#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);
int fd;
uint32_t pid;
int protocol;
- bool any_groups;
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'
{
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->any_groups = false;
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;
sock->dump = NULL;
} else {
close(sock->fd);
- free_pid(sock->pid);
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
multicast_group, strerror(errno));
return errno;
}
- sock->any_groups = true;
return 0;
}
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. */
nlmsghdr->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
dump->seq = nlmsghdr->nlmsg_seq;
dump->buffer = NULL;
- if (sock->any_groups || sock->dump) {
- /* 'sock' might belong to some multicast group, or it already has an
- * onoging dump. Clone the socket to avoid possibly intermixing
- * multicast messages or previous dump results with our results. */
+ 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;
{
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. */
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},
+ [CTRL_ATTR_MCAST_GROUPS] = {.type = NL_A_NESTED, .optional = true},
};
static struct genl_family *
}
static int
-do_lookup_genl_family(const char *name, struct nlattr **attrs)
+do_lookup_genl_family(const char *name, struct nlattr **attrs,
+ struct ofpbuf **replyp)
{
struct nl_sock *sock;
struct ofpbuf request, *reply;
- 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;
- } else {
- define_genl_family(retval, name);
- }
nl_sock_destroy(sock);
- ofpbuf_delete(reply);
-
- return retval;
+ *replyp = reply;
+ return 0;
}
/* 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. */
+ * 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_mcgroup(const char *family_name, const char *group_name,
- unsigned int *multicast_group)
+ unsigned int *multicast_group, unsigned int fallback)
{
struct nlattr *family_attrs[ARRAY_SIZE(family_policy)];
- struct ofpbuf all_mcs;
- struct nlattr *mc;
+ const struct nlattr *mc;
+ struct ofpbuf *reply;
unsigned int left;
- int retval;
+ int error;
*multicast_group = 0;
- retval = do_lookup_genl_family(family_name, family_attrs);
- if (retval <= 0) {
- assert(retval);
- return -retval;
+ error = do_lookup_genl_family(family_name, family_attrs, &reply);
+ if (error) {
+ return error;
+ }
+
+ 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;
}
- nl_attr_get_nested(family_attrs[CTRL_ATTR_MCAST_GROUPS], &all_mcs);
- NL_ATTR_FOR_EACH (mc, left, all_mcs.data, all_mcs.size) {
+ 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},
const char *mc_name;
if (!nl_parse_nested(mc, mc_policy, mc_attrs, ARRAY_SIZE(mc_policy))) {
- return EPROTO;
+ error = EPROTO;
+ goto exit;
}
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]);
- return 0;
+ error = 0;
+ goto exit;
}
}
+ error = EPROTO;
- return EPROTO;
+exit:
+ ofpbuf_delete(reply);
+ return error;
}
/* If '*number' is 0, translates the given Generic Netlink family 'name' to a
int
nl_lookup_genl_family(const char *name, int *number)
{
- struct nlattr *attrs[ARRAY_SIZE(family_policy)];
-
if (*number == 0) {
- *number = do_lookup_genl_family(name, attrs);
+ 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
-/* 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)
-
-#define PROCESS_BITS (32 - SOCKET_BITS)
-#define MAX_PROCESSES (1u << PROCESS_BITS)
-#define PROCESS_MASK ((uint32_t) (MAX_PROCESSES - 1))
-
-/* Bit vector of unused socket identifiers. */
-static uint32_t avail_sockets[ROUND_UP(MAX_SOCKETS, 32)];
-
-/* Allocates and returns a new Netlink PID. */
-static int
-alloc_pid(uint32_t *pid)
-{
- int i;
-
- 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;
- }
- }
- VLOG_ERR("netlink pid space exhausted");
- return ENOBUFS;
-}
-
-/* Makes the specified 'pid' available for reuse. */
-static void
-free_pid(uint32_t pid)
-{
- int sock = pid >> PROCESS_BITS;
- assert(avail_sockets[sock / 32] & (1u << (sock % 32)));
- avail_sockets[sock / 32] &= ~(1u << (sock % 32));
-}
-\f
static void
nlmsghdr_to_string(const struct nlmsghdr *h, int protocol, struct ds *ds)
{
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 *
git://git.onelab.eu / sliver-openvswitch.git / blobdiff