lwip: add custom TCP ISN hook implementation

Source:
https://git.savannah.nongnu.org/cgit/lwip/lwip-contrib.git/

components/lwip/port/esp32/tcp_isn/tcp_isn.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2016 The MINIX 3 Project.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: David van Moolenbroek <david@minix3.org>
+ */
+
+#ifndef LWIP_HDR_CONTRIB_ADDONS_TCP_ISN_H
+#define LWIP_HDR_CONTRIB_ADDONS_TCP_ISN_H
+
+#include "lwip/opt.h"
+#include "lwip/ip_addr.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void lwip_init_tcp_isn(u32_t boot_time, const u8_t *secret_16_bytes);
+u32_t lwip_hook_tcp_isn(const ip_addr_t *local_ip, u16_t local_port,
+                        const ip_addr_t *remote_ip, u16_t remote_port);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_HDR_CONTRIB_ADDONS_TCP_ISN_H */