SMB2_COMPRESSION_CHAINED_HDR_LEN
const u8 *src = (const u8 *)hdr + SMB2_COMPRESSION_CHAINED_HDR_LEN;
u32 remaining = slen - SMB2_COMPRESSION_CHAINED_HDR_LEN;
*dlen <= SMB2_COMPRESSION_CHAINED_HDR_LEN || !slen)
builder.pos = (u8 *)dst + SMB2_COMPRESSION_CHAINED_HDR_LEN;
builder.remaining = *dlen - SMB2_COMPRESSION_CHAINED_HDR_LEN;