1 files changed, 187 insertions, 0 deletions
diff --git a/nsock/src/nsock_engines.c b/nsock/src/nsock_engines.c
new file mode 100644
index 0000000..de9d44e
--- /dev/null
+++ b/nsock/src/nsock_engines.c
@@ -0,0 +1,187 @@
+/***************************************************************************
+ * nsock_engines.c -- This contains the functions and definitions to       *
+ * manage the list of available IO engines.  Each IO engine leverages a    *
+ * specific IO notification function to wait for events.  Nsock will try   *
+ * to use the most efficient engine for your system.                       *
+ *                                                                         *
+ ***********************IMPORTANT NSOCK LICENSE TERMS***********************
+ *
+ * The nsock parallel socket event library is (C) 1999-2023 Nmap Software LLC
+ * This library is free software; you may redistribute and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; Version 2. This guarantees your right to use, modify, and
+ * redistribute this software under certain conditions. If this license is
+ * unacceptable to you, Nmap Software LLC may be willing to sell alternative
+ * licenses (contact sales@nmap.com ).
+ *
+ * As a special exception to the GPL terms, Nmap Software LLC grants permission
+ * to link the code of this program with any version of the OpenSSL library
+ * which is distributed under a license identical to that listed in the included
+ * docs/licenses/OpenSSL.txt file, and distribute linked combinations including
+ * the two. You must obey the GNU GPL in all respects for all of the code used
+ * other than OpenSSL. If you modify this file, you may extend this exception to
+ * your version of the file, but you are not obligated to do so.
+ *
+ * If you received these files with a written license agreement stating terms
+ * other than the (GPL) terms above, then that alternative license agreement
+ * takes precedence over this comment.
+ *
+ * Source is provided to this software because we believe users have a right to
+ * know exactly what a program is going to do before they run it. This also
+ * allows you to audit the software for security holes.
+ *
+ * Source code also allows you to port Nmap to new platforms, fix bugs, and add
+ * new features. You are highly encouraged to send your changes to the
+ * dev@nmap.org mailing list for possible incorporation into the main
+ * distribution. By sending these changes to Fyodor or one of the Insecure.Org
+ * development mailing lists, or checking them into the Nmap source code
+ * repository, it is understood (unless you specify otherwise) that you are
+ * offering the Nmap Project (Nmap Software LLC) the unlimited, non-exclusive
+ * right to reuse, modify, and relicense the code. Nmap will always be available
+ * Open Source, but this is important because the inability to relicense code
+ * has caused devastating problems for other Free Software projects (such as KDE
+ * and NASM). We also occasionally relicense the code to third parties as
+ * discussed above. If you wish to specify special license conditions of your
+ * contributions, just say so when you send them.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License v2.0 for more
+ * details (http://www.gnu.org/licenses/gpl-2.0.html).
+ *
+ ***************************************************************************/
+
+/* $Id$ */
+
+#ifdef HAVE_CONFIG_H
+#include "nsock_config.h"
+#endif
+
+#include "nsock_internal.h"
+
+#if HAVE_IOCP
+  extern struct io_engine engine_iocp;
+  #define ENGINE_IOCP &engine_iocp,
+#else
+  #define ENGINE_IOCP
+#endif /* HAVE_IOCP */
+
+#if HAVE_EPOLL
+  extern struct io_engine engine_epoll;
+  #define ENGINE_EPOLL &engine_epoll,
+#else
+  #define ENGINE_EPOLL
+#endif /* HAVE_EPOLL */
+
+#if HAVE_KQUEUE
+  extern struct io_engine engine_kqueue;
+  #define ENGINE_KQUEUE &engine_kqueue,
+#else
+  #define ENGINE_KQUEUE
+#endif /* HAVE_KQUEUE */
+
+#if HAVE_POLL
+  extern struct io_engine engine_poll;
+  #define ENGINE_POLL &engine_poll,
+#else
+  #define ENGINE_POLL
+#endif /* HAVE_POLL */
+
+/* select() based engine is the fallback engine, we assume it's always available */
+extern struct io_engine engine_select;
+#define ENGINE_SELECT &engine_select,
+
+/* Available IO engines. This depends on which IO management interfaces are
+ * available on your system. Engines must be sorted by order of preference */
+static struct io_engine *available_engines[] = {
+  ENGINE_EPOLL
+  ENGINE_KQUEUE
+  ENGINE_POLL
+  ENGINE_IOCP
+  ENGINE_SELECT
+  NULL
+};
+
+static char *engine_hint;
+
+int posix_iod_connect(struct npool *nsp, int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
+  return connect(sockfd, addr, addrlen);
+}
+
+int posix_iod_read(struct npool *nsp, int sockfd, void *buf, size_t len, int flags, struct sockaddr *src_addr, socklen_t *addrlen) {
+  return recvfrom(sockfd, (char *)buf, len, flags, src_addr, addrlen);
+}
+
+int posix_iod_write(struct npool *nsp, int sockfd, const void *buf, size_t len, int flags, const struct sockaddr *dest_addr, socklen_t addrlen) {
+  struct sockaddr_storage *dest = (struct sockaddr_storage *)dest_addr;
+  if (dest->ss_family == AF_UNSPEC)
+    return send(sockfd, (char *)buf, len, flags);
+  else
+    return sendto(sockfd, (char *)buf, len, flags, dest_addr, addrlen);
+}
+
+struct io_operations posix_io_operations = {
+  posix_iod_connect,
+  posix_iod_read,
+  posix_iod_write
+};
+
+struct io_engine *get_io_engine(void) {
+  struct io_engine *engine = NULL;
+  int i;
+
+  if (!engine_hint) {
+    engine = available_engines[0];
+  } else {
+    for (i = 0; available_engines[i] != NULL; i++)
+      if (strcmp(engine_hint, available_engines[i]->name) == 0) {
+        engine = available_engines[i];
+        break;
+      }
+  }
+
+  if (!engine)
+    fatal("No suitable IO engine found! (%s)\n",
+          engine_hint ? engine_hint : "no hint");
+
+  return engine;
+}
+
+int nsock_set_default_engine(char *engine) {
+  if (engine_hint)
+    free(engine_hint);
+
+  if (engine) {
+    int i;
+
+    for (i = 0; available_engines[i] != NULL; i++) {
+      if (strcmp(engine, available_engines[i]->name) == 0) {
+        engine_hint = strdup(engine);
+        return 0;
+      }
+    }
+    return -1;
+  }
+  /* having engine = NULL is fine. This is actually the
+   * way to tell nsock to use the default engine again. */
+  engine_hint = NULL;
+  return 0;
+}
+
+const char *nsock_list_engines(void) {
+  return
+#if HAVE_IOCP
+  "iocp "
+#endif
+#if HAVE_EPOLL
+  "epoll "
+#endif
+#if HAVE_KQUEUE
+  "kqueue "
+#endif
+#if HAVE_POLL
+  "poll "
+#endif
+  "select";
+}
+