/* Schedules 'msg' to be sent on 'rpc' and returns 'rpc''s status (as with
* jsonrpc_get_status()).
*
* If 'msg' cannot be sent immediately, it is appended to a buffer. The caller
* is responsible for ensuring that the amount of buffered data is somehow
* limited. (jsonrpc_get_backlog() returns the amount of data currently
* buffered in 'rpc'.)
*
* Always takes ownership of 'msg', regardless of success. */
int
jsonrpc_send(struct jsonrpc *rpc, struct jsonrpc_msg *msg)
{
struct ofpbuf *buf;
struct json *json;
size_t length;
char *s;
if (rpc->status) {
jsonrpc_msg_destroy(msg);
return rpc->status;
}
jsonrpc_log_msg(rpc, "send", msg);
json = jsonrpc_msg_to_json(msg);
s = json_to_string(json, 0);
length = strlen(s);
json_destroy(json);
buf = xmalloc(sizeof *buf);
ofpbuf_use(buf, s, length);
ofpbuf_set_size(buf, length);
list_push_back(&rpc->output, &buf->list_node);
rpc->backlog += length;
if (rpc->backlog == length) {
jsonrpc_run(rpc);
}
return rpc->status;
}
/* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
* data if necessary. Returns a pointer to the first byte of the data's
* location in the ofpbuf. The new data is left uninitialized. */
void *
ofpbuf_push_uninit(struct ofpbuf *b, size_t size)
{
ofpbuf_prealloc_headroom(b, size);
ofpbuf_set_data(b, (char*)ofpbuf_data(b) - size);
ofpbuf_set_size(b, ofpbuf_size(b) + size);
return ofpbuf_data(b);
}
/* Appends 'size' bytes of data to the tail end of 'b', reallocating and
* copying its data if necessary. Returns a pointer to the first byte of the
* new data, which is left uninitialized. */
void *
ofpbuf_put_uninit(struct ofpbuf *b, size_t size)
{
void *p;
ofpbuf_prealloc_tailroom(b, size);
p = ofpbuf_tail(b);
ofpbuf_set_size(b, ofpbuf_size(b) + size);
return p;
}
static void
ofpbuf_use__(struct ofpbuf *b, void *base, size_t allocated,
enum ofpbuf_source source)
{
ofpbuf_set_base(b, base);
ofpbuf_set_data(b, base);
ofpbuf_set_size(b, 0);
ofpbuf_init__(b, allocated, source);
}
/* Schedules 'msg' to be sent on 'rpc' and returns 'rpc''s status (as with
* jsonrpc_get_status()).
*
* If 'msg' cannot be sent immediately, it is appended to a buffer. The caller
* is responsible for ensuring that the amount of buffered data is somehow
* limited. (jsonrpc_get_backlog() returns the amount of data currently
* buffered in 'rpc'.)
*
* Always takes ownership of 'msg', regardless of success. */
int
jsonrpc_send(struct jsonrpc *rpc, struct jsonrpc_msg *msg)
{
struct ofpbuf *buf;
struct json *json;
size_t length;
char *s;
if (rpc->status) {
jsonrpc_msg_destroy(msg);
return rpc->status;
}
jsonrpc_log_msg(rpc, "send", msg);
json = jsonrpc_msg_to_json(msg);
s = json_to_string(json, 0);
length = strlen(s);
json_destroy(json);
buf = xmalloc(sizeof *buf);
ofpbuf_use(buf, s, length);
ofpbuf_set_size(buf, length);
list_push_back(&rpc->output, &buf->list_node);
rpc->output_count++;
rpc->backlog += length;
if (rpc->output_count >= 50) {
VLOG_INFO_RL(&rl, "excessive sending backlog, jsonrpc: %s, num of"
" msgs: %"PRIuSIZE", backlog: %"PRIuSIZE".", rpc->name,
rpc->output_count, rpc->backlog);
}
if (rpc->backlog == length) {
jsonrpc_run(rpc);
}
return rpc->status;
}
/* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for
* 'size' bytes. This is appropriate for an ofpbuf that will be used to
* inspect existing data, without moving it around or reallocating it, and
* generally without modifying it at all.
*
* An ofpbuf operation that requires reallocating data will assert-fail if this
* function was used to initialize it. */
void
ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size)
{
ofpbuf_use__(b, CONST_CAST(void *, data), size, OFPBUF_STACK);
ofpbuf_set_size(b, size);
}
static int
nl_sock_recv__(struct nl_sock *sock, struct ofpbuf *buf, bool wait)
{
/* We can't accurately predict the size of the data to be received. The
* caller is supposed to have allocated enough space in 'buf' to handle the
* "typical" case. To handle exceptions, we make available enough space in
* 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable
* figure since that's the maximum length of a Netlink attribute). */
struct nlmsghdr *nlmsghdr;
#ifdef _WIN32
#define MAX_STACK_LENGTH 81920
uint8_t tail[MAX_STACK_LENGTH];
#else
uint8_t tail[65536];
#endif
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 = ofpbuf_base(buf);
iov[0].iov_len = buf->allocated;
iov[1].iov_base = tail;
iov[1].iov_len = sizeof tail;
memset(&msg, 0, sizeof msg);
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;
#ifdef _WIN32
boolean result = false;
DWORD last_error = 0;
result = ReadFile(sock->handle, tail, MAX_STACK_LENGTH, &retval, NULL);
last_error = GetLastError();
if (last_error != ERROR_SUCCESS && !result) {
retval = -1;
errno = EAGAIN;
} else {
ofpbuf_put(buf, tail, retval);
}
#else
retval = recvmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
#endif
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. */
COVERAGE_INC(netlink_overflow);
}
return error;
}
if (msg.msg_flags & MSG_TRUNC) {
VLOG_ERR_RL(&rl, "truncated message (longer than %"PRIuSIZE" bytes)",
sizeof tail);
return E2BIG;
}
if (retval < sizeof *nlmsghdr
|| nlmsghdr->nlmsg_len < sizeof *nlmsghdr
|| nlmsghdr->nlmsg_len > retval) {
VLOG_ERR_RL(&rl, "received invalid nlmsg (%"PRIuSIZE" bytes < %"PRIuSIZE")",
retval, sizeof *nlmsghdr);
return EPROTO;
}
#ifndef _WIN32
ofpbuf_set_size(buf, MIN(retval, buf->allocated));
if (retval > buf->allocated) {
COVERAGE_INC(netlink_recv_jumbo);
ofpbuf_put(buf, tail, retval - buf->allocated);
}
#endif
log_nlmsg(__func__, 0, ofpbuf_data(buf), ofpbuf_size(buf), sock->protocol);
COVERAGE_INC(netlink_received);
return 0;
}
