/*
- * 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"
COVERAGE_DEFINE(netlink_overflow);
COVERAGE_DEFINE(netlink_received);
COVERAGE_DEFINE(netlink_recv_jumbo);
-COVERAGE_DEFINE(netlink_send);
COVERAGE_DEFINE(netlink_sent);
/* Linux header file confusion causes this to be undefined. */
struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
int error;
- nlmsg->nlmsg_len = msg->size;
+ nlmsg->nlmsg_len = ofpbuf_size(msg);
nlmsg->nlmsg_seq = nlmsg_seq;
nlmsg->nlmsg_pid = sock->pid;
do {
int retval;
- retval = send(sock->fd, msg->data, msg->size, wait ? 0 : MSG_DONTWAIT);
+ retval = send(sock->fd, ofpbuf_data(msg), ofpbuf_size(msg), wait ? 0 : MSG_DONTWAIT);
error = retval < 0 ? errno : 0;
} while (error == EINTR);
- log_nlmsg(__func__, error, msg->data, msg->size, sock->protocol);
+ log_nlmsg(__func__, error, ofpbuf_data(msg), ofpbuf_size(msg), sock->protocol);
if (!error) {
COVERAGE_INC(netlink_sent);
}
}
/* Tries to send 'msg', which must contain a Netlink message, to the kernel on
- * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
+ * 'sock'. nlmsg_len in 'msg' will be finalized to match ofpbuf_size(msg), nlmsg_pid
* will be set to 'sock''s pid, and nlmsg_seq will be initialized to a fresh
* sequence number, before the message is sent.
*
}
/* Tries to send 'msg', which must contain a Netlink message, to the kernel on
- * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
+ * 'sock'. nlmsg_len in 'msg' will be finalized to match ofpbuf_size(msg), nlmsg_pid
* will be set to 'sock''s pid, and nlmsg_seq will be initialized to
* 'nlmsg_seq', before the message is sent.
*
struct iovec iov[2];
struct msghdr msg;
ssize_t retval;
+ int error;
ovs_assert(buf->allocated >= sizeof *nlmsghdr);
ofpbuf_clear(buf);
- iov[0].iov_base = buf->base;
+ iov[0].iov_base = ofpbuf_base(buf);
iov[0].iov_len = buf->allocated;
iov[1].iov_base = tail;
iov[1].iov_len = sizeof tail;
msg.msg_iov = iov;
msg.msg_iovlen = 2;
+ /* Receive a Netlink message from the kernel.
+ *
+ * This works around a kernel bug in which the kernel returns an error code
+ * as if it were the number of bytes read. It doesn't actually modify
+ * anything in the receive buffer in that case, so we can initialize the
+ * Netlink header with an impossible message length and then, upon success,
+ * check whether it changed. */
+ nlmsghdr = ofpbuf_base(buf);
do {
+ nlmsghdr->nlmsg_len = UINT32_MAX;
retval = recvmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
- } while (retval < 0 && errno == EINTR);
-
- if (retval < 0) {
- int error = errno;
+ error = (retval < 0 ? errno
+ : retval == 0 ? ECONNRESET /* not possible? */
+ : nlmsghdr->nlmsg_len != UINT32_MAX ? 0
+ : retval);
+ } while (error == EINTR);
+ if (error) {
if (error == ENOBUFS) {
/* Socket receive buffer overflow dropped one or more messages that
* the kernel tried to send to us. */
}
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;
}
- nlmsghdr = buf->data;
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" bytes < %"PRIuSIZE")",
retval, sizeof *nlmsghdr);
return EPROTO;
}
- buf->size = MIN(retval, buf->allocated);
+ ofpbuf_set_size(buf, MIN(retval, buf->allocated));
if (retval > buf->allocated) {
COVERAGE_INC(netlink_recv_jumbo);
ofpbuf_put(buf, tail, retval - buf->allocated);
}
- log_nlmsg(__func__, 0, buf->data, buf->size, sock->protocol);
+ log_nlmsg(__func__, 0, ofpbuf_data(buf), ofpbuf_size(buf), sock->protocol);
COVERAGE_INC(netlink_received);
return 0;
struct nl_transaction *txn = transactions[i];
struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(txn->request);
- nlmsg->nlmsg_len = txn->request->size;
+ nlmsg->nlmsg_len = ofpbuf_size(txn->request);
nlmsg->nlmsg_seq = base_seq + i;
nlmsg->nlmsg_pid = sock->pid;
- iovs[i].iov_base = txn->request->data;
- iovs[i].iov_len = txn->request->size;
+ iovs[i].iov_base = ofpbuf_data(txn->request);
+ iovs[i].iov_len = ofpbuf_size(txn->request);
}
memset(&msg, 0, sizeof msg);
for (i = 0; i < n; i++) {
struct nl_transaction *txn = transactions[i];
- log_nlmsg(__func__, error, txn->request->data, txn->request->size,
+ log_nlmsg(__func__, error, ofpbuf_data(txn->request), ofpbuf_size(txn->request),
sock->protocol);
}
if (!error) {
#else
enum { MAX_BATCH_BYTES = 4096 - 512 };
#endif
- bytes = transactions[0]->request->size;
+ bytes = ofpbuf_size(transactions[0]->request);
for (count = 1; count < n && count < max_batch_count; count++) {
- if (bytes + transactions[count]->request->size > MAX_BATCH_BYTES) {
+ if (bytes + ofpbuf_size(transactions[count]->request) > MAX_BATCH_BYTES) {
break;
}
- bytes += transactions[count]->request->size;
+ bytes += ofpbuf_size(transactions[count]->request);
}
error = nl_sock_transact_multiple__(sock, transactions, count, &done);
* reply, if any, is discarded.
*
* Before the message is sent, nlmsg_len in 'request' will be finalized to
- * match msg->size, nlmsg_pid will be set to 'sock''s pid, and nlmsg_seq will
+ * match ofpbuf_size(msg), nlmsg_pid will be set to 'sock''s pid, and nlmsg_seq will
* be initialized, NLM_F_ACK will be set in nlmsg_flags.
*
* The caller is responsible for destroying 'request'.
* 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();
+ ovs_mutex_init(&dump->mutex);
}
-/* 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).
+ * If successful, returns true and points 'reply->data' and 'ofpbuf_size(reply)' to
+ * 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'
+ * On failure, returns false and sets 'reply->data' to NULL and 'ofpbuf_size(reply)'
* 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;
- }
+ ofpbuf_set_data(reply, NULL);
+ ofpbuf_set_size(reply, 0);
+
+ /* If 'buffer' is empty, fetch another batch of nlmsgs. */
+ while (!ofpbuf_size(buffer)) {
+ unsigned int status;
+ int retval, seq;
+
+ seq = seq_read(dump->status_seq);
+ atomic_read(&dump->status, &status);
+ if (status) {
+ return false;
+ }
+
+ /* Take the mutex here to avoid an in-kernel race. If two threads try
+ * to read from a Netlink dump socket at once, then the socket error
+ * can be set to EINVAL, which will be encountered on the next recv on
+ * that socket, which could be anywhere due to the way that we pool
+ * Netlink sockets. Serializing the recv calls avoids the issue. */
+ ovs_mutex_lock(&dump->mutex);
+ retval = nl_sock_recv__(dump->sock, buffer, false);
+ ovs_mutex_unlock(&dump->mutex);
- while (!dump->buffer.size) {
- int retval = nl_dump_recv(dump);
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;
+ }
+
+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;
+}
- return true;
+/* Attempts to look ahead in 'buffer' to obtain the next reply that will be
+ * returned by nl_dump_next(). Returns true if successful, in which case
+ * 'reply' will be initialize to the message that will be obtained by the next
+ * call to nl_dump_next(), or false on failure. Failure doesn't necessarily
+ * mean that the nl_dump_next() will fail, only that it needs to obtain a new
+ * block of dump results from the kernel. */
+bool
+nl_dump_peek(struct ofpbuf *reply, struct ofpbuf *buffer)
+{
+ struct ofpbuf tmp = *buffer;
+ return nl_msg_next(&tmp, reply);
}
/* 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);
}
nl_pool_release(dump->sock);
- ofpbuf_uninit(&dump->buffer);
- return dump->status == EOF ? 0 : dump->status;
+ seq_destroy(dump->status_seq);
+ ovs_mutex_destroy(&dump->mutex);
+ return status >> 1;
}
/* Causes poll_block() to wake up when any of the specified 'events' (which is
projects / cascardo / ovs.git / blobdiff