jtag_vpi: ensured constant packet size & endianness

[openocd.git] / src / jtag / drivers / jtag_vpi.c

diff --git a/src/jtag/drivers/jtag_vpi.c b/src/jtag/drivers/jtag_vpi.c
index 3e39420fb39b80bebb8e1cdc924c49222b50fe69..27b9da116187adaf0de4bea6415e119975826414 100644 (file)
--- a/src/jtag/drivers/jtag_vpi.c
+++ b/src/jtag/drivers/jtag_vpi.c
@@ -53,16 +53,34 @@ char *server_address;
 int sockfd;
 struct sockaddr_in serv_addr;
 
+/* One jtag_vpi "packet" as sent over a TCP channel. */
 struct vpi_cmd {
-       int cmd;
+       union {
+               uint32_t cmd;
+               unsigned char cmd_buf[4];
+       };
        unsigned char buffer_out[XFERT_MAX_SIZE];
        unsigned char buffer_in[XFERT_MAX_SIZE];
-       int length;
-       int nb_bits;
+       union {
+               uint32_t length;
+               unsigned char length_buf[4];
+       };
+       union {
+               uint32_t nb_bits;
+               unsigned char nb_bits_buf[4];
+       };
 };
 
 static int jtag_vpi_send_cmd(struct vpi_cmd *vpi)
 {
+       /* Use little endian when transmitting/receiving jtag_vpi cmds.
+          The choice of little endian goes against usual networking conventions
+          but is intentional to remain compatible with most older OpenOCD builds
+          (i.e. builds on little-endian platforms). */
+       h_u32_to_le(vpi->cmd_buf, vpi->cmd);
+       h_u32_to_le(vpi->length_buf, vpi->length);
+       h_u32_to_le(vpi->nb_bits_buf, vpi->nb_bits);
+
        int retval = write_socket(sockfd, vpi, sizeof(struct vpi_cmd));
        if (retval <= 0)
                return ERROR_FAIL;
@@ -76,6 +94,11 @@ static int jtag_vpi_receive_cmd(struct vpi_cmd *vpi)
        if (retval < (int)sizeof(struct vpi_cmd))
                return ERROR_FAIL;
 
+       /* Use little endian when transmitting/receiving jtag_vpi cmds. */
+       vpi->cmd = le_to_h_u32(vpi->cmd_buf);
+       vpi->length = le_to_h_u32(vpi->length_buf);
+       vpi->nb_bits = le_to_h_u32(vpi->nb_bits_buf);
+
        return ERROR_OK;
 }