From 14a6540671a9a6e7f5e3c1a3b508b9f1a2429ad1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kacper=20Ko=C5=82odziej?= <kacper@kolodziej.it>
Date: Tue, 27 Aug 2019 15:43:07 +0200
Subject: [PATCH] Initial version of MPTCP module for Nginx

---
 config                  |  3 ++
 ngx_http_mptcp_module.c | 84 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 87 insertions(+)
 create mode 100644 config
 create mode 100644 ngx_http_mptcp_module.c

diff --git a/config b/config
new file mode 100644
index 0000000..608a86f
--- /dev/null
+++ b/config
@@ -0,0 +1,3 @@
+ngx_addon_name=ngx_http_mptcp_module
+HTTP_MODULES="$HTTP_MODULES ngx_http_mptcp_module"
+NGX_ADDON_SRCS="$NGX_ADDON_SRCS ${ngx_addon_dir}/ngx_http_mptcp_module.c"
diff --git a/ngx_http_mptcp_module.c b/ngx_http_mptcp_module.c
new file mode 100644
index 0000000..2be8898
--- /dev/null
+++ b/ngx_http_mptcp_module.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2019 Kacper Kołodziej <kacper@kolodziej.it> https://kacperkolodziej.pl/
+ */
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+#include <sys/socket.h>
+
+extern ngx_module_t ngx_http_mptcp_module;
+
+static ngx_int_t ngx_http_mptcp_variable(ngx_http_request_t *r,
+		ngx_http_variable_value_t *v, uintptr_t data)
+{
+	int fd, result, mptcp_enabled;
+#define MPTCP_ENABLED 42
+	socklen_t mptcp_enabled_len = sizeof(mptcp_enabled);
+
+	fd = r->connection->fd;
+	result = getsockopt(fd, SOL_TCP, MPTCP_ENABLED, &mptcp_enabled, &mptcp_enabled_len);
+	if (result == 0) {
+		if (mptcp_enabled) {
+			v->len = 2;
+			v->data = (u_char*)"on";
+			v->not_found = 0;
+			v->valid = 1;
+			v->no_cacheable = 1;
+		} else {
+			v->len = 3;
+			v->data = (u_char*)"off";
+			v->not_found = 0;
+			v->valid = 1;
+			v->no_cacheable = 1;
+		}
+	} else {
+		v->not_found = 1;
+	}
+
+	return NGX_OK;
+}
+
+static ngx_str_t ngx_http_mptcp_enabled_name = ngx_string("mptcp_enabled");
+
+static ngx_int_t ngx_http_mptcp_init(ngx_conf_t* cf) {
+	ngx_http_variable_t *var;
+	var = ngx_http_add_variable(cf, &ngx_http_mptcp_enabled_name,
+			NGX_HTTP_VAR_NOCACHEABLE);
+	if (var == NULL) {
+		return NGX_ERROR;
+	}
+
+	var->get_handler = ngx_http_mptcp_variable;
+
+	return NGX_OK;
+}
+
+static ngx_http_module_t ngx_http_mptcp_module_ctx = {
+	ngx_http_mptcp_init,			/* preconfiguration */
+	NULL,					/* postconfiguration */
+
+	NULL,					/* create main configuration */
+	NULL,					/* init main configuration */
+
+	NULL,					/* create server configuration */
+	NULL,					/* merge server configuration */
+
+	NULL,					/* create location configuration */
+	NULL 					/* merge location configuration */
+};
+
+ngx_module_t ngx_http_mptcp_module = {
+	NGX_MODULE_V1,
+	&ngx_http_mptcp_module_ctx,		/* module context */
+	NULL,					/* module directives */ 
+	NGX_HTTP_MODULE,			/* module type */
+	NULL,					/* init master */
+	NULL,					/* init module */
+	NULL,					/* init process */
+	NULL,					/* init thread */
+	NULL,					/* exit thread */
+	NULL,					/* exit process */
+	NULL,					/* exit master */
+	NGX_MODULE_V1_PADDING
+};
-- 
2.26.2