add support for deferring script requests, limit maximum number of script calls to 3, maximum number of connections to 100

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

7 files changed, 139 insertions, 15 deletions

diff --git a/cgi.c b/cgi.c
index 7b47e7d..c4438b0 100644
--- a/cgi.c
+++ b/cgi.c
@@ -107,6 +107,7 @@ static bool check_cgi_path(struct path_info *pi, const char *url)
 }
 
 struct dispatch_handler cgi_dispatch = {
+	.script = true,
 	.check_path = check_cgi_path,
 	.handle_request = cgi_handle_request,
 };
diff --git a/client.c b/client.c
index e1fdca4..7604d7e 100644
--- a/client.c
+++ b/client.c
@@ -73,6 +73,8 @@ static void uh_dispatch_done(struct client *cl)
 {
 	if (cl->dispatch.free)
 		cl->dispatch.free(cl);
+	if (cl->dispatch.req_free)
+		cl->dispatch.req_free(cl);
 }
 
 static void client_timeout(struct uloop_timeout *timeout)
diff --git a/file.c b/file.c
index 3ac863c..f16b893 100644
--- a/file.c
+++ b/file.c
@@ -34,6 +34,16 @@
 
 static LIST_HEAD(index_files);
 static LIST_HEAD(dispatch_handlers);
+static LIST_HEAD(pending_requests);
+static int n_requests;
+
+struct deferred_request {
+	struct list_head list;
+	struct dispatch_handler *d;
+	struct client *cl;
+	struct path_info pi;
+	bool called, path;
+};
 
 struct index_file {
 	struct list_head list;
@@ -650,6 +660,106 @@ dispatch_find(const char *url, struct path_info *pi)
 	return NULL;
 }
 
+static void
+uh_invoke_script(struct client *cl, struct dispatch_handler *d, struct path_info *pi)
+{
+	char *url = blobmsg_data(blob_data(cl->hdr.head));
+
+	n_requests++;
+	d->handle_request(cl, url, pi);
+}
+
+static void uh_complete_request(struct client *cl)
+{
+	struct deferred_request *dr;
+
+	n_requests--;
+
+	while (!list_empty(&pending_requests)) {
+		if (n_requests >= conf.max_script_requests)
+			return;
+
+		dr = list_first_entry(&pending_requests, struct deferred_request, list);
+		list_del(&dr->list);
+
+		dr->called = true;
+		uh_invoke_script(dr->cl, dr->d, dr->path ? &dr->pi : NULL);
+	}
+}
+
+
+static void
+uh_free_pending_request(struct client *cl)
+{
+	struct deferred_request *dr = cl->dispatch.req_data;
+
+	if (dr->called)
+		uh_complete_request(cl);
+	else
+		list_del(&dr->list);
+	free(dr);
+}
+
+static int field_len(const char *ptr)
+{
+	if (!ptr)
+		return 0;
+
+	return strlen(ptr) + 1;
+}
+
+#define path_info_fields \
+	_field(root) \
+	_field(phys) \
+	_field(name) \
+	_field(info) \
+	_field(query) \
+	_field(auth)
+
+static void
+uh_defer_script(struct client *cl, struct dispatch_handler *d, struct path_info *pi)
+{
+	struct deferred_request *dr;
+	char *_root, *_phys, *_name, *_info, *_query, *_auth;
+
+	cl->dispatch.req_free = uh_free_pending_request;
+
+	if (pi) {
+		/* allocate enough memory to duplicate all path_info strings in one block */
+#undef _field
+#define _field(_name) &_##_name, field_len(pi->_name),
+		dr = calloc_a(sizeof(*dr), path_info_fields NULL);
+
+		memcpy(&dr->pi, pi, sizeof(*pi));
+		dr->path = true;
+
+		/* copy all path_info strings */
+#undef _field
+#define _field(_name) if (pi->_name) dr->pi._name = strcpy(_##_name, pi->_name);
+		path_info_fields
+	} else {
+		dr = calloc(1, sizeof(*dr));
+	}
+
+	cl->dispatch.req_data = dr;
+	dr->cl = cl;
+	dr->d = d;
+	list_add(&dr->list, &pending_requests);
+}
+
+static void
+uh_invoke_handler(struct client *cl, struct dispatch_handler *d, char *url, struct path_info *pi)
+{
+	if (!d->script)
+		return d->handle_request(cl, url, pi);
+
+	if (n_requests >= conf.max_script_requests)
+		return uh_defer_script(cl, d, pi);
+
+	cl->dispatch.req_free = uh_complete_request;
+	uh_invoke_script(cl, d, pi);
+}
+
 static bool __handle_file_request(struct client *cl, char *url)
 {
 	static const struct blobmsg_policy hdr_policy[__HDR_MAX] = {
@@ -680,7 +790,7 @@ static bool __handle_file_request(struct client *cl, char *url)
 
 	d = dispatch_find(url, pi);
 	if (d)
-		d->handle_request(cl, url, pi);
+		uh_invoke_handler(cl, d, url, pi);
 	else
 		uh_file_request(cl, url, pi, tb);
 
@@ -691,15 +801,13 @@ void uh_handle_request(struct client *cl)
 {
 	struct http_request *req = &cl->request;
 	struct dispatch_handler *d;
-	char *url = blobmsg_data(blob_data(cl->hdr.head));;
+	char *url = blobmsg_data(blob_data(cl->hdr.head));
 	char *error_handler;
 
 	req->redirect_status = 200;
 	d = dispatch_find(url, NULL);
-	if (d) {
-		d->handle_request(cl, url, NULL);
-		return;
-	}
+	if (d)
+		return uh_invoke_handler(cl, d, url, NULL);
 
 	if (__handle_file_request(cl, url))
 		return;
diff --git a/listen.c b/listen.c
index 37fc4bb..adf8b16 100644
--- a/listen.c
+++ b/listen.c
@@ -56,8 +56,8 @@ static void uh_poll_listeners(struct uloop_timeout *timeout)
 {
 	struct listener *l;
 
-	if ((!n_blocked && conf.max_requests) ||
-	    n_clients >= conf.max_requests)
+	if ((!n_blocked && conf.max_connections) ||
+	    n_clients >= conf.max_connections)
 		return;
 
 	list_for_each_entry(l, &listeners, list) {
@@ -65,7 +65,7 @@ static void uh_poll_listeners(struct uloop_timeout *timeout)
 			continue;
 
 		l->fd.cb(&l->fd, ULOOP_READ);
-	    if (n_clients >= conf.max_requests)
+	    if (n_clients >= conf.max_connections)
 			break;
 
 		n_blocked--;
@@ -92,7 +92,7 @@ static void listener_cb(struct uloop_fd *fd, unsigned int events)
 			break;
 	}
 
-	if (conf.max_requests && n_clients >= conf.max_requests)
+	if (conf.max_connections && n_clients >= conf.max_connections)
 		uh_block_listener(l);
 }
 
diff --git a/lua.c b/lua.c
index 6bf5c24..c6f27e9 100644
--- a/lua.c
+++ b/lua.c
@@ -280,6 +280,7 @@ static bool check_lua_url(const char *url)
 }
 
 static struct dispatch_handler lua_dispatch = {
+	.script = true,
 	.check_url = check_lua_url,
 	.handle_request = lua_handle_request,
 };
diff --git a/main.c b/main.c
index 56cff80..31700c7 100644
--- a/main.c
+++ b/main.c
@@ -132,7 +132,8 @@ static int usage(const char *name)
 		"	-S              Do not follow symbolic links outside of the docroot\n"
 		"	-D              Do not allow directory listings, send 403 instead\n"
 		"	-R              Enable RFC1918 filter\n"
-		"	-n count        Maximum allowed number of concurrent requests\n"
+		"	-n count        Maximum allowed number of concurrent script requests\n"
+		"	-N count        Maximum allowed number of concurrent connections\n"
 #ifdef HAVE_LUA
 		"	-l string       URL prefix for Lua handler, default is '/lua'\n"
 		"	-L file         Lua handler script, omit to disable Lua\n"
@@ -159,7 +160,8 @@ static void init_defaults(void)
 	conf.script_timeout = 60;
 	conf.network_timeout = 30;
 	conf.http_keepalive = 20;
-	conf.max_requests = 3;
+	conf.max_script_requests = 3;
+	conf.max_connections = 100;
 	conf.realm = "Protected Area";
 	conf.cgi_prefix = "/cgi-bin";
 	conf.cgi_path = "/sbin:/usr/sbin:/bin:/usr/bin";
@@ -201,7 +203,7 @@ int main(int argc, char **argv)
 	init_defaults();
 	signal(SIGPIPE, SIG_IGN);
 
-	while ((ch = getopt(argc, argv, "fSDRC:K:E:I:p:s:h:c:l:L:d:r:m:n:x:i:t:k:T:A:u:U:")) != -1) {
+	while ((ch = getopt(argc, argv, "fSDRC:K:E:I:p:s:h:c:l:L:d:r:m:n:N:x:i:t:k:T:A:u:U:")) != -1) {
 		bool tls = false;
 
 		switch(ch) {
@@ -253,7 +255,11 @@ int main(int argc, char **argv)
 			break;
 
 		case 'n':
-			conf.max_requests = atoi(optarg);
+			conf.max_script_requests = atoi(optarg);
+			break;
+
+		case 'N':
+			conf.max_connections = atoi(optarg);
 			break;
 
 		case 'x':
diff --git a/uhttpd.h b/uhttpd.h
index 38f60d3..807070c 100644
--- a/uhttpd.h
+++ b/uhttpd.h
@@ -62,7 +62,8 @@ struct config {
 	int network_timeout;
 	int rfc1918_filter;
 	int tcp_keepalive;
-	int max_requests;
+	int max_script_requests;
+	int max_connections;
 	int http_keepalive;
 	int script_timeout;
 };
@@ -165,6 +166,7 @@ struct dispatch_proc {
 
 struct dispatch_handler {
 	struct list_head list;
+	bool script;
 
 	bool (*check_url)(const char *url);
 	bool (*check_path)(struct path_info *pi, const char *url);
@@ -198,6 +200,10 @@ struct dispatch {
 	void (*write_cb)(struct client *cl);
 	void (*close_fds)(struct client *cl);
 	void (*free)(struct client *cl);
+
+	void *req_data;
+	void (*req_free)(struct client *cl);
+
 	bool data_blocked;
 
 	union {