Made local copies of dependencies

examples/ws_ssl/net_skeleton.c

+// Copyright (c) 2014 Cesanta Software Limited
+// All rights reserved
+//
+// This software is dual-licensed: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation. For the terms of this
+// license, see <http://www.gnu.org/licenses/>.
+//
+// You are free to use this software under the terms of the GNU General
+// Public License, but WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// Alternatively, you can license this software under a commercial
+// license, as set out in <http://cesanta.com/>.
+//
+// $Date: 2014-09-09 16:03:50 UTC $
+
+#include "net_skeleton.h"
+
+#ifndef NS_MALLOC
+#define NS_MALLOC malloc
+#endif
+
+#ifndef NS_REALLOC
+#define NS_REALLOC realloc
+#endif
+
+#ifndef NS_FREE
+#define NS_FREE free
+#endif
+
+#define NS_UDP_RECEIVE_BUFFER_SIZE  2000
+#define NS_VPRINTF_BUFFER_SIZE      500
+
+struct ctl_msg {
+  ns_callback_t callback;
+  char message[1024 * 8];
+};
+
+void iobuf_init(struct iobuf *iobuf, size_t size) {
+  iobuf->len = iobuf->size = 0;
+  iobuf->buf = NULL;
+
+  if (size > 0 && (iobuf->buf = (char *) NS_MALLOC(size)) != NULL) {
+    iobuf->size = size;
+  }
+}
+
+void iobuf_free(struct iobuf *iobuf) {
+  if (iobuf != NULL) {
+    if (iobuf->buf != NULL) NS_FREE(iobuf->buf);
+    iobuf_init(iobuf, 0);
+  }
+}
+
+size_t iobuf_append(struct iobuf *io, const void *buf, size_t len) {
+  char *p = NULL;
+
+  assert(io != NULL);
+  assert(io->len <= io->size);
+
+  if (len <= 0) {
+  } else if (io->len + len <= io->size) {
+    memcpy(io->buf + io->len, buf, len);
+    io->len += len;
+  } else if ((p = (char *) NS_REALLOC(io->buf, io->len + len)) != NULL) {
+    io->buf = p;
+    memcpy(io->buf + io->len, buf, len);
+    io->len += len;
+    io->size = io->len;
+  } else {
+    len = 0;
+  }
+
+  return len;
+}
+
+void iobuf_remove(struct iobuf *io, size_t n) {
+  if (n > 0 && n <= io->len) {
+    memmove(io->buf, io->buf + n, io->len - n);
+    io->len -= n;
+  }
+}
+
+static size_t ns_out(struct ns_connection *nc, const void *buf, size_t len) {
+  if (nc->flags & NSF_UDP) {
+    long n = send(nc->sock, buf, len, 0);
+    DBG(("%p %d send %ld (%d)", nc, nc->sock, n, errno));
+    return n < 0 ? 0 : n;
+  } else {
+    return iobuf_append(&nc->send_iobuf, buf, len);
+  }
+}
+
+#ifndef NS_DISABLE_THREADS
+void *ns_start_thread(void *(*f)(void *), void *p) {
+#ifdef _WIN32
+  return (void *) _beginthread((void (__cdecl *)(void *)) f, 0, p);
+#else
+  pthread_t thread_id = (pthread_t) 0;
+  pthread_attr_t attr;
+
+  (void) pthread_attr_init(&attr);
+  (void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+#if defined(NS_STACK_SIZE) && NS_STACK_SIZE > 1
+  (void) pthread_attr_setstacksize(&attr, NS_STACK_SIZE);
+#endif
+
+  pthread_create(&thread_id, &attr, f, p);
+  pthread_attr_destroy(&attr);
+
+  return (void *) thread_id;
+#endif
+}
+#endif  // NS_DISABLE_THREADS
+
+static void ns_add_conn(struct ns_mgr *mgr, struct ns_connection *c) {
+  c->next = mgr->active_connections;
+  mgr->active_connections = c;
+  c->prev = NULL;
+  if (c->next != NULL) c->next->prev = c;
+}
+
+static void ns_remove_conn(struct ns_connection *conn) {
+  if (conn->prev == NULL) conn->mgr->active_connections = conn->next;
+  if (conn->prev) conn->prev->next = conn->next;
+  if (conn->next) conn->next->prev = conn->prev;
+}
+
+// Print message to buffer. If buffer is large enough to hold the message,
+// return buffer. If buffer is to small, allocate large enough buffer on heap,
+// and return allocated buffer.
+int ns_avprintf(char **buf, size_t size, const char *fmt, va_list ap) {
+  va_list ap_copy;
+  int len;
+
+  va_copy(ap_copy, ap);
+  len = vsnprintf(*buf, size, fmt, ap_copy);
+  va_end(ap_copy);
+
+  if (len < 0) {
+    // eCos and Windows are not standard-compliant and return -1 when
+    // the buffer is too small. Keep allocating larger buffers until we
+    // succeed or out of memory.
+    *buf = NULL;
+    while (len < 0) {
+      if (*buf) free(*buf);
+      size *= 2;
+      if ((*buf = (char *) NS_MALLOC(size)) == NULL) break;
+      va_copy(ap_copy, ap);
+      len = vsnprintf(*buf, size, fmt, ap_copy);
+      va_end(ap_copy);
+    }
+  } else if (len > (int) size) {
+    // Standard-compliant code path. Allocate a buffer that is large enough.
+    if ((*buf = (char *) NS_MALLOC(len + 1)) == NULL) {
+      len = -1;
+    } else {
+      va_copy(ap_copy, ap);
+      len = vsnprintf(*buf, len + 1, fmt, ap_copy);
+      va_end(ap_copy);
+    }
+  }
+
+  return len;
+}
+
+int ns_vprintf(struct ns_connection *nc, const char *fmt, va_list ap) {
+  char mem[NS_VPRINTF_BUFFER_SIZE], *buf = mem;
+  int len;
+
+  if ((len = ns_avprintf(&buf, sizeof(mem), fmt, ap)) > 0) {
+    ns_out(nc, buf, len);
+  }
+  if (buf != mem && buf != NULL) {
+    free(buf);
+  }
+
+  return len;
+}
+
+int ns_printf(struct ns_connection *conn, const char *fmt, ...) {
+  int len;
+  va_list ap;
+  va_start(ap, fmt);
+  len = ns_vprintf(conn, fmt, ap);
+  va_end(ap);
+  return len;
+}
+
+static void hexdump(struct ns_connection *nc, const char *path,
+                    int num_bytes, enum ns_event ev) {
+  const struct iobuf *io = ev == NS_SEND ? &nc->send_iobuf : &nc->recv_iobuf;
+  FILE *fp;
+  char *buf, src[60], dst[60];
+  int buf_size = num_bytes * 5 + 100;
+
+  if ((fp = fopen(path, "a")) != NULL) {
+    ns_sock_to_str(nc->sock, src, sizeof(src), 3);
+    ns_sock_to_str(nc->sock, dst, sizeof(dst), 7);
+    fprintf(fp, "%lu %p %s %s %s %d\n", (unsigned long) time(NULL),
+            nc->connection_data, src,
+            ev == NS_RECV ? "<-" : ev == NS_SEND ? "->" :
+            ev == NS_ACCEPT ? "<A" : ev == NS_CONNECT ? "C>" : "XX",
+            dst, num_bytes);
+    if (num_bytes > 0 && (buf = (char *) NS_MALLOC(buf_size)) != NULL) {
+      ns_hexdump(io->buf + (ev == NS_SEND ? 0 : io->len) -
+        (ev == NS_SEND ? 0 : num_bytes), num_bytes, buf, buf_size);
+      fprintf(fp, "%s", buf);
+      free(buf);
+    }
+    fclose(fp);
+  }
+}
+
+static void ns_call(struct ns_connection *conn, enum ns_event ev, void *p) {
+  if (conn->mgr->hexdump_file != NULL && ev != NS_POLL) {
+    int len = (ev == NS_RECV || ev == NS_SEND) ? * (int *) p : 0;
+    hexdump(conn, conn->mgr->hexdump_file, len, ev);
+  }
+  if (conn->mgr->callback) conn->mgr->callback(conn, ev, p);
+}
+
+static void ns_destroy_conn(struct ns_connection *conn) {
+  closesocket(conn->sock);
+  iobuf_free(&conn->recv_iobuf);
+  iobuf_free(&conn->send_iobuf);
+#ifdef NS_ENABLE_SSL
+  if (conn->ssl != NULL) {
+    SSL_free(conn->ssl);
+  }
+  if (conn->ssl_ctx != NULL) {
+    SSL_CTX_free(conn->ssl_ctx);
+  }
+#endif
+  NS_FREE(conn);
+}
+
+static void ns_close_conn(struct ns_connection *conn) {
+  DBG(("%p %d", conn, conn->flags));
+  ns_call(conn, NS_CLOSE, NULL);
+  ns_remove_conn(conn);
+  ns_destroy_conn(conn);
+}
+
+void ns_set_close_on_exec(sock_t sock) {
+#ifdef _WIN32
+  (void) SetHandleInformation((HANDLE) sock, HANDLE_FLAG_INHERIT, 0);
+#else
+  fcntl(sock, F_SETFD, FD_CLOEXEC);
+#endif
+}
+
+static void ns_set_non_blocking_mode(sock_t sock) {
+#ifdef _WIN32
+  unsigned long on = 1;
+  ioctlsocket(sock, FIONBIO, &on);
+#else
+  int flags = fcntl(sock, F_GETFL, 0);
+  fcntl(sock, F_SETFL, flags | O_NONBLOCK);
+#endif
+}
+
+#ifndef NS_DISABLE_SOCKETPAIR
+int ns_socketpair2(sock_t sp[2], int sock_type) {
+  union socket_address sa;
+  sock_t sock;
+  socklen_t len = sizeof(sa.sin);
+  int ret = 0;
+
+  sp[0] = sp[1] = INVALID_SOCKET;
+
+  (void) memset(&sa, 0, sizeof(sa));
+  sa.sin.sin_family = AF_INET;
+  sa.sin.sin_port = htons(0);
+  sa.sin.sin_addr.s_addr = htonl(0x7f000001);
+
+  if ((sock = socket(AF_INET, sock_type, 0)) != INVALID_SOCKET &&
+      !bind(sock, &sa.sa, len) &&
+      (sock_type == SOCK_DGRAM || !listen(sock, 1)) &&
+      !getsockname(sock, &sa.sa, &len) &&
+      (sp[0] = socket(AF_INET, sock_type, 0)) != INVALID_SOCKET &&
+      !connect(sp[0], &sa.sa, len) &&
+      (sock_type == SOCK_STREAM ||
+       (!getsockname(sp[0], &sa.sa, &len) && !connect(sock, &sa.sa, len))) &&
+      (sp[1] = (sock_type == SOCK_DGRAM ? sock :
+                accept(sock, &sa.sa, &len))) != INVALID_SOCKET) {
+    ns_set_close_on_exec(sp[0]);
+    ns_set_close_on_exec(sp[1]);
+    ret = 1;
+  } else {
+    if (sp[0] != INVALID_SOCKET) closesocket(sp[0]);
+    if (sp[1] != INVALID_SOCKET) closesocket(sp[1]);
+    sp[0] = sp[1] = INVALID_SOCKET;
+  }
+  if (sock_type != SOCK_DGRAM) closesocket(sock);
+
+  return ret;
+}
+
+int ns_socketpair(sock_t sp[2]) {
+  return ns_socketpair2(sp, SOCK_STREAM);
+}
+#endif  // NS_DISABLE_SOCKETPAIR
+
+// TODO(lsm): use non-blocking resolver
+static int ns_resolve2(const char *host, struct in_addr *ina) {
+  struct hostent *he;
+  if ((he = gethostbyname(host)) == NULL) {
+    DBG(("gethostbyname(%s) failed: %s", host, strerror(errno)));
+  } else {
+    memcpy(ina, he->h_addr_list[0], sizeof(*ina));
+    return 1;
+  }
+  return 0;
+}
+
+// Resolve FDQN "host", store IP address in the "ip".
+// Return > 0 (IP address length) on success.
+int ns_resolve(const char *host, char *buf, size_t n) {
+  struct in_addr ad;
+  return ns_resolve2(host, &ad) ? snprintf(buf, n, "%s", inet_ntoa(ad)) : 0;
+}
+
+// Address format: [PROTO://][IP_ADDRESS:]PORT[:CERT][:CA_CERT]
+static int ns_parse_address(const char *str, union socket_address *sa,
+                            int *proto, int *use_ssl, char *cert, char *ca) {
+  unsigned int a, b, c, d, port;
+  int n = 0, len = 0;
+  char host[200];
+#ifdef NS_ENABLE_IPV6
+  char buf[100];
+#endif
+
+  // MacOS needs that. If we do not zero it, subsequent bind() will fail.
+  // Also, all-zeroes in the socket address means binding to all addresses
+  // for both IPv4 and IPv6 (INADDR_ANY and IN6ADDR_ANY_INIT).
+  memset(sa, 0, sizeof(*sa));
+  sa->sin.sin_family = AF_INET;
+
+  *proto = SOCK_STREAM;
+  *use_ssl = 0;
+  cert[0] = ca[0] = '\0';
+
+  if (memcmp(str, "ssl://", 6) == 0) {
+    str += 6;
+    *use_ssl = 1;
+  } else if (memcmp(str, "udp://", 6) == 0) {
+    str += 6;
+    *proto = SOCK_DGRAM;
+  } else if (memcmp(str, "tcp://", 6) == 0) {
+    str += 6;
+  }
+
+  if (sscanf(str, "%u.%u.%u.%u:%u%n", &a, &b, &c, &d, &port, &len) == 5) {
+    // Bind to a specific IPv4 address, e.g. 192.168.1.5:8080
+    sa->sin.sin_addr.s_addr = htonl((a << 24) | (b << 16) | (c << 8) | d);
+    sa->sin.sin_port = htons((uint16_t) port);
+#ifdef NS_ENABLE_IPV6
+  } else if (sscanf(str, "[%99[^]]]:%u%n", buf, &port, &len) == 2 &&
+             inet_pton(AF_INET6, buf, &sa->sin6.sin6_addr)) {
+    // IPv6 address, e.g. [3ffe:2a00:100:7031::1]:8080
+    sa->sin6.sin6_family = AF_INET6;
+    sa->sin6.sin6_port = htons((uint16_t) port);
+#endif
+  } else if (sscanf(str, "%199[^ :]:%u%n", host, &port, &len) == 2) {
+    sa->sin.sin_port = htons((uint16_t) port);
+    ns_resolve2(host, &sa->sin.sin_addr);
+  } else if (sscanf(str, "%u%n", &port, &len) == 1) {
+    // If only port is specified, bind to IPv4, INADDR_ANY
+    sa->sin.sin_port = htons((uint16_t) port);
+  }
+
+  if (*use_ssl && (sscanf(str + len, ":%99[^:]:%99[^:]%n", cert, ca, &n) == 2 ||
+                   sscanf(str + len, ":%99[^:]%n", cert, &n) == 1)) {
+    len += n;
+  }
+
+  return port < 0xffff && str[len] == '\0' ? len : 0;
+}
+
+// 'sa' must be an initialized address to bind to
+static sock_t ns_open_listening_socket(union socket_address *sa, int proto) {
+  socklen_t sa_len = (sa->sa.sa_family == AF_INET) ?
+    sizeof(sa->sin) : sizeof(sa->sin6);
+  sock_t sock = INVALID_SOCKET;
+#ifndef _WIN32
+  int on = 1;
+#endif
+
+  if ((sock = socket(sa->sa.sa_family, proto, 0)) != INVALID_SOCKET &&
+#ifndef _WIN32
+      // SO_RESUSEADDR is not enabled on Windows because the semantics of
+      // SO_REUSEADDR on UNIX and Windows is different. On Windows,
+      // SO_REUSEADDR allows to bind a socket to a port without error even if
+      // the port is already open by another program. This is not the behavior
+      // SO_REUSEADDR was designed for, and leads to hard-to-track failure
+      // scenarios. Therefore, SO_REUSEADDR was disabled on Windows.
+      !setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *) &on, sizeof(on)) &&
+#endif
+      !bind(sock, &sa->sa, sa_len) &&
+      (proto == SOCK_DGRAM || listen(sock, SOMAXCONN) == 0)) {
+    ns_set_non_blocking_mode(sock);
+    // In case port was set to 0, get the real port number
+    (void) getsockname(sock, &sa->sa, &sa_len);
+  } else if (sock != INVALID_SOCKET) {
+    closesocket(sock);
+    sock = INVALID_SOCKET;
+  }
+
+  return sock;
+}
+
+#ifdef NS_ENABLE_SSL
+// Certificate generation script is at
+// https://github.com/cesanta/net_skeleton/blob/master/scripts/gen_certs.sh
+
+static int ns_use_ca_cert(SSL_CTX *ctx, const char *cert) {
+  if (ctx == NULL) {
+    return -1;
+  } else if (cert == NULL || cert[0] == '\0') {
+    return 0;
+  }
+  SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, 0);
+  return SSL_CTX_load_verify_locations(ctx, cert, NULL) == 1 ? 0 : -2;
+}
+
+static int ns_use_cert(SSL_CTX *ctx, const char *pem_file) {
+  if (ctx == NULL) {
+    return -1;
+  } else if (pem_file == NULL || pem_file[0] == '\0') {
+    return 0;
+  } else if (SSL_CTX_use_certificate_file(ctx, pem_file, 1) == 0 ||
+             SSL_CTX_use_PrivateKey_file(ctx, pem_file, 1) == 0) {
+    return -2;
+  } else {
+    SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
+    SSL_CTX_use_certificate_chain_file(ctx, pem_file);
+    return 0;
+  }
+}
+#endif  // NS_ENABLE_SSL
+
+struct ns_connection *ns_bind(struct ns_mgr *srv, const char *str, void *data) {
+  union socket_address sa;
+  struct ns_connection *nc = NULL;
+  int use_ssl, proto;
+  char cert[100], ca_cert[100];
+  sock_t sock;
+
+  ns_parse_address(str, &sa, &proto, &use_ssl, cert, ca_cert);
+  if (use_ssl && cert[0] == '\0') return NULL;
+
+  if ((sock = ns_open_listening_socket(&sa, proto)) == INVALID_SOCKET) {
+  } else if ((nc = ns_add_sock(srv, sock, NULL)) == NULL) {
+    closesocket(sock);
+  } else {
+    nc->sa = sa;
+    nc->flags |= NSF_LISTENING;
+    nc->connection_data = data;
+
+    if (proto == SOCK_DGRAM) {
+      nc->flags |= NSF_UDP;
+    }
+
+#ifdef NS_ENABLE_SSL
+    if (use_ssl) {
+      nc->ssl_ctx = SSL_CTX_new(SSLv23_server_method());
+      if (ns_use_cert(nc->ssl_ctx, cert) != 0 ||
+          ns_use_ca_cert(nc->ssl_ctx, ca_cert) != 0) {
+        ns_close_conn(nc);
+        nc = NULL;
+      }
+    }
+#endif
+
+    DBG(("%p sock %d/%d ssl %p %p", nc, sock, proto, nc->ssl_ctx, nc->ssl));
+  }
+
+  return nc;
+}
+
+static struct ns_connection *accept_conn(struct ns_connection *ls) {
+  struct ns_connection *c = NULL;
+  union socket_address sa;
+  socklen_t len = sizeof(sa);
+  sock_t sock = INVALID_SOCKET;
+
+  // NOTE(lsm): on Windows, sock is always > FD_SETSIZE
+  if ((sock = accept(ls->sock, &sa.sa, &len)) == INVALID_SOCKET) {
+  } else if ((c = ns_add_sock(ls->mgr, sock, NULL)) == NULL) {
+    closesocket(sock);
+#ifdef NS_ENABLE_SSL
+  } else if (ls->ssl_ctx != NULL &&
+             ((c->ssl = SSL_new(ls->ssl_ctx)) == NULL ||
+              SSL_set_fd(c->ssl, sock) != 1)) {
+    DBG(("SSL error"));
+    ns_close_conn(c);
+    c = NULL;
+#endif
+  } else {
+    c->listener = ls;
+    ns_call(c, NS_ACCEPT, &sa);
+    DBG(("%p %d %p %p", c, c->sock, c->ssl_ctx, c->ssl));
+  }
+
+  return c;
+}
+
+static int ns_is_error(int n) {
+  return n == 0 ||
+    (n < 0 && errno != EINTR && errno != EINPROGRESS &&
+     errno != EAGAIN && errno != EWOULDBLOCK
+#ifdef _WIN32
+     && WSAGetLastError() != WSAEINTR && WSAGetLastError() != WSAEWOULDBLOCK
+#endif
+    );
+}
+
+void ns_sock_to_str(sock_t sock, char *buf, size_t len, int flags) {
+  union socket_address sa;
+  socklen_t slen = sizeof(sa);
+
+  if (buf != NULL && len > 0) {
+    buf[0] = '\0';
+    memset(&sa, 0, sizeof(sa));
+    if (flags & 4) {
+      getpeername(sock, &sa.sa, &slen);
+    } else {
+      getsockname(sock, &sa.sa, &slen);
+    }
+    if (flags & 1) {
+#if defined(NS_ENABLE_IPV6)
+      inet_ntop(sa.sa.sa_family, sa.sa.sa_family == AF_INET ?
+                (void *) &sa.sin.sin_addr :
+                (void *) &sa.sin6.sin6_addr, buf, len);
+#elif defined(_WIN32)
+      // Only Windoze Vista (and newer) have inet_ntop()
+      strncpy(buf, inet_ntoa(sa.sin.sin_addr), len);
+#else
+      inet_ntop(sa.sa.sa_family, (void *) &sa.sin.sin_addr, buf,(socklen_t)len);
+#endif
+    }
+    if (flags & 2) {
+      snprintf(buf + strlen(buf), len - (strlen(buf) + 1), "%s%d",
+               flags & 1 ? ":" : "", (int) ntohs(sa.sin.sin_port));
+    }
+  }
+}
+
+int ns_hexdump(const void *buf, int len, char *dst, int dst_len) {
+  const unsigned char *p = (const unsigned char *) buf;
+  char ascii[17] = "";
+  int i, idx, n = 0;
+
+  for (i = 0; i < len; i++) {
+    idx = i % 16;
+    if (idx == 0) {
+      if (i > 0) n += snprintf(dst + n, dst_len - n, "  %s\n", ascii);
+      n += snprintf(dst + n, dst_len - n, "%04x ", i);
+    }
+    n += snprintf(dst + n, dst_len - n, " %02x", p[i]);
+    ascii[idx] = p[i] < 0x20 || p[i] > 0x7e ? '.' : p[i];
+    ascii[idx + 1] = '\0';
+  }
+
+  while (i++ % 16) n += snprintf(dst + n, dst_len - n, "%s", "   ");
+  n += snprintf(dst + n, dst_len - n, "  %s\n\n", ascii);
+
+  return n;
+}
+
+#ifdef NS_ENABLE_SSL
+static int ns_ssl_err(struct ns_connection *conn, int res) {
+  int ssl_err = SSL_get_error(conn->ssl, res);
+  if (ssl_err == SSL_ERROR_WANT_READ) conn->flags |= NSF_WANT_READ;
+  if (ssl_err == SSL_ERROR_WANT_WRITE) conn->flags |= NSF_WANT_WRITE;
+  return ssl_err;
+}
+#endif
+
+static void ns_read_from_socket(struct ns_connection *conn) {
+  char buf[2048];
+  int n = 0;
+
+  if (conn->flags & NSF_CONNECTING) {
+    int ok = 1, ret;
+    socklen_t len = sizeof(ok);
+
+    ret = getsockopt(conn->sock, SOL_SOCKET, SO_ERROR, (char *) &ok, &len);
+    (void) ret;
+#ifdef NS_ENABLE_SSL
+    if (ret == 0 && ok == 0 && conn->ssl != NULL) {
+      int res = SSL_connect(conn->ssl);
+      int ssl_err = ns_ssl_err(conn, res);
+      if (res == 1) {
+        conn->flags |= NSF_SSL_HANDSHAKE_DONE;
+      } else if (ssl_err == SSL_ERROR_WANT_READ ||
+                 ssl_err == SSL_ERROR_WANT_WRITE) {
+        return; // Call us again
+      } else {
+        ok = 1;
+      }
+    }
+#endif
+    conn->flags &= ~NSF_CONNECTING;
+    DBG(("%p ok=%d", conn, ok));
+    if (ok != 0) {
+      conn->flags |= NSF_CLOSE_IMMEDIATELY;
+    }
+    ns_call(conn, NS_CONNECT, &ok);
+    return;
+  }
+
+#ifdef NS_ENABLE_SSL
+  if (conn->ssl != NULL) {
+    if (conn->flags & NSF_SSL_HANDSHAKE_DONE) {
+      // SSL library may have more bytes ready to read then we ask to read.
+      // Therefore, read in a loop until we read everything. Without the loop,
+      // we skip to the next select() cycle which can just timeout.
+      while ((n = SSL_read(conn->ssl, buf, sizeof(buf))) > 0) {
+        DBG(("%p %d <- %d bytes (SSL)", conn, conn->flags, n));
+        iobuf_append(&conn->recv_iobuf, buf, n);
+        ns_call(conn, NS_RECV, &n);
+      }
+      ns_ssl_err(conn, n);
+    } else {
+      int res = SSL_accept(conn->ssl);
+      int ssl_err = ns_ssl_err(conn, res);
+      if (res == 1) {
+        conn->flags |= NSF_SSL_HANDSHAKE_DONE;
+      } else if (ssl_err == SSL_ERROR_WANT_READ ||
+                 ssl_err == SSL_ERROR_WANT_WRITE) {
+        return; // Call us again
+      } else {
+        conn->flags |= NSF_CLOSE_IMMEDIATELY;
+      }
+      return;
+    }
+  } else
+#endif
+  {
+    while ((n = (int) recv(conn->sock, buf, sizeof(buf), 0)) > 0) {
+      DBG(("%p %d <- %d bytes (PLAIN)", conn, conn->flags, n));
+      iobuf_append(&conn->recv_iobuf, buf, n);
+      ns_call(conn, NS_RECV, &n);
+    }
+  }
+
+  if (ns_is_error(n)) {
+    conn->flags |= NSF_CLOSE_IMMEDIATELY;
+  }
+}
+
+static void ns_write_to_socket(struct ns_connection *conn) {
+  struct iobuf *io = &conn->send_iobuf;
+  int n = 0;
+
+#ifdef NS_ENABLE_SSL
+  if (conn->ssl != NULL) {
+    n = SSL_write(conn->ssl, io->buf, io->len);
+    if (n <= 0) {
+      int ssl_err = ns_ssl_err(conn, n);
+      if (ssl_err == SSL_ERROR_WANT_READ || ssl_err == SSL_ERROR_WANT_WRITE) {
+        return; // Call us again
+      } else {
+        conn->flags |= NSF_CLOSE_IMMEDIATELY;
+      }
+    }
+  } else
+#endif
+  { n = (int) send(conn->sock, io->buf, io->len, 0); }
+
+  DBG(("%p %d -> %d bytes", conn, conn->flags, n));
+
+  ns_call(conn, NS_SEND, &n);
+  if (ns_is_error(n)) {
+    conn->flags |= NSF_CLOSE_IMMEDIATELY;
+  } else if (n > 0) {
+    iobuf_remove(io, n);
+  }
+}
+
+int ns_send(struct ns_connection *conn, const void *buf, int len) {
+  return (int) ns_out(conn, buf, len);
+}
+
+static void ns_handle_udp(struct ns_connection *ls) {
+  struct ns_connection nc;
+  char buf[NS_UDP_RECEIVE_BUFFER_SIZE];
+  int n;
+  socklen_t s_len = sizeof(nc.sa);
+
+  memset(&nc, 0, sizeof(nc));
+  n = recvfrom(ls->sock, buf, sizeof(buf), 0, &nc.sa.sa, &s_len);
+  if (n <= 0) {
+    DBG(("%p recvfrom: %s", ls, strerror(errno)));
+  } else {
+    nc.recv_iobuf.buf = buf;
+    nc.recv_iobuf.len = nc.recv_iobuf.size = n;
+    nc.sock = ls->sock;
+    nc.mgr = ls->mgr;
+    DBG(("%p %d bytes received", ls, n));
+    ns_call(&nc, NS_RECV, &n);
+  }
+}
+
+static void ns_add_to_set(sock_t sock, fd_set *set, sock_t *max_fd) {
+  if (sock != INVALID_SOCKET) {
+    FD_SET(sock, set);
+    if (*max_fd == INVALID_SOCKET || sock > *max_fd) {
+      *max_fd = sock;
+    }
+  }
+}
+
+int ns_mgr_poll(struct ns_mgr *mgr, int milli) {
+  struct ns_connection *conn, *tmp_conn;
+  struct timeval tv;
+  fd_set read_set, write_set;
+  int num_active_connections = 0;
+  sock_t max_fd = INVALID_SOCKET;
+  time_t current_time = time(NULL);
+
+  FD_ZERO(&read_set);
+  FD_ZERO(&write_set);
+  ns_add_to_set(mgr->ctl[1], &read_set, &max_fd);
+
+  for (conn = mgr->active_connections; conn != NULL; conn = tmp_conn) {
+    tmp_conn = conn->next;
+    ns_call(conn, NS_POLL, &current_time);
+    if (!(conn->flags & NSF_WANT_WRITE)) {
+      //DBG(("%p read_set", conn));
+      ns_add_to_set(conn->sock, &read_set, &max_fd);
+    }
+    if (((conn->flags & NSF_CONNECTING) && !(conn->flags & NSF_WANT_READ)) ||
+        (conn->send_iobuf.len > 0 && !(conn->flags & NSF_CONNECTING) &&
+         !(conn->flags & NSF_BUFFER_BUT_DONT_SEND))) {
+      //DBG(("%p write_set", conn));
+      ns_add_to_set(conn->sock, &write_set, &max_fd);
+    }
+    if (conn->flags & NSF_CLOSE_IMMEDIATELY) {
+      ns_close_conn(conn);
+    }
+  }
+
+  tv.tv_sec = milli / 1000;
+  tv.tv_usec = (milli % 1000) * 1000;
+
+  if (select((int) max_fd + 1, &read_set, &write_set, NULL, &tv) > 0) {
+    // select() might have been waiting for a long time, reset current_time
+    // now to prevent last_io_time being set to the past.
+    current_time = time(NULL);
+
+    // Read wakeup messages
+    if (mgr->ctl[1] != INVALID_SOCKET &&
+        FD_ISSET(mgr->ctl[1], &read_set)) {
+      struct ctl_msg ctl_msg;
+      int len = (int) recv(mgr->ctl[1], (char *) &ctl_msg, sizeof(ctl_msg), 0);
+      send(mgr->ctl[1], ctl_msg.message, 1, 0);
+      if (len >= (int) sizeof(ctl_msg.callback) && ctl_msg.callback != NULL) {
+        struct ns_connection *c;
+        for (c = ns_next(mgr, NULL); c != NULL; c = ns_next(mgr, c)) {
+          ctl_msg.callback(c, NS_POLL, ctl_msg.message);
+        }
+      }
+    }
+
+    for (conn = mgr->active_connections; conn != NULL; conn = tmp_conn) {
+      tmp_conn = conn->next;
+      if (FD_ISSET(conn->sock, &read_set)) {
+        if (conn->flags & NSF_LISTENING) {
+          if (conn->flags & NSF_UDP) {
+            ns_handle_udp(conn);
+          } else {
+            // We're not looping here, and accepting just one connection at
+            // a time. The reason is that eCos does not respect non-blocking
+            // flag on a listening socket and hangs in a loop.
+            accept_conn(conn);
+          }
+        } else {
+          conn->last_io_time = current_time;
+          ns_read_from_socket(conn);
+        }
+      }
+
+      if (FD_ISSET(conn->sock, &write_set)) {
+        if (conn->flags & NSF_CONNECTING) {
+          ns_read_from_socket(conn);
+        } else if (!(conn->flags & NSF_BUFFER_BUT_DONT_SEND)) {
+          conn->last_io_time = current_time;
+          ns_write_to_socket(conn);
+        }
+      }
+    }
+  }
+
+  for (conn = mgr->active_connections; conn != NULL; conn = tmp_conn) {
+    tmp_conn = conn->next;
+    num_active_connections++;
+    if ((conn->flags & NSF_CLOSE_IMMEDIATELY) ||
+        (conn->send_iobuf.len == 0 &&
+          (conn->flags & NSF_FINISHED_SENDING_DATA))) {
+      ns_close_conn(conn);
+    }
+  }
+  //DBG(("%d active connections", num_active_connections));
+
+  return num_active_connections;
+}
+
+struct ns_connection *ns_connect(struct ns_mgr *mgr,
+                                 const char *address, void *param) {
+  sock_t sock = INVALID_SOCKET;
+  struct ns_connection *nc = NULL;
+  union socket_address sa;
+  char cert[100], ca_cert[100];
+  int connect_ret_val, use_ssl, proto;
+
+  ns_parse_address(address, &sa, &proto, &use_ssl, cert, ca_cert);
+  if ((sock = socket(AF_INET, proto, 0)) == INVALID_SOCKET) {
+    return NULL;
+  }
+  ns_set_non_blocking_mode(sock);
+  connect_ret_val = connect(sock, &sa.sa, sizeof(sa.sin));
+
+  if (connect_ret_val != 0 && ns_is_error(connect_ret_val)) {
+    closesocket(sock);
+    return NULL;
+  } else if ((nc = ns_add_sock(mgr, sock, param)) == NULL) {
+    closesocket(sock);
+    return NULL;
+  }
+
+  nc->sa = sa;   // Essential, cause UDP conns will use sendto()
+  if (proto == SOCK_DGRAM) {
+    nc->flags = NSF_UDP;
+  } else {
+    nc->flags = NSF_CONNECTING;
+  }
+
+#ifdef NS_ENABLE_SSL
+  if (use_ssl) {
+    if ((nc->ssl_ctx = SSL_CTX_new(SSLv23_client_method())) == NULL ||
+        ns_use_cert(nc->ssl_ctx, cert) != 0 ||
+        ns_use_ca_cert(nc->ssl_ctx, ca_cert) != 0 ||
+        (nc->ssl = SSL_new(nc->ssl_ctx)) == NULL) {
+      ns_close_conn(nc);
+      return NULL;
+    } else {
+      SSL_set_fd(nc->ssl, sock);
+    }
+  }
+#endif
+
+  return nc;
+}
+
+struct ns_connection *ns_add_sock(struct ns_mgr *s, sock_t sock, void *p) {
+  struct ns_connection *conn;
+  if ((conn = (struct ns_connection *) NS_MALLOC(sizeof(*conn))) != NULL) {
+    memset(conn, 0, sizeof(*conn));
+    ns_set_non_blocking_mode(sock);
+    ns_set_close_on_exec(sock);
+    conn->sock = sock;
+    conn->connection_data = p;
+    conn->mgr = s;
+    conn->last_io_time = time(NULL);
+    ns_add_conn(s, conn);
+    DBG(("%p %d", conn, sock));
+  }
+  return conn;
+}
+
+struct ns_connection *ns_next(struct ns_mgr *s, struct ns_connection *conn) {
+  return conn == NULL ? s->active_connections : conn->next;
+}
+
+void ns_broadcast(struct ns_mgr *mgr, ns_callback_t cb,void *data, size_t len) {
+  struct ctl_msg ctl_msg;
+  if (mgr->ctl[0] != INVALID_SOCKET && data != NULL &&
+      len < sizeof(ctl_msg.message)) {
+    ctl_msg.callback = cb;
+    memcpy(ctl_msg.message, data, len);
+    send(mgr->ctl[0], (char *) &ctl_msg,
+         offsetof(struct ctl_msg, message) + len, 0);
+    recv(mgr->ctl[0], (char *) &len, 1, 0);
+  }
+}
+
+void ns_mgr_init(struct ns_mgr *s, void *user_data, ns_callback_t cb) {
+  memset(s, 0, sizeof(*s));
+  s->ctl[0] = s->ctl[1] = INVALID_SOCKET;
+  s->user_data = user_data;
+  s->callback = cb;
+
+#ifdef _WIN32
+  { WSADATA data; WSAStartup(MAKEWORD(2, 2), &data); }
+#else
+  // Ignore SIGPIPE signal, so if client cancels the request, it
+  // won't kill the whole process.
+  signal(SIGPIPE, SIG_IGN);
+#endif
+
+#ifndef NS_DISABLE_SOCKETPAIR
+  do {
+    ns_socketpair2(s->ctl, SOCK_DGRAM);
+  } while (s->ctl[0] == INVALID_SOCKET);
+#endif
+
+#ifdef NS_ENABLE_SSL
+  {static int init_done; if (!init_done) { SSL_library_init(); init_done++; }}
+#endif
+}
+
+void ns_mgr_free(struct ns_mgr *s) {
+  struct ns_connection *conn, *tmp_conn;
+
+  DBG(("%p", s));
+  if (s == NULL) return;
+  // Do one last poll, see https://github.com/cesanta/mongoose/issues/286
+  ns_mgr_poll(s, 0);
+
+  if (s->ctl[0] != INVALID_SOCKET) closesocket(s->ctl[0]);
+  if (s->ctl[1] != INVALID_SOCKET) closesocket(s->ctl[1]);
+  s->ctl[0] = s->ctl[1] = INVALID_SOCKET;
+
+  for (conn = s->active_connections; conn != NULL; conn = tmp_conn) {
+    tmp_conn = conn->next;
+    ns_close_conn(conn);
+  }
+}

examples/ws_ssl/net_skeleton.h

+// Copyright (c) 2014 Cesanta Software Limited
+// All rights reserved
+//
+// This software is dual-licensed: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation. For the terms of this
+// license, see <http://www.gnu.org/licenses/>.
+//
+// You are free to use this software under the terms of the GNU General
+// Public License, but WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// Alternatively, you can license this software under a commercial
+// license, as set out in <http://cesanta.com/>.
+//
+// $Date: 2014-09-09 16:03:50 UTC $
+
+#ifndef NS_SKELETON_HEADER_INCLUDED
+#define NS_SKELETON_HEADER_INCLUDED
+
+#define NS_SKELETON_VERSION "2.0.0"
+
+#undef UNICODE                  // Use ANSI WinAPI functions
+#undef _UNICODE                 // Use multibyte encoding on Windows
+#define _MBCS                   // Use multibyte encoding on Windows
+#define _INTEGRAL_MAX_BITS 64   // Enable _stati64() on Windows
+#define _CRT_SECURE_NO_WARNINGS // Disable deprecation warning in VS2005+
+#undef WIN32_LEAN_AND_MEAN      // Let windows.h always include winsock2.h
+#define _XOPEN_SOURCE 600       // For flockfile() on Linux
+#define __STDC_FORMAT_MACROS    // <inttypes.h> wants this for C++
+#define __STDC_LIMIT_MACROS     // C++ wants that for INT64_MAX
+#ifndef _LARGEFILE_SOURCE
+#define _LARGEFILE_SOURCE       // Enable fseeko() and ftello() functions
+#endif
+#define _FILE_OFFSET_BITS 64    // Enable 64-bit file offsets
+
+#ifdef _MSC_VER
+#pragma warning (disable : 4127)  // FD_SET() emits warning, disable it
+#pragma warning (disable : 4204)  // missing c99 support
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <signal.h>
+
+#ifdef _WIN32
+#ifdef _MSC_VER
+#pragma comment(lib, "ws2_32.lib")    // Linking with winsock library
+#endif
+#include <windows.h>
+#include <process.h>
+#ifndef EINPROGRESS
+#define EINPROGRESS WSAEINPROGRESS
+#endif
+#ifndef EWOULDBLOCK
+#define EWOULDBLOCK WSAEWOULDBLOCK
+#endif
+#ifndef __func__
+#define STRX(x) #x
+#define STR(x) STRX(x)
+#define __func__ __FILE__ ":" STR(__LINE__)
+#endif
+#ifndef va_copy
+#define va_copy(x,y) x = y
+#endif // MINGW #defines va_copy
+#define snprintf _snprintf
+#define vsnprintf _vsnprintf
+#define sleep(x) Sleep((x) * 1000)
+#define to64(x) _atoi64(x)
+typedef int socklen_t;
+typedef unsigned char uint8_t;
+typedef unsigned int uint32_t;
+typedef unsigned short uint16_t;
+typedef unsigned __int64 uint64_t;
+typedef __int64   int64_t;
+typedef SOCKET sock_t;
+#ifndef S_ISDIR
+#define S_ISDIR(x) ((x) & _S_IFDIR)
+#endif
+#else
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <pthread.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <arpa/inet.h>  // For inet_pton() when NS_ENABLE_IPV6 is defined
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#define closesocket(x) close(x)
+#define __cdecl
+#define INVALID_SOCKET (-1)
+#define to64(x) strtoll(x, NULL, 10)
+typedef int sock_t;
+#endif
+
+#ifdef NS_ENABLE_DEBUG
+#define DBG(x) do { printf("%-20s ", __func__); printf x; putchar('\n'); \
+  fflush(stdout); } while(0)
+#else
+#define DBG(x)
+#endif
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
+#endif
+
+#ifdef NS_ENABLE_SSL
+#ifdef __APPLE__
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
+#include <openssl/ssl.h>
+#else
+typedef void *SSL;
+typedef void *SSL_CTX;
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+union socket_address {
+  struct sockaddr sa;
+  struct sockaddr_in sin;
+#ifdef NS_ENABLE_IPV6
+  struct sockaddr_in6 sin6;
+#else
+  struct sockaddr sin6;
+#endif
+};
+
+// IO buffers interface
+struct iobuf {
+  char *buf;
+  size_t len;
+  size_t size;
+};
+
+void iobuf_init(struct iobuf *, size_t initial_size);
+void iobuf_free(struct iobuf *);
+size_t iobuf_append(struct iobuf *, const void *data, size_t data_size);
+void iobuf_remove(struct iobuf *, size_t data_size);
+
+// Net skeleton interface
+// Events. Meaning of event parameter (evp) is given in the comment.
+enum ns_event {
+  NS_POLL,     // Sent to each connection on each call to ns_mgr_poll()
+  NS_ACCEPT,   // New connection accept()-ed. union socket_address *remote_addr
+  NS_CONNECT,  // connect() succeeded or failed. int *success_status
+  NS_RECV,     // Data has benn received. int *num_bytes
+  NS_SEND,     // Data has been written to a socket. int *num_bytes
+  NS_CLOSE     // Connection is closed. NULL
+};
+
+// Callback function (event handler) prototype, must be defined by user.
+// Net skeleton will call event handler, passing events defined above.
+struct ns_connection;
+typedef void (*ns_callback_t)(struct ns_connection *, enum ns_event, void *evp);
+
+struct ns_mgr {
+  struct ns_connection *active_connections;
+  ns_callback_t callback;           // Event handler function
+  const char *hexdump_file;         // Debug hexdump file path
+  sock_t ctl[2];                    // Socketpair for mg_wakeup()
+  void *user_data;                  // User data
+};
+
+struct ns_connection {
+  struct ns_connection *next, *prev;  // ns_mgr::active_connections linkage
+  struct ns_connection *listener;     // Set only for accept()-ed connections
+  struct ns_mgr *mgr;
+  sock_t sock;
+  union socket_address sa;
+  struct iobuf recv_iobuf;
+  struct iobuf send_iobuf;
+  SSL *ssl;
+  SSL_CTX *ssl_ctx;
+  void *connection_data;
+  time_t last_io_time;
+
+  unsigned int flags;
+#define NSF_FINISHED_SENDING_DATA   (1 << 0)
+#define NSF_BUFFER_BUT_DONT_SEND    (1 << 1)
+#define NSF_SSL_HANDSHAKE_DONE      (1 << 2)
+#define NSF_CONNECTING              (1 << 3)
+#define NSF_CLOSE_IMMEDIATELY       (1 << 4)
+#define NSF_WANT_READ               (1 << 5)
+#define NSF_WANT_WRITE              (1 << 6)
+#define NSF_LISTENING               (1 << 7)
+#define NSF_UDP                     (1 << 8)
+
+#define NSF_USER_1                  (1 << 20)
+#define NSF_USER_2                  (1 << 21)
+#define NSF_USER_3                  (1 << 22)
+#define NSF_USER_4                  (1 << 23)
+#define NSF_USER_5                  (1 << 24)
+#define NSF_USER_6                  (1 << 25)
+};
+
+void ns_mgr_init(struct ns_mgr *, void *data, ns_callback_t);
+void ns_mgr_free(struct ns_mgr *);
+int ns_mgr_poll(struct ns_mgr *, int milli);
+void ns_broadcast(struct ns_mgr *, ns_callback_t, void *, size_t);
+
+struct ns_connection *ns_next(struct ns_mgr *, struct ns_connection *);
+struct ns_connection *ns_add_sock(struct ns_mgr *, sock_t sock, void *p);
+struct ns_connection *ns_bind(struct ns_mgr *, const char *addr, void *p);
+struct ns_connection *ns_connect(struct ns_mgr *, const char *addr, void *p);
+
+int ns_send(struct ns_connection *, const void *buf, int len);
+int ns_printf(struct ns_connection *, const char *fmt, ...);
+int ns_vprintf(struct ns_connection *, const char *fmt, va_list ap);
+
+// Utility functions
+void *ns_start_thread(void *(*f)(void *), void *p);
+int ns_socketpair(sock_t [2]);
+int ns_socketpair2(sock_t [2], int sock_type);  // SOCK_STREAM or SOCK_DGRAM
+void ns_set_close_on_exec(sock_t);
+void ns_sock_to_str(sock_t sock, char *buf, size_t len, int flags);
+int ns_hexdump(const void *buf, int len, char *dst, int dst_len);
+int ns_avprintf(char **buf, size_t size, const char *fmt, va_list ap);
+int ns_resolve(const char *domain_name, char *ip_addr_buf, size_t buf_len);
+
+#ifdef __cplusplus
+}
+#endif // __cplusplus
+
+#endif // NS_SKELETON_HEADER_INCLUDED

examples/ws_ssl/ssl_wrapper.c

+// Copyright (c) 2014 Cesanta Software Limited
+// All rights reserved
+//
+// This software is dual-licensed: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation. For the terms of this
+// license, see <http://www.gnu.org/licenses/>.
+//
+// You are free to use this software under the terms of the GNU General
+// Public License, but WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// Alternatively, you can license this software under a commercial
+// license, as set out in <http://cesanta.com/products.html>.
+//
+// $Date: 2014-09-09 16:03:50 UTC $
+
+#include "net_skeleton.h"
+#include "ssl_wrapper.h"
+
+static void ev_handler(struct ns_connection *nc, enum ns_event ev, void *p) {
+  const char *target_addr = (const char *) nc->mgr->user_data;
+  struct ns_connection *pc = (struct ns_connection *) nc->connection_data;
+  struct iobuf *io = &nc->recv_iobuf;
+
+  (void) p;
+  switch (ev) {
+    case NS_ACCEPT:
+      // Create a connection to the target, and interlink both connections
+      nc->connection_data = ns_connect(nc->mgr, target_addr, nc);
+      if (nc->connection_data == NULL) {
+        nc->flags |= NSF_CLOSE_IMMEDIATELY;
+      }
+      break;
+
+    case NS_CLOSE:
+      // If either connection closes, unlink them and shedule closing
+      if (pc != NULL) {
+        pc->flags |= NSF_FINISHED_SENDING_DATA;
+        pc->connection_data = NULL;
+      }
+      nc->connection_data = NULL;
+      break;
+
+    case NS_RECV:
+      // Forward arrived data to the other connection, and discard from buffer
+      if (pc != NULL) {
+        ns_send(pc, io->buf, io->len);
+        iobuf_remove(io, io->len);
+      }
+      break;
+
+    default:
+      break;
+  }
+}
+
+void *ssl_wrapper_init(const char *local_addr, const char *target_addr,
+                       const char **err_msg) {
+  struct ns_mgr *mgr = (struct ns_mgr *) calloc(1, sizeof(mgr[0]));
+  *err_msg = NULL;
+
+  if (mgr == NULL) {
+    *err_msg = "malloc failed";
+  } else {
+    ns_mgr_init(mgr, (void *) target_addr, ev_handler);
+    if (ns_bind(mgr, local_addr, NULL) == NULL) {
+      *err_msg = "ns_bind() failed: bad listening_port";
+      ns_mgr_free(mgr);
+      free(mgr);
+      mgr = NULL;
+    }
+  }
+
+  return mgr;
+}
+
+void ssl_wrapper_serve(void *param, volatile int *quit) {
+  struct ns_mgr *mgr = (struct ns_mgr *) param;
+
+  while (*quit == 0) {
+    ns_mgr_poll(mgr, 1000);
+  }
+  ns_mgr_free(mgr);
+  free(mgr);
+}
+
+#ifndef SSL_WRAPPER_USE_AS_LIBRARY
+static int s_received_signal = 0;
+
+static void signal_handler(int sig_num) {
+  signal(sig_num, signal_handler);
+  s_received_signal = sig_num;
+}
+
+static void show_usage_and_exit(const char *prog) {
+  fprintf(stderr, "Usage: %s <listening_address> <target_address>\n", prog);
+  exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[]) {
+  void *wrapper;
+  const char *err_msg;
+
+  if (argc != 3) {
+    show_usage_and_exit(argv[0]);
+  }
+
+  // Setup signal handlers
+  signal(SIGTERM, signal_handler);
+  signal(SIGINT, signal_handler);
+  signal(SIGPIPE, SIG_IGN);
+
+  if ((wrapper = ssl_wrapper_init(argv[1], argv[2], &err_msg)) == NULL) {
+    fprintf(stderr, "Error: %s\n", err_msg);
+    exit(EXIT_FAILURE);
+  }
+  ssl_wrapper_serve(wrapper, &s_received_signal);
+
+  return EXIT_SUCCESS;
+}
+#endif // SSL_WRAPPER_USE_AS_LIBRARY

examples/ws_ssl/ssl_wrapper.h

+// Copyright (c) 2014 Cesanta Software Limited
+// All rights reserved
+//
+// This software is dual-licensed: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation. For the terms of this
+// license, see <http://www.gnu.org/licenses/>.
+//
+// You are free to use this software under the terms of the GNU General
+// Public License, but WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// Alternatively, you can license this software under a commercial
+// license, as set out in <http://cesanta.com/products.html>.
+//
+// $Date: 2014-09-09 16:03:50 UTC $
+
+#ifndef SSL_WRAPPER_HEADER_INCLUDED
+#define SSL_WRAPPER_HEADER_INCLUDED
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+void *ssl_wrapper_init(const char *listen_addr, const char *target_addr,
+                       const char **err_msg);
+void ssl_wrapper_serve(void *, volatile int *stop_marker);
+
+#ifdef __cplusplus
+}
+#endif // __cplusplus
+
+#endif // SSL_WRAPPER_HEADER_INCLUDED