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;
- bool any_groups;
struct nl_dump *dump;
};
goto error;
}
sock->protocol = protocol;
- sock->any_groups = false;
sock->dump = NULL;
retval = alloc_pid(&sock->pid);
/* 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_send__(sock, msg, wait);
}
-/* 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.)
- *
- * 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)
-{
- 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);
- }
- }
- return error;
-}
-
/* This stress option is useful for testing that OVS properly tolerates
* -ENOBUFS on NetLink sockets. Such errors are unavoidable because they can
* occur if the kernel cannot temporarily allocate enough GFP_ATOMIC memory to
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;
}
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);
}
+
+/* Checks whether this socket caused a wakeup in the previous run of the poll
+ * loop. */
+short int
+nl_sock_woke(const struct nl_sock *sock)
+{
+ return poll_fd_woke(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, .optional = true},
};
static struct genl_family *
}
}
-static int do_lookup_genl_family(const char *name)
+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;
- } else {
- define_genl_family(retval, name);
- }
nl_sock_destroy(sock);
- ofpbuf_delete(reply);
+ *replyp = reply;
+ return 0;
+}
- return retval;
+/* 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_mcgroup(const char *family_name, const char *group_name,
+ unsigned int *multicast_group, unsigned int fallback)
+{
+ 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;
+ }
+
+ 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_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},
+ };
+
+ struct nlattr *mc_attrs[ARRAY_SIZE(mc_policy)];
+ const char *mc_name;
+
+ if (!nl_parse_nested(mc, mc_policy, mc_attrs, ARRAY_SIZE(mc_policy))) {
+ 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]);
+ error = 0;
+ goto exit;
+ }
+ }
+ error = EPROTO;
+
+exit:
+ ofpbuf_delete(reply);
+ return error;
}
/* If '*number' is 0, translates the given Generic Netlink family 'name' to a
nl_lookup_genl_family(const char *name, int *number)
{
if (*number == 0) {
- *number = do_lookup_genl_family(name);
+ 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;
git://git.onelab.eu / sliver-openvswitch.git / blobdiff