net: lib: websocket: call socket poll for websocket

If we couldn't send all (or any data) via the socket,
invoke poll instead of blindly retrying and flooding the socket

Signed-off-by: Andrey Dodonov <Andrey.Dodonov@endress.com>

subsys/net/lib/websocket/websocket.c

@@ -544,7 +544,8 @@ static int websocket_ioctl_vmeth(void *obj, unsigned int request, va_list args)
 }
 
 #if !defined(CONFIG_NET_TEST)
-static int sendmsg_all(int sock, const struct msghdr *message, int flags)
+static int sendmsg_all(int sock, const struct msghdr *message, int flags,
+ const k_timepoint_t req_end_timepoint)
 {
  int ret, i;
  size_t offset = 0;
@@ -556,7 +557,25 @@ static int sendmsg_all(int sock, const struct msghdr *message, int flags)
 
  while (offset < total_len) {
  ret = zsock_sendmsg(sock, message, flags);
- if (ret < 0) {
+
+ if ((ret == 0) || (ret < 0 && errno == EAGAIN)) {
+ struct zsock_pollfd pfd;
+ int pollres;
+ k_ticks_t req_timeout_ticks =
+ sys_timepoint_timeout(req_end_timepoint).ticks;
+ int req_timeout_ms = k_ticks_to_ms_floor32(req_timeout_ticks);
+
+ pfd.fd = sock;
+ pfd.events = ZSOCK_POLLOUT;
+ pollres = zsock_poll(&pfd, 1, req_timeout_ms);
+ if (pollres == 0) {
+ return -ETIMEDOUT;
+ } else if (pollres > 0) {
+ continue;
+ } else {
+ return -errno;
+ }
+ } else if (ret < 0) {
  return -errno;
  }
 
@@ -622,8 +641,11 @@ static int websocket_prepare_and_send(struct websocket_context *ctx,
  tout = K_MSEC(timeout);
  }
 
+ k_timeout_t req_timeout = K_MSEC(timeout);
+ k_timepoint_t req_end_timepoint = sys_timepoint_calc(req_timeout);
+
  return sendmsg_all(ctx->real_sock, &msg,
- K_TIMEOUT_EQ(tout, K_NO_WAIT) ? MSG_DONTWAIT : 0);
+ K_TIMEOUT_EQ(tout, K_NO_WAIT) ? MSG_DONTWAIT : 0, req_end_timepoint);
 #endif /* CONFIG_NET_TEST */
 }