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nghttp2/examples/client.c

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/*
* nghttp2 - HTTP/2.0 C Library
*
* Copyright (c) 2013 Tatsuhiro Tsujikawa
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* This program is written to show how to use nghttp2 API in C and
* intentionally made simple.
*/
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <assert.h>
#include <nghttp2/nghttp2.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
enum {
IO_NONE,
WANT_READ,
WANT_WRITE
};
struct Connection {
SSL *ssl;
nghttp2_session *session;
/* WANT_READ if SSL/TLS connection needs more input; or WANT_WRITE
if it needs more output; or IO_NONE. This is necessary because
SSL/TLS re-negotiation is possible at any time. nghttp2 API
offers similar functions like nghttp2_session_want_read() and
nghttp2_session_want_write() but they do not take into account
SSL/TSL connection. */
int want_io;
};
struct Request {
char *host;
uint16_t port;
/* In this program, path contains query component as well. */
char *path;
/* This is the concatenation of host and port with ":" in
between. */
char *hostport;
/* Stream ID for this request. */
int32_t stream_id;
/* The gzip stream inflater for the compressed response. */
nghttp2_gzip *inflater;
};
struct URI {
const char *host;
size_t hostlen;
uint16_t port;
/* In this program, path contains query component as well. */
const char *path;
size_t pathlen;
const char *hostport;
size_t hostportlen;
};
/*
* Returns copy of string |s| with the length |len|. The returned
* string is NULL-terminated.
*/
static char* strcopy(const char *s, size_t len)
{
char *dst;
dst = malloc(len+1);
memcpy(dst, s, len);
dst[len] = '\0';
return dst;
}
/*
* Prints error message |msg| and exit.
*/
static void die(const char *msg)
{
fprintf(stderr, "FATAL: %s\n", msg);
exit(EXIT_FAILURE);
}
/*
* Prints error containing the function name |func| and message |msg|
* and exit.
*/
static void dief(const char *func, const char *msg)
{
fprintf(stderr, "FATAL: %s: %s\n", func, msg);
exit(EXIT_FAILURE);
}
/*
* Prints error containing the function name |func| and error code
* |error_code| and exit.
*/
static void diec(const char *func, int error_code)
{
fprintf(stderr, "FATAL: %s: error_code=%d, msg=%s\n", func, error_code,
nghttp2_strerror(error_code));
exit(EXIT_FAILURE);
}
static char CONTENT_LENGTH[] = "content-encoding";
static size_t CONTENT_LENGTH_LEN = sizeof(CONTENT_LENGTH) - 1;
static char GZIP[] = "gzip";
static size_t GZIP_LEN = sizeof(GZIP) - 1;
/*
* Check response is content-encoding: gzip. We need this because
* HTTP/2.0 client is required to support gzip.
*/
static void check_gzip(struct Request *req, nghttp2_nv *nva, size_t nvlen)
{
size_t i;
if(req->inflater) {
return;
}
for(i = 0; i < nvlen; ++i) {
if(CONTENT_LENGTH_LEN == nva[i].namelen &&
memcmp(CONTENT_LENGTH, nva[i].name, nva[i].namelen) == 0 &&
GZIP_LEN == nva[i].valuelen &&
memcmp(GZIP, nva[i].value, nva[i].valuelen) == 0) {
int rv;
rv = nghttp2_gzip_inflate_new(&req->inflater);
if(rv != 0) {
die("Can't allocate inflate stream.");
}
break;
}
}
}
/*
* The implementation of nghttp2_send_callback type. Here we write
* |data| with size |length| to the network and return the number of
* bytes actually written. See the documentation of
* nghttp2_send_callback for the details.
*/
static ssize_t send_callback(nghttp2_session *session,
const uint8_t *data, size_t length, int flags,
void *user_data)
{
struct Connection *connection;
ssize_t rv;
connection = (struct Connection*)user_data;
connection->want_io = IO_NONE;
ERR_clear_error();
rv = SSL_write(connection->ssl, data, length);
if(rv < 0) {
int err = SSL_get_error(connection->ssl, rv);
if(err == SSL_ERROR_WANT_WRITE || err == SSL_ERROR_WANT_READ) {
connection->want_io = (err == SSL_ERROR_WANT_READ ?
WANT_READ : WANT_WRITE);
rv = NGHTTP2_ERR_WOULDBLOCK;
} else {
rv = NGHTTP2_ERR_CALLBACK_FAILURE;
}
}
return rv;
}
/*
* The implementation of nghttp2_recv_callback type. Here we read data
* from the network and write them in |buf|. The capacity of |buf| is
* |length| bytes. Returns the number of bytes stored in |buf|. See
* the documentation of nghttp2_recv_callback for the details.
*/
static ssize_t recv_callback(nghttp2_session *session,
uint8_t *buf, size_t length, int flags,
void *user_data)
{
struct Connection *connection;
ssize_t rv;
connection = (struct Connection*)user_data;
connection->want_io = IO_NONE;
ERR_clear_error();
rv = SSL_read(connection->ssl, buf, length);
if(rv < 0) {
int err = SSL_get_error(connection->ssl, rv);
if(err == SSL_ERROR_WANT_WRITE || err == SSL_ERROR_WANT_READ) {
connection->want_io = (err == SSL_ERROR_WANT_READ ?
WANT_READ : WANT_WRITE);
rv = NGHTTP2_ERR_WOULDBLOCK;
} else {
rv = NGHTTP2_ERR_CALLBACK_FAILURE;
}
} else if(rv == 0) {
rv = NGHTTP2_ERR_EOF;
}
return rv;
}
/*
* The implementation of nghttp2_before_frame_send_callback type. We
* use this function to get stream ID of the request. This is because
* stream ID is not known when we submit the request
* (nghttp2_submit_request).
*/
static int before_frame_send_callback(nghttp2_session *session,
const nghttp2_frame *frame,
void *user_data)
{
if(frame->hd.type == NGHTTP2_HEADERS &&
frame->headers.cat == NGHTTP2_HCAT_REQUEST) {
struct Request *req;
int32_t stream_id = frame->hd.stream_id;
req = nghttp2_session_get_stream_user_data(session, stream_id);
if(req && req->stream_id == -1) {
req->stream_id = stream_id;
printf("[INFO] Stream ID = %d\n", stream_id);
}
}
return 0;
}
static int on_frame_send_callback(nghttp2_session *session,
const nghttp2_frame *frame, void *user_data)
{
size_t i;
switch(frame->hd.type) {
case NGHTTP2_HEADERS:
if(nghttp2_session_get_stream_user_data(session, frame->hd.stream_id)) {
const nghttp2_nv *nva = frame->headers.nva;
printf("[INFO] C ----------------------------> S (HEADERS)\n");
for(i = 0; i < frame->headers.nvlen; ++i) {
fwrite(nva[i].name, nva[i].namelen, 1, stdout);
printf(": ");
fwrite(nva[i].value, nva[i].valuelen, 1, stdout);
printf("\n");
}
}
break;
case NGHTTP2_RST_STREAM:
printf("[INFO] C ----------------------------> S (RST_STREAM)\n");
break;
case NGHTTP2_GOAWAY:
printf("[INFO] C ----------------------------> S (GOAWAY)\n");
break;
}
return 0;
}
static int on_frame_recv_callback(nghttp2_session *session,
const nghttp2_frame *frame, void *user_data)
{
size_t i;
switch(frame->hd.type) {
case NGHTTP2_HEADERS:
if(frame->headers.cat == NGHTTP2_HCAT_RESPONSE) {
const nghttp2_nv *nva = frame->headers.nva;
struct Request *req;
req = nghttp2_session_get_stream_user_data(session, frame->hd.stream_id);
if(req) {
check_gzip(req, frame->headers.nva, frame->headers.nvlen);
printf("[INFO] C <---------------------------- S (HEADERS)\n");
for(i = 0; i < frame->headers.nvlen; ++i) {
fwrite(nva[i].name, nva[i].namelen, 1, stdout);
printf(": ");
fwrite(nva[i].value, nva[i].valuelen, 1, stdout);
printf("\n");
}
}
}
break;
case NGHTTP2_RST_STREAM:
printf("[INFO] C <---------------------------- S (RST_STREAM)\n");
break;
case NGHTTP2_GOAWAY:
printf("[INFO] C <---------------------------- S (GOAWAY)\n");
break;
}
return 0;
}
/*
* The implementation of nghttp2_on_stream_close_callback type. We use
* this function to know the response is fully received. Since we just
* fetch 1 resource in this program, after reception of the response,
* we submit GOAWAY and close the session.
*/
static int on_stream_close_callback(nghttp2_session *session,
int32_t stream_id,
nghttp2_error_code error_code,
void *user_data)
{
struct Request *req;
req = nghttp2_session_get_stream_user_data(session, stream_id);
if(req) {
int rv;
rv = nghttp2_submit_goaway(session, NGHTTP2_FLAG_NONE, NGHTTP2_NO_ERROR,
NULL, 0);
if(rv != 0) {
diec("nghttp2_submit_goaway", rv);
}
}
return 0;
}
#define MAX_OUTLEN 4096
/*
* The implementation of nghttp2_on_data_chunk_recv_callback type. We
* use this function to print the received response body.
*/
static int on_data_chunk_recv_callback(nghttp2_session *session, uint8_t flags,
int32_t stream_id,
const uint8_t *data, size_t len,
void *user_data)
{
struct Request *req;
req = nghttp2_session_get_stream_user_data(session, stream_id);
if(req) {
printf("[INFO] C <---------------------------- S (DATA chunk)\n"
"%lu bytes\n", (unsigned long int)len);
if(req->inflater) {
while(len > 0) {
uint8_t out[MAX_OUTLEN];
size_t outlen = MAX_OUTLEN;
size_t tlen = len;
int rv;
rv = nghttp2_gzip_inflate(req->inflater, out, &outlen, data, &tlen);
if(rv == -1) {
nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE, stream_id,
NGHTTP2_INTERNAL_ERROR);
break;
}
fwrite(out, 1, outlen, stdout);
data += tlen;
len -= tlen;
}
} else {
fwrite(data, 1, len, stdout);
}
printf("\n");
}
return 0;
}
/*
* Setup callback functions. nghttp2 API offers many callback
* functions, but most of them are optional. The send_callback is
* always required. Since we use nghttp2_session_recv(), the
* recv_callback is also required.
*/
static void setup_nghttp2_callbacks(nghttp2_session_callbacks *callbacks)
{
memset(callbacks, 0, sizeof(nghttp2_session_callbacks));
callbacks->send_callback = send_callback;
callbacks->recv_callback = recv_callback;
callbacks->before_frame_send_callback = before_frame_send_callback;
callbacks->on_frame_send_callback = on_frame_send_callback;
callbacks->on_frame_recv_callback = on_frame_recv_callback;
callbacks->on_stream_close_callback = on_stream_close_callback;
callbacks->on_data_chunk_recv_callback = on_data_chunk_recv_callback;
}
/*
* Callback function for TLS NPN. Since this program only supports
* HTTP/2.0 protocol, if server does not offer HTTP/2.0 the nghttp2
* library supports, we terminate program.
*/
static int select_next_proto_cb(SSL* ssl,
unsigned char **out, unsigned char *outlen,
const unsigned char *in, unsigned int inlen,
void *arg)
{
int rv;
/* nghttp2_select_next_protocol() selects HTTP/2.0 protocol the
nghttp2 library supports. */
rv = nghttp2_select_next_protocol(out, outlen, in, inlen);
if(rv <= 0) {
die("Server did not advertise HTTP/2.0 protocol");
}
return SSL_TLSEXT_ERR_OK;
}
/*
* Setup SSL/TLS context.
*/
static void init_ssl_ctx(SSL_CTX *ssl_ctx)
{
/* Disable SSLv2 and enable all workarounds for buggy servers */
SSL_CTX_set_options(ssl_ctx, SSL_OP_ALL|SSL_OP_NO_SSLv2);
SSL_CTX_set_mode(ssl_ctx, SSL_MODE_AUTO_RETRY);
SSL_CTX_set_mode(ssl_ctx, SSL_MODE_RELEASE_BUFFERS);
/* Set NPN callback */
SSL_CTX_set_next_proto_select_cb(ssl_ctx, select_next_proto_cb, NULL);
}
static void ssl_handshake(SSL *ssl, int fd)
{
int rv;
if(SSL_set_fd(ssl, fd) == 0) {
dief("SSL_set_fd", ERR_error_string(ERR_get_error(), NULL));
}
ERR_clear_error();
rv = SSL_connect(ssl);
if(rv <= 0) {
dief("SSL_connect", ERR_error_string(ERR_get_error(), NULL));
}
}
/*
* Connects to the host |host| and port |port|. This function returns
* the file descriptor of the client socket.
*/
static int connect_to(const char *host, uint16_t port)
{
struct addrinfo hints;
int fd = -1;
int rv;
char service[NI_MAXSERV];
struct addrinfo *res, *rp;
snprintf(service, sizeof(service), "%u", port);
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
rv = getaddrinfo(host, service, &hints, &res);
if(rv != 0) {
dief("getaddrinfo", gai_strerror(rv));
}
for(rp = res; rp; rp = rp->ai_next) {
fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if(fd == -1) {
continue;
}
while((rv = connect(fd, rp->ai_addr, rp->ai_addrlen)) == -1 &&
errno == EINTR);
if(rv == 0) {
break;
}
close(fd);
fd = -1;
}
freeaddrinfo(res);
return fd;
}
static void make_non_block(int fd)
{
int flags, rv;
while((flags = fcntl(fd, F_GETFL, 0)) == -1 && errno == EINTR);
if(flags == -1) {
dief("fcntl", strerror(errno));
}
while((rv = fcntl(fd, F_SETFL, flags | O_NONBLOCK)) == -1 && errno == EINTR);
if(rv == -1) {
dief("fcntl", strerror(errno));
}
}
static void set_tcp_nodelay(int fd)
{
int val = 1;
int rv;
rv = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, (socklen_t)sizeof(val));
if(rv == -1) {
dief("setsockopt", strerror(errno));
}
}
/*
* Update |pollfd| based on the state of |connection|.
*/
static void ctl_poll(struct pollfd *pollfd, struct Connection *connection)
{
pollfd->events = 0;
if(nghttp2_session_want_read(connection->session) ||
connection->want_io == WANT_READ) {
pollfd->events |= POLLIN;
}
if(nghttp2_session_want_write(connection->session) ||
connection->want_io == WANT_WRITE) {
pollfd->events |= POLLOUT;
}
}
/*
* Submits the request |req| to the connection |connection|. This
* function does not send packets; just append the request to the
* internal queue in |connection->session|.
*/
static void submit_request(struct Connection *connection, struct Request *req)
{
int pri = 0;
int rv;
const char *nv[13];
/* Make sure that the last item is NULL */
nv[0] = ":method"; nv[1] = "GET";
nv[2] = ":path"; nv[3] = req->path;
nv[4] = ":scheme"; nv[5] = "https";
nv[6] = ":host"; nv[7] = req->hostport;
nv[8] = "accept"; nv[9] = "*/*";
nv[10] = "user-agent"; nv[11] = "nghttp2/"NGHTTP2_VERSION;
nv[12] = NULL;
rv = nghttp2_submit_request(connection->session, pri, nv, NULL, req);
if(rv != 0) {
diec("nghttp2_submit_request", rv);
}
}
/*
* Performs the network I/O.
*/
static void exec_io(struct Connection *connection)
{
int rv;
rv = nghttp2_session_recv(connection->session);
if(rv != 0) {
diec("nghttp2_session_recv", rv);
}
rv = nghttp2_session_send(connection->session);
if(rv != 0) {
diec("nghttp2_session_send", rv);
}
}
static void request_init(struct Request *req, const struct URI *uri)
{
req->host = strcopy(uri->host, uri->hostlen);
req->port = uri->port;
req->path = strcopy(uri->path, uri->pathlen);
req->hostport = strcopy(uri->hostport, uri->hostportlen);
req->stream_id = -1;
req->inflater = NULL;
}
static void request_free(struct Request *req)
{
free(req->host);
free(req->path);
free(req->hostport);
nghttp2_gzip_inflate_del(req->inflater);
}
/*
* Fetches the resource denoted by |uri|.
*/
static void fetch_uri(const struct URI *uri)
{
nghttp2_session_callbacks callbacks;
int fd;
SSL_CTX *ssl_ctx;
SSL *ssl;
struct Request req;
struct Connection connection;
int rv;
nfds_t npollfds = 1;
struct pollfd pollfds[1];
request_init(&req, uri);
setup_nghttp2_callbacks(&callbacks);
/* Establish connection and setup SSL */
fd = connect_to(req.host, req.port);
if(fd == -1) {
die("Could not open file descriptor");
}
ssl_ctx = SSL_CTX_new(SSLv23_client_method());
if(ssl_ctx == NULL) {
dief("SSL_CTX_new", ERR_error_string(ERR_get_error(), NULL));
}
init_ssl_ctx(ssl_ctx);
ssl = SSL_new(ssl_ctx);
if(ssl == NULL) {
dief("SSL_new", ERR_error_string(ERR_get_error(), NULL));
}
/* To simplify the program, we perform SSL/TLS handshake in blocking
I/O. */
ssl_handshake(ssl, fd);
connection.ssl = ssl;
connection.want_io = IO_NONE;
/* Send connection header in blocking I/O mode */
SSL_write(ssl, NGHTTP2_CLIENT_CONNECTION_HEADER,
NGHTTP2_CLIENT_CONNECTION_HEADER_LEN);
/* Here make file descriptor non-block */
make_non_block(fd);
set_tcp_nodelay(fd);
printf("[INFO] SSL/TLS handshake completed\n");
rv = nghttp2_session_client_new(&connection.session, &callbacks,
&connection);
if(rv != 0) {
diec("nghttp2_session_client_new", rv);
}
/* Submit the HTTP request to the outbound queue. */
submit_request(&connection, &req);
pollfds[0].fd = fd;
ctl_poll(pollfds, &connection);
/* Event loop */
while(nghttp2_session_want_read(connection.session) ||
nghttp2_session_want_write(connection.session)) {
int nfds = poll(pollfds, npollfds, -1);
if(nfds == -1) {
dief("poll", strerror(errno));
}
if(pollfds[0].revents & (POLLIN | POLLOUT)) {
exec_io(&connection);
}
if((pollfds[0].revents & POLLHUP) || (pollfds[0].revents & POLLERR)) {
die("Connection error");
}
ctl_poll(pollfds, &connection);
}
/* Resource cleanup */
nghttp2_session_del(connection.session);
SSL_shutdown(ssl);
SSL_free(ssl);
SSL_CTX_free(ssl_ctx);
shutdown(fd, SHUT_WR);
close(fd);
request_free(&req);
}
static int parse_uri(struct URI *res, const char *uri)
{
/* We only interested in https */
size_t len, i, offset;
int ipv6addr = 0;
memset(res, 0, sizeof(struct URI));
len = strlen(uri);
if(len < 9 || memcmp("https://", uri, 8) != 0) {
return -1;
}
offset = 8;
res->host = res->hostport = &uri[offset];
res->hostlen = 0;
if(uri[offset] == '[') {
/* IPv6 literal address */
++offset;
++res->host;
ipv6addr = 1;
for(i = offset; i < len; ++i) {
if(uri[i] == ']') {
res->hostlen = i-offset;
offset = i+1;
break;
}
}
} else {
const char delims[] = ":/?#";
for(i = offset; i < len; ++i) {
if(strchr(delims, uri[i]) != NULL) {
break;
}
}
res->hostlen = i-offset;
offset = i;
}
if(res->hostlen == 0) {
return -1;
}
/* Assuming https */
res->port = 443;
if(offset < len) {
if(uri[offset] == ':') {
/* port */
const char delims[] = "/?#";
int port = 0;
++offset;
for(i = offset; i < len; ++i) {
if(strchr(delims, uri[i]) != NULL) {
break;
}
if('0' <= uri[i] && uri[i] <= '9') {
port *= 10;
port += uri[i]-'0';
if(port > 65535) {
return -1;
}
} else {
return -1;
}
}
if(port == 0) {
return -1;
}
offset = i;
res->port = port;
}
}
res->hostportlen = uri+offset+ipv6addr-res->host;
for(i = offset; i < len; ++i) {
if(uri[i] == '#') {
break;
}
}
if(i-offset == 0) {
res->path = "/";
res->pathlen = 1;
} else {
res->path = &uri[offset];
res->pathlen = i-offset;
}
return 0;
}
int main(int argc, char **argv)
{
struct URI uri;
struct sigaction act;
int rv;
if(argc < 2) {
die("Specify a https URI");
}
memset(&act, 0, sizeof(struct sigaction));
act.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &act, 0);
SSL_load_error_strings();
SSL_library_init();
rv = parse_uri(&uri, argv[1]);
if(rv != 0) {
die("parse_uri failed");
}
fetch_uri(&uri);
return EXIT_SUCCESS;
}
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