Adding upstream version 1.59.0.upstream/1.59.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 787 insertions, 0 deletions

diff --git a/examples/libevent-server.c b/examples/libevent-server.c
new file mode 100644
index 0000000..fa45d37
--- /dev/null
+++ b/examples/libevent-server.c
@@ -0,0 +1,787 @@
+/*
+ * nghttp2 - HTTP/2 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.
+ */
+#ifdef __sgi
+#  define errx(exitcode, format, args...)                                      \
+    {                                                                          \
+      warnx(format, ##args);                                                   \
+      exit(exitcode);                                                          \
+    }
+#  define warn(format, args...) warnx(format ": %s", ##args, strerror(errno))
+#  define warnx(format, args...) fprintf(stderr, format "\n", ##args)
+#endif
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#  include <sys/socket.h>
+#endif /* HAVE_SYS_SOCKET_H */
+#ifdef HAVE_NETDB_H
+#  include <netdb.h>
+#endif /* HAVE_NETDB_H */
+#include <signal.h>
+#ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+#endif /* HAVE_UNISTD_H */
+#include <sys/stat.h>
+#ifdef HAVE_FCNTL_H
+#  include <fcntl.h>
+#endif /* HAVE_FCNTL_H */
+#include <ctype.h>
+#ifdef HAVE_NETINET_IN_H
+#  include <netinet/in.h>
+#endif /* HAVE_NETINET_IN_H */
+#include <netinet/tcp.h>
+#ifndef __sgi
+#  include <err.h>
+#endif
+#include <string.h>
+#include <errno.h>
+
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+#include <openssl/conf.h>
+
+#include <event.h>
+#include <event2/event.h>
+#include <event2/bufferevent_ssl.h>
+#include <event2/listener.h>
+
+#include <nghttp2/nghttp2.h>
+
+#define OUTPUT_WOULDBLOCK_THRESHOLD (1 << 16)
+
+#define ARRLEN(x) (sizeof(x) / sizeof(x[0]))
+
+#define MAKE_NV(NAME, VALUE)                                                   \
+  {                                                                            \
+    (uint8_t *)NAME, (uint8_t *)VALUE, sizeof(NAME) - 1, sizeof(VALUE) - 1,    \
+        NGHTTP2_NV_FLAG_NONE                                                   \
+  }
+
+struct app_context;
+typedef struct app_context app_context;
+
+typedef struct http2_stream_data {
+  struct http2_stream_data *prev, *next;
+  char *request_path;
+  int32_t stream_id;
+  int fd;
+} http2_stream_data;
+
+typedef struct http2_session_data {
+  struct http2_stream_data root;
+  struct bufferevent *bev;
+  app_context *app_ctx;
+  nghttp2_session *session;
+  char *client_addr;
+} http2_session_data;
+
+struct app_context {
+  SSL_CTX *ssl_ctx;
+  struct event_base *evbase;
+};
+
+static int alpn_select_proto_cb(SSL *ssl, const unsigned char **out,
+                                unsigned char *outlen, const unsigned char *in,
+                                unsigned int inlen, void *arg) {
+  int rv;
+  (void)ssl;
+  (void)arg;
+
+  rv = nghttp2_select_alpn(out, outlen, in, inlen);
+
+  if (rv != 1) {
+    return SSL_TLSEXT_ERR_NOACK;
+  }
+
+  return SSL_TLSEXT_ERR_OK;
+}
+
+/* Create SSL_CTX. */
+static SSL_CTX *create_ssl_ctx(const char *key_file, const char *cert_file) {
+  SSL_CTX *ssl_ctx;
+
+  ssl_ctx = SSL_CTX_new(TLS_server_method());
+  if (!ssl_ctx) {
+    errx(1, "Could not create SSL/TLS context: %s",
+         ERR_error_string(ERR_get_error(), NULL));
+  }
+  SSL_CTX_set_options(ssl_ctx,
+                      SSL_OP_ALL | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 |
+                          SSL_OP_NO_COMPRESSION |
+                          SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION);
+#if OPENSSL_VERSION_NUMBER >= 0x30000000L
+  if (SSL_CTX_set1_curves_list(ssl_ctx, "P-256") != 1) {
+    errx(1, "SSL_CTX_set1_curves_list failed: %s",
+         ERR_error_string(ERR_get_error(), NULL));
+  }
+#else  /* !(OPENSSL_VERSION_NUMBER >= 0x30000000L) */
+  {
+    EC_KEY *ecdh;
+    ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
+    if (!ecdh) {
+      errx(1, "EC_KEY_new_by_curv_name failed: %s",
+           ERR_error_string(ERR_get_error(), NULL));
+    }
+    SSL_CTX_set_tmp_ecdh(ssl_ctx, ecdh);
+    EC_KEY_free(ecdh);
+  }
+#endif /* !(OPENSSL_VERSION_NUMBER >= 0x30000000L) */
+
+  if (SSL_CTX_use_PrivateKey_file(ssl_ctx, key_file, SSL_FILETYPE_PEM) != 1) {
+    errx(1, "Could not read private key file %s", key_file);
+  }
+  if (SSL_CTX_use_certificate_chain_file(ssl_ctx, cert_file) != 1) {
+    errx(1, "Could not read certificate file %s", cert_file);
+  }
+
+  SSL_CTX_set_alpn_select_cb(ssl_ctx, alpn_select_proto_cb, NULL);
+
+  return ssl_ctx;
+}
+
+/* Create SSL object */
+static SSL *create_ssl(SSL_CTX *ssl_ctx) {
+  SSL *ssl;
+  ssl = SSL_new(ssl_ctx);
+  if (!ssl) {
+    errx(1, "Could not create SSL/TLS session object: %s",
+         ERR_error_string(ERR_get_error(), NULL));
+  }
+  return ssl;
+}
+
+static void add_stream(http2_session_data *session_data,
+                       http2_stream_data *stream_data) {
+  stream_data->next = session_data->root.next;
+  session_data->root.next = stream_data;
+  stream_data->prev = &session_data->root;
+  if (stream_data->next) {
+    stream_data->next->prev = stream_data;
+  }
+}
+
+static void remove_stream(http2_session_data *session_data,
+                          http2_stream_data *stream_data) {
+  (void)session_data;
+
+  stream_data->prev->next = stream_data->next;
+  if (stream_data->next) {
+    stream_data->next->prev = stream_data->prev;
+  }
+}
+
+static http2_stream_data *
+create_http2_stream_data(http2_session_data *session_data, int32_t stream_id) {
+  http2_stream_data *stream_data;
+  stream_data = malloc(sizeof(http2_stream_data));
+  memset(stream_data, 0, sizeof(http2_stream_data));
+  stream_data->stream_id = stream_id;
+  stream_data->fd = -1;
+
+  add_stream(session_data, stream_data);
+  return stream_data;
+}
+
+static void delete_http2_stream_data(http2_stream_data *stream_data) {
+  if (stream_data->fd != -1) {
+    close(stream_data->fd);
+  }
+  free(stream_data->request_path);
+  free(stream_data);
+}
+
+static http2_session_data *create_http2_session_data(app_context *app_ctx,
+                                                     int fd,
+                                                     struct sockaddr *addr,
+                                                     int addrlen) {
+  int rv;
+  http2_session_data *session_data;
+  SSL *ssl;
+  char host[NI_MAXHOST];
+  int val = 1;
+
+  ssl = create_ssl(app_ctx->ssl_ctx);
+  session_data = malloc(sizeof(http2_session_data));
+  memset(session_data, 0, sizeof(http2_session_data));
+  session_data->app_ctx = app_ctx;
+  setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char *)&val, sizeof(val));
+  session_data->bev = bufferevent_openssl_socket_new(
+      app_ctx->evbase, fd, ssl, BUFFEREVENT_SSL_ACCEPTING,
+      BEV_OPT_CLOSE_ON_FREE | BEV_OPT_DEFER_CALLBACKS);
+  bufferevent_enable(session_data->bev, EV_READ | EV_WRITE);
+  rv = getnameinfo(addr, (socklen_t)addrlen, host, sizeof(host), NULL, 0,
+                   NI_NUMERICHOST);
+  if (rv != 0) {
+    session_data->client_addr = strdup("(unknown)");
+  } else {
+    session_data->client_addr = strdup(host);
+  }
+
+  return session_data;
+}
+
+static void delete_http2_session_data(http2_session_data *session_data) {
+  http2_stream_data *stream_data;
+  SSL *ssl = bufferevent_openssl_get_ssl(session_data->bev);
+  fprintf(stderr, "%s disconnected\n", session_data->client_addr);
+  if (ssl) {
+    SSL_shutdown(ssl);
+  }
+  bufferevent_free(session_data->bev);
+  nghttp2_session_del(session_data->session);
+  for (stream_data = session_data->root.next; stream_data;) {
+    http2_stream_data *next = stream_data->next;
+    delete_http2_stream_data(stream_data);
+    stream_data = next;
+  }
+  free(session_data->client_addr);
+  free(session_data);
+}
+
+/* Serialize the frame and send (or buffer) the data to
+   bufferevent. */
+static int session_send(http2_session_data *session_data) {
+  int rv;
+  rv = nghttp2_session_send(session_data->session);
+  if (rv != 0) {
+    warnx("Fatal error: %s", nghttp2_strerror(rv));
+    return -1;
+  }
+  return 0;
+}
+
+/* Read the data in the bufferevent and feed them into nghttp2 library
+   function. Invocation of nghttp2_session_mem_recv() may make
+   additional pending frames, so call session_send() at the end of the
+   function. */
+static int session_recv(http2_session_data *session_data) {
+  ssize_t readlen;
+  struct evbuffer *input = bufferevent_get_input(session_data->bev);
+  size_t datalen = evbuffer_get_length(input);
+  unsigned char *data = evbuffer_pullup(input, -1);
+
+  readlen = nghttp2_session_mem_recv(session_data->session, data, datalen);
+  if (readlen < 0) {
+    warnx("Fatal error: %s", nghttp2_strerror((int)readlen));
+    return -1;
+  }
+  if (evbuffer_drain(input, (size_t)readlen) != 0) {
+    warnx("Fatal error: evbuffer_drain failed");
+    return -1;
+  }
+  if (session_send(session_data) != 0) {
+    return -1;
+  }
+  return 0;
+}
+
+static ssize_t send_callback(nghttp2_session *session, const uint8_t *data,
+                             size_t length, int flags, void *user_data) {
+  http2_session_data *session_data = (http2_session_data *)user_data;
+  struct bufferevent *bev = session_data->bev;
+  (void)session;
+  (void)flags;
+
+  /* Avoid excessive buffering in server side. */
+  if (evbuffer_get_length(bufferevent_get_output(session_data->bev)) >=
+      OUTPUT_WOULDBLOCK_THRESHOLD) {
+    return NGHTTP2_ERR_WOULDBLOCK;
+  }
+  bufferevent_write(bev, data, length);
+  return (ssize_t)length;
+}
+
+/* Returns nonzero if the string |s| ends with the substring |sub| */
+static int ends_with(const char *s, const char *sub) {
+  size_t slen = strlen(s);
+  size_t sublen = strlen(sub);
+  if (slen < sublen) {
+    return 0;
+  }
+  return memcmp(s + slen - sublen, sub, sublen) == 0;
+}
+
+/* Returns int value of hex string character |c| */
+static uint8_t hex_to_uint(uint8_t c) {
+  if ('0' <= c && c <= '9') {
+    return (uint8_t)(c - '0');
+  }
+  if ('A' <= c && c <= 'F') {
+    return (uint8_t)(c - 'A' + 10);
+  }
+  if ('a' <= c && c <= 'f') {
+    return (uint8_t)(c - 'a' + 10);
+  }
+  return 0;
+}
+
+/* Decodes percent-encoded byte string |value| with length |valuelen|
+   and returns the decoded byte string in allocated buffer. The return
+   value is NULL terminated. The caller must free the returned
+   string. */
+static char *percent_decode(const uint8_t *value, size_t valuelen) {
+  char *res;
+
+  res = malloc(valuelen + 1);
+  if (valuelen > 3) {
+    size_t i, j;
+    for (i = 0, j = 0; i < valuelen - 2;) {
+      if (value[i] != '%' || !isxdigit(value[i + 1]) ||
+          !isxdigit(value[i + 2])) {
+        res[j++] = (char)value[i++];
+        continue;
+      }
+      res[j++] =
+          (char)((hex_to_uint(value[i + 1]) << 4) + hex_to_uint(value[i + 2]));
+      i += 3;
+    }
+    memcpy(&res[j], &value[i], 2);
+    res[j + 2] = '\0';
+  } else {
+    memcpy(res, value, valuelen);
+    res[valuelen] = '\0';
+  }
+  return res;
+}
+
+static ssize_t file_read_callback(nghttp2_session *session, int32_t stream_id,
+                                  uint8_t *buf, size_t length,
+                                  uint32_t *data_flags,
+                                  nghttp2_data_source *source,
+                                  void *user_data) {
+  int fd = source->fd;
+  ssize_t r;
+  (void)session;
+  (void)stream_id;
+  (void)user_data;
+
+  while ((r = read(fd, buf, length)) == -1 && errno == EINTR)
+    ;
+  if (r == -1) {
+    return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
+  }
+  if (r == 0) {
+    *data_flags |= NGHTTP2_DATA_FLAG_EOF;
+  }
+  return r;
+}
+
+static int send_response(nghttp2_session *session, int32_t stream_id,
+                         nghttp2_nv *nva, size_t nvlen, int fd) {
+  int rv;
+  nghttp2_data_provider data_prd;
+  data_prd.source.fd = fd;
+  data_prd.read_callback = file_read_callback;
+
+  rv = nghttp2_submit_response(session, stream_id, nva, nvlen, &data_prd);
+  if (rv != 0) {
+    warnx("Fatal error: %s", nghttp2_strerror(rv));
+    return -1;
+  }
+  return 0;
+}
+
+static const char ERROR_HTML[] = "<html><head><title>404</title></head>"
+                                 "<body><h1>404 Not Found</h1></body></html>";
+
+static int error_reply(nghttp2_session *session,
+                       http2_stream_data *stream_data) {
+  int rv;
+  ssize_t writelen;
+  int pipefd[2];
+  nghttp2_nv hdrs[] = {MAKE_NV(":status", "404")};
+
+  rv = pipe(pipefd);
+  if (rv != 0) {
+    warn("Could not create pipe");
+    rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
+                                   stream_data->stream_id,
+                                   NGHTTP2_INTERNAL_ERROR);
+    if (rv != 0) {
+      warnx("Fatal error: %s", nghttp2_strerror(rv));
+      return -1;
+    }
+    return 0;
+  }
+
+  writelen = write(pipefd[1], ERROR_HTML, sizeof(ERROR_HTML) - 1);
+  close(pipefd[1]);
+
+  if (writelen != sizeof(ERROR_HTML) - 1) {
+    close(pipefd[0]);
+    return -1;
+  }
+
+  stream_data->fd = pipefd[0];
+
+  if (send_response(session, stream_data->stream_id, hdrs, ARRLEN(hdrs),
+                    pipefd[0]) != 0) {
+    close(pipefd[0]);
+    return -1;
+  }
+  return 0;
+}
+
+/* nghttp2_on_header_callback: Called when nghttp2 library emits
+   single header name/value pair. */
+static int on_header_callback(nghttp2_session *session,
+                              const nghttp2_frame *frame, const uint8_t *name,
+                              size_t namelen, const uint8_t *value,
+                              size_t valuelen, uint8_t flags, void *user_data) {
+  http2_stream_data *stream_data;
+  const char PATH[] = ":path";
+  (void)flags;
+  (void)user_data;
+
+  switch (frame->hd.type) {
+  case NGHTTP2_HEADERS:
+    if (frame->headers.cat != NGHTTP2_HCAT_REQUEST) {
+      break;
+    }
+    stream_data =
+        nghttp2_session_get_stream_user_data(session, frame->hd.stream_id);
+    if (!stream_data || stream_data->request_path) {
+      break;
+    }
+    if (namelen == sizeof(PATH) - 1 && memcmp(PATH, name, namelen) == 0) {
+      size_t j;
+      for (j = 0; j < valuelen && value[j] != '?'; ++j)
+        ;
+      stream_data->request_path = percent_decode(value, j);
+    }
+    break;
+  }
+  return 0;
+}
+
+static int on_begin_headers_callback(nghttp2_session *session,
+                                     const nghttp2_frame *frame,
+                                     void *user_data) {
+  http2_session_data *session_data = (http2_session_data *)user_data;
+  http2_stream_data *stream_data;
+
+  if (frame->hd.type != NGHTTP2_HEADERS ||
+      frame->headers.cat != NGHTTP2_HCAT_REQUEST) {
+    return 0;
+  }
+  stream_data = create_http2_stream_data(session_data, frame->hd.stream_id);
+  nghttp2_session_set_stream_user_data(session, frame->hd.stream_id,
+                                       stream_data);
+  return 0;
+}
+
+/* Minimum check for directory traversal. Returns nonzero if it is
+   safe. */
+static int check_path(const char *path) {
+  /* We don't like '\' in url. */
+  return path[0] && path[0] == '/' && strchr(path, '\\') == NULL &&
+         strstr(path, "/../") == NULL && strstr(path, "/./") == NULL &&
+         !ends_with(path, "/..") && !ends_with(path, "/.");
+}
+
+static int on_request_recv(nghttp2_session *session,
+                           http2_session_data *session_data,
+                           http2_stream_data *stream_data) {
+  int fd;
+  nghttp2_nv hdrs[] = {MAKE_NV(":status", "200")};
+  char *rel_path;
+
+  if (!stream_data->request_path) {
+    if (error_reply(session, stream_data) != 0) {
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    }
+    return 0;
+  }
+  fprintf(stderr, "%s GET %s\n", session_data->client_addr,
+          stream_data->request_path);
+  if (!check_path(stream_data->request_path)) {
+    if (error_reply(session, stream_data) != 0) {
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    }
+    return 0;
+  }
+  for (rel_path = stream_data->request_path; *rel_path == '/'; ++rel_path)
+    ;
+  fd = open(rel_path, O_RDONLY);
+  if (fd == -1) {
+    if (error_reply(session, stream_data) != 0) {
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    }
+    return 0;
+  }
+  stream_data->fd = fd;
+
+  if (send_response(session, stream_data->stream_id, hdrs, ARRLEN(hdrs), fd) !=
+      0) {
+    close(fd);
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  }
+  return 0;
+}
+
+static int on_frame_recv_callback(nghttp2_session *session,
+                                  const nghttp2_frame *frame, void *user_data) {
+  http2_session_data *session_data = (http2_session_data *)user_data;
+  http2_stream_data *stream_data;
+  switch (frame->hd.type) {
+  case NGHTTP2_DATA:
+  case NGHTTP2_HEADERS:
+    /* Check that the client request has finished */
+    if (frame->hd.flags & NGHTTP2_FLAG_END_STREAM) {
+      stream_data =
+          nghttp2_session_get_stream_user_data(session, frame->hd.stream_id);
+      /* For DATA and HEADERS frame, this callback may be called after
+         on_stream_close_callback. Check that stream still alive. */
+      if (!stream_data) {
+        return 0;
+      }
+      return on_request_recv(session, session_data, stream_data);
+    }
+    break;
+  default:
+    break;
+  }
+  return 0;
+}
+
+static int on_stream_close_callback(nghttp2_session *session, int32_t stream_id,
+                                    uint32_t error_code, void *user_data) {
+  http2_session_data *session_data = (http2_session_data *)user_data;
+  http2_stream_data *stream_data;
+  (void)error_code;
+
+  stream_data = nghttp2_session_get_stream_user_data(session, stream_id);
+  if (!stream_data) {
+    return 0;
+  }
+  remove_stream(session_data, stream_data);
+  delete_http2_stream_data(stream_data);
+  return 0;
+}
+
+static void initialize_nghttp2_session(http2_session_data *session_data) {
+  nghttp2_session_callbacks *callbacks;
+
+  nghttp2_session_callbacks_new(&callbacks);
+
+  nghttp2_session_callbacks_set_send_callback(callbacks, send_callback);
+
+  nghttp2_session_callbacks_set_on_frame_recv_callback(callbacks,
+                                                       on_frame_recv_callback);
+
+  nghttp2_session_callbacks_set_on_stream_close_callback(
+      callbacks, on_stream_close_callback);
+
+  nghttp2_session_callbacks_set_on_header_callback(callbacks,
+                                                   on_header_callback);
+
+  nghttp2_session_callbacks_set_on_begin_headers_callback(
+      callbacks, on_begin_headers_callback);
+
+  nghttp2_session_server_new(&session_data->session, callbacks, session_data);
+
+  nghttp2_session_callbacks_del(callbacks);
+}
+
+/* Send HTTP/2 client connection header, which includes 24 bytes
+   magic octets and SETTINGS frame */
+static int send_server_connection_header(http2_session_data *session_data) {
+  nghttp2_settings_entry iv[1] = {
+      {NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS, 100}};
+  int rv;
+
+  rv = nghttp2_submit_settings(session_data->session, NGHTTP2_FLAG_NONE, iv,
+                               ARRLEN(iv));
+  if (rv != 0) {
+    warnx("Fatal error: %s", nghttp2_strerror(rv));
+    return -1;
+  }
+  return 0;
+}
+
+/* readcb for bufferevent after client connection header was
+   checked. */
+static void readcb(struct bufferevent *bev, void *ptr) {
+  http2_session_data *session_data = (http2_session_data *)ptr;
+  (void)bev;
+
+  if (session_recv(session_data) != 0) {
+    delete_http2_session_data(session_data);
+    return;
+  }
+}
+
+/* writecb for bufferevent. To greaceful shutdown after sending or
+   receiving GOAWAY, we check the some conditions on the nghttp2
+   library and output buffer of bufferevent. If it indicates we have
+   no business to this session, tear down the connection. If the
+   connection is not going to shutdown, we call session_send() to
+   process pending data in the output buffer. This is necessary
+   because we have a threshold on the buffer size to avoid too much
+   buffering. See send_callback(). */
+static void writecb(struct bufferevent *bev, void *ptr) {
+  http2_session_data *session_data = (http2_session_data *)ptr;
+  if (evbuffer_get_length(bufferevent_get_output(bev)) > 0) {
+    return;
+  }
+  if (nghttp2_session_want_read(session_data->session) == 0 &&
+      nghttp2_session_want_write(session_data->session) == 0) {
+    delete_http2_session_data(session_data);
+    return;
+  }
+  if (session_send(session_data) != 0) {
+    delete_http2_session_data(session_data);
+    return;
+  }
+}
+
+/* eventcb for bufferevent */
+static void eventcb(struct bufferevent *bev, short events, void *ptr) {
+  http2_session_data *session_data = (http2_session_data *)ptr;
+  if (events & BEV_EVENT_CONNECTED) {
+    const unsigned char *alpn = NULL;
+    unsigned int alpnlen = 0;
+    SSL *ssl;
+    (void)bev;
+
+    fprintf(stderr, "%s connected\n", session_data->client_addr);
+
+    ssl = bufferevent_openssl_get_ssl(session_data->bev);
+
+    SSL_get0_alpn_selected(ssl, &alpn, &alpnlen);
+
+    if (alpn == NULL || alpnlen != 2 || memcmp("h2", alpn, 2) != 0) {
+      fprintf(stderr, "%s h2 is not negotiated\n", session_data->client_addr);
+      delete_http2_session_data(session_data);
+      return;
+    }
+
+    initialize_nghttp2_session(session_data);
+
+    if (send_server_connection_header(session_data) != 0 ||
+        session_send(session_data) != 0) {
+      delete_http2_session_data(session_data);
+      return;
+    }
+
+    return;
+  }
+  if (events & BEV_EVENT_EOF) {
+    fprintf(stderr, "%s EOF\n", session_data->client_addr);
+  } else if (events & BEV_EVENT_ERROR) {
+    fprintf(stderr, "%s network error\n", session_data->client_addr);
+  } else if (events & BEV_EVENT_TIMEOUT) {
+    fprintf(stderr, "%s timeout\n", session_data->client_addr);
+  }
+  delete_http2_session_data(session_data);
+}
+
+/* callback for evconnlistener */
+static void acceptcb(struct evconnlistener *listener, int fd,
+                     struct sockaddr *addr, int addrlen, void *arg) {
+  app_context *app_ctx = (app_context *)arg;
+  http2_session_data *session_data;
+  (void)listener;
+
+  session_data = create_http2_session_data(app_ctx, fd, addr, addrlen);
+
+  bufferevent_setcb(session_data->bev, readcb, writecb, eventcb, session_data);
+}
+
+static void start_listen(struct event_base *evbase, const char *service,
+                         app_context *app_ctx) {
+  int rv;
+  struct addrinfo hints;
+  struct addrinfo *res, *rp;
+
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+  hints.ai_flags = AI_PASSIVE;
+#ifdef AI_ADDRCONFIG
+  hints.ai_flags |= AI_ADDRCONFIG;
+#endif /* AI_ADDRCONFIG */
+
+  rv = getaddrinfo(NULL, service, &hints, &res);
+  if (rv != 0) {
+    errx(1, "Could not resolve server address");
+  }
+  for (rp = res; rp; rp = rp->ai_next) {
+    struct evconnlistener *listener;
+    listener = evconnlistener_new_bind(
+        evbase, acceptcb, app_ctx, LEV_OPT_CLOSE_ON_FREE | LEV_OPT_REUSEABLE,
+        16, rp->ai_addr, (int)rp->ai_addrlen);
+    if (listener) {
+      freeaddrinfo(res);
+
+      return;
+    }
+  }
+  errx(1, "Could not start listener");
+}
+
+static void initialize_app_context(app_context *app_ctx, SSL_CTX *ssl_ctx,
+                                   struct event_base *evbase) {
+  memset(app_ctx, 0, sizeof(app_context));
+  app_ctx->ssl_ctx = ssl_ctx;
+  app_ctx->evbase = evbase;
+}
+
+static void run(const char *service, const char *key_file,
+                const char *cert_file) {
+  SSL_CTX *ssl_ctx;
+  app_context app_ctx;
+  struct event_base *evbase;
+
+  ssl_ctx = create_ssl_ctx(key_file, cert_file);
+  evbase = event_base_new();
+  initialize_app_context(&app_ctx, ssl_ctx, evbase);
+  start_listen(evbase, service, &app_ctx);
+
+  event_base_loop(evbase, 0);
+
+  event_base_free(evbase);
+  SSL_CTX_free(ssl_ctx);
+}
+
+int main(int argc, char **argv) {
+  struct sigaction act;
+
+  if (argc < 4) {
+    fprintf(stderr, "Usage: libevent-server PORT KEY_FILE CERT_FILE\n");
+    exit(EXIT_FAILURE);
+  }
+
+  memset(&act, 0, sizeof(struct sigaction));
+  act.sa_handler = SIG_IGN;
+  sigaction(SIGPIPE, &act, NULL);
+
+  run(argv[1], argv[2], argv[3]);
+  return 0;
+}