stream: New library for bidirectional streams (e.g. TCP, SSL, Unix sockets).

This code is heavily based on the vconn code.  Eventually we should make
the stream-based vconns (currently that's all of them) a wrapper around
streams, but I haven't done that yet.

SSL is not implemented yet.

1 files changed, 490 insertions, 0 deletions

diff --git a/lib/stream.c b/lib/stream.c
new file mode 100644
index 00000000..1a0ea7ba
--- /dev/null
+++ b/lib/stream.c
@@ -0,0 +1,490 @@
+/*
+ * Copyright (c) 2008, 2009 Nicira Networks.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+#include "stream-provider.h"
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <string.h>
+#include "coverage.h"
+#include "dynamic-string.h"
+#include "flow.h"
+#include "ofp-print.h"
+#include "ofpbuf.h"
+#include "openflow/nicira-ext.h"
+#include "openflow/openflow.h"
+#include "packets.h"
+#include "poll-loop.h"
+#include "random.h"
+#include "util.h"
+
+#define THIS_MODULE VLM_stream
+#include "vlog.h"
+
+/* State of an active stream.*/
+enum stream_state {
+    SCS_CONNECTING,             /* Underlying stream is not connected. */
+    SCS_CONNECTED,              /* Connection established. */
+    SCS_DISCONNECTED            /* Connection failed or connection closed. */
+};
+
+static struct stream_class *stream_classes[] = {
+    &tcp_stream_class,
+    &unix_stream_class,
+};
+
+static struct pstream_class *pstream_classes[] = {
+    &ptcp_pstream_class,
+    &punix_pstream_class,
+};
+
+/* Check the validity of the stream class structures. */
+static void
+check_stream_classes(void)
+{
+#ifndef NDEBUG
+    size_t i;
+
+    for (i = 0; i < ARRAY_SIZE(stream_classes); i++) {
+        struct stream_class *class = stream_classes[i];
+        assert(class->name != NULL);
+        assert(class->open != NULL);
+        if (class->close || class->recv || class->send || class->wait) {
+            assert(class->close != NULL);
+            assert(class->recv != NULL);
+            assert(class->send != NULL);
+            assert(class->wait != NULL);
+        } else {
+            /* This class delegates to another one. */
+        }
+    }
+
+    for (i = 0; i < ARRAY_SIZE(pstream_classes); i++) {
+        struct pstream_class *class = pstream_classes[i];
+        assert(class->name != NULL);
+        assert(class->listen != NULL);
+        if (class->close || class->accept || class->wait) {
+            assert(class->close != NULL);
+            assert(class->accept != NULL);
+            assert(class->wait != NULL);
+        } else {
+            /* This class delegates to another one. */
+        }
+    }
+#endif
+}
+
+/* Prints information on active (if 'active') and passive (if 'passive')
+ * connection methods supported by the stream. */
+void
+stream_usage(const char *name, bool active, bool passive)
+{
+    /* Really this should be implemented via callbacks into the stream
+     * providers, but that seems too heavy-weight to bother with at the
+     * moment. */
+
+    printf("\n");
+    if (active) {
+        printf("Active %s connection methods:\n", name);
+        printf("  tcp:IP:PORT             "
+               "PORT at remote IP\n");
+        printf("  unix:FILE               "
+               "Unix domain socket named FILE\n");
+    }
+
+    if (passive) {
+        printf("Passive %s connection methods:\n", name);
+        printf("  ptcp:PORT[:IP]          "
+               "listen to TCP PORT on IP\n");
+        printf("  punix:FILE              "
+               "listen on Unix domain socket FILE\n");
+    }
+}
+
+/* Attempts to connect a stream to a remote peer.  'name' is a connection name
+ * in the form "TYPE:ARGS", where TYPE is an active stream class's name and
+ * ARGS are stream class-specific.
+ *
+ * Returns 0 if successful, otherwise a positive errno value.  If successful,
+ * stores a pointer to the new connection in '*streamp', otherwise a null
+ * pointer.  */
+int
+stream_open(const char *name, struct stream **streamp)
+{
+    size_t prefix_len;
+    size_t i;
+
+    COVERAGE_INC(stream_open);
+    check_stream_classes();
+
+    *streamp = NULL;
+    prefix_len = strcspn(name, ":");
+    if (prefix_len == strlen(name)) {
+        return EAFNOSUPPORT;
+    }
+    for (i = 0; i < ARRAY_SIZE(stream_classes); i++) {
+        struct stream_class *class = stream_classes[i];
+        if (strlen(class->name) == prefix_len
+            && !memcmp(class->name, name, prefix_len)) {
+            struct stream *stream;
+            char *suffix_copy = xstrdup(name + prefix_len + 1);
+            int retval = class->open(name, suffix_copy, &stream);
+            free(suffix_copy);
+            if (!retval) {
+                assert(stream->state != SCS_CONNECTING
+                       || stream->class->connect);
+                *streamp = stream;
+            }
+            return retval;
+        }
+    }
+    return EAFNOSUPPORT;
+}
+
+int
+stream_open_block(const char *name, struct stream **streamp)
+{
+    struct stream *stream;
+    int error;
+
+    error = stream_open(name, &stream);
+    while (error == EAGAIN) {
+        stream_connect_wait(stream);
+        poll_block();
+        error = stream_connect(stream);
+        assert(error != EINPROGRESS);
+    }
+    if (error) {
+        stream_close(stream);
+        *streamp = NULL;
+    } else {
+        *streamp = stream;
+    }
+    return error;
+}
+
+/* Closes 'stream'. */
+void
+stream_close(struct stream *stream)
+{
+    if (stream != NULL) {
+        char *name = stream->name;
+        (stream->class->close)(stream);
+        free(name);
+    }
+}
+
+/* Returns the name of 'stream', that is, the string passed to
+ * stream_open(). */
+const char *
+stream_get_name(const struct stream *stream)
+{
+    return stream ? stream->name : "(null)";
+}
+
+/* Returns the IP address of the peer, or 0 if the peer is not connected over
+ * an IP-based protocol or if its IP address is not yet known. */
+uint32_t
+stream_get_remote_ip(const struct stream *stream)
+{
+    return stream->remote_ip;
+}
+
+/* Returns the transport port of the peer, or 0 if the connection does not
+ * contain a port or if the port is not yet known. */
+uint16_t
+stream_get_remote_port(const struct stream *stream)
+{
+    return stream->remote_port;
+}
+
+/* Returns the IP address used to connect to the peer, or 0 if the connection
+ * is not an IP-based protocol or if its IP address is not yet known. */
+uint32_t
+stream_get_local_ip(const struct stream *stream)
+{
+    return stream->local_ip;
+}
+
+/* Returns the transport port used to connect to the peer, or 0 if the
+ * connection does not contain a port or if the port is not yet known. */
+uint16_t
+stream_get_local_port(const struct stream *stream)
+{
+    return stream->local_port;
+}
+
+static void
+scs_connecting(struct stream *stream)
+{
+    int retval = (stream->class->connect)(stream);
+    assert(retval != EINPROGRESS);
+    if (!retval) {
+        stream->state = SCS_CONNECTED;
+    } else if (retval != EAGAIN) {
+        stream->state = SCS_DISCONNECTED;
+        stream->error = retval;
+    }
+}
+
+/* Tries to complete the connection on 'stream', which must be an active
+ * stream.  If 'stream''s connection is complete, returns 0 if the connection
+ * was successful or a positive errno value if it failed.  If the
+ * connection is still in progress, returns EAGAIN. */
+int
+stream_connect(struct stream *stream)
+{
+    enum stream_state last_state;
+
+    do {
+        last_state = stream->state;
+        switch (stream->state) {
+        case SCS_CONNECTING:
+            scs_connecting(stream);
+            break;
+
+        case SCS_CONNECTED:
+            return 0;
+
+        case SCS_DISCONNECTED:
+            return stream->error;
+
+        default:
+            NOT_REACHED();
+        }
+    } while (stream->state != last_state);
+
+    return EAGAIN;
+}
+
+/* Tries to receive up to 'n' bytes from 'stream' into 'buffer', and returns:
+ *
+ *     - If successful, the number of bytes received (between 1 and 'n').
+ *
+ *     - On error, a negative errno value.
+ *
+ *     - 0, if the connection has been closed in the normal fashion, or if 'n'
+ *       is zero.
+ *
+ * The recv function will not block waiting for a packet to arrive.  If no
+ * data have been received, it returns -EAGAIN immediately. */
+int
+stream_recv(struct stream *stream, void *buffer, size_t n)
+{
+    int retval = stream_connect(stream);
+    return (retval ? -retval
+            : n == 0 ? 0
+            : (stream->class->recv)(stream, buffer, n));
+}
+
+/* Tries to send up to 'n' bytes of 'buffer' on 'stream', and returns:
+ *
+ *     - If successful, the number of bytes sent (between 1 and 'n').  0 is
+ *       only a valid return value if 'n' is 0.
+ *
+ *     - On error, a negative errno value.
+ *
+ * The send function will not block.  If no bytes can be immediately accepted
+ * for transmission, it returns -EAGAIN immediately. */
+int
+stream_send(struct stream *stream, const void *buffer, size_t n)
+{
+    int retval = stream_connect(stream);
+    return (retval ? -retval
+            : n == 0 ? 0
+            : (stream->class->send)(stream, buffer, n));
+}
+
+void
+stream_wait(struct stream *stream, enum stream_wait_type wait)
+{
+    assert(wait == STREAM_CONNECT || wait == STREAM_RECV
+           || wait == STREAM_SEND);
+
+    switch (stream->state) {
+    case SCS_CONNECTING:
+        wait = STREAM_CONNECT;
+        break;
+
+    case SCS_DISCONNECTED:
+        poll_immediate_wake();
+        return;
+    }
+    (stream->class->wait)(stream, wait);
+}
+
+void
+stream_connect_wait(struct stream *stream)
+{
+    stream_wait(stream, STREAM_CONNECT);
+}
+
+void
+stream_recv_wait(struct stream *stream)
+{
+    stream_wait(stream, STREAM_RECV);
+}
+
+void
+stream_send_wait(struct stream *stream)
+{
+    stream_wait(stream, STREAM_SEND);
+}
+
+/* Attempts to start listening for remote stream connections.  'name' is a
+ * connection name in the form "TYPE:ARGS", where TYPE is an passive stream
+ * class's name and ARGS are stream class-specific.
+ *
+ * Returns 0 if successful, otherwise a positive errno value.  If successful,
+ * stores a pointer to the new connection in '*pstreamp', otherwise a null
+ * pointer.  */
+int
+pstream_open(const char *name, struct pstream **pstreamp)
+{
+    size_t prefix_len;
+    size_t i;
+
+    check_stream_classes();
+
+    *pstreamp = NULL;
+    prefix_len = strcspn(name, ":");
+    if (prefix_len == strlen(name)) {
+        return EAFNOSUPPORT;
+    }
+    for (i = 0; i < ARRAY_SIZE(pstream_classes); i++) {
+        struct pstream_class *class = pstream_classes[i];
+        if (strlen(class->name) == prefix_len
+            && !memcmp(class->name, name, prefix_len)) {
+            char *suffix_copy = xstrdup(name + prefix_len + 1);
+            int retval = class->listen(name, suffix_copy, pstreamp);
+            free(suffix_copy);
+            if (retval) {
+                *pstreamp = NULL;
+            }
+            return retval;
+        }
+    }
+    return EAFNOSUPPORT;
+}
+
+/* Returns the name that was used to open 'pstream'.  The caller must not
+ * modify or free the name. */
+const char *
+pstream_get_name(const struct pstream *pstream)
+{
+    return pstream->name;
+}
+
+/* Closes 'pstream'. */
+void
+pstream_close(struct pstream *pstream)
+{
+    if (pstream != NULL) {
+        char *name = pstream->name;
+        (pstream->class->close)(pstream);
+        free(name);
+    }
+}
+
+/* Tries to accept a new connection on 'pstream'.  If successful, stores the
+ * new connection in '*new_stream' and returns 0.  Otherwise, returns a
+ * positive errno value.
+ *
+ * pstream_accept() will not block waiting for a connection.  If no connection
+ * is ready to be accepted, it returns EAGAIN immediately. */
+int
+pstream_accept(struct pstream *pstream, struct stream **new_stream)
+{
+    int retval = (pstream->class->accept)(pstream, new_stream);
+    if (retval) {
+        *new_stream = NULL;
+    } else {
+        assert((*new_stream)->state != SCS_CONNECTING
+               || (*new_stream)->class->connect);
+    }
+    return retval;
+}
+
+void
+pstream_wait(struct pstream *pstream)
+{
+    (pstream->class->wait)(pstream);
+}
+
+/* Initializes 'stream' as a new stream named 'name', implemented via 'class'.
+ * The initial connection status, supplied as 'connect_status', is interpreted
+ * as follows:
+ *
+ *      - 0: 'stream' is connected.  Its 'send' and 'recv' functions may be
+ *        called in the normal fashion.
+ *
+ *      - EAGAIN: 'stream' is trying to complete a connection.  Its 'connect'
+ *        function should be called to complete the connection.
+ *
+ *      - Other positive errno values indicate that the connection failed with
+ *        the specified error.
+ *
+ * After calling this function, stream_close() must be used to destroy
+ * 'stream', otherwise resources will be leaked.
+ *
+ * The caller retains ownership of 'name'. */
+void
+stream_init(struct stream *stream, struct stream_class *class,
+            int connect_status, const char *name)
+{
+    stream->class = class;
+    stream->state = (connect_status == EAGAIN ? SCS_CONNECTING
+                    : !connect_status ? SCS_CONNECTED
+                    : SCS_DISCONNECTED);
+    stream->error = connect_status;
+    stream->name = xstrdup(name);
+}
+
+void
+stream_set_remote_ip(struct stream *stream, uint32_t ip)
+{
+    stream->remote_ip = ip;
+}
+
+void
+stream_set_remote_port(struct stream *stream, uint16_t port)
+{
+    stream->remote_port = port;
+}
+
+void
+stream_set_local_ip(struct stream *stream, uint32_t ip)
+{
+    stream->local_ip = ip;
+}
+
+void
+stream_set_local_port(struct stream *stream, uint16_t port)
+{
+    stream->local_port = port;
+}
+
+void
+pstream_init(struct pstream *pstream, struct pstream_class *class,
+            const char *name)
+{
+    pstream->class = class;
+    pstream->name = xstrdup(name);
+}