#include <inttypes.h>
#include <stdlib.h>
#include <sys/types.h>
+#include <sys/uio.h>
#include <unistd.h>
#include "coverage.h"
#include "dynamic-string.h"
#include "poll-loop.h"
#include "socket-util.h"
#include "stress.h"
+#include "util.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(netlink_socket);
uint32_t pid;
int protocol;
struct nl_dump *dump;
+ unsigned int rcvbuf; /* Receive buffer size (SO_RCVBUF). */
};
+/* Compile-time limit on iovecs, so that we can allocate a maximum-size array
+ * of iovecs on the stack. */
+#define MAX_IOVS 128
+
+/* Maximum number of iovecs that may be passed to sendmsg, capped at a
+ * minimum of _XOPEN_IOV_MAX (16) and a maximum of MAX_IOVS.
+ *
+ * Initialized by nl_sock_create(). */
+static int max_iovs;
+
static int alloc_pid(uint32_t *);
static void free_pid(uint32_t);
static int nl_sock_cow__(struct nl_sock *);
struct sockaddr_nl local, remote;
int retval = 0;
+ if (!max_iovs) {
+ int save_errno = errno;
+ errno = 0;
+
+ max_iovs = sysconf(_SC_UIO_MAXIOV);
+ if (max_iovs < _XOPEN_IOV_MAX) {
+ if (max_iovs == -1 && errno) {
+ VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", strerror(errno));
+ }
+ max_iovs = _XOPEN_IOV_MAX;
+ } else if (max_iovs > MAX_IOVS) {
+ max_iovs = MAX_IOVS;
+ }
+
+ errno = save_errno;
+ }
+
*sockp = NULL;
sock = malloc(sizeof *sock);
if (sock == NULL) {
sock->protocol = protocol;
sock->dump = NULL;
+ retval = get_socket_rcvbuf(sock->fd);
+ if (retval < 0) {
+ retval = -retval;
+ goto error;
+ }
+ sock->rcvbuf = retval;
+
retval = alloc_pid(&sock->pid);
if (retval) {
goto error;
return nl_sock_recv__(sock, bufp, wait);
}
+static int
+find_nl_transaction_by_seq(struct nl_transaction **transactions, size_t n,
+ uint32_t seq)
+{
+ int i;
+
+ for (i = 0; i < n; i++) {
+ struct nl_transaction *t = transactions[i];
+
+ if (seq == nl_msg_nlmsghdr(t->request)->nlmsg_seq) {
+ return i;
+ }
+ }
+
+ return -1;
+}
+
+static void
+nl_sock_record_errors__(struct nl_transaction **transactions, size_t n,
+ int error)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++) {
+ transactions[i]->error = error;
+ transactions[i]->reply = NULL;
+ }
+}
+
+static int
+nl_sock_transact_multiple__(struct nl_sock *sock,
+ struct nl_transaction **transactions, size_t n,
+ size_t *done)
+{
+ struct iovec iovs[MAX_IOVS];
+ struct msghdr msg;
+ int error;
+ int i;
+
+ *done = 0;
+ for (i = 0; i < n; i++) {
+ struct ofpbuf *request = transactions[i]->request;
+ struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(request);
+
+ nlmsg->nlmsg_len = request->size;
+ nlmsg->nlmsg_pid = sock->pid;
+ if (i == n - 1) {
+ /* Ensure that we get a reply even if the final request doesn't
+ * ordinarily call for one. */
+ nlmsg->nlmsg_flags |= NLM_F_ACK;
+ }
+
+ iovs[i].iov_base = request->data;
+ iovs[i].iov_len = request->size;
+ }
+
+ memset(&msg, 0, sizeof msg);
+ msg.msg_iov = iovs;
+ msg.msg_iovlen = n;
+ do {
+ error = sendmsg(sock->fd, &msg, 0) < 0 ? errno : 0;
+ } while (error == EINTR);
+
+ for (i = 0; i < n; i++) {
+ struct ofpbuf *request = transactions[i]->request;
+
+ log_nlmsg(__func__, error, request->data, request->size,
+ sock->protocol);
+ }
+ if (!error) {
+ COVERAGE_ADD(netlink_sent, n);
+ }
+
+ if (error) {
+ return error;
+ }
+
+ while (n > 0) {
+ struct ofpbuf *reply;
+
+ error = nl_sock_recv__(sock, &reply, true);
+ if (error) {
+ return error;
+ }
+
+ i = find_nl_transaction_by_seq(transactions, n,
+ nl_msg_nlmsghdr(reply)->nlmsg_seq);
+ if (i < 0) {
+ VLOG_DBG_RL(&rl, "ignoring unexpected seq %#"PRIx32,
+ nl_msg_nlmsghdr(reply)->nlmsg_seq);
+ ofpbuf_delete(reply);
+ continue;
+ }
+
+ nl_sock_record_errors__(transactions, i, 0);
+ if (nl_msg_nlmsgerr(reply, &error)) {
+ transactions[i]->reply = NULL;
+ transactions[i]->error = error;
+ if (error) {
+ VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
+ error, strerror(error));
+ }
+ ofpbuf_delete(reply);
+ } else {
+ transactions[i]->reply = reply;
+ transactions[i]->error = 0;
+ }
+
+ *done += i + 1;
+ transactions += i + 1;
+ n -= i + 1;
+ }
+
+ return 0;
+}
+
+/* Sends the 'request' member of the 'n' transactions in 'transactions' to the
+ * kernel, in order, and waits for responses to all of them. Fills in the
+ * 'error' member of each transaction with 0 if it was successful, otherwise
+ * with a positive errno value. 'reply' will be NULL on error or if the
+ * transaction was successful but had no reply beyond an indication of success.
+ * For a successful transaction that did have a more detailed reply, 'reply'
+ * will be set to the reply message.
+ *
+ * The caller is responsible for destroying each request and reply, and the
+ * transactions array itself.
+ *
+ * Before sending each message, this function will finalize nlmsg_len in each
+ * 'request' to match the ofpbuf's size, and set nlmsg_pid to 'sock''s pid.
+ * NLM_F_ACK will be added to some requests' nlmsg_flags.
+ *
+ * Bare Netlink is an unreliable transport protocol. This function layers
+ * reliable delivery and reply semantics on top of bare Netlink. See
+ * nl_sock_transact() for some caveats.
+ */
+void
+nl_sock_transact_multiple(struct nl_sock *sock,
+ struct nl_transaction **transactions, size_t n)
+{
+ int max_batch_count;
+ int error;
+
+ if (!n) {
+ return;
+ }
+
+ error = nl_sock_cow__(sock);
+ if (error) {
+ nl_sock_record_errors__(transactions, n, error);
+ return;
+ }
+
+ /* In theory, every request could have a 64 kB reply. But the default and
+ * maximum socket rcvbuf size with typical Dom0 memory sizes both tend to
+ * be a bit below 128 kB, so that would only allow a single message in a
+ * "batch". So we assume that replies average (at most) 4 kB, which allows
+ * a good deal of batching.
+ *
+ * In practice, most of the requests that we batch either have no reply at
+ * all or a brief reply. */
+ max_batch_count = MAX(sock->rcvbuf / 4096, 1);
+ max_batch_count = MIN(max_batch_count, max_iovs);
+
+ while (n > 0) {
+ size_t count, bytes;
+ size_t done;
+
+ /* Batch up to 'max_batch_count' transactions. But cap it at about a
+ * page of requests total because big skbuffs are expensive to
+ * allocate in the kernel. */
+#if defined(PAGESIZE)
+ enum { MAX_BATCH_BYTES = MAX(1, PAGESIZE - 512) };
+#else
+ enum { MAX_BATCH_BYTES = 4096 - 512 };
+#endif
+ bytes = transactions[0]->request->size;
+ for (count = 1; count < n && count < max_batch_count; count++) {
+ if (bytes + transactions[count]->request->size > MAX_BATCH_BYTES) {
+ break;
+ }
+ bytes += transactions[count]->request->size;
+ }
+
+ error = nl_sock_transact_multiple__(sock, transactions, count, &done);
+ transactions += done;
+ n -= done;
+
+ if (error == ENOBUFS) {
+ VLOG_DBG_RL(&rl, "receive buffer overflow, resending request");
+ } else if (error) {
+ VLOG_ERR_RL(&rl, "transaction error (%s)", strerror(error));
+ nl_sock_record_errors__(transactions, n, error);
+ }
+ }
+}
+
/* Sends 'request' to the kernel via 'sock' and waits for a response. If
* successful, returns 0. On failure, returns a positive errno value.
*
* needs to be idempotent.
*/
int
-nl_sock_transact(struct nl_sock *sock,
- const struct ofpbuf *request, struct ofpbuf **replyp)
+nl_sock_transact(struct nl_sock *sock, const struct ofpbuf *request,
+ struct ofpbuf **replyp)
{
- uint32_t seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
- struct nlmsghdr *nlmsghdr;
- struct ofpbuf *reply;
- int retval;
+ struct nl_transaction *transactionp;
+ struct nl_transaction transaction;
+ transaction.request = (struct ofpbuf *) request;
+ transactionp = &transaction;
+ nl_sock_transact_multiple(sock, &transactionp, 1);
if (replyp) {
- *replyp = NULL;
- }
-
- /* Ensure that we get a reply even if this message doesn't ordinarily call
- * for one. */
- nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_ACK;
-
-send:
- retval = nl_sock_send(sock, request, true);
- if (retval) {
- return retval;
- }
-
-recv:
- retval = nl_sock_recv(sock, &reply, true);
- if (retval) {
- if (retval == ENOBUFS) {
- COVERAGE_INC(netlink_overflow);
- VLOG_DBG_RL(&rl, "receive buffer overflow, resending request");
- goto send;
- } else {
- return retval;
- }
- }
- nlmsghdr = nl_msg_nlmsghdr(reply);
- if (seq != nlmsghdr->nlmsg_seq) {
- VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
- nl_msg_nlmsghdr(reply)->nlmsg_seq, seq);
- ofpbuf_delete(reply);
- goto recv;
- }
-
- /* If the reply is an error, discard the reply and return the error code.
- *
- * Except: if the reply is just an acknowledgement (error code of 0), and
- * the caller is interested in the reply (replyp != NULL), pass the reply
- * up to the caller. Otherwise the caller will get a return value of 0
- * and null '*replyp', which makes unwary callers likely to segfault. */
- if (nl_msg_nlmsgerr(reply, &retval) && (retval || !replyp)) {
- ofpbuf_delete(reply);
- if (retval) {
- VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
- retval, strerror(retval));
- }
- return retval != EAGAIN ? retval : EPROTO;
- }
-
- if (replyp) {
- *replyp = reply;
+ *replyp = transaction.reply;
} else {
- ofpbuf_delete(reply);
+ ofpbuf_delete(transaction.reply);
}
- return 0;
+ return transaction.error;
}
/* Drain all the messages currently in 'sock''s receive queue. */
projects / openvswitch / commitdiff