Turn stream into abstract interface class

include/stream-common.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2020 - 2023 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#pragma once
+
+#include "stream.h"
+
+#include <aml.h>
+
+static inline void stream__poll_r(struct stream* self)
+{
+	aml_set_event_mask(self->handler, AML_EVENT_READ);
+}
+
+static inline void stream__poll_w(struct stream* self)
+{
+	aml_set_event_mask(self->handler, AML_EVENT_WRITE);
+}
+
+static inline void stream__poll_rw(struct stream* self)
+{
+	aml_set_event_mask(self->handler, AML_EVENT_READ | AML_EVENT_WRITE);
+}
+
+void stream_req__finish(struct stream_req* req, enum stream_req_status status);
+void stream__remote_closed(struct stream* self);

include/stream.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020 Andri Yngvason
+ * Copyright (c) 2020 - 2023 Andri Yngvason
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -14,6 +14,8 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
+#pragma once
+
 #include "config.h"
 #include "sys/queue.h"
 #include "rcbuf.h"
@@ -33,11 +35,6 @@ enum stream_state {
 #endif
 };
 
-enum stream_status {
-	STREAM_READY = 0,
-	STREAM_CLOSED,
-};
-
 enum stream_req_status {
 	STREAM_REQ_DONE = 0,
 	STREAM_REQ_FAILED,
@@ -62,7 +59,17 @@ struct stream_req {
 
 TAILQ_HEAD(stream_send_queue, stream_req);
 
+struct stream_impl {
+	int (*close)(struct stream*);
+	void (*destroy)(struct stream*);
+	ssize_t (*read)(struct stream*, void* dst, size_t size);
+	int (*send)(struct stream*, struct rcbuf* payload,
+			stream_req_fn on_done, void* userdata);
+};
+
 struct stream {
+	struct stream_impl *impl;
+
 	enum stream_state state;
 
 	int fd;

meson.build

@@ -77,6 +77,8 @@ sources = [
 	'src/fb_pool.c',
 	'src/rcbuf.c',
 	'src/stream.c',
+	'src/stream-common.c',
+	'src/stream-tcp.c',
 	'src/desktop-layout.c',
 	'src/display.c',
 	'src/tight.c',
@@ -107,6 +109,7 @@ if libturbojpeg.found()
 endif
 
 if gnutls.found()
+	sources += 'src/stream-gnutls.c'
 	dependencies += gnutls
 	config.set('ENABLE_TLS', true)
 endif

src/stream-common.c

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2020 - 2023 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "stream.h"
+#include "stream-common.h"
+
+#include <stdlib.h>
+
+void stream_req__finish(struct stream_req* req, enum stream_req_status status)
+{
+	if (req->on_done)
+		req->on_done(req->userdata, status);
+
+	rcbuf_unref(req->payload);
+	free(req);
+}
+
+void stream__remote_closed(struct stream* self)
+{
+	stream_close(self);
+
+	if (self->on_event)
+		self->on_event(self, STREAM_EVENT_REMOTE_CLOSED);
+}

src/stream-gnutls.c

@@ -0,0 +1,271 @@
+/*
+ * Copyright (c) 2020 - 2023 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <sys/uio.h>
+#include <limits.h>
+#include <aml.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <sys/socket.h>
+
+#include <gnutls/gnutls.h>
+
+#include "rcbuf.h"
+#include "stream.h"
+#include "stream-common.h"
+#include "sys/queue.h"
+
+static int stream__try_tls_accept(struct stream* self);
+
+static int stream_gnutls_close(struct stream* self)
+{
+	if (self->state == STREAM_STATE_CLOSED)
+		return -1;
+
+	self->state = STREAM_STATE_CLOSED;
+
+	while (!TAILQ_EMPTY(&self->send_queue)) {
+		struct stream_req* req = TAILQ_FIRST(&self->send_queue);
+		TAILQ_REMOVE(&self->send_queue, req, link);
+		stream_req__finish(req, STREAM_REQ_FAILED);
+	}
+
+	if (self->tls_session)
+		gnutls_deinit(self->tls_session);
+	self->tls_session = NULL;
+
+	aml_stop(aml_get_default(), self->handler);
+	close(self->fd);
+	self->fd = -1;
+
+	return 0;
+}
+
+static void stream_gnutls_destroy(struct stream* self)
+{
+	stream_close(self);
+	aml_unref(self->handler);
+}
+
+static int stream_gnutls__flush(struct stream* self)
+{
+	while (!TAILQ_EMPTY(&self->send_queue)) {
+		struct stream_req* req = TAILQ_FIRST(&self->send_queue);
+
+		ssize_t rc = gnutls_record_send(
+			self->tls_session, req->payload->payload,
+			req->payload->size);
+		if (rc < 0) {
+			gnutls_record_discard_queued(self->tls_session);
+			if (gnutls_error_is_fatal(rc))
+				stream_close(self);
+			return -1;
+		}
+
+		self->bytes_sent += rc;
+
+		ssize_t remaining = req->payload->size - rc;
+
+		if (remaining > 0) {
+			char* p = req->payload->payload;
+			size_t s = req->payload->size;
+			memmove(p, p + s - remaining, remaining);
+			req->payload->size = remaining;
+			stream__poll_rw(self);
+			return 1;
+		}
+
+		assert(remaining == 0);
+
+		TAILQ_REMOVE(&self->send_queue, req, link);
+		stream_req__finish(req, STREAM_REQ_DONE);
+	}
+
+	if (TAILQ_EMPTY(&self->send_queue) && self->state != STREAM_STATE_CLOSED)
+		stream__poll_r(self);
+
+	return 1;
+}
+
+static void stream_gnutls__on_readable(struct stream* self)
+{
+	switch (self->state) {
+	case STREAM_STATE_NORMAL:
+		/* fallthrough */
+	case STREAM_STATE_TLS_READY:
+		if (self->on_event)
+			self->on_event(self, STREAM_EVENT_READ);
+		break;
+	case STREAM_STATE_TLS_HANDSHAKE:
+		stream__try_tls_accept(self);
+		break;
+	case STREAM_STATE_CLOSED:
+		break;
+	}
+}
+
+static void stream_gnutls__on_writable(struct stream* self)
+{
+	switch (self->state) {
+	case STREAM_STATE_NORMAL:
+		/* fallthrough */
+	case STREAM_STATE_TLS_READY:
+		stream_gnutls__flush(self);
+		break;
+	case STREAM_STATE_TLS_HANDSHAKE:
+		stream__try_tls_accept(self);
+		break;
+	case STREAM_STATE_CLOSED:
+		break;
+	}
+}
+
+static void stream_gnutls__on_event(void* obj)
+{
+	struct stream* self = aml_get_userdata(obj);
+	uint32_t events = aml_get_revents(obj);
+
+	if (events & AML_EVENT_READ)
+		stream_gnutls__on_readable(self);
+
+	if (events & AML_EVENT_WRITE)
+		stream_gnutls__on_writable(self);
+}
+
+static int stream_gnutls_send(struct stream* self, struct rcbuf* payload,
+                stream_req_fn on_done, void* userdata)
+{
+	if (self->state == STREAM_STATE_CLOSED)
+		return -1;
+
+	struct stream_req* req = calloc(1, sizeof(*req));
+	if (!req)
+		return -1;
+
+	req->payload = payload;
+	req->on_done = on_done;
+	req->userdata = userdata;
+
+	TAILQ_INSERT_TAIL(&self->send_queue, req, link);
+
+	return stream_gnutls__flush(self);
+}
+
+static ssize_t stream_gnutls_read(struct stream* self, void* dst, size_t size)
+{
+	ssize_t rc = gnutls_record_recv(self->tls_session, dst, size);
+	if (rc == 0) {
+		stream__remote_closed(self);
+		return rc;
+	}
+	if (rc > 0) {
+		self->bytes_received += rc;
+		return rc;
+	}
+
+	switch (rc) {
+	case GNUTLS_E_INTERRUPTED:
+		errno = EINTR;
+		break;
+	case GNUTLS_E_AGAIN:
+		errno = EAGAIN;
+		break;
+	default:
+		errno = 0;
+		break;
+	}
+
+	// Make sure data wasn't being written.
+	assert(gnutls_record_get_direction(self->tls_session) == 0);
+	return -1;
+}
+
+static int stream__try_tls_accept(struct stream* self)
+{
+	int rc;
+
+	rc = gnutls_handshake(self->tls_session);
+	if (rc == GNUTLS_E_SUCCESS) {
+		self->state = STREAM_STATE_TLS_READY;
+		stream__poll_r(self);
+		return 0;
+	}
+
+	if (gnutls_error_is_fatal(rc)) {
+		aml_stop(aml_get_default(), self->handler);
+		return -1;
+	}
+
+	int was_writing = gnutls_record_get_direction(self->tls_session);
+	if (was_writing)
+		stream__poll_w(self);
+	else
+		stream__poll_r(self);
+
+	self->state = STREAM_STATE_TLS_HANDSHAKE;
+	return 0;
+}
+
+static struct stream_impl impl = {
+	.close = stream_gnutls_close,
+	.destroy = stream_gnutls_destroy,
+	.read = stream_gnutls_read,
+	.send = stream_gnutls_send,
+};
+
+int stream_upgrade_to_tls(struct stream* self, void* context)
+{
+	int rc;
+
+	rc = gnutls_init(&self->tls_session, GNUTLS_SERVER | GNUTLS_NONBLOCK);
+	if (rc != GNUTLS_E_SUCCESS)
+		return -1;
+
+	rc = gnutls_set_default_priority(self->tls_session);
+	if (rc != GNUTLS_E_SUCCESS)
+		goto failure;
+
+	rc = gnutls_credentials_set(self->tls_session, GNUTLS_CRD_CERTIFICATE,
+	                            context);
+	if (rc != GNUTLS_E_SUCCESS)
+		goto failure;
+
+	aml_stop(aml_get_default(), self->handler);
+	aml_unref(self->handler);
+
+	self->handler = aml_handler_new(self->fd, stream_gnutls__on_event, self,
+			free);
+	assert(self->handler);
+
+	rc = aml_start(aml_get_default(), self->handler);
+	assert(rc >= 0);
+
+	gnutls_transport_set_int(self->tls_session, self->fd);
+
+	self->impl = &impl;
+
+	return stream__try_tls_accept(self);
+
+failure:
+	gnutls_deinit(self->tls_session);
+	return -1;
+}

src/stream-tcp.c

@@ -0,0 +1,237 @@
+/*
+ * Copyright (c) 2020 - 2023 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <sys/uio.h>
+#include <limits.h>
+#include <aml.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <sys/socket.h>
+
+#include "rcbuf.h"
+#include "stream.h"
+#include "stream-common.h"
+#include "sys/queue.h"
+
+static int stream_tcp_close(struct stream* self)
+{
+	if (self->state == STREAM_STATE_CLOSED)
+		return -1;
+
+	self->state = STREAM_STATE_CLOSED;
+
+	while (!TAILQ_EMPTY(&self->send_queue)) {
+		struct stream_req* req = TAILQ_FIRST(&self->send_queue);
+		TAILQ_REMOVE(&self->send_queue, req, link);
+		stream_req__finish(req, STREAM_REQ_FAILED);
+	}
+
+	aml_stop(aml_get_default(), self->handler);
+	close(self->fd);
+	self->fd = -1;
+
+	return 0;
+}
+
+static void stream_tcp_destroy(struct stream* self)
+{
+	stream_close(self);
+	aml_unref(self->handler);
+}
+
+static int stream_tcp__flush(struct stream* self)
+{
+	static struct iovec iov[IOV_MAX];
+	size_t n_msgs = 0;
+	ssize_t bytes_sent;
+
+	struct stream_req* req;
+	TAILQ_FOREACH(req, &self->send_queue, link) {
+		iov[n_msgs].iov_base = req->payload->payload;
+		iov[n_msgs].iov_len = req->payload->size;
+
+		if (++n_msgs >= IOV_MAX)
+			break;
+	}
+
+	if (n_msgs == 0)
+		return 0;
+
+	struct msghdr msghdr = {
+		.msg_iov = iov,
+		.msg_iovlen = n_msgs,
+	};
+	bytes_sent = sendmsg(self->fd, &msghdr, MSG_NOSIGNAL);
+	if (bytes_sent < 0) {
+		if (errno == EAGAIN || errno == EWOULDBLOCK) {
+			stream__poll_rw(self);
+			errno = EAGAIN;
+		} else if (errno == EPIPE) {
+			stream__remote_closed(self);
+			errno = EPIPE;
+		}
+
+		return bytes_sent;
+	}
+
+	self->bytes_sent += bytes_sent;
+
+	ssize_t bytes_left = bytes_sent;
+
+	struct stream_req* tmp;
+	TAILQ_FOREACH_SAFE(req, &self->send_queue, link, tmp) {
+		bytes_left -= req->payload->size;
+
+		if (bytes_left >= 0) {
+			TAILQ_REMOVE(&self->send_queue, req, link);
+			stream_req__finish(req, STREAM_REQ_DONE);
+		} else {
+			char* p = req->payload->payload;
+			size_t s = req->payload->size;
+			memmove(p, p + s + bytes_left, -bytes_left);
+			req->payload->size = -bytes_left;
+			stream__poll_rw(self);
+		}
+
+		if (bytes_left <= 0)
+			break;
+	}
+
+	if (bytes_left == 0 && self->state != STREAM_STATE_CLOSED)
+		stream__poll_r(self);
+
+	assert(bytes_left <= 0);
+
+	return bytes_sent;
+}
+
+static void stream_tcp__on_readable(struct stream* self)
+{
+	switch (self->state) {
+	case STREAM_STATE_NORMAL:
+		/* fallthrough */
+		if (self->on_event)
+			self->on_event(self, STREAM_EVENT_READ);
+		break;
+	case STREAM_STATE_CLOSED:
+		break;
+	default:;
+	}
+}
+
+static void stream_tcp__on_writable(struct stream* self)
+{
+	switch (self->state) {
+	case STREAM_STATE_NORMAL:
+		/* fallthrough */
+		stream_tcp__flush(self);
+		break;
+	case STREAM_STATE_CLOSED:
+		break;
+	default:;
+	}
+}
+
+static void stream_tcp__on_event(void* obj)
+{
+	struct stream* self = aml_get_userdata(obj);
+	uint32_t events = aml_get_revents(obj);
+
+	if (events & AML_EVENT_READ)
+		stream_tcp__on_readable(self);
+
+	if (events & AML_EVENT_WRITE)
+		stream_tcp__on_writable(self);
+}
+
+static ssize_t stream_tcp_read(struct stream* self, void* dst, size_t size)
+{
+	if (self->state != STREAM_STATE_NORMAL)
+		return -1;
+
+	ssize_t rc = read(self->fd, dst, size);
+	if (rc == 0)
+		stream__remote_closed(self);
+	if (rc > 0)
+		self->bytes_received += rc;
+	return rc;
+}
+
+static int stream_tcp_send(struct stream* self, struct rcbuf* payload,
+                stream_req_fn on_done, void* userdata)
+{
+	if (self->state == STREAM_STATE_CLOSED)
+		return -1;
+
+	struct stream_req* req = calloc(1, sizeof(*req));
+	if (!req)
+		return -1;
+
+	req->payload = payload;
+	req->on_done = on_done;
+	req->userdata = userdata;
+
+	TAILQ_INSERT_TAIL(&self->send_queue, req, link);
+
+	return stream_tcp__flush(self);
+}
+
+static struct stream_impl impl = {
+	.close = stream_tcp_close,
+	.destroy = stream_tcp_destroy,
+	.read = stream_tcp_read,
+	.send = stream_tcp_send,
+};
+
+struct stream* stream_new(int fd, stream_event_fn on_event, void* userdata)
+{
+	struct stream* self = calloc(1, sizeof(*self));
+	if (!self)
+		return NULL;
+
+	self->impl = &impl,
+	self->fd = fd;
+	self->on_event = on_event;
+	self->userdata = userdata;
+
+	TAILQ_INIT(&self->send_queue);
+
+	fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
+
+	self->handler = aml_handler_new(fd, stream_tcp__on_event, self, free);
+	if (!self->handler)
+		goto failure;
+
+	if (aml_start(aml_get_default(), self->handler) < 0)
+		goto start_failure;
+
+	stream__poll_r(self);
+
+	return self;
+
+start_failure:
+	aml_unref(self->handler);
+	self = NULL; /* Handled in unref */
+failure:
+	free(self);
+	return NULL;
+}

src/stream.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020 Andri Yngvason
+ * Copyright (c) 2023 Andri Yngvason
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -14,323 +14,27 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <assert.h>
-#include <errno.h>
-#include <sys/uio.h>
-#include <limits.h>
-#include <aml.h>
-#include <fcntl.h>
-#include <poll.h>
-#include <sys/socket.h>
-
-#ifdef ENABLE_TLS
-#include <gnutls/gnutls.h>
-#endif
-
-#include "rcbuf.h"
 #include "stream.h"
-#include "sys/queue.h"
 
-static void stream__on_event(void* obj);
+#include <assert.h>
-#ifdef ENABLE_TLS
-static int stream__try_tls_accept(struct stream* self);
-#endif
-
-static inline void stream__poll_r(struct stream* self)
-{
-	aml_set_event_mask(self->handler, AML_EVENT_READ);
-}
-
-static inline void stream__poll_w(struct stream* self)
-{
-	aml_set_event_mask(self->handler, AML_EVENT_WRITE);
-}
-
-static inline void stream__poll_rw(struct stream* self)
-{
-	aml_set_event_mask(self->handler, AML_EVENT_READ | AML_EVENT_WRITE);
-}
-
-static void stream_req__finish(struct stream_req* req,
-                               enum stream_req_status status)
-{
-	if (req->on_done)
-		req->on_done(req->userdata, status);
-
-	rcbuf_unref(req->payload);
-	free(req);
-}
 
 int stream_close(struct stream* self)
 {
-	if (self->state == STREAM_STATE_CLOSED)
+	assert(self->impl && self->impl->close);
-		return -1;
+	return self->impl->close(self);
-
-	self->state = STREAM_STATE_CLOSED;
-
-	while (!TAILQ_EMPTY(&self->send_queue)) {
-		struct stream_req* req = TAILQ_FIRST(&self->send_queue);
-		TAILQ_REMOVE(&self->send_queue, req, link);
-		stream_req__finish(req, STREAM_REQ_FAILED);
-	}
-
-#ifdef ENABLE_TLS
-	if (self->tls_session)
-		gnutls_deinit(self->tls_session);
-	self->tls_session = NULL;
-#endif
-
-	// TODO: Maybe use explicit loop object instead of the default one?
-	aml_stop(aml_get_default(), self->handler);
-	close(self->fd);
-	self->fd = -1;
-
-	return 0;
 }
 
 void stream_destroy(struct stream* self)
 {
-	stream_close(self);
+	assert(self->impl && self->impl->destroy);
-	aml_unref(self->handler);
+	return self->impl->destroy(self);
-}
-
-static void stream__remote_closed(struct stream* self)
-{
-	stream_close(self);
-
-	if (self->on_event)
-		self->on_event(self, STREAM_EVENT_REMOTE_CLOSED);
-}
-
-static int stream__flush_plain(struct stream* self)
-{
-	static struct iovec iov[IOV_MAX];
-	size_t n_msgs = 0;
-	ssize_t bytes_sent;
-
-	struct stream_req* req;
-	TAILQ_FOREACH(req, &self->send_queue, link) {
-		iov[n_msgs].iov_base = req->payload->payload;
-		iov[n_msgs].iov_len = req->payload->size;
-
-		if (++n_msgs >= IOV_MAX)
-			break;
-	}
-
-	if (n_msgs == 0)
-		return 0;
-
-	struct msghdr msghdr = {
-		.msg_iov = iov,
-		.msg_iovlen = n_msgs,
-	};
-	bytes_sent = sendmsg(self->fd, &msghdr, MSG_NOSIGNAL);
-	if (bytes_sent < 0) {
-		if (errno == EAGAIN || errno == EWOULDBLOCK) {
-			stream__poll_rw(self);
-			errno = EAGAIN;
-		} else if (errno == EPIPE) {
-			stream__remote_closed(self);
-			errno = EPIPE;
-		}
-
-		return bytes_sent;
-	}
-
-	self->bytes_sent += bytes_sent;
-
-	ssize_t bytes_left = bytes_sent;
-
-	struct stream_req* tmp;
-	TAILQ_FOREACH_SAFE(req, &self->send_queue, link, tmp) {
-		bytes_left -= req->payload->size;
-
-		if (bytes_left >= 0) {
-			TAILQ_REMOVE(&self->send_queue, req, link);
-			stream_req__finish(req, STREAM_REQ_DONE);
-		} else {
-			char* p = req->payload->payload;
-			size_t s = req->payload->size;
-			memmove(p, p + s + bytes_left, -bytes_left);
-			req->payload->size = -bytes_left;
-			stream__poll_rw(self);
-		}
-
-		if (bytes_left <= 0)
-			break;
-	}
-
-	if (bytes_left == 0 && self->state != STREAM_STATE_CLOSED)
-		stream__poll_r(self);
-
-	assert(bytes_left <= 0);
-
-	return bytes_sent;
-}
-
-#ifdef ENABLE_TLS
-static int stream__flush_tls(struct stream* self)
-{
-	while (!TAILQ_EMPTY(&self->send_queue)) {
-		struct stream_req* req = TAILQ_FIRST(&self->send_queue);
-
-		ssize_t rc = gnutls_record_send(
-			self->tls_session, req->payload->payload,
-			req->payload->size);
-		if (rc < 0) {
-			gnutls_record_discard_queued(self->tls_session);
-			if (gnutls_error_is_fatal(rc))
-				stream_close(self);
-			return -1;
-		}
-
-		self->bytes_sent += rc;
-
-		ssize_t remaining = req->payload->size - rc;
-
-		if (remaining > 0) {
-			char* p = req->payload->payload;
-			size_t s = req->payload->size;
-			memmove(p, p + s - remaining, remaining);
-			req->payload->size = remaining;
-			stream__poll_rw(self);
-			return 1;
-		}
-
-		assert(remaining == 0);
-
-		TAILQ_REMOVE(&self->send_queue, req, link);
-		stream_req__finish(req, STREAM_REQ_DONE);
-	}
-
-	if (TAILQ_EMPTY(&self->send_queue) && self->state != STREAM_STATE_CLOSED)
-		stream__poll_r(self);
-
-	return 1;
-}
-#endif
-
-static int stream__flush(struct stream* self)
-{
-	switch (self->state) {
-	case STREAM_STATE_NORMAL: return stream__flush_plain(self);
-#ifdef ENABLE_TLS
-	case STREAM_STATE_TLS_READY: return stream__flush_tls(self);
-#endif
-	default:
-		break;
-	}
-	abort();
-	return -1;
-}
-
-static void stream__on_readable(struct stream* self)
-{
-	switch (self->state) {
-	case STREAM_STATE_NORMAL:
-		/* fallthrough */
-#ifdef ENABLE_TLS
-	case STREAM_STATE_TLS_READY:
-#endif
-		if (self->on_event)
-			self->on_event(self, STREAM_EVENT_READ);
-		break;
-#ifdef ENABLE_TLS
-	case STREAM_STATE_TLS_HANDSHAKE:
-		stream__try_tls_accept(self);
-		break;
-#endif
-	case STREAM_STATE_CLOSED:
-		break;
-	}
-}
-
-static void stream__on_writable(struct stream* self)
-{
-	switch (self->state) {
-	case STREAM_STATE_NORMAL:
-		/* fallthrough */
-#ifdef ENABLE_TLS
-	case STREAM_STATE_TLS_READY:
-#endif
-		stream__flush(self);
-		break;
-#ifdef ENABLE_TLS
-	case STREAM_STATE_TLS_HANDSHAKE:
-		stream__try_tls_accept(self);
-		break;
-#endif
-	case STREAM_STATE_CLOSED:
-		break;
-	}
-}
-
-static void stream__on_event(void* obj)
-{
-	struct stream* self = aml_get_userdata(obj);
-	uint32_t events = aml_get_revents(obj);
-
-	if (events & AML_EVENT_READ)
-		stream__on_readable(self);
-
-	if (events & AML_EVENT_WRITE)
-		stream__on_writable(self);
-}
-
-struct stream* stream_new(int fd, stream_event_fn on_event, void* userdata)
-{
-	struct stream* self = calloc(1, sizeof(*self));
-	if (!self)
-		return NULL;
-
-	self->fd = fd;
-	self->on_event = on_event;
-	self->userdata = userdata;
-
-	TAILQ_INIT(&self->send_queue);
-
-	fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
-
-	self->handler = aml_handler_new(fd, stream__on_event, self, free);
-	if (!self->handler)
-		goto failure;
-
-	if (aml_start(aml_get_default(), self->handler) < 0)
-		goto start_failure;
-
-	stream__poll_r(self);
-
-	return self;
-
-start_failure:
-	aml_unref(self->handler);
-	self = NULL; /* Handled in unref */
-failure:
-	free(self);
-	return NULL;
 }
 
 int stream_send(struct stream* self, struct rcbuf* payload,
                 stream_req_fn on_done, void* userdata)
 {
-	if (self->state == STREAM_STATE_CLOSED)
+	assert(self->impl && self->impl->send);
-		return -1;
+	return self->impl->send(self, payload, on_done, userdata);
-
-	struct stream_req* req = calloc(1, sizeof(*req));
-	if (!req)
-		return -1;
-
-	req->payload = payload;
-	req->on_done = on_done;
-	req->userdata = userdata;
-
-	TAILQ_INSERT_TAIL(&self->send_queue, req, link);
-
-	return stream__flush(self);
 }
 
 int stream_write(struct stream* self, const void* payload, size_t len,
@@ -340,111 +44,8 @@ int stream_write(struct stream* self, const void* payload, size_t len,
 	return buf ? stream_send(self, buf, on_done, userdata) : -1;
 }
 
-static ssize_t stream__read_plain(struct stream* self, void* dst, size_t size)
-{
-	ssize_t rc = read(self->fd, dst, size);
-	if (rc == 0)
-		stream__remote_closed(self);
-	if (rc > 0)
-		self->bytes_received += rc;
-	return rc;
-}
-
-#ifdef ENABLE_TLS
-static ssize_t stream__read_tls(struct stream* self, void* dst, size_t size)
-{
-	ssize_t rc = gnutls_record_recv(self->tls_session, dst, size);
-	if (rc == 0) {
-		stream__remote_closed(self);
-		return rc;
-	}
-	if (rc > 0) {
-		self->bytes_received += rc;
-		return rc;
-	}
-
-	switch (rc) {
-	case GNUTLS_E_INTERRUPTED:
-		errno = EINTR;
-		break;
-	case GNUTLS_E_AGAIN:
-		errno = EAGAIN;
-		break;
-	default:
-		errno = 0;
-		break;
-	}
-
-	// Make sure data wasn't being written.
-	assert(gnutls_record_get_direction(self->tls_session) == 0);
-	return -1;
-}
-#endif
-
 ssize_t stream_read(struct stream* self, void* dst, size_t size)
 {
-	switch (self->state) {
+	assert(self->impl && self->impl->read);
-	case STREAM_STATE_NORMAL: return stream__read_plain(self, dst, size);
+	return self->impl->read(self, dst, size);
-#ifdef ENABLE_TLS
-	case STREAM_STATE_TLS_READY: return stream__read_tls(self, dst, size);
-#endif
-	default: break;
 }
-
-	abort();
-	return -1;
-}
-
-#ifdef ENABLE_TLS
-static int stream__try_tls_accept(struct stream* self)
-{
-	int rc;
-
-	rc = gnutls_handshake(self->tls_session);
-	if (rc == GNUTLS_E_SUCCESS) {
-		self->state = STREAM_STATE_TLS_READY;
-		stream__poll_r(self);
-		return 0;
-	}
-
-	if (gnutls_error_is_fatal(rc)) {
-		aml_stop(aml_get_default(), self->handler);
-		return -1;
-	}
-
-	int was_writing = gnutls_record_get_direction(self->tls_session);
-	if (was_writing)
-		stream__poll_w(self);
-	else
-		stream__poll_r(self);
-
-	self->state = STREAM_STATE_TLS_HANDSHAKE;
-	return 0;
-}
-
-int stream_upgrade_to_tls(struct stream* self, void* context)
-{
-	int rc;
-
-	rc = gnutls_init(&self->tls_session, GNUTLS_SERVER | GNUTLS_NONBLOCK);
-	if (rc != GNUTLS_E_SUCCESS)
-		return -1;
-
-	rc = gnutls_set_default_priority(self->tls_session);
-	if (rc != GNUTLS_E_SUCCESS)
-		goto failure;
-
-	rc = gnutls_credentials_set(self->tls_session, GNUTLS_CRD_CERTIFICATE,
-	                            context);
-	if (rc != GNUTLS_E_SUCCESS)
-		goto failure;
-
-	gnutls_transport_set_int(self->tls_session, self->fd);
-
-	return stream__try_tls_accept(self);
-
-failure:
-	gnutls_deinit(self->tls_session);
-	return -1;
-}
-#endif