#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 "hash.h"
+#include "hmap.h"
#include "netlink.h"
#include "netlink-protocol.h"
#include "ofpbuf.h"
#include "poll-loop.h"
#include "socket-util.h"
#include "stress.h"
+#include "util.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(netlink_socket);
COVERAGE_DEFINE(netlink_overflow);
COVERAGE_DEFINE(netlink_received);
-COVERAGE_DEFINE(netlink_recv_retry);
+COVERAGE_DEFINE(netlink_recv_jumbo);
COVERAGE_DEFINE(netlink_send);
COVERAGE_DEFINE(netlink_sent);
int fd;
uint32_t pid;
int protocol;
+ struct nl_dump *dump;
+ unsigned int rcvbuf; /* Receive buffer size (SO_RCVBUF). */
};
-static int alloc_pid(uint32_t *);
-static void free_pid(uint32_t);
+/* 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 nl_sock_cow__(struct nl_sock *);
/* Creates a new netlink socket for the given netlink 'protocol'
* (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
{
struct nl_sock *sock;
struct sockaddr_nl local, remote;
+ socklen_t local_size;
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) {
goto error;
}
sock->protocol = protocol;
+ sock->dump = NULL;
- retval = alloc_pid(&sock->pid);
- if (retval) {
+ retval = get_socket_rcvbuf(sock->fd);
+ if (retval < 0) {
+ retval = -retval;
goto error;
}
+ sock->rcvbuf = retval;
- /* Bind local address as our selected pid. */
- memset(&local, 0, sizeof local);
- local.nl_family = AF_NETLINK;
- local.nl_pid = sock->pid;
- if (bind(sock->fd, (struct sockaddr *) &local, sizeof local) < 0) {
- VLOG_ERR("bind(%"PRIu32"): %s", sock->pid, strerror(errno));
- goto error_free_pid;
- }
-
- /* Bind remote address as the kernel (pid 0). */
+ /* Connect to kernel (pid 0) as remote address. */
memset(&remote, 0, sizeof remote);
remote.nl_family = AF_NETLINK;
remote.nl_pid = 0;
if (connect(sock->fd, (struct sockaddr *) &remote, sizeof remote) < 0) {
VLOG_ERR("connect(0): %s", strerror(errno));
- goto error_free_pid;
+ goto error;
+ }
+
+ /* Obtain pid assigned by kernel. */
+ local_size = sizeof local;
+ if (getsockname(sock->fd, (struct sockaddr *) &local, &local_size) < 0) {
+ VLOG_ERR("getsockname: %s", strerror(errno));
+ goto error;
+ }
+ if (local_size < sizeof local || local.nl_family != AF_NETLINK) {
+ VLOG_ERR("getsockname returned bad Netlink name");
+ retval = EINVAL;
+ goto error;
}
+ sock->pid = local.nl_pid;
*sockp = sock;
return 0;
-error_free_pid:
- free_pid(sock->pid);
error:
if (retval == 0) {
retval = errno;
return retval;
}
+/* Creates a new netlink socket for the same protocol as 'src'. Returns 0 and
+ * sets '*sockp' to the new socket if successful, otherwise returns a positive
+ * errno value. */
+int
+nl_sock_clone(const struct nl_sock *src, struct nl_sock **sockp)
+{
+ return nl_sock_create(src->protocol, sockp);
+}
+
/* Destroys netlink socket 'sock'. */
void
nl_sock_destroy(struct nl_sock *sock)
{
if (sock) {
- close(sock->fd);
- free_pid(sock->pid);
- free(sock);
+ if (sock->dump) {
+ sock->dump = NULL;
+ } else {
+ close(sock->fd);
+ free(sock);
+ }
}
}
/* Tries to add 'sock' as a listener for 'multicast_group'. Returns 0 if
* successful, otherwise a positive errno value.
*
+ * A socket that is subscribed to a multicast group that receives asynchronous
+ * notifications must not be used for Netlink transactions or dumps, because
+ * transactions and dumps can cause notifications to be lost.
+ *
* Multicast group numbers are always positive.
*
* It is not an error to attempt to join a multicast group to which a socket
int
nl_sock_join_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
{
+ int error = nl_sock_cow__(sock);
+ if (error) {
+ return error;
+ }
if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
&multicast_group, sizeof multicast_group) < 0) {
VLOG_WARN("could not join multicast group %u (%s)",
int
nl_sock_leave_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
{
+ assert(!sock->dump);
if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP,
&multicast_group, sizeof multicast_group) < 0) {
VLOG_WARN("could not leave multicast group %u (%s)",
return 0;
}
-/* 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, and
- * nlmsg_pid will be set to 'sock''s pid, before the message is sent.
- *
- * Returns 0 if successful, otherwise a positive errno value. If
- * 'wait' is true, then the send will wait until buffer space is ready;
- * otherwise, returns EAGAIN if the 'sock' send buffer is full. */
-int
-nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
+static int
+nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
{
struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
int error;
return error;
}
-/* Tries to send the 'n_iov' chunks of data in 'iov' to the kernel on 'sock' as
- * a single Netlink message. (The message must be fully formed and not require
- * finalization of its nlmsg_len or nlmsg_pid fields.)
+/* 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, and
+ * nlmsg_pid will be set to 'sock''s pid, before the message is sent.
*
- * Returns 0 if successful, otherwise a positive errno value. If 'wait' is
- * true, then the send will wait until buffer space is ready; otherwise,
- * returns EAGAIN if the 'sock' send buffer is full. */
+ * Returns 0 if successful, otherwise a positive errno value. If
+ * 'wait' is true, then the send will wait until buffer space is ready;
+ * otherwise, returns EAGAIN if the 'sock' send buffer is full. */
int
-nl_sock_sendv(struct nl_sock *sock, const struct iovec iov[], size_t n_iov,
- bool wait)
+nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
{
- struct msghdr msg;
- int error;
-
- COVERAGE_INC(netlink_send);
- memset(&msg, 0, sizeof msg);
- msg.msg_iov = (struct iovec *) iov;
- msg.msg_iovlen = n_iov;
- do {
- int retval;
- retval = sendmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
- error = retval < 0 ? errno : 0;
- } while (error == EINTR);
- if (error != EAGAIN) {
- log_nlmsg(__func__, error, iov[0].iov_base, iov[0].iov_len,
- sock->protocol);
- if (!error) {
- COVERAGE_INC(netlink_sent);
- }
+ int error = nl_sock_cow__(sock);
+ if (error) {
+ return error;
}
- return error;
+ return nl_sock_send__(sock, msg, wait);
}
/* This stress option is useful for testing that OVS properly tolerates
netlink_overflow, "simulate netlink socket receive buffer overflow",
5, 1, -1, 100);
-/* Tries to receive a netlink message from the kernel on 'sock'. If
- * successful, stores the received message into '*bufp' and returns 0. The
- * caller is responsible for destroying the message with ofpbuf_delete(). On
- * failure, returns a positive errno value and stores a null pointer into
- * '*bufp'.
- *
- * If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise,
- * returns EAGAIN if the 'sock' receive buffer is empty. */
-int
-nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
+static int
+nl_sock_recv__(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
{
- uint8_t tmp;
- ssize_t bufsize = 2048;
- ssize_t nbytes, nbytes2;
- struct ofpbuf *buf;
+ /* We can't accurately predict the size of the data to be received. Most
+ * received data will fit in a 2 kB buffer, so we allocate that much space.
+ * In case the data is actually bigger than that, we make available enough
+ * additional space to allow Netlink messages to be up to 64 kB long (a
+ * reasonable figure since that's the maximum length of a Netlink
+ * attribute). */
+ enum { MAX_SIZE = 65536 };
+ enum { HEAD_SIZE = 2048 };
+ enum { TAIL_SIZE = MAX_SIZE - HEAD_SIZE };
+
struct nlmsghdr *nlmsghdr;
- struct iovec iov;
- struct msghdr msg = {
- .msg_name = NULL,
- .msg_namelen = 0,
- .msg_iov = &iov,
- .msg_iovlen = 1,
- .msg_control = NULL,
- .msg_controllen = 0,
- .msg_flags = 0
- };
+ uint8_t tail[TAIL_SIZE];
+ struct iovec iov[2];
+ struct ofpbuf *buf;
+ struct msghdr msg;
+ ssize_t retval;
- buf = ofpbuf_new(bufsize);
*bufp = NULL;
-try_again:
- /* Attempt to read the message. We don't know the size of the data
- * yet, so we take a guess at 2048. If we're wrong, we keep trying
- * and doubling the buffer size each time.
- */
- nlmsghdr = ofpbuf_put_uninit(buf, bufsize);
- iov.iov_base = nlmsghdr;
- iov.iov_len = bufsize;
+ buf = ofpbuf_new(HEAD_SIZE);
+ iov[0].iov_base = buf->data;
+ iov[0].iov_len = HEAD_SIZE;
+ iov[1].iov_base = tail;
+ iov[1].iov_len = TAIL_SIZE;
+
+ memset(&msg, 0, sizeof msg);
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 2;
+
do {
- nbytes = recvmsg(sock->fd, &msg, (wait ? 0 : MSG_DONTWAIT) | MSG_PEEK);
- } while (nbytes < 0 && errno == EINTR);
- if (nbytes < 0) {
+ retval = recvmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
+ } while (retval < 0 && errno == EINTR);
+
+ if (retval < 0) {
+ int error = errno;
+ if (error == ENOBUFS) {
+ /* Socket receive buffer overflow dropped one or more messages that
+ * the kernel tried to send to us. */
+ COVERAGE_INC(netlink_overflow);
+ }
ofpbuf_delete(buf);
- return errno;
+ return error;
}
+
if (msg.msg_flags & MSG_TRUNC) {
- COVERAGE_INC(netlink_recv_retry);
- bufsize *= 2;
- ofpbuf_reinit(buf, bufsize);
- goto try_again;
+ VLOG_ERR_RL(&rl, "truncated message (longer than %d bytes)", MAX_SIZE);
+ ofpbuf_delete(buf);
+ return E2BIG;
}
- buf->size = nbytes;
- /* We successfully read the message, so recv again to clear the queue */
- iov.iov_base = &tmp;
- iov.iov_len = 1;
- do {
- nbytes2 = recvmsg(sock->fd, &msg, MSG_DONTWAIT);
- } while (nbytes2 < 0 && errno == EINTR);
- if (nbytes2 < 0) {
- if (errno == ENOBUFS) {
- /* The kernel is notifying us that a message it tried to send to us
- * was dropped. We have to pass this along to the caller in case
- * it wants to retry a request. So kill the buffer, which we can
- * re-read next time. */
- COVERAGE_INC(netlink_overflow);
- ofpbuf_delete(buf);
- return ENOBUFS;
- } else {
- VLOG_ERR_RL(&rl, "failed to remove nlmsg from socket: %s\n",
- strerror(errno));
- }
+ ofpbuf_put_uninit(buf, MIN(retval, HEAD_SIZE));
+ if (retval > HEAD_SIZE) {
+ COVERAGE_INC(netlink_recv_jumbo);
+ ofpbuf_put(buf, tail, retval - HEAD_SIZE);
}
- if (nbytes < sizeof *nlmsghdr
+
+ nlmsghdr = buf->data;
+ if (retval < sizeof *nlmsghdr
|| nlmsghdr->nlmsg_len < sizeof *nlmsghdr
- || nlmsghdr->nlmsg_len > nbytes) {
+ || nlmsghdr->nlmsg_len > retval) {
VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %d)",
- bufsize, NLMSG_HDRLEN);
+ retval, NLMSG_HDRLEN);
ofpbuf_delete(buf);
return EPROTO;
}
return 0;
}
+/* Tries to receive a netlink message from the kernel on 'sock'. If
+ * successful, stores the received message into '*bufp' and returns 0. The
+ * caller is responsible for destroying the message with ofpbuf_delete(). On
+ * failure, returns a positive errno value and stores a null pointer into
+ * '*bufp'.
+ *
+ * If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise,
+ * returns EAGAIN if the 'sock' receive buffer is empty. */
+int
+nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
+{
+ int error = nl_sock_cow__(sock);
+ if (error) {
+ return 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;
-
- 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 %"PRIu32" != expected %"PRIu32,
- 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;
- }
+ 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 = 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. */
int
nl_sock_drain(struct nl_sock *sock)
{
+ int error = nl_sock_cow__(sock);
+ if (error) {
+ return error;
+ }
return drain_rcvbuf(sock->fd);
}
+/* The client is attempting some operation on 'sock'. If 'sock' has an ongoing
+ * dump operation, then replace 'sock''s fd with a new socket and hand 'sock''s
+ * old fd over to the dump. */
+static int
+nl_sock_cow__(struct nl_sock *sock)
+{
+ struct nl_sock *copy;
+ uint32_t tmp_pid;
+ int tmp_fd;
+ int error;
+
+ if (!sock->dump) {
+ return 0;
+ }
+
+ error = nl_sock_clone(sock, ©);
+ if (error) {
+ return error;
+ }
+
+ tmp_fd = sock->fd;
+ sock->fd = copy->fd;
+ copy->fd = tmp_fd;
+
+ tmp_pid = sock->pid;
+ sock->pid = copy->pid;
+ copy->pid = tmp_pid;
+
+ sock->dump->sock = copy;
+ sock->dump = NULL;
+
+ return 0;
+}
+
/* Starts a Netlink "dump" operation, by sending 'request' to the kernel via
* 'sock', and initializes 'dump' to reflect the state of the operation.
*
* be set to 'sock''s pid, before the message is sent. NLM_F_DUMP and
* NLM_F_ACK will be set in nlmsg_flags.
*
- * The properties of Netlink make dump operations reliable as long as all of
- * the following are true:
- *
- * - At most a single dump is in progress at a time on a given nl_sock.
+ * This Netlink socket library is designed to ensure that the dump is reliable
+ * and that it will not interfere with other operations on 'sock', including
+ * destroying or sending and receiving messages on 'sock'. One corner case is
+ * not handled:
*
- * - The nl_sock is not subscribed to any multicast groups.
- *
- * - The nl_sock is not used to send any other messages before the dump
- * operation is complete.
+ * - If 'sock' has been used to send a request (e.g. with nl_sock_send())
+ * whose response has not yet been received (e.g. with nl_sock_recv()).
+ * This is unusual: usually nl_sock_transact() is used to send a message
+ * and receive its reply all in one go.
*
* 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().
*
- * The caller is responsible for destroying 'request'. The caller must not
- * close 'sock' before it completes the dump operation (by calling
- * nl_dump_done()) or before nl_dump_next() returns false, whichever comes
- * first.
+ * The caller is responsible for destroying 'request'.
+ *
+ * The new 'dump' is independent of 'sock'. 'sock' and 'dump' may be destroyed
+ * in either order.
*/
void
nl_dump_start(struct nl_dump *dump,
struct nlmsghdr *nlmsghdr = nl_msg_nlmsghdr(request);
nlmsghdr->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
dump->seq = nlmsghdr->nlmsg_seq;
- dump->sock = sock;
- dump->status = nl_sock_send(sock, request, true);
dump->buffer = NULL;
+ if (sock->dump) {
+ /* 'sock' already has an ongoing dump. Clone the socket because
+ * Netlink only allows one dump at a time. */
+ dump->status = nl_sock_clone(sock, &dump->sock);
+ if (dump->status) {
+ return;
+ }
+ } else {
+ sock->dump = dump;
+ dump->sock = sock;
+ dump->status = 0;
+ }
+ dump->status = nl_sock_send__(sock, request, true);
}
/* Helper function for nl_dump_next(). */
struct ofpbuf *buffer;
int retval;
- retval = nl_sock_recv(dump->sock, bufferp, true);
+ retval = nl_sock_recv__(dump->sock, bufferp, true);
if (retval) {
return retval == EINTR ? EAGAIN : retval;
}
nlmsghdr = nl_msg_nlmsghdr(buffer);
if (dump->seq != nlmsghdr->nlmsg_seq) {
- VLOG_DBG_RL(&rl, "ignoring seq %"PRIu32" != expected %"PRIu32,
+ VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
nlmsghdr->nlmsg_seq, dump->seq);
return EAGAIN;
}
}
}
+ if (dump->sock) {
+ if (dump->sock->dump) {
+ dump->sock->dump = NULL;
+ } else {
+ nl_sock_destroy(dump->sock);
+ }
+ }
ofpbuf_delete(dump->buffer);
return dump->status == EOF ? 0 : dump->status;
}
{
poll_fd_wait(sock->fd, events);
}
+
+/* Returns the underlying fd for 'sock', for use in "poll()"-like operations
+ * that can't use nl_sock_wait().
+ *
+ * It's a little tricky to use the returned fd correctly, because nl_sock does
+ * "copy on write" to allow a single nl_sock to be used for notifications,
+ * transactions, and dumps. If 'sock' is used only for notifications and
+ * transactions (and never for dump) then the usage is safe. */
+int
+nl_sock_fd(const struct nl_sock *sock)
+{
+ return sock->fd;
+}
+
+/* Returns the PID associated with this socket. */
+uint32_t
+nl_sock_pid(const struct nl_sock *sock)
+{
+ return sock->pid;
+}
\f
/* Miscellaneous. */
+struct genl_family {
+ struct hmap_node hmap_node;
+ uint16_t id;
+ char *name;
+};
+
+static struct hmap genl_families = HMAP_INITIALIZER(&genl_families);
+
static const struct nl_policy family_policy[CTRL_ATTR_MAX + 1] = {
[CTRL_ATTR_FAMILY_ID] = {.type = NL_A_U16},
+ [CTRL_ATTR_MCAST_GROUPS] = {.type = NL_A_NESTED, .optional = true},
};
-static int do_lookup_genl_family(const char *name)
+static struct genl_family *
+find_genl_family_by_id(uint16_t id)
+{
+ struct genl_family *family;
+
+ HMAP_FOR_EACH_IN_BUCKET (family, hmap_node, hash_int(id, 0),
+ &genl_families) {
+ if (family->id == id) {
+ return family;
+ }
+ }
+ return NULL;
+}
+
+static void
+define_genl_family(uint16_t id, const char *name)
+{
+ struct genl_family *family = find_genl_family_by_id(id);
+
+ if (family) {
+ if (!strcmp(family->name, name)) {
+ return;
+ }
+ free(family->name);
+ } else {
+ family = xmalloc(sizeof *family);
+ family->id = id;
+ hmap_insert(&genl_families, &family->hmap_node, hash_int(id, 0));
+ }
+ family->name = xstrdup(name);
+}
+
+static const char *
+genl_family_to_name(uint16_t id)
+{
+ if (id == GENL_ID_CTRL) {
+ return "control";
+ } else {
+ struct genl_family *family = find_genl_family_by_id(id);
+ return family ? family->name : "unknown";
+ }
+}
+
+static int
+do_lookup_genl_family(const char *name, struct nlattr **attrs,
+ struct ofpbuf **replyp)
{
struct nl_sock *sock;
struct ofpbuf request, *reply;
- struct nlattr *attrs[ARRAY_SIZE(family_policy)];
- int retval;
+ int error;
- retval = nl_sock_create(NETLINK_GENERIC, &sock);
- if (retval) {
- return -retval;
+ *replyp = NULL;
+ error = nl_sock_create(NETLINK_GENERIC, &sock);
+ if (error) {
+ return error;
}
ofpbuf_init(&request, 0);
nl_msg_put_genlmsghdr(&request, 0, GENL_ID_CTRL, NLM_F_REQUEST,
CTRL_CMD_GETFAMILY, 1);
nl_msg_put_string(&request, CTRL_ATTR_FAMILY_NAME, name);
- retval = nl_sock_transact(sock, &request, &reply);
+ error = nl_sock_transact(sock, &request, &reply);
ofpbuf_uninit(&request);
- if (retval) {
+ if (error) {
nl_sock_destroy(sock);
- return -retval;
+ return error;
}
if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
- family_policy, attrs, ARRAY_SIZE(family_policy))) {
+ family_policy, attrs, ARRAY_SIZE(family_policy))
+ || nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]) == 0) {
nl_sock_destroy(sock);
ofpbuf_delete(reply);
- return -EPROTO;
+ return EPROTO;
}
- retval = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]);
- if (retval == 0) {
- retval = -EPROTO;
- }
nl_sock_destroy(sock);
- ofpbuf_delete(reply);
- return retval;
+ *replyp = reply;
+ return 0;
}
-/* If '*number' is 0, translates the given Generic Netlink family 'name' to a
- * number and stores it in '*number'. If successful, returns 0 and the caller
- * may use '*number' as the family number. On failure, returns a positive
- * errno value and '*number' caches the errno value. */
+/* Finds the multicast group called 'group_name' in genl family 'family_name'.
+ * When successful, writes its result to 'multicast_group' and returns 0.
+ * Otherwise, clears 'multicast_group' and returns a positive error code.
+ *
+ * Some kernels do not support looking up a multicast group with this function.
+ * In this case, 'multicast_group' will be populated with 'fallback'. */
int
-nl_lookup_genl_family(const char *name, int *number)
+nl_lookup_genl_mcgroup(const char *family_name, const char *group_name,
+ unsigned int *multicast_group, unsigned int fallback)
{
- if (*number == 0) {
- *number = do_lookup_genl_family(name);
- assert(*number != 0);
+ struct nlattr *family_attrs[ARRAY_SIZE(family_policy)];
+ const struct nlattr *mc;
+ struct ofpbuf *reply;
+ unsigned int left;
+ int error;
+
+ *multicast_group = 0;
+ error = do_lookup_genl_family(family_name, family_attrs, &reply);
+ if (error) {
+ return error;
}
- return *number > 0 ? 0 : -*number;
-}
-\f
-/* Netlink PID.
- *
- * Every Netlink socket must be bound to a unique 32-bit PID. By convention,
- * programs that have a single Netlink socket use their Unix process ID as PID,
- * and programs with multiple Netlink sockets add a unique per-socket
- * identifier in the bits above the Unix process ID.
- *
- * The kernel has Netlink PID 0.
- */
-/* Parameters for how many bits in the PID should come from the Unix process ID
- * and how many unique per-socket. */
-#define SOCKET_BITS 10
-#define MAX_SOCKETS (1u << SOCKET_BITS)
+ if (!family_attrs[CTRL_ATTR_MCAST_GROUPS]) {
+ *multicast_group = fallback;
+ VLOG_WARN("%s-%s: has no multicast group, using fallback %d",
+ family_name, group_name, *multicast_group);
+ error = 0;
+ goto exit;
+ }
-#define PROCESS_BITS (32 - SOCKET_BITS)
-#define MAX_PROCESSES (1u << PROCESS_BITS)
-#define PROCESS_MASK ((uint32_t) (MAX_PROCESSES - 1))
+ NL_NESTED_FOR_EACH (mc, left, family_attrs[CTRL_ATTR_MCAST_GROUPS]) {
+ static const struct nl_policy mc_policy[] = {
+ [CTRL_ATTR_MCAST_GRP_ID] = {.type = NL_A_U32},
+ [CTRL_ATTR_MCAST_GRP_NAME] = {.type = NL_A_STRING},
+ };
-/* Bit vector of unused socket identifiers. */
-static uint32_t avail_sockets[ROUND_UP(MAX_SOCKETS, 32)];
+ struct nlattr *mc_attrs[ARRAY_SIZE(mc_policy)];
+ const char *mc_name;
-/* Allocates and returns a new Netlink PID. */
-static int
-alloc_pid(uint32_t *pid)
-{
- int i;
+ if (!nl_parse_nested(mc, mc_policy, mc_attrs, ARRAY_SIZE(mc_policy))) {
+ error = EPROTO;
+ goto exit;
+ }
- for (i = 0; i < MAX_SOCKETS; i++) {
- if ((avail_sockets[i / 32] & (1u << (i % 32))) == 0) {
- avail_sockets[i / 32] |= 1u << (i % 32);
- *pid = (getpid() & PROCESS_MASK) | (i << PROCESS_BITS);
- return 0;
+ mc_name = nl_attr_get_string(mc_attrs[CTRL_ATTR_MCAST_GRP_NAME]);
+ if (!strcmp(group_name, mc_name)) {
+ *multicast_group =
+ nl_attr_get_u32(mc_attrs[CTRL_ATTR_MCAST_GRP_ID]);
+ error = 0;
+ goto exit;
}
}
- VLOG_ERR("netlink pid space exhausted");
- return ENOBUFS;
+ error = EPROTO;
+
+exit:
+ ofpbuf_delete(reply);
+ return error;
}
-/* Makes the specified 'pid' available for reuse. */
-static void
-free_pid(uint32_t pid)
+/* If '*number' is 0, translates the given Generic Netlink family 'name' to a
+ * number and stores it in '*number'. If successful, returns 0 and the caller
+ * may use '*number' as the family number. On failure, returns a positive
+ * errno value and '*number' caches the errno value. */
+int
+nl_lookup_genl_family(const char *name, int *number)
{
- int sock = pid >> PROCESS_BITS;
- assert(avail_sockets[sock / 32] & (1u << (sock % 32)));
- avail_sockets[sock / 32] &= ~(1u << (sock % 32));
+ if (*number == 0) {
+ struct nlattr *attrs[ARRAY_SIZE(family_policy)];
+ struct ofpbuf *reply;
+ int error;
+
+ error = do_lookup_genl_family(name, attrs, &reply);
+ if (!error) {
+ *number = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]);
+ define_genl_family(*number, name);
+ } else {
+ *number = -error;
+ }
+ ofpbuf_delete(reply);
+
+ assert(*number != 0);
+ }
+ return *number > 0 ? 0 : -*number;
}
\f
static void
-nlmsghdr_to_string(const struct nlmsghdr *h, struct ds *ds)
+nlmsghdr_to_string(const struct nlmsghdr *h, int protocol, struct ds *ds)
{
struct nlmsg_flag {
unsigned int bits;
ds_put_cstr(ds, "(overrun)");
} else if (h->nlmsg_type < NLMSG_MIN_TYPE) {
ds_put_cstr(ds, "(reserved)");
+ } else if (protocol == NETLINK_GENERIC) {
+ ds_put_format(ds, "(%s)", genl_family_to_name(h->nlmsg_type));
} else {
ds_put_cstr(ds, "(family-defined)");
}
if (flags_left) {
ds_put_format(ds, "[OTHER:%"PRIx16"]", flags_left);
}
- ds_put_format(ds, ", seq=%"PRIx32", pid=%"PRIu32"(%d:%d))",
- h->nlmsg_seq, h->nlmsg_pid,
- (int) (h->nlmsg_pid & PROCESS_MASK),
- (int) (h->nlmsg_pid >> PROCESS_BITS));
+ ds_put_format(ds, ", seq=%"PRIx32", pid=%"PRIu32,
+ h->nlmsg_seq, h->nlmsg_pid);
}
static char *
struct ds ds = DS_EMPTY_INITIALIZER;
const struct nlmsghdr *h = ofpbuf_at(buffer, 0, NLMSG_HDRLEN);
if (h) {
- nlmsghdr_to_string(h, &ds);
+ nlmsghdr_to_string(h, protocol, &ds);
if (h->nlmsg_type == NLMSG_ERROR) {
const struct nlmsgerr *e;
e = ofpbuf_at(buffer, NLMSG_HDRLEN,
ds_put_format(&ds, "(%s)", strerror(-e->error));
}
ds_put_cstr(&ds, ", in-reply-to(");
- nlmsghdr_to_string(&e->msg, &ds);
+ nlmsghdr_to_string(&e->msg, protocol, &ds);
ds_put_cstr(&ds, "))");
} else {
ds_put_cstr(&ds, " error(truncated)");
git://git.onelab.eu / sliver-openvswitch.git / blobdiff