[nrf fromlist] net: zperf: Fix TCP packet counting

Make sure we send the entire packet buffer before bumping the packet
counter, send() does not guarantee that all of the requested data will
be sent at once with STREAM socket.

Upstream PR: zephyrproject-rtos/zephyr#65251

Signed-off-by: Robert Lubos <[email protected]>

Author: rlubos

subsys/net/lib/zperf/zperf_tcp_uploader.c

@@ -20,6 +20,22 @@ static char sample_packet[PACKET_SIZE_MAX];
 
 static struct zperf_async_upload_context tcp_async_upload_ctx;
 
+static ssize_t sendall(int sock, const void *buf, size_t len)
+{
+	while (len) {
+		ssize_t out_len = zsock_send(sock, buf, len, 0);
+
+		if (out_len < 0) {
+			return out_len;
+		}
+
+		buf = (const char *)buf + out_len;
+		len -= out_len;
+	}
+
+	return 0;
+}
+
 static int tcp_upload(int sock,
 		      unsigned int duration_in_ms,
 		      unsigned int packet_size,
@@ -50,7 +66,7 @@ static int tcp_upload(int sock,
 
 	do {
 		/* Send the packet */
-		ret = zsock_send(sock, sample_packet, packet_size, 0);
+		ret = sendall(sock, sample_packet, packet_size);
 		if (ret < 0) {
 			if (nb_errors == 0 && ret != -ENOMEM) {
 				NET_ERR("Failed to send the packet (%d)", errno);