Add support for already-listening sockets

Makefile

@@ -89,6 +89,9 @@ boringssl:
 examples: default
 	for f in examples/*.c; do $(CC) -O3 $(CFLAGS) -o $$(basename "$$f" ".c")$(EXEC_SUFFIX) "$$f" $(LDFLAGS); done
 
+linux_examples: 
+	for f in examples/linux/*.c; do $(CC) -O3 $(CFLAGS) -o $$(basename "$$f" ".c")$(EXEC_SUFFIX) "$$f" $(LDFLAGS); done
+
 swift_examples:
 	swiftc -O -I . examples/swift_http_server/main.swift uSockets.a -o swift_http_server
 

examples/linux/netns_server.c

@@ -0,0 +1,178 @@
+/* This is a more advanced version of the HTTP server test which
+ * runs the server within a Linux network namespace. The socket
+ * is bound and listened by the parent process, and passed to 
+ * the namespaced child process which runs the server. 
+ * 
+ * Creating network namespaces (and therefore running this test) 
+ * requires root privileges. 
+ */
+#include <libusockets.h>
+
+/* Steal internal BSD socket ops */
+#include <bsd.c>
+
+/* clone() */
+#define _GNU_SOURCE
+#include <sched.h>
+#include <sys/wait.h>
+
+/* Compiling with LIBUS_NO_SSL will ignore SSL */
+const int SSL = 1;
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct http_socket {
+	/* How far we have streamed our response */
+	int offset;
+};
+
+struct http_context {
+	/* The shared response */
+	char *response;
+	int length;
+};
+
+/* We don't need any of these */
+void on_wakeup(struct us_loop_t *loop) {
+
+}
+
+void on_pre(struct us_loop_t *loop) {
+
+}
+
+/* This is not HTTP POST, it is merely an event emitted post loop iteration */
+void on_post(struct us_loop_t *loop) {
+
+}
+
+struct us_socket_t *on_http_socket_writable(struct us_socket_t *s) {
+	struct http_socket *http_socket = (struct http_socket *) us_socket_ext(SSL, s);
+	struct http_context *http_context = (struct http_context *) us_socket_context_ext(SSL, us_socket_context(SSL, s));
+
+	/* Stream whatever is remaining of the response */
+	http_socket->offset += us_socket_write(SSL, s, http_context->response + http_socket->offset, http_context->length - http_socket->offset, 0);
+
+	return s;
+}
+
+struct us_socket_t *on_http_socket_close(struct us_socket_t *s, int code, void *reason) {
+	printf("Client disconnected\n");
+
+	return s;
+}
+
+struct us_socket_t *on_http_socket_end(struct us_socket_t *s) {
+	/* HTTP does not support half-closed sockets */
+	us_socket_shutdown(SSL, s);
+	return us_socket_close(SSL, s, 0, NULL);
+}
+
+struct us_socket_t *on_http_socket_data(struct us_socket_t *s, char *data, int length) {
+	/* Get socket extension and the socket's context's extension */
+	struct http_socket *http_socket = (struct http_socket *) us_socket_ext(SSL, s);
+	struct http_context *http_context = (struct http_context *) us_socket_context_ext(SSL, us_socket_context(SSL, s));
+
+	/* We treat all data events as a request */
+	http_socket->offset = us_socket_write(SSL, s, http_context->response, http_context->length, 0);
+
+	/* Reset idle timer */
+	us_socket_timeout(SSL, s, 30);
+
+	return s;
+}
+
+struct us_socket_t *on_http_socket_open(struct us_socket_t *s, int is_client, char *ip, int ip_length) {
+	struct http_socket *http_socket = (struct http_socket *) us_socket_ext(SSL, s);
+
+	/* Reset offset */
+	http_socket->offset = 0;
+
+	/* Timeout idle HTTP connections */
+	us_socket_timeout(SSL, s, 30);
+
+	printf("Client connected\n");
+
+	return s;
+}
+
+struct us_socket_t *on_http_socket_timeout(struct us_socket_t *s) {
+	/* Close idle HTTP sockets */
+	return us_socket_close(SSL, s, 0, NULL);
+}
+
+int server(void* arg) { 
+	LIBUS_SOCKET_DESCRIPTOR listen_fd = *(LIBUS_SOCKET_DESCRIPTOR*)arg;
+
+	/* Create the event loop */
+	struct us_loop_t *loop = us_create_loop(0, on_wakeup, on_pre, on_post, 0);
+
+	/* Create a socket context for HTTP */
+	struct us_socket_context_options_t options = {};
+	options.key_file_name = "../../misc/key.pem";
+	options.cert_file_name = "../../misc/cert.pem";
+	options.passphrase = "1234";
+
+	struct us_socket_context_t *http_context = us_create_socket_context(SSL, loop, sizeof(struct http_context), options);
+
+	if (!http_context) {
+		printf("Could not load SSL cert/key\n");
+		exit(1);
+	}
+
+	/* Generate the shared response */
+	const char body[] = "<html><body><h1>Why hello there!</h1></body></html>";
+
+	struct http_context *http_context_ext = (struct http_context *) us_socket_context_ext(SSL, http_context);
+	http_context_ext->response = (char *) malloc(128 + sizeof(body) - 1);
+	http_context_ext->length = snprintf(http_context_ext->response, 128 + sizeof(body) - 1, "HTTP/1.1 200 OK\r\nContent-Length: %ld\r\n\r\n%s", sizeof(body) - 1, body);
+
+	/* Set up event handlers */
+	us_socket_context_on_open(SSL, http_context, on_http_socket_open);
+	us_socket_context_on_data(SSL, http_context, on_http_socket_data);
+	us_socket_context_on_writable(SSL, http_context, on_http_socket_writable);
+	us_socket_context_on_close(SSL, http_context, on_http_socket_close);
+	us_socket_context_on_timeout(SSL, http_context, on_http_socket_timeout);
+	us_socket_context_on_end(SSL, http_context, on_http_socket_end);
+
+	/* Start serving HTTP connections */
+	struct us_listen_socket_t *listen_socket = us_socket_context_listen_direct(SSL, http_context, listen_fd, 0, sizeof(struct http_socket));
+
+	if (listen_socket) {
+		printf("Listening on passed socket...\n");
+		us_loop_run(loop);
+	} else {
+		printf("Failed to listen!\n");
+	}
+
+	return 0;
+}
+
+#define STACK_SIZE 8192
+static char child_stack[STACK_SIZE];
+
+int main() {
+	LIBUS_SOCKET_DESCRIPTOR listen_fd = bsd_create_listen_socket(0, 3000, 0);
+	if (!listen_fd) {
+		printf("Could not bind and listen to port: %s\n", strerror(errno));
+		exit(1);
+	}
+	printf("Listening on port 3000...\n");
+
+	int child_pid = clone(
+		server,
+		child_stack + STACK_SIZE,
+		CLONE_NEWNET | CLONE_FILES | SIGCHLD,
+		(void*)&listen_fd);
+	if (child_pid < 0) {
+		printf("Could not create namespaced server process: %s\n", strerror(errno));
+		exit(1);
+	};
+
+	printf("Started server with pid %d\n", child_pid);
+	int status;
+	waitpid(child_pid, &status, 0);
+	return status;
+}

src/context.c

@@ -258,22 +258,7 @@ struct us_listen_socket_t *us_socket_context_listen(int ssl, struct us_socket_co
         return 0;
     }
 
-    struct us_poll_t *p = us_create_poll(context->loop, 0, sizeof(struct us_listen_socket_t));
-    us_poll_init(p, listen_socket_fd, POLL_TYPE_SEMI_SOCKET);
-    us_poll_start(p, context->loop, LIBUS_SOCKET_READABLE);
-
-    struct us_listen_socket_t *ls = (struct us_listen_socket_t *) p;
-
-    ls->s.context = context;
-    ls->s.timeout = 255;
-    ls->s.long_timeout = 255;
-    ls->s.low_prio_state = 0;
-    ls->s.next = 0;
-    us_internal_socket_context_link_listen_socket(context, ls);
-
-    ls->socket_ext_size = socket_ext_size;
-
-    return ls;
+    return us_socket_context_listen_direct(ssl, context, listen_socket_fd, options, socket_ext_size); 
 }
 
 struct us_listen_socket_t *us_socket_context_listen_unix(int ssl, struct us_socket_context_t *context, const char *path, int options, int socket_ext_size) {
@@ -289,6 +274,16 @@ struct us_listen_socket_t *us_socket_context_listen_unix(int ssl, struct us_sock
         return 0;
     }
 
+    return us_socket_context_listen_direct(ssl, context, listen_socket_fd, options, socket_ext_size); 
+}
+
+struct us_listen_socket_t *us_socket_context_listen_direct(int ssl, struct us_socket_context_t *context, LIBUS_SOCKET_DESCRIPTOR listen_socket_fd, int options, int socket_ext_size) {
+#ifndef LIBUS_NO_SSL
+    if (ssl) {
+        return us_internal_ssl_socket_context_listen_direct((struct us_internal_ssl_socket_context_t *) context, listen_socket_fd, options, socket_ext_size);
+    }
+#endif
+
     struct us_poll_t *p = us_create_poll(context->loop, 0, sizeof(struct us_listen_socket_t));
     us_poll_init(p, listen_socket_fd, POLL_TYPE_SEMI_SOCKET);
     us_poll_start(p, context->loop, LIBUS_SOCKET_READABLE);
@@ -307,6 +302,7 @@ struct us_listen_socket_t *us_socket_context_listen_unix(int ssl, struct us_sock
     return ls;
 }
 
+
 struct us_socket_t *us_socket_context_connect(int ssl, struct us_socket_context_t *context, const char *host, int port, const char *source_host, int options, int socket_ext_size) {
 #ifndef LIBUS_NO_SSL
     if (ssl) {

src/crypto/openssl.c

@@ -693,6 +693,10 @@ struct us_listen_socket_t *us_internal_ssl_socket_context_listen_unix(struct us_
     return us_socket_context_listen_unix(0, &context->sc, path, options, sizeof(struct us_internal_ssl_socket_t) - sizeof(struct us_socket_t) + socket_ext_size);
 }
 
+struct us_listen_socket_t *us_internal_ssl_socket_context_listen_direct(struct us_internal_ssl_socket_context_t *context, LIBUS_SOCKET_DESCRIPTOR listen_socket_fd, int options, int socket_ext_size) {
+    return us_socket_context_listen_direct(0, &context->sc, listen_socket_fd, options, sizeof(struct us_internal_ssl_socket_t) - sizeof(struct us_socket_t) + socket_ext_size);
+}
+
 struct us_internal_ssl_socket_t *us_internal_ssl_socket_context_connect(struct us_internal_ssl_socket_context_t *context, const char *host, int port, const char *source_host, int options, int socket_ext_size) {
     return (struct us_internal_ssl_socket_t *) us_socket_context_connect(0, &context->sc, host, port, source_host, options, sizeof(struct us_internal_ssl_socket_t) - sizeof(struct us_socket_t) + socket_ext_size);
 }

src/internal/internal.h

@@ -186,6 +186,9 @@ struct us_listen_socket_t *us_internal_ssl_socket_context_listen(struct us_inter
 struct us_listen_socket_t *us_internal_ssl_socket_context_listen_unix(struct us_internal_ssl_socket_context_t *context,
     const char *path, int options, int socket_ext_size);
 
+struct us_listen_socket_t *us_internal_ssl_socket_context_listen_direct(struct us_internal_ssl_socket_context_t *context,
+    LIBUS_SOCKET_DESCRIPTOR listen_socket_fd, int options, int socket_ext_size);
+
 struct us_internal_ssl_socket_t *us_internal_ssl_socket_context_connect(struct us_internal_ssl_socket_context_t *context,
     const char *host, int port, const char *source_host, int options, int socket_ext_size);
 

src/libusockets.h

@@ -184,6 +184,9 @@ struct us_listen_socket_t *us_socket_context_listen(int ssl, struct us_socket_co
 struct us_listen_socket_t *us_socket_context_listen_unix(int ssl, struct us_socket_context_t *context,
     const char *path, int options, int socket_ext_size);
 
+struct us_listen_socket_t *us_socket_context_listen_direct(int ssl, struct us_socket_context_t *context,
+    LIBUS_SOCKET_DESCRIPTOR listen_socket_fd, int options, int socket_ext_size);
+
 /* listen_socket.c/.h */
 void us_listen_socket_close(int ssl, struct us_listen_socket_t *ls);