/*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include "ofpbuf.h"
#include "ovs-thread.h"
#include "poll-loop.h"
+#include "seq.h"
#include "socket-util.h"
#include "util.h"
#include "vlog.h"
}
if (msg.msg_flags & MSG_TRUNC) {
- VLOG_ERR_RL(&rl, "truncated message (longer than %zu bytes)",
+ VLOG_ERR_RL(&rl, "truncated message (longer than %"PRIuSIZE" bytes)",
sizeof tail);
return E2BIG;
}
if (retval < sizeof *nlmsghdr
|| nlmsghdr->nlmsg_len < sizeof *nlmsghdr
|| nlmsghdr->nlmsg_len > retval) {
- VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %zu)",
+ VLOG_ERR_RL(&rl, "received invalid nlmsg (%"PRIuSIZE"d bytes < %"PRIuSIZE")",
retval, sizeof *nlmsghdr);
return EPROTO;
}
* Netlink socket created with the given 'protocol', and initializes 'dump' to
* reflect the state of the operation.
*
- * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
- * be set to the Netlink socket's pid, before the message is sent. NLM_F_DUMP
- * and NLM_F_ACK will be set in nlmsg_flags.
+ * 'request' must contain a Netlink message. Before sending the message,
+ * nlmsg_len will be finalized to match request->size, and nlmsg_pid will be
+ * set to the Netlink socket's pid. NLM_F_DUMP and NLM_F_ACK will be set in
+ * nlmsg_flags.
*
* The design of this Netlink socket library ensures that the dump is reliable.
*
- * This function provides no status indication. An error status for the entire
- * dump operation is provided when it is completed by calling nl_dump_done().
+ * This function provides no status indication. nl_dump_done() provides an
+ * error status for the entire dump operation.
*
- * The caller is responsible for destroying 'request'.
+ * The caller must eventually destroy 'request'.
*/
void
nl_dump_start(struct nl_dump *dump, int protocol, const struct ofpbuf *request)
{
- ofpbuf_init(&dump->buffer, 4096);
- dump->status = nl_pool_alloc(protocol, &dump->sock);
- if (dump->status) {
+ int status = nl_pool_alloc(protocol, &dump->sock);
+
+ if (status) {
return;
}
nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
- dump->status = nl_sock_send__(dump->sock, request,
- nl_sock_allocate_seq(dump->sock, 1), true);
- dump->seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
-}
-
-/* Helper function for nl_dump_next(). */
-static int
-nl_dump_recv(struct nl_dump *dump)
-{
- struct nlmsghdr *nlmsghdr;
- int retval;
-
- retval = nl_sock_recv__(dump->sock, &dump->buffer, true);
- if (retval) {
- return retval == EINTR ? EAGAIN : retval;
- }
-
- nlmsghdr = nl_msg_nlmsghdr(&dump->buffer);
- if (dump->seq != nlmsghdr->nlmsg_seq) {
- VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
- nlmsghdr->nlmsg_seq, dump->seq);
- return EAGAIN;
- }
-
- if (nl_msg_nlmsgerr(&dump->buffer, &retval)) {
- VLOG_INFO_RL(&rl, "netlink dump request error (%s)",
- ovs_strerror(retval));
- return retval && retval != EAGAIN ? retval : EPROTO;
- }
-
- return 0;
+ status = nl_sock_send__(dump->sock, request,
+ nl_sock_allocate_seq(dump->sock, 1), true);
+ atomic_init(&dump->status, status << 1);
+ dump->nl_seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
+ dump->status_seq = seq_create();
}
-/* Attempts to retrieve another reply from 'dump', which must have been
- * initialized with nl_dump_start().
+/* Attempts to retrieve another reply from 'dump' into 'buffer'. 'dump' must
+ * have been initialized with nl_dump_start(), and 'buffer' must have been
+ * initialized. 'buffer' should be at least NL_DUMP_BUFSIZE bytes long.
*
* If successful, returns true and points 'reply->data' and 'reply->size' to
- * the message that was retrieved. The caller must not modify 'reply' (because
- * it points into the middle of a larger buffer).
+ * the message that was retrieved. The caller must not modify 'reply' (because
+ * it points within 'buffer', which will be used by future calls to this
+ * function).
*
* On failure, returns false and sets 'reply->data' to NULL and 'reply->size'
* to 0. Failure might indicate an actual error or merely the end of replies.
* An error status for the entire dump operation is provided when it is
* completed by calling nl_dump_done().
+ *
+ * Multiple threads may call this function, passing the same nl_dump, however
+ * each must provide independent buffers. This function may cache multiple
+ * replies in the buffer, and these will be processed before more replies are
+ * fetched. When this function returns false, other threads may continue to
+ * process replies in their buffers, but they will not fetch more replies.
*/
bool
-nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply)
+nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply, struct ofpbuf *buffer)
{
struct nlmsghdr *nlmsghdr;
+ int error = 0;
reply->data = NULL;
reply->size = 0;
- if (dump->status) {
- return false;
- }
- while (!dump->buffer.size) {
- int retval = nl_dump_recv(dump);
+ /* If 'buffer' is empty, fetch another batch of nlmsgs. */
+ while (!buffer->size) {
+ unsigned int status;
+ int retval, seq;
+
+ seq = seq_read(dump->status_seq);
+ atomic_read(&dump->status, &status);
+ if (status) {
+ return false;
+ }
+
+ retval = nl_sock_recv__(dump->sock, buffer, false);
if (retval) {
- ofpbuf_clear(&dump->buffer);
- if (retval != EAGAIN) {
- dump->status = retval;
- return false;
+ ofpbuf_clear(buffer);
+ if (retval == EAGAIN) {
+ nl_sock_wait(dump->sock, POLLIN);
+ seq_wait(dump->status_seq, seq);
+ poll_block();
+ continue;
+ } else {
+ error = retval;
+ goto exit;
}
}
+
+ nlmsghdr = nl_msg_nlmsghdr(buffer);
+ if (dump->nl_seq != nlmsghdr->nlmsg_seq) {
+ VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
+ nlmsghdr->nlmsg_seq, dump->nl_seq);
+ ofpbuf_clear(buffer);
+ continue;
+ }
+
+ if (nl_msg_nlmsgerr(buffer, &retval) && retval) {
+ VLOG_INFO_RL(&rl, "netlink dump request error (%s)",
+ ovs_strerror(retval));
+ error = retval == EAGAIN ? EPROTO : retval;
+ ofpbuf_clear(buffer);
+ goto exit;
+ }
}
- nlmsghdr = nl_msg_next(&dump->buffer, reply);
+ /* Fetch the next nlmsg in the current batch. */
+ nlmsghdr = nl_msg_next(buffer, reply);
if (!nlmsghdr) {
VLOG_WARN_RL(&rl, "netlink dump reply contains message fragment");
- dump->status = EPROTO;
- return false;
+ error = EPROTO;
} else if (nlmsghdr->nlmsg_type == NLMSG_DONE) {
- dump->status = EOF;
- return false;
+ error = EOF;
}
- return true;
+exit:
+ if (error == EOF) {
+ unsigned int old;
+ atomic_or(&dump->status, 1, &old);
+ seq_change(dump->status_seq);
+ } else if (error) {
+ atomic_store(&dump->status, error << 1);
+ seq_change(dump->status_seq);
+ }
+ return !error;
}
/* Completes Netlink dump operation 'dump', which must have been initialized
int
nl_dump_done(struct nl_dump *dump)
{
+ int status;
+
/* Drain any remaining messages that the client didn't read. Otherwise the
* kernel will continue to queue them up and waste buffer space.
*
* XXX We could just destroy and discard the socket in this case. */
- while (!dump->status) {
- struct ofpbuf reply;
- if (!nl_dump_next(dump, &reply)) {
- ovs_assert(dump->status);
+ atomic_read(&dump->status, &status);
+ if (!status) {
+ uint64_t tmp_reply_stub[NL_DUMP_BUFSIZE / 8];
+ struct ofpbuf reply, buf;
+
+ ofpbuf_use_stub(&buf, tmp_reply_stub, sizeof tmp_reply_stub);
+ while (nl_dump_next(dump, &reply, &buf)) {
+ /* Nothing to do. */
}
+ atomic_read(&dump->status, &status);
+ ovs_assert(status);
+ ofpbuf_uninit(&buf);
}
+ atomic_destroy(&dump->status);
nl_pool_release(dump->sock);
- ofpbuf_uninit(&dump->buffer);
- return dump->status == EOF ? 0 : dump->status;
+ seq_destroy(dump->status_seq);
+ return status >> 1;
}
/* Causes poll_block() to wake up when any of the specified 'events' (which is