svm_fifo_peek (f, sizeof (ph), sizeof (*at), (u8 *) at);
len = clib_min (len, ph.data_length - ph.data_offset);
rv = svm_fifo_peek (f, ph.data_offset + SESSION_CONN_HDR_LEN, len, buf);
svm_fifo_peek (f, sizeof (ph), sizeof (*at), (u8 *) at);
len = clib_min (len, ph.data_length - ph.data_offset);
rv = svm_fifo_peek (f, ph.data_offset + SESSION_CONN_HDR_LEN, len, buf);