r20889: import ctdb cluster backend from bzr

it will be interesting to see how the build farm handles this
(This used to be commit 53be449630bd67d649a9e70cc7e25a9799c0616b)

1 files changed, 254 insertions, 0 deletions

diff --git a/source4/cluster/ctdb/tcp/tcp_io.c b/source4/cluster/ctdb/tcp/tcp_io.c
new file mode 100644
index 0000000000..82e24f7260
--- /dev/null
+++ b/source4/cluster/ctdb/tcp/tcp_io.c
@@ -0,0 +1,254 @@
+/* 
+   ctdb over TCP
+
+   Copyright (C) Andrew Tridgell  2006
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include "includes.h"
+#include "lib/events/events.h"
+#include "lib/util/dlinklist.h"
+#include "lib/tdb/include/tdb.h"
+#include "system/network.h"
+#include "system/filesys.h"
+#include "cluster/ctdb/include/ctdb_private.h"
+#include "ctdb_tcp.h"
+
+
+/*
+  called when we fail to send a message to a node
+*/
+static void ctdb_tcp_node_dead(struct event_context *ev, struct timed_event *te, 
+			       struct timeval t, void *private)
+{
+	struct ctdb_node *node = talloc_get_type(private, struct ctdb_node);
+	struct ctdb_tcp_node *tnode = talloc_get_type(node->private, 
+						      struct ctdb_tcp_node);
+
+	/* flush the queue */
+	while (tnode->queue) {
+		struct ctdb_tcp_packet *pkt = tnode->queue;
+		DLIST_REMOVE(tnode->queue, pkt);
+		talloc_free(pkt);
+	}
+
+	/* start a new connect cycle to try to re-establish the
+	   link */
+	talloc_free(tnode->fde);
+	close(tnode->fd);
+	tnode->fd = -1;
+	event_add_timed(node->ctdb->ev, node, timeval_zero(), 
+			ctdb_tcp_node_connect, node);
+}
+
+/*
+  called when socket becomes readable
+*/
+void ctdb_tcp_node_write(struct event_context *ev, struct fd_event *fde, 
+			 uint16_t flags, void *private)
+{
+	struct ctdb_node *node = talloc_get_type(private, struct ctdb_node);
+	struct ctdb_tcp_node *tnode = talloc_get_type(node->private, 
+						      struct ctdb_tcp_node);
+	if (flags & EVENT_FD_READ) {
+		/* getting a read event on this fd in the current tcp model is
+		   always an error, as we have separate read and write
+		   sockets. In future we may combine them, but for now it must
+		   mean that the socket is dead, so we try to reconnect */
+		talloc_free(tnode->fde);
+		close(tnode->fd);
+		tnode->fd = -1;
+		event_add_timed(node->ctdb->ev, node, timeval_zero(), 
+				ctdb_tcp_node_connect, node);
+		return;
+	}
+
+	while (tnode->queue) {
+		struct ctdb_tcp_packet *pkt = tnode->queue;
+		ssize_t n;
+
+		n = write(tnode->fd, pkt->data, pkt->length);
+
+		if (n == -1 && errno != EAGAIN && errno != EWOULDBLOCK) {
+			event_add_timed(node->ctdb->ev, node, timeval_zero(), 
+					ctdb_tcp_node_dead, node);
+			EVENT_FD_NOT_WRITEABLE(tnode->fde);
+			return;
+		}
+		if (n <= 0) return;
+		
+		if (n != pkt->length) {
+			pkt->length -= n;
+			pkt->data += n;
+			return;
+		}
+
+		DLIST_REMOVE(tnode->queue, pkt);
+		talloc_free(pkt);
+	}
+
+	EVENT_FD_NOT_WRITEABLE(tnode->fde);
+}
+
+
+/*
+  called when an incoming connection is readable
+*/
+void ctdb_tcp_incoming_read(struct event_context *ev, struct fd_event *fde, 
+			    uint16_t flags, void *private)
+{
+	struct ctdb_incoming *in = talloc_get_type(private, struct ctdb_incoming);
+	int num_ready = 0;
+	ssize_t nread;
+	uint8_t *data, *data_base;
+
+	if (ioctl(in->fd, FIONREAD, &num_ready) != 0 ||
+	    num_ready == 0) {
+		/* we've lost the link from another node. We don't
+		   notify the upper layers, as we only want to trigger
+		   a full node reorganisation when a send fails - that
+		   allows nodes to restart without penalty as long as
+		   the network is idle */
+		talloc_free(in);
+		return;
+	}
+
+	in->partial.data = talloc_realloc_size(in, in->partial.data, 
+					       num_ready + in->partial.length);
+	if (in->partial.data == NULL) {
+		/* not much we can do except drop the socket */
+		talloc_free(in);
+		return;
+	}
+
+	nread = read(in->fd, in->partial.data+in->partial.length, num_ready);
+	if (nread <= 0) {
+		/* the connection must be dead */
+		talloc_free(in);
+		return;
+	}
+
+	data = in->partial.data;
+	nread += in->partial.length;
+
+	in->partial.data = NULL;
+	in->partial.length = 0;
+
+	if (nread >= 4 && *(uint32_t *)data == nread) {
+		/* most common case - we got a whole packet in one go
+		   tell the ctdb layer above that we have a packet */
+		in->ctdb->upcalls->recv_pkt(in->ctdb, data, nread);
+		return;
+	}
+
+	data_base = data;
+
+	while (nread >= 4 && *(uint32_t *)data <= nread) {
+		/* we have at least one packet */
+		uint8_t *d2;
+		uint32_t len;
+		len = *(uint32_t *)data;
+		d2 = talloc_memdup(in, data, len);
+		if (d2 == NULL) {
+			/* sigh */
+			talloc_free(in);
+			return;
+		}
+		in->ctdb->upcalls->recv_pkt(in->ctdb, d2, len);
+		data += len;
+		nread -= len;		
+		return;
+	}
+
+	if (nread < 4 || *(uint32_t *)data > nread) {
+		/* we have only part of a packet */
+		if (data_base == data) {
+			in->partial.data = data;
+			in->partial.length = nread;
+		} else {
+			in->partial.data = talloc_memdup(in, data, nread);
+			if (in->partial.data == NULL) {
+				talloc_free(in);
+				return;
+			}
+			in->partial.length = nread;
+			talloc_free(data_base);
+		}
+		return;
+	}
+
+	talloc_free(data_base);
+}
+
+/*
+  queue a packet for sending
+*/
+int ctdb_tcp_queue_pkt(struct ctdb_node *node, uint8_t *data, uint32_t length)
+{
+	struct ctdb_tcp_node *tnode = talloc_get_type(node->private, 
+						      struct ctdb_tcp_node);
+	struct ctdb_tcp_packet *pkt;
+	uint32_t length2;
+
+	/* enforce the length and alignment rules from the tcp packet allocator */
+	length2 = (length+(CTDB_TCP_ALIGNMENT-1)) & ~(CTDB_TCP_ALIGNMENT-1);
+	*(uint32_t *)data = length2;
+
+	if (length2 != length) {
+		memset(data+length, 0, length2-length);
+	}
+	{
+		int i, fd = open("/dev/null", O_WRONLY);
+		for (i=0;i<length2;i++) {
+			write(fd, &data[i], 1);
+		}
+		close(fd);
+	}
+	
+	/* if the queue is empty then try an immediate write, avoiding
+	   queue overhead. This relies on non-blocking sockets */
+	if (tnode->queue == NULL && tnode->fd != -1) {
+		ssize_t n = write(tnode->fd, data, length2);
+		if (n == -1 && errno != EAGAIN && errno != EWOULDBLOCK) {
+			event_add_timed(node->ctdb->ev, node, timeval_zero(), 
+					ctdb_tcp_node_dead, node);
+			/* yes, we report success, as the dead node is 
+			   handled via a separate event */
+			return 0;
+		}
+		if (n > 0) {
+			data += n;
+			length2 -= n;
+		}
+		if (length2 == 0) return 0;
+	}
+
+	pkt = talloc(tnode, struct ctdb_tcp_packet);
+	CTDB_NO_MEMORY(node->ctdb, pkt);
+
+	pkt->data = talloc_memdup(pkt, data, length2);
+	CTDB_NO_MEMORY(node->ctdb, pkt->data);
+
+	pkt->length = length2;
+
+	if (tnode->queue == NULL && tnode->fd != -1) {
+		EVENT_FD_WRITEABLE(tnode->fde);
+	}
+
+	DLIST_ADD_END(tnode->queue, pkt, struct ctdb_tcp_packet *);
+
+	return 0;
+}