_asn1, \& size_t max_resp_len, int timeout); \& BIO *OSSL_HTTP_transfer(OSSL_HTTP_REQ_CTX **prctx, \& const char *server, const char *port, \& const char *path, int use_ssl, \& const char *proxy, const char *no_proxy, \& BIO *bio, BIO *rbio, \& OSSL_HTTP_bio_cb_t bio_update_fn, void *arg, \& int buf_size, const STACK_OF(CONF_VALUE) *headers, \& const char *content_type, BIO *req, \& const char *expected_content_type, int expect_asn1, \& size_t max_resp_len, int timeout, int keep_alive); \& int OSSL_HTTP_close(OSSL_HTTP_REQ_CTX *rctx, int ok); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" \&\fBOSSL_HTTP_open()\fR initiates an \s-1HTTP\s0 session using the \fIbio\fR argument if not \&\s-1NULL,\s0 else by connecting to a given \fIserver\fR optionally via a \fIproxy\fR. .PP Typically the OpenSSL build supports sockets and the \fIbio\fR parameter is \s-1NULL.\s0 In this case \fIrbio\fR must be \s-1NULL\s0 as well and the \fIserver\fR must be non-NULL. The function creates a network \s-1BIO\s0 internally using \fBBIO_new_connect\fR\|(3) for connecting to the given server and the optionally given \fIport\fR, defaulting to 80 for \s-1HTTP\s0 or 443 for \s-1HTTPS.\s0 Then this internal \s-1BIO\s0 is used for setting up a connection and for exchanging one or more request and response. If \fIbio\fR is given and \fIrbio\fR is \s-1NULL\s0 then this \fIbio\fR is used instead. If both \fIbio\fR and \fIrbio\fR are given (which may be memory BIOs for instance) then no explicit connection is set up, but \&\fIbio\fR is used for writing requests and \fIrbio\fR for reading responses. As soon as the client has flushed \fIbio\fR the server must be ready to provide a response or indicate a waiting condition via \fIrbio\fR. .PP If \fIbio\fR is given, it is an error to provide \fIproxy\fR or \fIno_proxy\fR arguments, while \fIserver\fR and \fIport\fR arguments may be given to support diagnostic output. If \fIbio\fR is \s-1NULL\s0 the optional \fIproxy\fR parameter can be used to set an \&\s-1HTTP\s0(S) proxy to use (unless overridden by \*(L"no_proxy\*(R" settings). If \s-1TLS\s0 is not used this defaults to the environment variable \f(CW\*(C`http_proxy\*(C'\fR if set, else \f(CW\*(C`HTTP_PROXY\*(C'\fR. If \fIuse_ssl\fR != 0 it defaults to \f(CW\*(C`https_proxy\*(C'\fR if set, else \f(CW\*(C`HTTPS_PROXY\*(C'\fR. An empty proxy string \f(CW""\fR forbids using a proxy. Else the format is \&\f(CW\*(C`[http[s]://][userinfo@]host[:port][/path][?query][#fragment]\*(C'\fR, where any userinfo, path, query, and fragment given is ignored. The default proxy port number is 80, or 443 in case \*(L"https:\*(R" is given. The \s-1HTTP\s0 client functions connect via the given proxy unless the \fIserver\fR is found in the optional list \fIno_proxy\fR of proxy hostnames (if not \s-1NULL\s0; default is the environment variable \f(CW\*(C`no_proxy\*(C'\fR if set, else \f(CW\*(C`NO_PROXY\*(C'\fR). Proxying plain \s-1HTTP\s0 is supported directly, while using a proxy for \s-1HTTPS\s0 connections requires a suitable callback function such as \fBOSSL_HTTP_proxy_connect()\fR, described below. .PP If \fIuse_ssl\fR is nonzero a \s-1TLS\s0 connection is requested and the \fIbio_update_fn\fR parameter must be provided. .PP The parameter \fIbio_update_fn\fR, which is optional if \fIuse_ssl\fR is 0, may be used to modify the connection \s-1BIO\s0 used by the \s-1HTTP\s0 client, but cannot be used when both \fIbio\fR and \fIrbio\fR are given. \&\fIbio_update_fn\fR is a \s-1BIO\s0 connect/disconnect callback function with prototype .PP .Vb 1 \& BIO *(*OSSL_HTTP_bio_cb_t)(BIO *bio, void *arg, int connect, int detail) .Ve .PP The callback function may modify the \s-1BIO\s0 provided in the \fIbio\fR argument, whereby it may make use of a custom defined argument \fIarg\fR, which may for instance point to an \fB\s-1SSL_CTX\s0\fR structure. During connection establishment, just after calling \fBBIO_do_connect_retry()\fR, the callback function is invoked with the \fIconnect\fR argument being 1 and \&\fIdetail\fR being 1 if \fIuse_ssl\fR is nonzero (i.e., \s-1HTTPS\s0 is requested), else 0. On disconnect \fIconnect\fR is 0 and \fIdetail\fR is 1 if no error occurred, else 0. For instance, on connect the callback may push an \s-1SSL BIO\s0 to implement \s-1HTTPS\s0; after disconnect it may do some diagnostic output and pop and free the \s-1SSL BIO.\s0 .PP The callback function must return either the potentially modified \s-1BIO\s0 \fIbio\fR. or \s-1NULL\s0 to indicate failure, in which case it should not modify the \s-1BIO.\s0 .PP Here is a simple example that supports \s-1TLS\s0 connections (but not via a proxy): .PP .Vb 5 \& BIO *http_tls_cb(BIO *bio, void *arg, int connect, int detail) \& { \& if (connect && detail) { /* connecting with TLS */ \& SSL_CTX *ctx = (SSL_CTX *)arg; \& BIO *sbio = BIO_new_ssl(ctx, 1); \& \& bio = sbio != NULL ? BIO_push(sbio, bio) : NULL; \& } else if (!connect) { /* disconnecting */ \& BIO *hbio; \& \& if (!detail) { /* an error has occurred */ \& /* optionally add diagnostics here */ \& } \& BIO_ssl_shutdown(bio); \& hbio = BIO_pop(bio); \& BIO_free(bio); /* SSL BIO */ \& bio = hbio; \& } \& return bio; \& } .Ve .PP After disconnect the modified \s-1BIO\s0 will be deallocated using \fBBIO_free_all()\fR. .PP The \fIbuf_size\fR parameter specifies the response header maximum line length. A value <= 0 means that the \fB\s-1OSSL_HTTP_DEFAULT_MAX_LINE_LEN\s0\fR (4KiB) is used. \&\fIbuf_size\fR is also used as the number of content bytes that are read at a time. .PP If the \fIoverall_timeout\fR parameter is > 0 this indicates the maximum number of seconds the overall \s-1HTTP\s0 transfer (i.e., connection setup if needed, sending requests, and receiving responses) is allowed to take until completion. A value <= 0 enables waiting indefinitely, i.e., no timeout. .PP \&\fBOSSL_HTTP_proxy_connect()\fR may be used by an above \s-1BIO\s0 connect callback function to set up an \s-1SSL/TLS\s0 connection via an \s-1HTTPS\s0 proxy. It promotes the given \s-1BIO\s0 \fIbio\fR representing a connection pre-established with a \s-1TLS\s0 proxy using the \s-1HTTP CONNECT\s0 method, optionally using proxy client credentials \fIproxyuser\fR and \fIproxypass\fR, to connect with \s-1TLS\s0 protection ultimately to \fIserver\fR and \fIport\fR. If the \fIport\fR argument is \s-1NULL\s0 or the empty string it defaults to \*(L"443\*(R". If the \fItimeout\fR parameter is > 0 this indicates the maximum number of seconds the connection setup is allowed to take. A value <= 0 enables waiting indefinitely, i.e., no timeout. Since this function is typically called by applications such as \&\fBopenssl\-s_client\fR\|(1) it uses the \fIbio_err\fR and \fIprog\fR parameters (unless \&\s-1NULL\s0) to print additional diagnostic information in a user-oriented way. .PP \&\fBOSSL_HTTP_set1_request()\fR sets up in \fIrctx\fR the request header and content data and expectations on the response using the following parameters. If indicates using a proxy for \s-1HTTP\s0 (but not \s-1HTTPS\s0), the server host (and optionally port) needs to be placed in the header; thus it must be present in \fIrctx\fR. For backward compatibility, the server (and optional port) may also be given in the \fIpath\fR argument beginning with \f(CW\*(C`http://\*(C'\fR (thus giving an absoluteURI). If \fIpath\fR is \s-1NULL\s0 it defaults to \*(L"/\*(R". If \fIreq\fR is \s-1NULL\s0 the \s-1HTTP GET\s0 method will be used to send the request else \s-1HTTP POST\s0 with the contents of \fIreq\fR and optional \fIcontent_type\fR, where the length of the data in \fIreq\fR does not need to be determined in advance: the \&\s-1BIO\s0 will be read on-the-fly while sending the request, which supports streaming. The optional list \fIheaders\fR may contain additional custom \s-1HTTP\s0 header lines. If the parameter \fIexpected_content_type\fR is not \s-1NULL\s0 then the client will check that the given content type string is included in the \s-1HTTP\s0 header of the response and return an error if not. If the \fIexpect_asn1\fR parameter is nonzero, a structure in \s-1ASN.1\s0 encoding will be expected as response content. The \fImax_resp_len\fR parameter specifies the maximum allowed response content length, where the value 0 indicates no limit. If the \fItimeout\fR parameter is > 0 this indicates the maximum number of seconds the subsequent \s-1HTTP\s0 transfer (sending the request and receiving a response) is allowed to take. A value of 0 enables waiting indefinitely, i.e., no timeout. A value < 0 indicates that the \fIoverall_timeout\fR parameter value given when opening the \s-1HTTP\s0 transfer will be used instead. If \fIkeep_alive\fR is 0 the connection is not kept open after receiving a response, which is the default behavior for \s-1HTTP 1.0.\s0 If the value is 1 or 2 then a persistent connection is requested. If the value is 2 then a persistent connection is required, i.e., an error occurs in case the server does not grant it. .PP \&\fBOSSL_HTTP_exchange()\fR exchanges any form of \s-1HTTP\s0 request and response as specified by \fIrctx\fR, which must include both connection and request data, typically set up using \fBOSSL_HTTP_open()\fR and \fBOSSL_HTTP_set1_request()\fR. It implements the core of the functions described below. If the \s-1HTTP\s0 method is \s-1GET\s0 and \fIredirection_url\fR is not \s-1NULL\s0 the latter pointer is used to provide any new location that the server may return with \s-1HTTP\s0 code 301 (\s-1MOVED_PERMANENTLY\s0) or 302 (\s-1FOUND\s0). In this case the function returns \s-1NULL\s0 and the caller is responsible for deallocating the \s-1URL\s0 with \fBOPENSSL_free\fR\|(3). If the response header contains one or more \*(L"Content-Length\*(R" header lines and/or an \s-1ASN\s0.1\-encoded response is expected, which should include a total length, the length indications received are checked for consistency and for not exceeding any given maximum response length. If an \s-1ASN\s0.1\-encoded response is expected, the function returns on success the contents buffered in a memory \s-1BIO,\s0 which does not support streaming. Otherwise it returns directly the read \s-1BIO\s0 that holds the response contents, which allows a response of indefinite length and may support streaming. The caller is responsible for freeing the \s-1BIO\s0 pointer obtained. .PP \&\fBOSSL_HTTP_get()\fR uses \s-1HTTP GET\s0 to obtain data from \fIbio\fR if non-NULL, else from the server contained in the \fIurl\fR, and returns it as a \s-1BIO.\s0 It supports redirection via \s-1HTTP\s0 status code 301 or 302. It is meant for transfers with a single round trip, so does not support persistent connections. If \fIbio\fR is non-NULL, any host and port components in the \fIurl\fR are not used for connecting but the hostname is used, as usual, for the \f(CW\*(C`Host\*(C'\fR header. Any userinfo and fragment components in the \fIurl\fR are ignored. Any query component is handled as part of the path component. If the scheme component of the \fIurl\fR is \f(CW\*(C`https\*(C'\fR a \s-1TLS\s0 connection is requested and the \fIbio_update_fn\fR, as described for \fBOSSL_HTTP_open()\fR, must be provided. Also the remaining parameters are interpreted as described for \fBOSSL_HTTP_open()\fR and \fBOSSL_HTTP_set1_request()\fR, respectively. The caller is responsible for freeing the \s-1BIO\s0 pointer obtained. .PP \&\fBOSSL_HTTP_transfer()\fR exchanges an \s-1HTTP\s0 request and response over a connection managed via \fIprctx\fR without supporting redirection. It combines \fBOSSL_HTTP_open()\fR, \fBOSSL_HTTP_set1_request()\fR, \fBOSSL_HTTP_exchange()\fR, and \fBOSSL_HTTP_close()\fR. If \fIprctx\fR is not \s-1NULL\s0 it reuses any open connection represented by a non-NULL \&\fI*prctx\fR. It keeps the connection open if a persistent connection is requested or required and this was granted by the server, else it closes the connection and assigns \s-1NULL\s0 to \fI*prctx\fR. The remaining parameters are interpreted as described for \fBOSSL_HTTP_open()\fR and \fBOSSL_HTTP_set1_request()\fR, respectively. The caller is responsible for freeing the \s-1BIO\s0 pointer obtained. .PP \&\fBOSSL_HTTP_close()\fR closes the connection and releases \fIrctx\fR. The \fIok\fR parameter is passed to any \s-1BIO\s0 update function given during setup as described above for \fBOSSL_HTTP_open()\fR. It must be 1 if no error occurred during the \s-1HTTP\s0 transfer and 0 otherwise. .SH "NOTES" .IX Header "NOTES" The names of the environment variables used by this implementation: \&\f(CW\*(C`http_proxy\*(C'\fR, \f(CW\*(C`HTTP_PROXY\*(C'\fR, \f(CW\*(C`https_proxy\*(C'\fR, \f(CW\*(C`HTTPS_PROXY\*(C'\fR, \f(CW\*(C`no_proxy\*(C'\fR, and \&\f(CW\*(C`NO_PROXY\*(C'\fR, have been chosen for maximal compatibility with other \s-1HTTP\s0 client implementations such as wget, curl, and git. .SH "RETURN VALUES" .IX Header "RETURN VALUES" \&\fBOSSL_HTTP_open()\fR returns on success a \fB\s-1OSSL_HTTP_REQ_CTX\s0\fR, else \s-1NULL.\s0 .PP \&\fBOSSL_HTTP_proxy_connect()\fR and \fBOSSL_HTTP_set1_request()\fR return 1 on success, 0 on error. .PP On success, \fBOSSL_HTTP_exchange()\fR, \fBOSSL_HTTP_get()\fR, and \fBOSSL_HTTP_transfer()\fR return a memory \s-1BIO\s0 that buffers all the data received if an \s-1ASN\s0.1\-encoded response is expected, otherwise a \s-1BIO\s0 that may support streaming. The \s-1BIO\s0 must be freed by the caller. On failure, they return \s-1NULL.\s0 Failure conditions include connection/transfer timeout, parse errors, etc. The caller is responsible for freeing the \s-1BIO\s0 pointer obtained. .PP \&\fBOSSL_HTTP_close()\fR returns 0 if anything went wrong while disconnecting, else 1. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBOSSL_HTTP_parse_url\fR\|(3), \fBBIO_new_connect\fR\|(3), \&\fBASN1_item_i2d_mem_bio\fR\|(3), \fBASN1_item_d2i_bio\fR\|(3), \&\fBOSSL_HTTP_is_alive\fR\|(3) .SH "HISTORY" .IX Header "HISTORY" All the functions described here were added in OpenSSL 3.0. .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright 2019\-2023 The OpenSSL Project Authors. All Rights Reserved. .PP Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at .