[tftp] Allow fetching larger files by wrapping block number

This patch adds TFTP support for files larger than 65535 blocks by
wrapping the 16-bit block number.

Reported-by: Mark Johnson <johnson.nh@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

diff --git a/src/net/udp/tftp.c b/src/net/udp/tftp.c
index bb031ec..82055fc 100644 (file)
--- a/src/net/udp/tftp.c
+++ b/src/net/udp/tftp.c
@@ -747,7 +747,7 @@ static int tftp_rx_data ( struct tftp_request *tftp,
                          struct io_buffer *iobuf ) {
        struct tftp_data *data = iobuf->data;
        struct xfer_metadata meta;
-       int block;
+       unsigned int block;
        off_t offset;
        size_t data_len;
        int rc;
@@ -759,14 +759,17 @@ static int tftp_rx_data ( struct tftp_request *tftp,
                rc = -EINVAL;
                goto done;
        }
-       if ( data->block == 0 ) {
+
+       /* Calculate block number */
+       block = ( ( bitmap_first_gap ( &tftp->bitmap ) + 1 ) & ~0xffff );
+       if ( data->block == 0 && block == 0 ) {
                DBGC ( tftp, "TFTP %p received data block 0\n", tftp );
                rc = -EINVAL;
                goto done;
        }
+       block += ( ntohs ( data->block ) - 1 );
 
        /* Extract data */
-       block = ( ntohs ( data->block ) - 1 );
        offset = ( block * tftp->blksize );
        iob_pull ( iobuf, sizeof ( *data ) );
        data_len = iob_len ( iobuf );